Item 8.01. Other Events.

As previously disclosed, Tecogen Inc. (the TGEN) filed a
registration statement on Form S-4, which contains a proxy
statement of American DG Energy Inc., (the “Company’) and a
prospectus of TGEN (the Registration Statement), with the
Securities and Exchange Commission (the SEC). On April 12, 2017,
the Registration Statement was declared effective by the SEC, and
the Company announced that a special meeting of the Companys
stockholders (the Special Meeting) is scheduled to be held on May
18, 2017, at 1 p.m., Eastern Time, at the Companys principal
executive offices at 45 First Avenue, Waltham, Massachusetts 02451,
to consider and vote on (1) a proposal to adopt the Agreement and
Plan of Merger, dated as of November 1, 2016, as the same may be
amended from time to time (the “Merger Agreement”), by and among
the Company, TGEN, and TGEN.ADGE Acquisition Corp., a Delaware
corporation formed for the purpose of effecting the merger, and a
wholly-owned subsidiary of TGEN (the “Merger Sub”), to where
Merger Sub will merge with and into the Company, or the Merger,
with the Company continuing as the surviving entity (the
“Merger”), approval of the transactions contemplated thereby,
including the Merger, and (2) a proposal to approve the adjournment
or postponement of the Special Meeting, if necessary or
appropriate, to solicit additional proxies. Stockholders of record
of the Company at the close of business on April 24, 2017, will be
entitled to vote by proxy or in person at the Special Meeting. The
proxy statement is expected to be mailed to stockholders of record
on or about May 4, 2017.

Completion of the Merger is subject to certain conditions,
including approval by the Companys stockholders and other customary
closing conditions.

A copy of the press release is furnished as Exhibit 99.1 hereto and
incorporated herein by reference.

CAUTIONARY NOTE REGARDING FORWARD LOOKING STATEMENTS

This Current Report on Form 8-K, or this Current Report, contains
forward looking statements within the meaning of the Private
Securities Litigation Reform Act of 1995 and other securities laws.
The forward looking statements are subject to various known and
unknown risks, uncertainties and other factors. When the Company
uses words such as believes, expects, anticipates, estimates, plans
or similar expressions, the Company is making forward looking
statements. Although the Company believes that its forward-looking
statements are based on reasonable assumptions, its expected
results may not be achieved, and actual results may differ
materially from its expectations. For example, this Current Report
states the date that the Company expects to mail the proxy
statement to its stockholders and the date of the Special Meeting.
These dates could change and the mailing and/or the date of the
Special Meeting could be delayed.

You should not rely upon forward-looking statements except as
statements of the Companys present intentions and of the Companys
present expectations, which may or may not occur. You should read
these cautionary statements as being applicable to all
forward-looking statements wherever they appear. Except as required
by law, the Company undertakes no obligation to release publicly
the result of any revision to these forward-looking statements that
may be made to reflect events or circumstances after the date
hereof or to reflect the occurrence of unanticipated events.
Readers are also urged to carefully review and consider the various
disclosures the Company has made in this document as well as the
Companys other filings with the SEC, including the sections
captioned Risk Factors and Cautionary Note Regarding Forward
Looking Statements in the Companys Annual Report on Form 10-K for
the year ended December 31, 2016 filed with the SEC on March 21,
2017.

Additional Information

This Current Report may be deemed to be solicitation material in
respect of the proposed stockholder vote approving the Merger. The
Company has filed with the SEC a Registration Statement on Form
S-4, which Registration Statement will include a definitive proxy
statement of the Company, a definitive proxy statement of ADGE and
prospectus of the Company (when available). The Registration
Statement was declared effective by the SEC on April 12, 2017.
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 COMPANYS 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 the Company and ADGE file with the SEC from the SECs 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
Attn: Bonnie Brown, 45 First Ave., Waltham, MA 02451, 781-522-6020,
or from the Companys website, http://americandg.com/.

The Company, TGEN, their respective directors and executive
officers and certain other members of their management and
employees may be deemed to be participants in the solicitation of
proxies in connection with the Special Meeting at which the
Companys stockholders will have the opportunity to vote on the
proposed Merger. Additional information regarding the interests of
such potential participants will be included or incorporated by
reference in the definitive proxy statement/prospectus (when
available).

Item 9.01 Financial Statements and Exhibits

(d) Exhibits

The following exhibit relating to Item 8.01 shall be deemed to be
furnished, and not filed: