EuroSite Power Names Managing Director

WALTHAM, Massachusetts, May 12, 2011 - EuroSite Power Inc. (www.eurositepower.co.uk/), an On-Site
Utility, offering clean electricity, heat, hot water and cooling solutions to
healthcare, multifamily housing and hotel properties in the United Kingdom
and Europe, today announced that Mr. Paul Hamblyn has been named Managing
Director of the Company. Mr. Hamblyn will be responsible for developing and
leading the business under the guidance of CEO, Barry Sanders.

Mr. Hamblyn is a Council Member of the Energy Services and Technology
Association. Prior to joining EuroSite Power, he was the Head of Energy
Services for Corona Energy, an independent B2B gas supplier, where he
directed the creation of their energy services offer. He was previously with
the ENER-G Group and held a series of positions with the company including
three years as the Managing Director of ENER-G Efficiency, a company that he
took from a simple idea to become a leading provider of energy management
solutions based on Building Energy Management Systems (BEMS) technology. Mr.
Hamblyn is a Chartered Institution of Building Services Engineers (CIBSE)
accredited Low Carbon Consultant and Energy Assessor as well as principal
author of the highly successful Carbon Reduction Commitment (CRC) Toolkit
developed for the London Energy Project. His career has centred on a range of
low carbon technologies including Combined Heat and Power (CHP), renewable
generation and BEMS. As a leading expert on UK carbon regulation Paul is a
regular speaker at major conferences including those organised by the Major
Energy Users Council, Local Government Association and the Westminster Energy
Forum. Mr. Hamblyn has an HNC in Electronic and Micro-electronic Engineering
and completed an award winning apprenticeship early in his career with Landis
and Gyr (now part of Siemens).

"Paul has the right combination of skills, experience and aggressiveness
to build and grow our energy business," said Barry J. Sanders, CEO of
EuroSite Power.

Speaking about his appointment, Mr. Hamblyn said, "I am confident the
EuroSite Power solution will prove a big hit with British businesses and I am
looking forward to having the opportunity to establish EuroSite Power as the
leading provider of onsite energy in the UK."

About EuroSite Power

EuroSite Power provides institutional, commercial and small industrial
properties with clean, reliable power, cooling, heat and hot water at lower
costs than charged by local utilities - without any capital or start-up costs
to the energy user. EuroSite Power, formed to introduce the On-Site Utility
(www.americandg.com/On-Site-Utility) solution into the European
market, is a subsidiary of American DG Energy Inc. (NYSE Amex:ADGE) which is
headquartered in Waltham, Massachusetts. More information can be found at
www.eurositepower.co.uk.

Investor Contact: John N. Hatsopoulos, EuroSite Power Inc., +1-781-522-6020, john.hatsopoulos at eurositepower.co.uk, or Media Contact: Barry J. Sanders, EuroSite Power Inc., +1-781-522-6010, barry.sanders at eurositepower.co.uk