Northern Power Systems presented with DOE grant

March 24, 2004 — Northern Power Systems, Inc. a subsidiary of Distributed Energy Systems Corp., has received a two-year grant total of $600,000 from the United States Department of Energy (DOE) for development of the company’s MicroGrid® power network in the area known as Mad River Park in Waitsfield, Vermont.

In recognition of the grant, Vermont Senator James Jeffords presented a check to Northern executives at a news conference at the company’s headquarters.

Awarded in two parts in fiscal years 2003 and 2004, the DOE grant has supported development of Northern’s MicroGrid system, an advanced power network solution that incorporates distributed generation, energy storage, and load management subsystems into a highly reliable, efficient, and robust power systems.

MicroGrid power networks can operate either interconnected to or isolated from the overall utility distribution system, and can transition seamlessly between these operating modes with no interruption to the end user’s electrical loads.

As the first implementation of the new distributed power solution, the Mad River Park MicroGrid power network is being undertaken in concert with the local electric power utility — the Washington Electric Cooperative (WEC) — and with the support of the Vermont Department of Public Service. The Mad River Park MicroGrid power network will serve customers residing in the park — approximately five businesses and 12 residential power users — which is also the site of Northern’s headquarters.

About Northern Power Systems, Inc.

Northern Power Systems, Inc. designs, builds and installs reliable power solutions for commercial, industrial, government, and military customers. The company also conducts research and development in the areas of renewable energy, distributed generation and hydrogen technology. Since its founding in 1974, Northern has installed over 800 systems in 45 countries on all seven continents. Northern Power Systems, Inc., is headquartered in Waitsfield, Vermont and employs 100 people with engineering, fulfillment, and customer-support capabilities. The company is a wholly owned subsidiary of Distributed Energy Systems Corp. For more information, visit www.northernpower.com.

About Distributed Energy Systems Corp.

Distributed Energy Systems Corp. (Nasdaq: DESC) creates and delivers products and solutions to the emerging decentralized energy marketplace, giving users greater control over their energy cost, quality, and reliability. As the parent company of Proton Energy Systems, Inc. (www.protonenergy.com) and Northern Power Systems, Inc., Distributed Energy Systems delivers a combination of practical, ready-today energy solutions and the solid business platforms for capitalizing on the changing energy landscape. For more information, visit www.distributed-energy.com.