X0306 4 2020-08-19 0 0001093691 PLUG POWER INC PLUG 0001431827 Marsh Andrew C/O PLUG POWER INC. 968 ALBANY SHAKER ROAD LATHAM NY 12110 1 1 0 0 President & CEO Plug Power Common Stock 2020-08-19 4 M 0 216667 A 321079 D Plug Power Common Stock 2020-08-19 4 F 0 104369 13.65 D 216710 D Plug Power Common Stock 2020-08-28 4 M 0 166666 A 383376 D Plug Power Common Stock 2020-08-28 4 F 0 80284 13.07 D 303092 D Plug Power Common Stock 2020-08-28 4 M 0 166666 1.96 A 469758 D Plug Power Common Stock 2020-08-28 4 S 0 166666 12.9512 D 303092 D Plug Power Common Stock 2020-08-31 4 S 0 104412 12.9765 D 198680 D Restricted Stock Unit 2020-08-19 4 M 0 216667 0 D Common Stock 216667 433333 D Restricted Stock Unit 2020-08-28 4 M 0 166666 0 D Common Stock 166666 166667 D Stock Option (Right to Buy) 1.96 2020-08-28 4 M 0 166666 0 D 2028-08-28 Common Stock 166666 166667 D Each restricted stock unit is the equivalent of one share of Plug Power Inc. common stock. Tendered to Issuer to satisfy tax withholding obligations of the Reporting Person incurred in connection with the vesting of the Reporting Person's restricted stock unit awards. Shares sold pursuant to a pre-established 10b5-1 trading plan effective as of March 17, 2020. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $12.71 to $13.12, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $12.77 to $13.29, inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range. On August 19, 2019, the Reporting Person was granted 650,000 restricted stock units, vesting in three substantially equal annual installments beginning on the first anniversary of the grant date. On August 28, 2018, the Reporting Person was granted 500,000 restricted stock units, vesting in three substantially equal annual installments beginning on the first anniversary of the grant date. On August 28, 2018, the Reporting Person was granted 500,000 stock options, vesting in three substantially equal annual installments beginning on the first anniversary of the grant date. /s/ Gerard L. Conway, Jr., Attorney-in-Fact 2020-09-01