X0202 4 2005-11-17 0001103345 BEACON POWER CORP BCON 0001249695 SOCHA KENNETH M C/O PERSEUS CAPITAL, L.L.C. 2099 PENNSYLVANIA AVENUE, NW, SUITE 900 WASHINGTON DC 20006 1 0 0 0 Stock Option (Right to Buy) 2.19 2005-11-17 4 A 0 50000 A 2005-12-30 2015-11-16 Common Stock 50000 50000 D Grant of Option. Pursuant to an agreement with Perseus Capital, L.L.C. and Perseus 2000 Expansion, L.L.C., the stock options granted to Kenneth M. Socha are to be held for the benefit of Perseus Capital, L.L.C and Perseus 2000 Expansion, L.L.C., of which Mr. Socha is employed as a Senior Managing Director. Accordingly, Mr. Socha is acting as a nominee for Perseus Capital, L.L.C. and Perseus 2000 Expansion, L.L.C. with respect to his holding of the options and specifically disclaims beneficial ownership thereof. Option vests in monthly installments over a twelve month period. Option becomes fully vested and exercisable on 11/30/06. Albert L. Sokol as attorney-in-fact 2005-11-21