Washington, D.C. – November 19, 2025 – The Sierra Club has filed a legal challenge against the Federal Energy Regulatory Commission (FERC), contesting its decision to fast-track the interconnection of fossil fuel power plants to major U.S. electric grids, a move the environmental group says comes at the expense of renewable energy development. The challenge was filed with the D.C. Circuit Court of Appeals.

FERC approved the Southwest Power Pool (SPP), a grid operator spanning 14 states from North Dakota to Louisiana, to expedite fossil fuel project connections. The SPP grid, which is heavily dominated by wind energy, has seen wind account for 38% of its energy production, followed by natural gas at 28%. FERC cited surging electricity demand—particularly from artificial intelligence-powered data centers—as a reason for accelerating fossil fuel interconnections.

“FERC’s approval of SPP and MISO’s line-cutting proposals will only add to the disruption that has prevented hundreds of gigawatts of clean energy from coming online to serve projected resource needs,” said Greg Wannier, senior attorney at the Sierra Club.

Background on the Legal Challenge

The Sierra Club initially challenged the SPP proposal before FERC, but the agency denied the request. A rehearing petition was also rejected in September. In addition, the environmental group filed a similar lawsuit against FERC’s Midcontinent Independent System Operator (MISO) approval of fast-tracking fossil fuel projects in the Midwest.

The legal actions aim to ensure that renewable energy projects, including wind and solar, are not sidelined in favor of fossil fuel plants, particularly as the U.S. seeks to accelerate clean energy deployment to meet climate and electricity demand goals.

Implications for the U.S. Energy Grid

The Sierra Club’s lawsuits highlight ongoing tensions between fossil fuel interests and the renewable energy sector. Grid operators argue that fast-tracking fossil fuel interconnections is necessary to maintain grid reliability and meet short-term electricity demand. However, critics say the prioritization of fossil fuels threatens decarbonization efforts and slows progress toward net-zero energy goals.

As renewable energy capacity continues to expand across U.S. grids, legal and regulatory battles like this will play a pivotal role in shaping which energy sources dominate the country’s electricity mix in the coming decades.