X0202 4 2004-11-02 0 0001103345 BEACON POWER CORP BCON 0000927752 PEARL FRANK H C/O PERSEUS CAPITAL, L.L.C. 2099 PENNSYLVANIA AVENUE, SUITE 900 WASHINGTON DC 20006 0 0 1 0 Stock Option (right to buy) 0.485 2004-11-02 4 J 0 100000 A 2004-12-31 2014-11-01 Common Stock 100000 100000 I Through Perseus Capital, L.L.C. Stock Option (right to buy) 0.485 2004-11-02 4 J 0 100000 A 2004-12-31 2014-11-01 Common Stock 100000 100000 I Through Perseus Capital, L.L.C. A Stock Option granted to Mr. Kenneth M. Socha, a member of the Issuer's board of directors, and held for the benefit of Perseus Capital, L.L.C., of which Mr. Socha is employed as a Senior Managing Director. Mr. Socha disclaims beneficial ownership of the reported securities, except to the extent of his pecuniary interest therein, if any. Stock Option grant. The Reporting Person is the Chairman of Perseus, L.L.C., which through certain subsidiary entities controls Perseus Capital, L.L.C., which beneficially owns the reported securities. The Reporting Person disclaims beneficial ownership of the reported securities, except to the extent of his pecuniary interest therein. A Stock Option granted to Mr. Philip J. Deutch, a member of the Issuer's board of directors, and held for the benefit of Perseus Capital, L.L.C., of which Mr. Deutch is employed as a Managing Director. Mr. Deutch disclaims beneficial ownership of the reported securities, except to the extent of his pecuniary interest therein, if any. By: Rodd Macklin Attorney-in-Fact 2004-11-04