TGEN / Tecogen Inc. - Pemfailan SEC, Laporan Tahunan, Penyata Proksi

Tecogen Inc.
US ˙ NYSEAM ˙ US87876P2011

Statistik Asas
LEI 549300GD898YRLK9SS61
CIK 1537435
SEC Filings
All companies that sell securities in the United States must register with the Securities and Exchange Commission (SEC) and file reports on a regular basis. These reports include company annual reports (10K, 10Q), news updates (8K), investor presentations (found in 8Ks), insider trades (form 4), ownership reports (13D, and 13G), and reports related to the specific securities sold, such as registration statements and prospectus. This page shows recent SEC filings related to Tecogen Inc.
SEC Filings (Chronological Order)
Halaman ini menyediakan senarai kronologi lengkap bagi Pemfailan SEC, tidak termasuk pemfailan pemilikan yang kami sediakan di tempat lain.
September 4, 2025 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): September 2, 2025 TECOGEN INC. (E

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): September 2, 2025 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number)

August 13, 2025 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2025 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

August 12, 2025 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): August 12, 2025 TECOGEN INC. (Exa

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): August 12, 2025 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (

August 12, 2025 EX-99.2

Tecogen Q2 2025 NYSE American: TGEN August 13th 2025 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non-historical matters, or projected

q22025earningscallpresen Tecogen Q2 2025 NYSE American: TGEN August 13th 2025 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non-historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

August 12, 2025 EX-99.1

Tecogen Reports Second Quarter 2025 Financial Results

Tecogen Reports Second Quarter 2025 Financial Results NORTH BILLERICA, Mass., August 12, 2025 - Tecogen Inc. (NYSE American:TGEN), a leading manufacturer of clean energy products, reported revenues of $7.29 million and net loss of $1.47 million for the quarter ended June 30, 2025 compared to revenues of $4.73 million, and a net loss of $1.54 million in 2024. Our cash and cash equivalents balance w

July 28, 2025 EX-99.1

Tecogen Appoints Roger Deschenes as CFO

Tecogen Appoints Roger Deschenes as CFO NORTH BILLERICA, MA, July 28th, 2025 – Tecogen Inc.

July 28, 2025 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 24, 2025 TECOGEN INC. (Exact

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 24, 2025 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IR

July 21, 2025 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 21, 2025 TECOGEN INC. (Exact

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 21, 2025 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IR

July 21, 2025 EX-99.1

TECOGEN INC. ANNOUNCES CLOSING OF UNDERWRITTEN PUBLIC OFFERING

TECOGEN INC. ANNOUNCES CLOSING OF UNDERWRITTEN PUBLIC OFFERING NORTH BILLERICA, Massachusetts, July 21, 2025 – Tecogen Inc. (“Tecogen” or “Company”), (NYSE American: TGEN), a leading manufacturer of clean energy products, today announced the closing of its previously announced underwritten public offering of 3,985,000 shares of common stock, including the full exercise by the underwriter of its op

July 21, 2025 424B4

TECOGEN INC. 3,500,000 shares of our common stock

Filed Pursuant to Rule 424(b)(4) PROSPECTUS Registration No. 333-288740 TECOGEN INC. 3,500,000 shares of our common stock We are offering 3,500,000 shares of our common stock, $.001 par value per share (“common stock”), at a public offering price of $5.00 per share. The offering is being underwritten on a firm commitment basis. We have granted the underwriters an option for up to 45 days from the

July 18, 2025 EX-99.1

TECOGEN INC. ANNOUNCES PRICING OF PUBLIC OFFERING

TECOGEN INC. ANNOUNCES PRICING OF PUBLIC OFFERING NORTH BILLERICA, Massachusetts, July 18, 2025 – Tecogen Inc. (“Tecogen” or “Company”), (NYSE American: TGEN), a leading manufacturer of clean energy products, today announced the pricing of an underwritten public offering of 3,500,000 shares of its common stock at a price to the public of $5 per share. The gross proceeds from the offering to Tecoge

July 18, 2025 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 18, 2025 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IR

July 18, 2025 EX-1.1

, 2025 by and between the Registrant and

TECOGEN INC. UNDERWRITING AGREEMENT 3,500,000 Shares of Common Stock July 18, 2025 Roth Capital Partners, LLC 888 San Clemente Drive, Suite 400 Newport Beach, CA 92660 Ladies and Gentlemen: Tecogen Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to issue and sell to the underwriters named in Schedule I hereto (the “Underwriters,” or each,

July 17, 2025 EX-FILING FEES

Filing Fee Table, filed herewith.

Exhibit 107.1 Calculation of Filing Fee Table Form S-1 (Form Type) Tecogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered (1) Proposed Maximum Aggregate Offering Price Per Share (2) Maximum Aggregate Offering Price (2) Fee Rate Amount of Reg

July 17, 2025 S-1MEF

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-1 REGISTRATION STATEMENT THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter)

As filed with the United States Securities and Exchange Commission on July 18, 2025.

July 16, 2025 S-1/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 AMENDMENT NO. 1 FORM S-1 REGISTRATION STATEMENT THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter)

As filed with the United States Securities and Exchange Commission on July 16, 2025.

July 16, 2025 S-1/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 AMENDMENT NO. 3 FORM S-1 REGISTRATION STATEMENT THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter)

As filed with the United States Securities and Exchange Commission on July 16, 2025.

July 16, 2025 S-1/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 AMENDMENT NO. 2 FORM S-1 REGISTRATION STATEMENT THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter)

As filed with the United States Securities and Exchange Commission on July 16, 2025.

July 15, 2025 S-1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-1 REGISTRATION STATEMENT THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter)

As filed with the United States Securities and Exchange Commission on July 15, 2025.

July 15, 2025 CORRESP

TECOGEN INC. 76 Treble Cove Road Building 1 North Billerica, Massachusetts 01862 July 15, 2025

TECOGEN INC. 76 Treble Cove Road Building 1 North Billerica, Massachusetts 01862 July 15, 2025 VIA EDGAR United States Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549 Attn: Aliya Ishmukhamedova, Esq. Division of Corporation Finance Office of Technology Re: Tecogen Inc. Form S-1 Registration Statement (File No. 333-288668) Acceleration Request: Requested Date: July 17,

July 15, 2025 CORRESP

Roth Capital Partners, LLC 888 San Clemente Drive, Suite 400 Newport Beach, CA 92660

Roth Capital Partners, LLC 888 San Clemente Drive, Suite 400 Newport Beach, CA 92660 July 15, 2025 VIA EDGAR CORRESPONDENCE United States Securities and Exchange Commission 100 F Street, N.

July 15, 2025 EX-10.27

Form of Lock Up Agreement

EXHIBIT 10.27 Form of Lock-Up Agreement , 2025 Roth Capital Partners, LLC 888 San Clemente Drive Newport Beach, CA 92660 Ladies and Gentlemen: The undersigned understands that you, as the representative (the “Representative”) of the several underwriters named therein, propose to enter into an Underwriting Agreement (the “Underwriting Agreement”) with Tecogen Inc., a Delaware corporation (the “Comp

July 15, 2025 EX-10.25

Executive Officer Clawback Policy

EXHIBIT 10.25 TECOGEN INC. POLICY FOR RECOVERY OF ERRONEOUSLY AWARDED INCENTIVE COMPENSATION INTRODUCTION Tecogen Inc. (the “Company”) is adopting this policy (this “Policy”) to provide for the Company’s recovery of certain Incentive Compensation (as defined below) erroneously awarded to Affected Officers (as defined below) under certain circumstances. This Policy is effective as of April 1, 2025

July 15, 2025 EX-FILING FEES

Filing Fee Table.

Exhibit 107.1 Calculation of Filing Fee Table Form S-1 (Form Type) Tecogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered (1) Proposed Maximum Aggregate Offering Price Per Share Maximum Aggregate Offering Price (1) Fee Rate Amount of Registr

July 15, 2025 EX-1.1

Form of Underwriting Agreement between the Registrant and Roth Capital Partners, LLC.

EXHIBIT 1.1 TECOGEN INC. UNDERWRITING AGREEMENT [-] Shares of Common Stock [-], 2025 Roth Capital Partners, LLC 888 San Clemente Drive, Suite 400 Newport Beach, CA 92660 Ladies and Gentlemen: Tecogen Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to issue and sell to the underwriters named in Schedule I hereto (the “Underwriters,” or each

July 15, 2025 EX-10.24

Policy and Procedures Governing Related Person Transactions

EXHIBIT 10.24 TECOGEN INC. POLICY AND PROCEDURES GOVERNING RELATED PERSON TRANSACTIONS 1. Purpose. The Board of Directors of Tecogen Inc., a Delaware corporation (“Company”), has established this Policy and Procedures Governing Related Person Transactions (“Policy”) for the identification, review and approval or ratification of Related Person Transactions (as defined below) in order to avoid poten

June 26, 2025 DRS

CONFIDENTIAL TREATMENT REQUESTED BY TECOGEN INC. PURSUANT TO 17 CFR 200.83

CONFIDENTIAL TREATMENT REQUESTED BY TECOGEN INC. PURSUANT TO 17 CFR 200.83 As confidentially submitted to the United States Securities and Exchange Commission on June 26, 2025. This draft registration statement has not been publicly filed with the United States Securities and Exchange Commission, and all information herein remains strictly confidential. Registration No. 333- UNITED STATES SECURITI

June 10, 2025 8-K

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): June 10, 2025 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IR

May 22, 2025 424B3

TECOGEN INC. Up to 3,838,750 shares of common stock

Filed Pursuant to Rule 424(b)(3) and (c) Registration Nos. 333-187928 and 333-218244 PROSPECTUS SUPPLEMENT NO. 2 (To Reoffer Prospectus dated July 28, 2020) TECOGEN INC. Up to 3,838,750 shares of common stock This prospectus supplement dated May 22, 2025, supplements, amends and updates certain information included in the reoffer prospectus, dated July 28, 2020 (“reoffer prospectus”), filed by Tec

May 22, 2025 424B3

TECOGEN INC. Up to 3,800,000 shares of common stock

Filed Pursuant to Rule 424(b)(3) and (c) Registration No. 333-265799 PROSPECTUS SUPPLEMENT NO. 1 (To Reoffer Prospectus dated June 23, 2022) TECOGEN INC. Up to 3,800,000 shares of common stock This prospectus supplement dated May 22, 2025, supplements, amends and updates certain information included in the reoffer prospectus, dated June 23, 2022 (“reoffer prospectus”), filed by Tecogen Inc., a Del

May 13, 2025 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

May 12, 2025 EX-99.2

NYSE AMERICAN: TGEN Q1 2025 EARNINGS CALL MAY 13, 2025 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying docu

q12025earningspresentati NYSE AMERICAN: TGEN Q1 2025 EARNINGS CALL MAY 13, 2025 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

May 12, 2025 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): May 12, 2025 TECOGEN INC. (Exact

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): May 12, 2025 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS

May 12, 2025 EX-99.1

Tecogen Reports First Quarter 2025 Financial Results

Tecogen Reports First Quarter 2025 Financial Results NORTH BILLERICA, Mass., May 12, 2025 - Tecogen Inc. (NYSE American:TGEN), a leading manufacturer of clean energy products, reported revenues of $7.28 million and net loss of $0.66 million for the quarter ended March 31, 2025 compared to revenues of $6.19 million, and a net loss of $1.10 million in 2024. Our cash and cash equivalents balance was

May 5, 2025 8-A12B

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 TECOGEN INC. (Exact name of registrant as speci

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware 04-3536131 (State of incorporation or organization) (I.R.S. Employer Identification No.) 76 Treble Cover Road Building 1

May 2, 2025 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): May 1, 2025 TECOGEN INC. (OTCQX:

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): May 1, 2025 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File

May 1, 2025 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): April 30, 2025 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission F

May 1, 2025 EX-99.1

Tecogen Inc. 76 Treble Cove Road, Building 1, North Billerica, MA 01862 • ph: 781-466-6400 • fax: 781-466-6466 • www.tecogen.com Tecogen Announces Uplist to NYSE American Stock Exchange NORTH BILLERICA, MA, April 30, 2025 (ACCESS NEWSWIRE) – Tecogen

Tecogen Inc. 76 Treble Cove Road, Building 1, North Billerica, MA 01862 • ph: 781-466-6400 • fax: 781-466-6466 • www.tecogen.com Tecogen Announces Uplist to NYSE American Stock Exchange NORTH BILLERICA, MA, April 30, 2025 (ACCESS NEWSWIRE) – Tecogen Inc. (OTCQX: TGEN) (“Tecogen or “Company”), a leading manufacturer of clean energy products, today announced that its shares of common stock have been

April 29, 2025 DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (a

April 29, 2025 EX-99.01

. PROXY CARD

Signature [PLEASE SIGN WITHIN BOX] Date Signature (Joint Owners) Date TO VOTE, MARK BLOCKS BELOW IN BLUE OR BLACK INK AS FOLLOWS: KEEP THIS PORTION FOR YOUR RECORDS DETACH AND RETURN THIS PORTION ONLYTHIS PROXY CARD IS VALID ONLY WHEN SIGNED AND DATED.

March 28, 2025 S-8

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter)

As filed with the Securities and Exchange Commission on March 28, 2025. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 - FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 - TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware 04-3536131 (State or other jurisdiction of incorporation or organization) (I.R.S. Employ

March 28, 2025 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Tecogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount to be Registered (1) Proposed Maximum Aggregate Offering Price Per Share (2) Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Equity Common Stock,

March 18, 2025 EX-10.27

the Note Subscription Agreement by John

John N. Hatsopoulos March 21, 2024 Mr. Abinand Rangesh, CEO Tecogen Inc. 45 First Ave. Waltham, MA 02451 Re: Extension or Conversion of Tecogen Promissory Note Dear Abinand: This letter confirms my agreement to: (1) extend the maturity date of the Tecogen Inc. Promissory Note in my favor dated October 10, 2023 in the original principal amount of $500,000 (the “Promissory Note”) by one year, making

March 18, 2025 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTION

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

March 18, 2025 EX-19

Tecogen Policy Regarding Insider Trading

Exhibit 19.1 Tecogen Inc. Policy Regarding Insider Trading This Insider Trading Policy describes the standards of Tecogen Inc (the "Company") on trading, and causing the trading of, the Company's securities or securities of certain other publicly-traded companies while in possession of confidential information. This policy is divided into two parts: the first part prohibits trading in certain circ

March 17, 2025 EX-99.02

OTCQX: TGEN FY 2024 EARNINGS CALL MARCH 18, 2025 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying docu

OTCQX: TGEN FY 2024 EARNINGS CALL MARCH 18, 2025 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

March 17, 2025 EX-99.01

Tecogen Announces Fourth Quarter and Year-End 2024 Results

Tecogen Announces Fourth Quarter and Year-End 2024 Results NORTH BILLERICA, Mass., March 17, 2025 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $6.08 million and net loss of $1.19 million for the quarter ended December 31, 2024 compared to revenues of $5.90 million, and a net loss of $1.85 million in 2023. We generated $4.06 million in cash from

March 17, 2025 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): March 17, 2025 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission F

March 11, 2025 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): February 14, 2025 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commissio

March 3, 2025 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): February 28, 2025 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commissio

March 3, 2025 EX-99.01

[Information omitted from Schedule A is not material and is the type of information that the company treats as confidential.] Sales and Marketing Agreement Between Vertiv and Tecogen Regarding Data Center Cooling

[Information omitted from Schedule A is not material and is the type of information that the company treats as confidential.

February 19, 2025 8-K

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): February 19, 2025 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commissio

February 19, 2025 EX-99.01

AMENDMENT TO TECOGEN INC. PROMISSORY NOTES

AMENDMENT TO TECOGEN INC. PROMISSORY NOTES This Agreement dated February 18, 2025 by and between Tecogen Inc., a Delaware corporation with offices located at 76 Treble Cove Road, Bldg. 1, N. Billerica, MA 01862 (“Tecogen”) and John N. Hatsopoulos (“Mr. Hatsopoulos”). WHEREAS, Tecogen and Mr. Hatsopoulos desire to amend two promissory notes by Tecogen in favor of Mr. Hatsopoulos to extend the matur

January 17, 2025 8-K

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): January 14, 2025 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission

November 14, 2024 EX-99.01

Tecogen Announces Third Quarter 2024 Results

Tecogen Announces Third Quarter 2024 Results NORTH BILLERICA, Mass., November 13, 2024 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $5.63 million and net loss of $0.93 million for the quarter ended September 30, 2024 compared to revenues of $7.11 million, and a net loss of $0.48 million in 2023. We used $117 thousand in cash from operations and

November 14, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

November 14, 2024 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): November 13, 2024 TECOGEN INC. (O

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): November 13, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact name of registrant as specified in charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commissio

November 14, 2024 EX-99.02

OTCQX: TGEN Q3 2024 EARNINGS CALL NOVEMBER 14, 2024 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documen

OTCQX: TGEN Q3 2024 EARNINGS CALL NOVEMBER 14, 2024 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

September 23, 2024 8-K

Entry into a Material Definitive Agreement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): September 18, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commissi

August 8, 2024 EX-99.02

OTCQX: TGEN Q2 2024 EARNINGS CALL AUGUST 8, 2024 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents

OTCQX: TGEN Q2 2024 EARNINGS CALL AUGUST 8, 2024 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

August 8, 2024 EX-99.01

Tecogen Announces Second Quarter 2024 Results

Tecogen Announces Second Quarter 2024 Results NORTH BILLERICA, Mass., August 7, 2024 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $4.7 million and net loss of $1.5 million for the quarter ended June 30, 2024 compared to revenues of $6.7 million, and a net loss of $0.8 million in 2023. We generated $0.1 million in cash from operations during the

August 8, 2024 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): August 8, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact name of registrant as specified in charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission F

August 8, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

July 25, 2024 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 23, 2024 TECOGEN INC. (OTCQX

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 23, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission Fi

June 6, 2024 8-K

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): June 6, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission Fil

May 9, 2024 EX-99.02

OTCQX: TGEN Q1 2024 EARNINGS CALL MAY 9, 2024 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents con

OTCQX: TGEN Q1 2024 EARNINGS CALL MAY 9, 2024 1 MANAGEMENT Abinand Rangesh – CEO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

May 9, 2024 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): May 9, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File

May 9, 2024 EX-99.01

Tecogen Announces First Quarter 2024 Results Revenues of $6.2 million - 15% QoQ increase

Tecogen Announces First Quarter 2024 Results Revenues of $6.2 million - 15% QoQ increase NORTH BILLERICA, Mass., May 8, 2024 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $6.2 million and net loss of $1.1 million for the quarter ended March 31, 2024 compared to revenues of $5.4 million, and a net loss of $1.5 million in 2023. We generated $0.2 m

May 9, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

May 3, 2024 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): May 1, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File

May 3, 2024 EX-99.01

Second Amendment to Agreement Regarding Assignment of Maintenance Agreements dated as of May 1, 2024

April 23, 2024 DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (a

April 12, 2024 PRE 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant ¨ Check the appropriate box: þ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (a

March 25, 2024 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTION

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

March 25, 2024 EX-10.29

Letter Agreement to the Lease Agreement between King First West Owner LLC, successor-in-interest to Atlantic-Waltham Investment II, LLC and Tecogen Inc., dated March 1, 2024.

March 25, 2024 EX-10.30

Letter Agreement to the Note Subscription Agreement by John H. Hatsopoulos, dated March 21, 2024.

March 14, 2024 EX-99.01

Tecogen Announces Fourth Quarter 2023 Results Q4 2023 revenue of $5.9 million, an increase of 30.2% QoQ

Tecogen Announces Fourth Quarter 2023 Results Q4 2023 revenue of $5.9 million, an increase of 30.2% QoQ WALTHAM, Mass., March 14, 2024 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $5.9 million and a net loss of $1.8 million for the quarter ended December 31, 2023 compared to revenues of $4.5 million, and a net loss of $1.4 million in 2022. The

March 14, 2024 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): March 14, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission F

March 14, 2024 EX-99.02

OTCQX: TGEN FY 2023 EARNINGS CALL MARCH 14, 2024 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying docu

q4andfy2023earningsprese OTCQX: TGEN FY 2023 EARNINGS CALL MARCH 14, 2024 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

March 7, 2024 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): March 1, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission Fi

February 5, 2024 8-K

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): February 1, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission

February 5, 2024 EX-99.01

AMENDMENT TO AGREEMENT REGARDING THE ASSIGNMENT OF CERTAIN MAINTENANCE AGREEMENTS This AMENDMENT effective as of February 1, 2024 by and between Tecogen Inc., a Delaware corporation (“Tecogen”), and Aegis Energy Services LLC, a Delaware limited liabi

AMENDMENT TO AGREEMENT REGARDING THE ASSIGNMENT OF CERTAIN MAINTENANCE AGREEMENTS This AMENDMENT effective as of February 1, 2024 by and between Tecogen Inc.

January 16, 2024 EX-99.01

OTCQX: TGEN SIDOTI CONFERENCE JANUARY 17TH 2024 1 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected re

OTCQX: TGEN SIDOTI CONFERENCE JANUARY 17TH 2024 1 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

January 16, 2024 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): January 16, 2024 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission

December 14, 2023 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): December 12, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commissio

November 9, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

November 8, 2023 EX-99.01

Tecogen Announces Third Quarter 2023 Results Q3 2023 revenue of $7.1 million, an increase of 7.5% QoQ

Tecogen Announces Third Quarter 2023 Results Q3 2023 revenue of $7.1 million, an increase of 7.5% QoQ WALTHAM, Mass., November 8, 2023 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $7.1 million and a net loss of $0.5 million for the quarter ended September 30, 2023 compared to revenues of $6.6 million, and a net loss of $0.3 million in 2022. For

November 8, 2023 EX-99.02

OTCQX: TGEN Q3 2023 EARNINGS CALL NOVEMBER 9, 2023 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying do

OTCQX: TGEN Q3 2023 EARNINGS CALL NOVEMBER 9, 2023 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

November 8, 2023 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): November 8, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission

October 10, 2023 EX-99.01

Note Subscription Agreement dated October 9, 2023 by John H. Hatsopoulos, incorporated herein by reference to Exhibit 99.01 to the registrant's Current Report on Form 8-K filed with the SEC on October 10, 2023

October 10, 2023 8-K

Regulation FD Disclosure, Entry into a Material Definitive Agreement, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): October 9, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission

October 10, 2023 EX-99.02

NOTE SUBSCRIPTION AGREEMENT This Note Subscription Agreement, dated as of the 9th day of October, 2023 (this “Agreement”), is entered into by and between Tecogen Inc., a Delaware corporation with offices located at 45 First Ave., Waltham, MA 02451 (t

NOTE SUBSCRIPTION AGREEMENT This Note Subscription Agreement, dated as of the 9th day of October, 2023 (this “Agreement”), is entered into by and between Tecogen Inc.

October 10, 2023 EX-99.03

Tecogen Inc. 45 First Avenue, Waltham, MA 02451 • ph: 781-466-6400 • fax: 781-466-6466 • www.tecogen.com Tecogen Announces Obtaining $1.5m Credit Facility WALTHAM, MA, October 10th, 2023 – Tecogen Inc. (OTCQX: TGEN) a leading provider of clean energy

Tecogen Inc. 45 First Avenue, Waltham, MA 02451 • ph: 781-466-6400 • fax: 781-466-6466 • www.tecogen.com Tecogen Announces Obtaining $1.5m Credit Facility WALTHAM, MA, October 10th, 2023 – Tecogen Inc. (OTCQX: TGEN) a leading provider of clean energy products and services, is pleased to announce the signing of a $1.5 million Credit Agreement provided by our directors John Hatsopoulos and Earl Lewi

September 26, 2023 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): September 22, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commissi

September 26, 2023 EX-99.01

September 25, 2023 Tecogen Appoints Ms. Susan Hirsch to Board of Directors WALTHAM, MA, Sept. 25, 2023 (GLOBE NEWSWIRE) -- via NewMediaWire – Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and clean on-site power, heatin

September 25, 2023 Tecogen Appoints Ms. Susan Hirsch to Board of Directors WALTHAM, MA, Sept. 25, 2023 (GLOBE NEWSWIRE) - via NewMediaWire – Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and clean on-site power, heating, and cooling equipment, is pleased to announce the appointment of Ms. Susan Hirsch to the Board of Directors. Ms. Hirsch was formerly Managing Direct

August 10, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

August 9, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): August 9, 2023 TECOGEN INC. (OTCQ

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): August 9, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission F

August 9, 2023 EX-99.01

Tecogen Announces Second Quarter 2023 Results Q2 2023 revenue of $6.7 million, an increase of 5.2% QoQ

Tecogen Announces Second Quarter 2023 Results Q2 2023 revenue of $6.7 million, an increase of 5.2% QoQ WALTHAM, Mass., August 9, 2023 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $6.7 million and a net loss of $0.8 million for the quarter ended June 30, 2023 compared to revenues of $6.4 million, and a net loss of $0.9 million in 2022. For the s

August 9, 2023 EX-99.02

OTCQX: TGEN Q2 2023 EARNINGS CALL AUGUST 10, 2023 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying doc

q22023earningspresentati OTCQX: TGEN Q2 2023 EARNINGS CALL AUGUST 10, 2023 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

July 24, 2023 EX-9.01

Letter agreement dated July 19, 2023 amending the Advisory Agreement between Tecogen Inc. and John N. Hatsopoulos

letterextendingjnhadviso 45 First Avenue, Waltham, MA 02451 781-466-6400 • 781-466-6466 (fax) www.

July 24, 2023 8-K

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): July 19, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission Fi

June 8, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: June 8, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant a

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: June 8, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifica

May 11, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ☑ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

May 11, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 10, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant a

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 10, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifica

May 11, 2023 EX-2.02

for the three months ended March 31, 2023.

Tecogen Announces First Quarter 2023 Results Revenues of $5.4 million WALTHAM, Mass., May 10, 2023 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $5.4 million and net loss of $1.5 million for the quarter ended March 31, 2023 compared to revenues of $7.4 million, and a net profit of $0.1 million in 2022. We used $0.3 million in cash from operation

May 11, 2023 EX-7.01

Tecogen Earnings Call Presentation dated May 11, 2023.

q12023earningspresentati OTCQX: TGEN Q1 2023 EARNINGS CALL MAY 11, 2023 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

May 11, 2023 EX-10.2

Lease, dated March 31, 2023, between Alibrandi Realty Associates, LLC and Tecogen Inc., Building 3

tgenbillericabldg3lease LEASE BETWEEN ALIBRANDI REALTY ASSOCIATES, LLC AND TECOGEN INC FOR SPACE AT 76 TREBLE COVE ROAD, BUILDING 3, UNIT 3E, NORTH BILLERICA, MA Table of Contents PRT ICE 1 crea periensasta iene sting paommomnye womens a eth tren ENNen NRA RENN iapAsitillaeemnsas 4 REFERENCE DAT A wacessnsapnouterseearsdenesonenytesrginnsnas theenensnnnvenencink Givibneapiem aauniaianesatsepseence

May 11, 2023 EX-10.1

Lease, dated March 31, 2023, between Alibrandi Realty Associates, LLC and Tecogen Inc., Building 1

tgenbillericabldg1lease LEASE BETWEEN ALIBRANDI REALTY ASSOCIATES, LLC AND TECOGEN INC FOR SPACE AT 76 TREBLE COVE ROAD, BUILDING 1, NORTH BILLERICA, MA Table of Contents EEA her on I ccnassenowinnntesesninestii bic XSRARSIASEC ion oreenremensonereneesoensoinere geg n eresermttnatsemns sarnsb nmwerees 4 REFERENCE DAT Ais wsssassssusiaisssntsiisassanscntannnsnsemrsnsrarnvacnncesnnteses ante geervessierenersh te uacene me gurensres = 1.

May 3, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 3, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 3, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identificat

April 25, 2023 DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (a

March 23, 2023 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 ☐ TRANSITION REPORT PURSUANT TO SECTION

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

March 16, 2023 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 16, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 16, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifi

March 16, 2023 EX-99.03

OTCQX: TGEN FY 2022 EARNINGS CALL MARCH 16, 2023 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying docu

q4andfy2022earningsprese OTCQX: TGEN FY 2022 EARNINGS CALL MARCH 16, 2023 1 MANAGEMENT Abinand Rangesh – CEO & CFO Robert Panora – COO & President Roger Deschenes – CAO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

March 16, 2023 EX-99.01

AGREEMENT REGARDING ASSIGNMENTS OF CERTAIN MAINTENANCE AGREEMENTS, THE PURCHASE OF CERTAIN ASSETS, AND RELATED MATTERS BY AND BETWEEN AEGIS ENERGY SERVICES LLC, AS ASSIGNOR & SELLER AND TECOGEN INC., AS ASSIGNEE & PURCHASER DATED AS OF MARCH 15, 2023

aegisassignmentagreement AGREEMENT REGARDING ASSIGNMENTS OF CERTAIN MAINTENANCE AGREEMENTS, THE PURCHASE OF CERTAIN ASSETS, AND RELATED MATTERS BY AND BETWEEN AEGIS ENERGY SERVICES LLC, AS ASSIGNOR & SELLER AND TECOGEN INC.

March 16, 2023 EX-99.02

Tecogen Announces 2022 Results Revenue of $25.0 million for FY 2022 up 2.5% compared to FY 2021

Tecogen Announces 2022 Results Revenue of $25.0 million for FY 2022 up 2.5% compared to FY 2021 WALTHAM, Mass., March 16, 2023 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported a net loss of $1.4 million for the quarter ended December 31, 2022 and $2.4 million for the full year compared to net income of $0.1 million and $3.7 million, respectively, in 2021. The

January 30, 2023 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: January 30, 2023 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identi

January 30, 2023 EX-99.01

Tecogen Inc. 45 First Avenue, Waltham, MA 02451 • ph: 781-466-6400 • fax: 781-466-6466 • www.tecogen.com Tecogen Appoints Abinand Rangesh as CEO WALTHAM, MA, 1/30/2023 – Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and

Tecogen Inc. 45 First Avenue, Waltham, MA 02451 • ph: 781-466-6400 • fax: 781-466-6466 • www.tecogen.com Tecogen Appoints Abinand Rangesh as CEO WALTHAM, MA, 1/30/2023 – Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and clean on-site power, heating, and cooling equipment, is pleased to announce the appointment of Dr. Abinand Rangesh as CEO. Dr. Rangesh is presently t

December 8, 2022 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: December 8, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identi

November 10, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2022 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

November 10, 2022 EX-99.01

Tecogen Announces Third Quarter 2022 Results Q3 2022 revenue of $6.6 million, an increase of 31.9% QoQ and YTD 2022 revenue of $20.5 million, an increase of 18.9% YoY

Tecogen Announces Third Quarter 2022 Results Q3 2022 revenue of $6.6 million, an increase of 31.9% QoQ and YTD 2022 revenue of $20.5 million, an increase of 18.9% YoY WALTHAM, Mass., November 10, 2022 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $6.6 million and a net loss of $0.3 million for the quarter ended September 30, 2022 compared to rev

November 10, 2022 EX-99.02

OTCQX: TGEN NOVEMBER 10, 2022 Q3 2022 EARNINGS CALL 1 MANAGEMENT Benjamin Locke - CEO Abinand Rangesh – CFO & Treasurer Robert Panora – COO & President Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompany

OTCQX: TGEN NOVEMBER 10, 2022 Q3 2022 EARNINGS CALL 1 MANAGEMENT Benjamin Locke - CEO Abinand Rangesh ? CFO & Treasurer Robert Panora ? COO & President Jack Whiting ? General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain ?forward-looking statements? which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

November 10, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: November 10, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Ident

September 21, 2022 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

8-K 1 tgenformredirectordeparture.htm 8-K UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: September 21, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (

August 11, 2022 EX-99.01

Tecogen Announces Second Quarter 2022 Results Q2 2022 revenue of $6.4 million, an increase of 4.4% QoQ and H1 2022 revenue of $13.9 million, an increase of 13.5% YoY

Tecogen Announces Second Quarter 2022 Results Q2 2022 revenue of $6.4 million, an increase of 4.4% QoQ and H1 2022 revenue of $13.9 million, an increase of 13.5% YoY WALTHAM, Mass., August 11, 2022 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $6.4 million and a net loss of $856.2 thousand for the quarter ended June 30, 2022 compared to revenues

August 11, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: August 11, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identif

August 11, 2022 EX-99.02

OTCQX: TGEN AUGUST 11, 2022 Q2 2022 EARNINGS CALL 1 MANAGEMENT Benjamin Locke - CEO Abinand Rangesh – CFO & Treasurer Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-loo

OTCQX: TGEN AUGUST 11, 2022 Q2 2022 EARNINGS CALL 1 MANAGEMENT Benjamin Locke - CEO Abinand Rangesh ? CFO & Treasurer Jack Whiting ? General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain ?forward-looking statements? which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

August 11, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2022 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

July 20, 2022 8-K

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: July 20, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

July 20, 2022 EX-99.02

TECOGEN INVESTOR PRESENTATION OTC: TGEN BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- hist

EX-99.02 3 tecogenirpresentation202.htm EX-99.02 TECOGEN INVESTOR PRESENTATION OTC: TGEN BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, income, returns or other financial measures, that may include

July 20, 2022 EX-99.01

Tecogen to Establish New Business Unit Focused on Indoor Agriculture

Tecogen to Establish New Business Unit Focused on Indoor Agriculture WALTHAM, MA, July 20, 2022 ? Tecogen Inc.

July 20, 2022 EX-99.03

Financial News Media Commentary regarding CEA Market Size

July 1, 2022 424B3

TECOGEN INC. Up to 2,313,009 shares of common stock

Filed Pursuant to Rule 424(b)(3) and (c) Registration Nos. 333-187928 and 333-218244 PROSPECTUS SUPPLEMENT NO. 1 (To Reoffer Prospectus dated July 28, 2020) TECOGEN INC. Up to 2,313,009 shares of common stock This prospectus supplement dated July 1, 2022, supplements and/or amends certain information included in the reoffer prospectus, dated July 28, 2020, filed by Tecogen Inc., a Delaware corpora

June 23, 2022 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) Tecogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount to be Registered (1) Proposed Maximum Aggregate Offering Price Per Share Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Equity Common Stock, $.00

June 23, 2022 S-8

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter)

As filed with the Securities and Exchange Commission on June 23, 2022. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 - FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 - TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware 04-3536131 (State or other jurisdiction of incorporation or organization) (I.R.S. Employe

June 15, 2022 EX-99.01

TECOGEN INVESTOR PRESENTATION OTC: TGEN BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- hist

TECOGEN INVESTOR PRESENTATION OTC: TGEN BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain ?forward-looking statements? which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

June 15, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: June 15, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

June 10, 2022 8-K

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: June 10, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

May 12, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2022 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

May 12, 2022 EX-9.01

Earnings Release dated May 12, 2022 for the three months ended March 31, 202

EX-9.01 2 tgenq12022earningsrelease1.htm EX-9.01 Tecogen Announces First Quarter 2022 Results Revenues of $ 7.4 million, Positive Income from Operations and Net Income WALTHAM, Mass., May 12, 2022 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported revenues of $7.4 million and net income of $89 thousand for the quarter ended March 31, 2022 compared to revenues of

May 12, 2022 EX-9.02

Tecogen Earnings Call Presentation dated May 12, 2022

EX-9.02 3 q12022earningspresentati.htm EX-9.02 OTCQX: TGEN MAY 12, 2022 Q1 2022 EARNINGS CALL 1 MANAGEMENT Benjamin Locke - CEO Robert Panora – COO & President Abinand Rangesh – CFO & Treasurer Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other n

May 12, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 12, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifica

May 10, 2022 SC 13G

TGEN / Tecogen Inc / Pacheco Ann Marie Brown - SC 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* Tecogen Inc. (Name of Issuer) Common Stock, $.001 par value per share (Title of Class of Securities) 87876P201 (CUSIP Number) March 9, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to

April 25, 2022 DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (a

March 22, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 22, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifi

March 22, 2022 EX-99.01

Message To Our Investors 2021 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non-historical matters, or projected revenues, Income, retur

Message To Our Investors 2021 SAFE HARBOR STATEMENT This presentation and accompanying documents contain ?forward-looking statements? which may describe strategies, goals, outlooks or other non-historical matters, or projected revenues, Income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

March 10, 2022 EX-99.02

OTCQX: TGEN MARCH 10, 2022 FY 2021 EARNINGS CALL 1 MANAGEMENT Benjamin Locke - CEO Robert Panora – COO & President Abinand Rangesh – CFO & Treasurer Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying

EX-99.02 3 q4andfy2021earningsprese.htm EX-99.02 OTCQX: TGEN MARCH 10, 2022 FY 2021 EARNINGS CALL 1 MANAGEMENT Benjamin Locke - CEO Robert Panora – COO & President Abinand Rangesh – CFO & Treasurer Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or oth

March 10, 2022 EX-99.01

Tecogen Announces 2021 Results Net Income of $3.7 million for FY 2021 and $63.0 thousand for Q4 2021 Earnings of $0.15 per share for FY 2021

Tecogen Announces 2021 Results Net Income of $3.7 million for FY 2021 and $63.0 thousand for Q4 2021 Earnings of $0.15 per share for FY 2021 WALTHAM, Mass., March 10, 2022 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported net income of $63.0 thousand for the quarter ended December 31, 2021 and $3.7 million for the full year compared to a net loss of $4.1 millio

March 10, 2022 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ☑ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 ☐ TRANSITION REPORT PURSUANT TO SECTION

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

March 10, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 10, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifi

March 9, 2022 EX-10.6

Form of Non-Qualified Stock Option Award Agreement (Non-Employee Director Form), filed herewith.

TECOGEN INC. NON-QUALIFIED STOCK OPTION AWARD AGREEMENT 2022 STOCK INCENTIVE PLAN (Non-Employee Director Form) Name of Participant: (?Participant?) Number of Shares Covered by Option Grant: Option Exercise Price Per Share: $ Grant Date: , 20 (?Grant Date?) THIS NON-QUALIFIED STOCK OPTION AWARD AGREEMENT ("Award Agreement") is dated as of this day of , , by and between Tecogen Inc., a Delaware corp

March 9, 2022 EX-10.2

Form of Incentive Stock Option Award Agreement (Employee Form), filed herewith.

TECOGEN INC. INCENTIVE STOCK OPTION AWARD AGREEMENT 2022 STOCK INCENTIVE PLAN (Employee Form) Name of Participant: (?Participant?) Number of Shares Covered by Option Grant: Option Exercise Price Per Share: $ Grant Date: , 20 (?Grant Date?) THIS INCENTIVE STOCK OPTION AWARD AGREEMENT ("Award Agreement") is dated as of this day of , , by and between Tecogen Inc., a Delaware corporation (?Company?),

March 9, 2022 EX-10.3

Form of Non-Qualified Stock Option Award Agreement (Employee Form), filed herewith.

TECOGEN INC. NON-QUALIFIED STOCK OPTION AWARD AGREEMENT 2022 STOCK INCENTIVE PLAN (Employee Form) Name of Participant: (?Participant?) Number of Shares Covered by Option Grant: Option Exercise Price Per Share: $ Grant Date: , 20 (?Grant Date?) THIS NON-QUALIFIED STOCK OPTION AWARD AGREEMENT ("Award Agreement") is dated as of this day of , , by and between Tecogen Inc., a Delaware corporation (?Com

March 9, 2022 EX-10.4

Form of Restricted Stock Award Agreement, filed herewith.

TECOGEN INC. RESTRICTED STOCK AWARD AGREEMENT 2022 STOCK INCENTIVE PLAN Name of Participant: (?Participant?) Number of Restricted Shares Covered by Restricted Stock Award: Grant Date: , 20 (?Grant Date?) THIS RESTRICTED STOCK AWARD AGREEMENT (?Award Agreement?) is dated as of this day of , , by and between Tecogen Inc., a Delaware corporation (?Company?), and Participant set forth above. Unless ot

March 9, 2022 EX-10.5

Tecogen Inc. Policy Regarding Compensation of Non-Employee Directors, filed herewith.

TECOGEN INC. Policy Regarding Compensation of Non-Employee Directors Effective Commencing March 8, 2022 The board of directors (?Board?) of Tecogen Inc., a Delaware corporation (?Company?), has adopted the following Policy Regarding Compensation of Non-Employee Directors (?Policy?) pursuant to the recommendations of the Compensation Committee of the Company. The purpose of the Policy is to attract

March 9, 2022 EX-10.1

Tecogen Inc. 2022 Stock Incentive Plan, filed herewith.

TECOGEN INC. 2022 STOCK INCENTIVE PLAN ARTICLE I Establishment, Purpose, and Duration 1.1 Establishment of the Plan. Tecogen Inc., a Delaware corporation ("Company"), hereby establishes a stock incentive plan to be known as the "Tecogen Inc. 2022 Stock Incentive Plan," as set forth below. Unless otherwise defined herein, all capitalized terms shall have the meanings set forth in Section 2.1 herein

March 9, 2022 8-A12G

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 TECOGEN INC. (Exact name of registrant as speci

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-A FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware 04-3536131 (State of or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification No.) 45 Fir

March 9, 2022 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 8, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

January 20, 2022 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: January 20, 2022 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identi

January 20, 2022 EX-99.01

Tecogen Shareholder Update

Tecogen Shareholder Update WALTHAM, MA, January 20, 2022 ? Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and clean on-site power, heating, and cooling equipment, is pleased to provide the following shareholder update regarding accomplishments in 2021 and expectations for 2022. Dear Fellow Shareholders, On behalf of the entire Tecogen team, we enter the New Year with

January 20, 2022 EX-99.02

July 7, 2021 Tecogen Files Provisional Patent for New Hybrid Drive WALTHAM, MA, July 07, 2021 (GLOBE NEWSWIRE) -- via NewMediaWire -- Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and clean on-site power, heating, and c

July 7, 2021 Tecogen Files Provisional Patent for New Hybrid Drive WALTHAM, MA, July 07, 2021 (GLOBE NEWSWIRE) - via NewMediaWire - Tecogen Inc.

November 10, 2021 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2021 ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

November 10, 2021 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: November 10, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Ident

November 10, 2021 EX-99.02

OTCQX: TGEN THIRD QUARTER 2021 EARNINGS CALL NOV 11, 2021 1 MANAGEMENT Benjamin Locke - CEO Robert Panora – COO and President Abinand Rangesh – CFO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying

EX-99.02 3 tgenq32021earningspresen.htm EX-99.02 OTCQX: TGEN THIRD QUARTER 2021 EARNINGS CALL NOV 11, 2021 1 MANAGEMENT Benjamin Locke - CEO Robert Panora – COO and President Abinand Rangesh – CFO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or othe

November 10, 2021 EX-99.01

Tecogen Announces Third Quarter 2021 Results Net Income of $3.6 million YTD 2021 and $1.5 million for Q3 2021 Diluted earnings per share of $0.14/share YTD 2021 and $0.06/share for Q3 2021

Tecogen Announces Third Quarter 2021 Results Net Income of $3.6 million YTD 2021 and $1.5 million for Q3 2021 Diluted earnings per share of $0.14/share YTD 2021 and $0.06/share for Q3 2021 WALTHAM, Mass., November 10, 2021 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported net income of $1.5 million for the quarter ended September 30, 2021 compared to a net loss

November 10, 2021 EX-99.01

Tecogen Receives 2.5 MW Microgrid System Order for Controlled Environment Agriculture Facility

Tecogen Receives 2.5 MW Microgrid System Order for Controlled Environment Agriculture Facility WALTHAM, MA, November 10, 2021 ? Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and clean on-site power, heating, and cooling equipment, is pleased to announce an order for 12 InVerde e+? 125 kW microgrid-enabled cogeneration units and three 400 ton Tecochill? chillers for a

November 10, 2021 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: November 10, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Ident

October 12, 2021 EX-99.01

October 8, 2021 Tecogen to Present at the 14th Annual LD Micro Main Event on October 12, 2021 WALTHAM, MA, Oct. 08, 2021 (GLOBE NEWSWIRE) -- via NewMediaWire -- Tecogen Inc. (OTCQX: TGEN), a clean energy company providing ultra-efficient and clean on

October 8, 2021 Tecogen to Present at the 14th Annual LD Micro Main Event on October 12, 2021 WALTHAM, MA, Oct.

October 12, 2021 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: October 12, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identi

October 12, 2021 EX-99.02

TECOGEN INVESTOR PRESENTATION SEPTEMBER 13, 2021 OTC: TGEN CLEAN ENERGY SOLUTIONS BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe stra

TECOGEN INVESTOR PRESENTATION SEPTEMBER 13, 2021 OTC: TGEN CLEAN ENERGY SOLUTIONS BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain ?forward-looking statements? which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

September 21, 2021 EX-99.01

dated September 13, 2021 regarding forgiveness of Second Draw Paycheck Protection Program Loan to Tecogen Inc.

September 21, 2021 8-K

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: September 21, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Iden

September 13, 2021 EX-99.01

TECOGEN INVESTOR PRESENTATION SEPTEMBER 13, 2021 OTC: TGEN CLEAN ENERGY SOLUTIONS BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe stra

EX-99.01 2 tecogenirpresentation.htm EX-99.01 TECOGEN INVESTOR PRESENTATION SEPTEMBER 13, 2021 OTC: TGEN CLEAN ENERGY SOLUTIONS BENJAMIN LOCKE, CEO ABINAND RANGESH, CFO SAFE HARBOR STATEMENT This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, income, returns or othe

September 13, 2021 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: September 13, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Iden

August 12, 2021 EX-99.02

OTCQX: TGEN SECOND QUARTER 2021 EARNINGS CALL AUGUST 12, 2021 1 MANAGEMENT Benjamin Locke - CEO Robert Panora – COO and President Abinand Rangesh – CFO Jack Whiting – General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompany

OTCQX: TGEN SECOND QUARTER 2021 EARNINGS CALL AUGUST 12, 2021 1 MANAGEMENT Benjamin Locke - CEO Robert Panora ? COO and President Abinand Rangesh ? CFO Jack Whiting ? General Counsel & Secretary 2 SAFE HARBOR STATEMENT This presentation and accompanying documents contain ?forward-looking statements? which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

August 12, 2021 EX-99.01

Tecogen Announces Second Quarter 2021 Results Net Income of $2.2 million for H1 2021 and $0.4 million for Q2 2021 Earnings per share of $0.09/share for H1 2021 and $0.02/share for Q2 2021

EX-99.01 2 tgenq22021earningsrelease.htm EX-99.01 Tecogen Announces Second Quarter 2021 Results Net Income of $2.2 million for H1 2021 and $0.4 million for Q2 2021 Earnings per share of $0.09/share for H1 2021 and $0.02/share for Q2 2021 WALTHAM, Mass., August 12, 2021 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported net income of $0.4 million for the quarter

August 12, 2021 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: August 12, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identif

August 12, 2021 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

June 16, 2021 EX-99.01

Tecogen Appoints Chief Financial Officer

Tecogen Appoints Chief Financial Officer WALTHAM, MA, June 16, 2021 ? Tecogen Inc.

June 16, 2021 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report (Date of earliest event reported): June 8, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission Fil

May 13, 2021 EX-99.02

OCTQX: TGEN FIRST QUARTER 2021 Earnings Call May 13, 2021 Participants Chief Executive OfficerBenjamin Locke President & Chief Operating OfficerRobert Panora 2 General Counsel & SecretaryJack Whiting Chief Accounting OfficerRoger Deschenes Safe Harbo

EX-99.02 3 q12021earningspresentati.htm EX-99.02 OCTQX: TGEN FIRST QUARTER 2021 Earnings Call May 13, 2021 Participants Chief Executive OfficerBenjamin Locke President & Chief Operating OfficerRobert Panora 2 General Counsel & SecretaryJack Whiting Chief Accounting OfficerRoger Deschenes Safe Harbor Statement 3 This presentation and accompanying documents contain “forward-looking statements” which

May 13, 2021 EX-99.03

45 First Avenue Waltham, MA 02451 781-466-6402 1 May 13, 2021 Fellow Tecogen Shareholders, I would like to share with you Tecogen’s vision for growth as we begin to put the COVID-19 pandemic behind us. 2020 was a challenging year by any measure, from

EX-99.03 4 lettertotecogensharehold.htm EX-99.03 45 First Avenue Waltham, MA 02451 781-466-6402 1 May 13, 2021 Fellow Tecogen Shareholders, I would like to share with you Tecogen’s vision for growth as we begin to put the COVID-19 pandemic behind us. 2020 was a challenging year by any measure, from the pandemic to a global recession and Tecogen was not immune to the slowdown in economic activity.

May 13, 2021 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 13, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifica

May 13, 2021 EX-99.01

Tecogen Announces First Quarter 2021 Results Net Income of $1.8 million due to PPP Loan Forgiveness, Reduced Operating Expenses, Improved Margins, and Positive Adjusted EBITDA

EX-99.01 2 tgenq12021earningsrelease.htm EX-99.01 Tecogen Announces First Quarter 2021 Results Net Income of $1.8 million due to PPP Loan Forgiveness, Reduced Operating Expenses, Improved Margins, and Positive Adjusted EBITDA WALTHAM, Mass., May 13, 2021 - Tecogen Inc. (OTCQX:TGEN), a leading manufacturer of clean energy products, reported net income of $1.8 million for the quarter ended March 31,

May 13, 2021 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

March 30, 2021 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 29, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifi

March 23, 2021 424B3

TECOGEN INC. Up to 706,147 shares of our common stock by the selling stockholders

Filed Pursuant to Rule 424(b)(3) Registration No. 333-212433 PROSPECTUS TECOGEN INC. Up to 706,147 shares of our common stock by the selling stockholders This prospectus relates to up to 706,147 shares of our common stock that may be sold by the selling stockholders named in this prospectus and such additional selling stockholders, if any, as may be named in one or more prospectus supplements (?se

March 19, 2021 POS AM

- POS AM

As filed with the Securities and Exchange Commission on March 19, 2021 Registration No.

March 18, 2021 EX-10.24

Webster Bank, NA letter dated January 11, 2021, confirming receipt of payment in full of registrant's obligation under the Paycheck Protection Loan dated April 17, 2020.

March 18, 2021 10-K

Annual Report - 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2020 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

March 12, 2021 POS AM

Post-Effective Amendment No. 1 to Form S-3 on Form S-1 Registration Statement Under the Securities Act of 1933, filed with the SEC on March 12, 2021, incorporated herein by reference.

As filed with the Securities and Exchange Commission on March 12, 2021 Registration No.

March 12, 2021 EX-21.1

List of subsidiaries incorporated by reference to Exhibit 21.1 to the registrants Post-Effective Amendment No. 1 to Form S-3 on Form S-1 Registration Statement Under the Securities Act of 1933, filed with the SEC on March 12, 2021.

LIST OF SUBSIDIARIES TECOGEN INC. a Delaware corporation Subsidiaries Ownership % Jurisdiction of Incorporation American DG Energy Inc. 100% Delaware American DG New York, LLC 51% Delaware Tecogen CHP Solutions Inc. 100% Ontario, Canada

March 12, 2021 EX-10.27

Promissory Note for Paycheck Protection Program Second Draw Loan from Webster Bank, N.A. dated February 5, 2021 in the amount of $1,874,269

Congratulations! Your application for your SBA PPP Program loan is clear to close.

March 11, 2021 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 11, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifi

March 11, 2021 EX-99.02

OTCQX: TGEN FOURTH QUARTER & FISCAL 2020 YEAR END Earnings Call March 11, 2021 Participants 2 Chief Executive OfficerBenjamin Locke President & Chief Operating OfficerRobert Panora General Counsel & SecretaryJack Whiting Safe Harbor Statement 3 This

EX-99.02 3 ye-2020earningspresentat.htm EX-99.02 OTCQX: TGEN FOURTH QUARTER & FISCAL 2020 YEAR END Earnings Call March 11, 2021 Participants 2 Chief Executive OfficerBenjamin Locke President & Chief Operating OfficerRobert Panora General Counsel & SecretaryJack Whiting Safe Harbor Statement 3 This presentation and accompanying documents contain “forward-looking statements” which may describe strat

March 11, 2021 EX-99.01

Tecogen Reports 2020 Results

Exhibit 99.01 Tecogen Reports 2020 Results WALTHAM, Mass., March 11, 2021, Tecogen Inc. (OTCQX:TGEN, the "Company"), a leading manufacturer of clean energy products, reported revenues of $28.3 million for the year ended December 31, 2020 compared to $33.4 million for 2019, a 15.5% decrease. All segments were adversely impacted by business interruptions resulting from the COVID-19 pandemic. Product

February 25, 2021 8-K

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: February 25, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Ident

February 25, 2021 EX-99.01

Energy Efficiency Reimagined OTCQX: TGEN LPG Near Zero Emission System for Forklifts – Status Update Robert Panora President & COO Topics Tecogen Inc. Technology Background Ultera® Aftertreatment Process Application to Forklifts Regulatory issues MCF

Energy Efficiency Reimagined OTCQX: TGEN LPG Near Zero Emission System for Forklifts ? Status Update Robert Panora President & COO Topics Tecogen Inc.

February 9, 2021 8-K

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: February 9, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identi

January 20, 2021 8-K

Other Events - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: January 20, 2021 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identi

November 12, 2020 10-Q

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2020 or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-36103 TECOGEN INC.

November 12, 2020 EX-21

List of Subsidiaries

LIST OF SUBSIDIARIES TECOGEN INC. a Delaware Corporation Subsidiaries Ownership % Jurisdiction American DG Energy Inc. 100% Delaware American DG New York, LLC 51% Delaware

November 12, 2020 EX-99.2

OCTQX: TGEN THIRD QUARTER 2020 Earnings Call November 12, 2020 Participants Benjamin Locke Chief Executive Officer President & Chief Operating Robert Panora Officer Jack Whiting General Counsel & Secretary 2 Safe Harbor Statement This presentation an

q32020earningspresentati OCTQX: TGEN THIRD QUARTER 2020 Earnings Call November 12, 2020 Participants Benjamin Locke Chief Executive Officer President & Chief Operating Robert Panora Officer Jack Whiting General Counsel & Secretary 2 Safe Harbor Statement This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

November 12, 2020 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition - 8-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: November 12, 2020 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Ident

November 12, 2020 EX-99.1

Tecogen Announces Third Quarter 2020 Results Continued Improvement in Margin and OPEX

Tecogen Announces Third Quarter 2020 Results Continued Improvement in Margin and OPEX WALTHAM, Mass.

August 13, 2020 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: August 13, 2020 TECOGEN INC. (OTCQX: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identif

August 13, 2020 EX-99.1

Tecogen Announces Second Quarter 2020 Results Increased Product Sales and Significantly Improved Cash Flow and Cash Balance

Tecogen Announces Second Quarter 2020 Results Increased Product Sales and Significantly Improved Cash Flow and Cash Balance WALTHAM, Mass.

August 13, 2020 EX-99.2

OCTQX: TGEN SECOND QUARTER 2020 Earnings Call August 13, 2020 Participants Benjamin Locke Chief Executive Officer President & Chief Operating Robert Panora Officer Jack Whiting General Counsel & Secretary 2 Safe Harbor Statement This presentation and

q22020earningspresentati OCTQX: TGEN SECOND QUARTER 2020 Earnings Call August 13, 2020 Participants Benjamin Locke Chief Executive Officer President & Chief Operating Robert Panora Officer Jack Whiting General Counsel & Secretary 2 Safe Harbor Statement This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goals, outlooks or other non- historical matters, or projected revenues, income, returns or other financial measures, that may include words such as "believe," "expect," "anticipate," "intend," "plan," "estimate," "project," "target," "potential," "will," "should," "could," "likely," or "may" and similar expressions intended to identify forward-looking statements.

August 13, 2020 10-Q

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2020 or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 001-36103 TECOGEN INC.

July 28, 2020 EX-10.2

American DG Energy Inc.2005 Stock Incentive Plan, incorporated by reference to Exhibit 10.2 to Post-Effective Amendment No. 1 to the registrant’s Form S-8 Registration Statements (File No. 333-187928), filed with the SEC on July 28, 2020.

Exhibit 10.2 AMERICAN DG ENERGY INC. 2005 STOCK INCENTIVE PLAN 1. Purposes of the Plan. This 2005 Stock Incentive Plan (the "Plan"), as amended to date, is intended to provide incentives (a) to the officers and employees of American DG Energy Inc., a Delaware corporation (the "Company"), and any parent or subsidiary of the Company, by providing such officers and employees with opportunities to pur

July 28, 2020 S-8 POS

- S-8 POS

As filed with the Securities and Exchange Commission on July 28, 2020. Registration Nos. 333-187928 and 333-218244 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 - POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 - TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware 04-3536131 (State or other jurisd

July 27, 2020 AW

- AW

TECOGEN INC. 45 First Avenue Waltham, MA 02451 July 27, 2020 VIA EDGAR United States Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549 Attn: Jan Woo, Esq. Legal Branch Chief Division of Corporation Finance Re: Tecogen Inc. Post-Effective Amendment No. 1 to Registration Statements on Form S-8 Registration Nos. 333-187928 and 333-218244 Dear Sir or Madam: Pursuant to Rule

July 24, 2020 EX-10.2

American DG Energy Inc. 2005 Stock Incentive Plan

AMERICAN DG ENERGY INC. 2005 STOCK INCENTIVE PLAN 1. Purposes of the Plan. This 2005 Stock Incentive Plan (the "Plan"), as amended to date, is intended to provide incentives (a) to the officers and employees of American DG Energy Inc., a Delaware corporation (the "Company"), and any parent or subsidiary of the Company, by providing such officers and employees with opportunities to purchase stock i

July 24, 2020 POS AM

- POS AM

As filed with the Securities and Exchange Commission on July 24, 2020. Registration Nos. 333-187928 and 333-218244 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 - POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 - TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware 04-3536131 (State or other jurisd

July 21, 2020 EX-99.01

Tecogen Inc. Change in Control Severance Benefit Plan

Tecogen Inc. Change in Control Severance Benefit Plan 1. Introduction. The Tecogen Change in Control Executive Severance Benefit Plan (the “Plan”) is hereby established effective as of July 9, 2020 (the “Effective Date”). The Plan provides for the payment of certain severance benefits to eligible employees of Tecogen Inc. (the “Company”) in the event of a qualifying termination of employment in co

July 21, 2020 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: July 20, 2020 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identification No.) 45

July 10, 2020 POS AM

- POS AM

As filed with the Securities and Exchange Commission on July 9, 2020. Registration No. 333-237582 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware (State or other jurisdiction of incorporation or organiz

July 10, 2020 POS AM

- POS AM

As filed with the Securities and Exchange Commission on July 9, 2020. Registration No. 333-205147 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware (State or other jurisdiction of incorporation or organiz

July 8, 2020 8-K

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: July 8, 2020 TECOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identification No.) 45 F

June 9, 2020 25

- 25

June 9, 2020 EX-99.01

Tecogen Initiates Transition to Quotation on OTC Capital Markets OTCQX Best Market

Tecogen Initiates Transition to Quotation on OTC Capital Markets OTCQX Best Market WALTHAM, MA, June 9, 2020– Tecogen Inc.

June 9, 2020 8-K

Financial Statements and Exhibits, Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: June 9, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

June 5, 2020 8-K

Submission of Matters to a Vote of Security Holders

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: June 5, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

June 4, 2020 8-K

Regulation FD Disclosure

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: June 4, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

May 29, 2020 8-K

Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 29, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

May 29, 2020 EX-99.01

Tecogen to Transition Listing of Shares to OTC Markets

Tecogen to Transition Listing of Shares to OTC Markets WALTHAM, MA, May 29, 2020– Tecogen Inc.

May 26, 2020 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 26, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

May 26, 2020 EX-99.01

Building Electrification Policy and Combined Heat and Power Relevance Why Electrification Policy is Generally Counterproductive to its Carbon Reduction Goals Robert A. Panora, President and COO, Tecogen Inc. and Charles T. Maxwell, Consultant to Teco

electrificationpolicyabs Building Electrification Policy and Combined Heat and Power Relevance Why Electrification Policy is Generally Counterproductive to its Carbon Reduction Goals Robert A.

May 15, 2020 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 15, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

May 14, 2020 10-Q

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q þ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2020 or o TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number 001-36103 TECOGEN INC.

May 14, 2020 8-K

Regulation FD Disclosure, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 14, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

May 14, 2020 EX-99.01

Tecogen Announces First Quarter 2020 Results Increase in Product and Services Revenues of 4% Year over Year

Tecogen Announces First Quarter 2020 Results Increase in Product and Services Revenues of 4% Year over Year WALTHAM, Mass.

May 14, 2020 EX-10.61

Loan Documentation for Paycheck Protection Program Loan through Webster Bank, dated April 17, 2020, incorporated by reference to Exhibit 10.61 to the registrant’s Quarterly Report on Form 10-Q.

ppploanclosingdocumentat DocuSign Envelope ID: C730F4BB-CE88-4870-BBC6-EB7BE7FCFAC6 THIS IS A COPY BUSINESS BANKING This is a copy view of the Authoritative Copy held CLOSING DOCUMENTATION TRANSMITTAL / CHECKLISTby the designated custodian Return To: Borrower: TECOGEN INC Guarantor(s) Transaction: $ 1,874,200.

May 14, 2020 EX-99.02

NASDAQ: TGEN FIRST QUARTER 2020 Earnings Call May 14, 2020 Participants Benjamin Locke Chief Executive Officer President & Chief Operating Robert Panora Officer Bonnie Brown Chief Accounting Officer Jack Whiting General Counsel & Secretary 2 Safe Har

q12020earningspres NASDAQ: TGEN FIRST QUARTER 2020 Earnings Call May 14, 2020 Participants Benjamin Locke Chief Executive Officer President & Chief Operating Robert Panora Officer Bonnie Brown Chief Accounting Officer Jack Whiting General Counsel & Secretary 2 Safe Harbor Statement This presentation and accompanying documents contain “forward-looking statements” which may describe strategies, goal

May 12, 2020 8-K

Termination of a Material Definitive Agreement

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: May 11, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identific

April 22, 2020 DEFA14A

TGEN / Tecogen Inc DEFA14A - - DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (a

April 21, 2020 CORRESP

-

TECOGEN INC. 45 First Avenue Waltham, MA 02451 Tel: (781) 466-6400 April 21, 2020 VIA EDGAR United States Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549 Attn: Bernard Nolan, Esq. Attorney Adviser Division of Corporation Finance Re: Tecogen Inc. Form S-3 Registration Statement File No. 33-237582 Ladies and Gentlemen: Pursuant to the requirements of Rule 461 under the S

April 21, 2020 DEF 14A

TGEN / Tecogen Inc DEF 14A - - DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A (RULE 14a-101) SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant þ Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (a

April 17, 2020 8-K

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: April 17, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identif

April 14, 2020 8-K

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: April 14, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identif

April 7, 2020 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: April 7, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifi

April 7, 2020 EX-99.01

April 7, 2020 Dear Friends and Shareholders: I write to provide whatever comfort I can in the midst of the Coronavirus pandemic and the turmoil it has brought to us all, including our families, our home and work lives, and the economy and markets. I

EX-99.01 2 lettertoshareholders7apr.htm EXHIBIT 99.01 April 7, 2020 Dear Friends and Shareholders: I write to provide whatever comfort I can in the midst of the Coronavirus pandemic and the turmoil it has brought to us all, including our families, our home and work lives, and the economy and markets. I am sure that you are aware of the negative impact of the pandemic on market investments, includi

April 6, 2020 POS AM

Post Effective Amendment No. 1 to Registrant's Universal Shelf Registration on Form S-3 (Incorporated by reference to Form S-3 filed with the SEC on April 6, 2020).

As filed with the Securities and Exchange Commission on April 6, 2020. Registration No. 333-199634 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware (State or other jurisdiction of incorporation or organi

April 6, 2020 S-3

Registrant's Universal Shelf Registration on Form S-3 (Incorporated by reference to Form S-3 filed with the SEC on April 6, 2020).

As filed with the Securities and Exchange Commission on April 6, 2020. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware (State or other jurisdiction of incorporation or organization) 04-3536131 (I.R.S. Employer Iden

April 3, 2020 RW

TGEN / Tecogen Inc RW - - RW

Tecogen Inc. 45 First Avenue Waltham, MA 02451 April 3, 2020 United States Securities and Exchange Commission 100 F Street, N.E. Washington, D.C. 20549 Attention: Bernard Nolan, Esq. Attorney Advisor Division of Corporation Finance Re: Tecogen Inc. Post-Effective Amendment No. 1 to Registration Statement on Form S-3 File No. 333-199634 Dear Sir or Madam: Pursuant to Rule 477 under the Securities A

April 2, 2020 S-3/A

TGEN / Tecogen Inc S-3/A - - S-3/A

As filed with the Securities and Exchange Commission on April 1, 2020. Registration No. 333-199634 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TECOGEN INC. (Exact name of registrant as specified in its charter) Delaware (State or other jurisdiction of incorporation or organi

April 1, 2020 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: April 1, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identifi

April 1, 2020 EX-99.01

Comments of Benjamin Locke, CEO, and Robert Panora, President for Tecogen Inc. investor conference call on April 1, 2020 at 11:00 am regarding the impact of the Coronavirus on Tecogen Inc.

Comments of Benjamin Locke, CEO, and Robert Panora, President for Tecogen Inc. investor conference call on April 1, 2020 at 11:00 am regarding the impact of the Coronavirus on Tecogen Inc. Benjamin Locke Read Safe Harbor Statement. Good morning. Thank you for joining us on the call today during what is truly a concerning time for all of us. I hope that each of you are in a place of relative safety

March 18, 2020 8-K

Other Events

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 18, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identif

March 17, 2020 8-K

Regulation FD Disclosure, Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of report: March 17, 2020 TECOGEN INC. (NASDAQ: TGEN) (Exact Name of Registrant as Specified in Charter) Delaware (State or Other Jurisdiction of Incorporation) 001-36103 04-3536131 (Commission File Number) (IRS Employer Identif

March 17, 2020 EX-99.01

NASDAQ: TGEN Corporate Overview 32nd Annual ROTH Conference March 17, 2020 Senior Management Benjamin Locke Chief Executive Officer President, Chief Operating Robert Panora Officer Bonnie Brown Chief Accounting Officer John Hatsopoulos Lead Director

EX-99.01 2 march2020tecogenrothpres.htm EXHIBIT 99.01 NASDAQ: TGEN Corporate Overview 32nd Annual ROTH Conference March 17, 2020 Senior Management Benjamin Locke Chief Executive Officer President, Chief Operating Robert Panora Officer Bonnie Brown Chief Accounting Officer John Hatsopoulos Lead Director 2 Tecogen – Who We Are Clean Energy Distributed Generation Systems that are: Efficient Industry

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