Amazon says it will spend $20 billion on two data center complexes in Pennsylvania, including one it is building alongside a nuclear power plant that has drawn federal scrutiny.

Talen Energy (NASDAQ:TLN) +9.7% pre-market Wednesday after saying it has expanded its nuclear energy relationship with Amazon (NASDAQ:AMZN) to provide carbon-free energy from Talen’s Susquehanna nuclear power plant in Pennsylvania to Amazon Web Services data centers in the region.

The companies signed a 17-year Power Purchase Agreement (PPA) to supply AWS with 1.92GW of energy from the 2.5GW Susquehanna nuclear power plant. The PPA is contracted until 2042 and contains an option to extend. The delivery of the power is expected to be ramped up over the next seven years, with full volume anticipated no later than 2032.