(a) Preliminary permits.—Section 5 of the Federal Power Act (16 U.S.C. 798) is amended—

(1) in subsection (a), by striking “three” and inserting “4”; and

(2) in subsection (b)—

(A) by striking “Commission may extend the period of a preliminary permit once for not more than 2 additional years beyond the 3 years” and inserting the following: “Commission may—

“(1) extend the period of a preliminary permit once for not more than 4 additional years beyond the 4 years”;

(B) by striking the period at the end and inserting “; and”; and

(C) by adding at the end the following:

“(2) after the end of an extension period granted under paragraph (1), issue an additional permit to the permittee if the Commission determines that there are extraordinary circumstances that warrant the issuance of the additional permit.”.

(b) Time limit for construction of project works.—Section 13 of the Federal Power Act (16 U.S.C. 806) is amended in the second sentence by striking “once but not longer than two additional years” and inserting “for not more than 8 additional years,”.