Beacon Power Announces Strategic Investment in Evergreen Solar.

Energy Editors/Business Editors

WILMINGTON, Mass.--(BUSINESS WIRE)--March 24, 2003

Beacon Power Corporation (Nasdaq: BCON), a developer of high performance flywheel energy storage systems, announced that to develop strategic relationships in renewable energy, it has invested $1 million in the Series A Preferred Stock of Evergreen Solar, Inc. on the same terms as the other investors in the financing. In addition, Beacon has also purchased a three-year warrant for $100,000, exercisable for 2,400,000 shares of Evergreen's common stock. Evergreen Solar has issued a press release relating to the transaction.

Bill Capp, Beacon's CEO and President said, "This decision is an investment in a strategic market for our next product now in development. Also, we view this as an attractive investment opportunity.

Our next generation 25kWh product is an extension of our existing products that are performing very well in the field - now having passed over 250,000 hours of operation in critical applications without an interruption of the customers load. Because our composite flywheels scale well, we will be able to offer this new product with a much improved value proposition. One of the target markets for this product is renewable energy - both solar and wind. This investment will enhance our ability to develop strategic relationships in this rapidly growing industry."

About Beacon Power Corporation

Beacon Power Corporation is a development-stage company which designs, develops, configures, and offers for sale power systems that provide highly reliable, high-quality, uninterruptible electric power. It is best known for its environmentally friendly, flywheel-based products (employing a flywheel made from proprietary composite materials) that can store and deliver energy in a variety of configurations. Such products have longer life, reduced maintenance, quicker recharging, remote monitoring and other advantages over competing solutions.

For more information, please contact James Spiezio, Chief Financial Officer at Beacon Power Corporation, tel. [phone]; fax [phone]; email [e-mail],or send mail to 234 Ballardvale Street, Wilmington, MA 01887. Visit Beacon Power on the Internet at www.beaconpower.com.

Safe Harbor Statements under the Private Securities Litigation Reform Act of 1995:

Material contained in this press release may include statements that are not historical facts and are considered "forward-looking" within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements reflect Beacon Power Corporation's current views about future events and financial performances. These forward-looking statements are identified by the use of terms and phrases such as "believe," "expect," "plan," "anticipate," and similar expressions identifying forward-looking statements. Investors should not rely on forward-looking statements because they are subject to a variety of risks, uncertainties, and other factors that could cause actual results to differ materially from Beacon Power Corporation's expectation. These factors include: a short operating history; a history of losses and anticipated continued losses from operations; a need to raise additional capital combined with a questionable ability to do so; conditions in target markets; no experience manufacturing any product on a commercial basis; no commercial contracts for sales to date; the dependence of sales on the achievement of product development and commercialization milestones; the uncertainty of the political and economic climate of any foreign countries into which Beacon hopes to sell, including the uncertainty of enforcing contracts and the potential substantial fluctuation in currency exchange rates in those countries; significant technological challenges to successfully complete product development; dependence on third-party suppliers; intense competition from companies with greater financial resources; possible government regulation that would impede the ability to market products; possible product liability claims and the negative publicity which could result; any failure to protect intellectual property; the possible need in the future to hire and retain key executives, particularly in light of the substantial workforce reductions during 2001 and 2002; the recent volatility in the stock price of companies operating in the same sector; the power of controlling shareholders and the limited ability of others to influence the outcome of matters put to the vote of shareholders. These factors are elaborated upon and other factors may be disclosed from time to time in Beacon Power Corporation's filings with the Securities and Exchange Commission. Beacon Power Corporation expressly does not undertake any duty to update forward-looking statements.