Federal regulators rejected a request to boost electrical output from a Pennsylvania nuclear power plant to an Amazon data center, prompting a dip in some energy company stocks Monday.

The Federal Energy Regulatory Commission voted 2-1 Friday against an agreement that would have increased the amount of electricity coming from Talen Energy's Susquehanna nuclear facility from 300 megawatts to 480 megawatts.

Republican Commissioners Mark Christie and Lindsay See voted against the deal while Democratic Commissioner voted for it, according to the Hill. Two other Democratic commissioners, David Rosner and Judy Chang, abstained.

In a statement, Christie said, "Co-location arrangements of the type presented here present an array of complicated, nuanced and multifaceted issues, which collectively could have huge ramifications for both grid reliability and consumer costs."

Talen said Sunday that it "believes FERC erred and we are evaluating our options, with a focus on commercial solutions" and it warned that "FERC's decision will have a chilling effect on economic development in states such as Pennsylvania, Ohio, and New Jersey."

In a statement posted its website, the company also said that development of the Amazon Web Services data center "can proceed using those 300 megawatts" while it seeks approval to increase the output.

Talen sold the 960-megawatt data center for $650 million in March.

The data center is located next to the Susquehanna plant, which is the sixth-largest in the U.S. and can generate 2,475 megawatts, enough to power about 2 million homes, according to Talen.

On Monday, Talen stock closed at $170 a share, down 2.2%.

Shares in Constellation Energy and Vistra Corp., which are expected to announce deals similar to Talen's with Amazon, also fell more than 12% and about 3%, respectively, according to CNBC.

Constellation's price plunge marked the company's worst day of trading since it was spun off from Exelon in February 2022, CNBC said.