JOINT FILING AGREEMENT
Exhibit 1
Each of the undersigned hereby agrees that this statement on Schedule 13D is being filed with the Securities and Exchange Commission on behalf of each of the undersigned pursuant to Rule 13d-1(k) promulgated under the Securities Exchange Act of 1934, as amended.
Dated: December 23, 2011
| TOTAL S.A. | ||
| By: | /s/ Xxxxxx Xxxxxxx | |
| Name: Xxxxxx Xxxxxxx | ||
| Title: Treasurer | ||
| TOTAL GAS & POWER USA, SAS | ||
| By: | /s/ Xxxxxx Xxxxxxxx | |
| Name: Xxxxxx Xxxxxxxx | ||
| Title: Chairman | ||
