Exhibit 99.1
Filer: MMC Norilsk Nickel
Address: 22, Voznesensky Pereulok, Moscow, 125009, Russia
Relationship of Reporting Person to Issuer: 10% owner
Explanation of Response:
This Form 4 is being filed by MMC Norilsk Nickel (Norilsk Nickel) to disclose that it no longer owns a direct interest in OJSC Third Generation Company of the Wholesale Electricity Market (OGK-3), a former subsidiary of Norilsk Nickel, and therefore is not a beneficial owner of the 44,626,939 shares of common stock, par value $0.01 per share, of Plug Power Inc. held by OGK-3. CJSC INTER RAO Capital acquired 65.16% of the outstanding shares of OGK-3 from Norilsk Nickel on March 18, 2011 and 14.08% of the outstanding shares of OGK-3 shares from JSC Intergeneration, a subsidiary of Norilsk Nickel (9.58% on March 18, 2011 and 4.5% on March 22, 2011). As of March 22, 2011, Norilsk Nickel and its subsidiaries no longer own a direct interest in OGK-3.