AGREEMENT RELATING TO JOINT FILING OF SCHEDULE 13D

EXHIBIT K

AGREEMENT RELATING TO JOINT FILING OF SCHEDULE 13D

     The undersigned hereby agree that a joint statement on Schedule 13D be filed on behalf of all of the undersigned with respect to the securities of Plug Power Inc.

Date: April 20, 2006

		SMART HYDROGEN INC.
		By:		/s/ Xxxxxx Xxxxxxxxxx
		Name:		Xxxxxx Xxxxxxxxxx
		Title:		Director
		MMC NORILSK NICKEL
		By:		/s/ Xxxxxxx X. Xxxxxxxxx
		Name:		Xxxxxxx X. Xxxxxxxxx
		Title:		CEO and Chairman of the Management Board
		XXXXXXXX DEVELOPMENT INC.
		By:		/s/ Xxxxxx Xxxxxxx
		Name:		Xxxxxx Xxxxxxx
		Title:		Attorney-in-Fact
		XXXXXXX LIMITED
		By:		/s/ Xxxxx Xxxxxxxxxxxx
		Name:		Xxxxx Xxxxxxxxxxxx
		Title:		Director

		XXXXXXX X. XXXXXXXXX
		By:		/s/ Xxxxxxx X. Xxxxxxxxx
		Name:		Xxxxxxx X. Xxxxxxxxx
		XXXXXXXX X. XXXXXXX
		By:		/s/ Xxxxxxxx X. Xxxxxxx
		Name:		Xxxxxxxx X. Xxxxxxx