Tecogen, Inc. (NASDAQ: TGEN), or the Company, today announced that its registration statement on SEC Form S-4 filed with Securities and Exchange Commission in connection with its merger with American DG Energy, Inc., was declared effective by the SEC on April 12, 2017. The Registration Statement includes a definitive proxy statement of TGEN, a definitive proxy statement of ADGE and a prospectus of TGEN (when available). Notice of the Special Meeting and a definitive proxy statement/prospectus is expected to be mailed on or about May 4, 2017, to stockholders of the Company as of April 24, 2017. BEFORE MAKING ANY VOTING DECISION, THE COMPANY'S STOCKHOLDERS ARE URGED TO READ ALL RELEVANT DOCUMENTS FILED WITH THE SEC, INCLUDING, WHEN AVAILABLE, THE DEFINITIVE PROXY STATEMENT/PROSPECTUS, BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE MERGER. Stockholders will be able to obtain, without charge, a copy of the definitive proxy statement/prospectus (when available) and other documents that TGEN and ADGE file with the SEC from the SEC's website at www.sec.gov. The definitive proxy statement/prospectus (when available) and other relevant documents will also be available, without charge, by directing a request by mail or telephone to (781) 466-6400, or from the Company's website, www.tecogen.com.