X0303 4 2011-05-31 0 0001093691 PLUG POWER INC PLUG 0001008001 MCNAMEE GEORGE C 968 ALBANY SHAKER ROAD LATHAM NY 12110 1 0 0 1 Chairman of the Board Plug Power Common Stock 2011-05-31 4 P 0 40000 2.42 A 91096 D Warrants 3 2011-05-31 4 P 0 30000 2.42 A 2011-05-31 2016-05-31 Plug Power Common Stock 30000 70500 D The shares and warrants were acquired on May 31, 2011 as part of a public offering of shares of common stock and warrants to purchase shares of common stock. Pursuant to the terms of the public offering, each share of common stock was sold together with 0.75 of a 5-year warrant to purchase one share of common stock for an aggregate purchase price of $2.42 per combination. On May 19, 2011, Plug Power Inc. effected a 1-for-10 reverse stock split of its common stock, resulting in the reporting person's ownership of 459,873 fewer shares of common stock. Existing stock options held by the reporting person have been adjusted to reflect the 1-for-10 reverse stock split as follows: 2,000 granted 5/16/2002 exercise price $102.30; 1,500 granted 5/22/2003 exercise price $50.20; 1,500 granted 5/20/2004 exercise price $75.00; 1,500 granted 6/1/2005 exercise price $62.20; 1,500 granted 6/28/2006 exercise price $46.40; 1,500 granted 5/17/2007 exercise price $29.80; 1,500 granted 5/21/2008 exercise price $32.10; 12,500 granted 2/10/2009 exercise price $9.10; 1,500 granted 5/20/2009 exercise price $9.50; 12,500 granted 5/20/2009 exercise price $9.50; 1,500 granted 5/19/2010 exercise price $4.80; 1,500 granted 5/12/2011 exercise price $5.10. This total also accounts for 2,000 options that expired on May 16, 2011. /s/ Gerard L. Conway, Jr., Attorney in Fact 2011-06-02