At an emergency hearing on Tuesday, a federal judge will consider a request from conservation groups to block a transmission line from crossing a Mississippi River wildlife refuge, a project pitting environmentalist groups and clean energy advocates against each other. 

According to the conservationists — the National Wildlife Refuge Association, the Driftless Area Land Conservancy, and the Wisconsin Wildlife Federation — the line would endanger hundreds of thousands of birds, and construction went ahead without a chance for public comment. The line’s backers, though, insist that it would protect those species while expediting the country’s transition to renewable sources of energy. 

Earlier this month, the U.S. Seventh Circuit Court of Appeals lifted a decision by a district court judge that would have temporarily blocked the final phase of building the $649 million Cardinal-Hickory Creek transmission line on the Iowa-Wisconsin border. The utility companies behind the project appealed the lower court ruling that had halted their construction only two miles short of the proposed 102 miles.

Now, conservationist groups are again trying to throw a wrench in the power line. It’s the latest in a series of legal challenges that are highlighting deep divides between conservationists and clean energy developers. The epic battle matters to the future of America’s electrical grid — and to the president, whose administration has set aside $73 billion to modernize it. 

The suit takes aim at the agreement between utility companies and the U.S. Fish and Wildlife Service to swap 20 acres of the existing refuge for 36 new acres elsewhere. They say that deal violates the 1997 National Wildlife Refuge System Improvement Act, which set a protocol for determining refuge use.

“The transmission companies did not evaluate alternative crossings outside of the Refuge in their environmental impact statement,” the executive director of the Driftless Area Land Conservancy, Jennifer Filipiak, said in a statement, “and we should not set a precedent that a simple land swap is all it takes to plow through a national treasure.”

The Cardinal-Hickory Creek line would run through the Upper Mississippi River National Wildlife and Fish Refuge near Cassville, Wisconsin — home to fish and wildlife and a migratory bird flyway used by hundreds of thousands of birds annually. Yet according to the utilities, the new land “has tremendous conservation value to the Refuge,” they assert in federal fillings, “since it provides higher quality habitat and less fragmentation.”

The backers, American Transmission Company, ITC Midwest, and Dairyland Power Cooperative Inc., insist that the transmission line would improve electrical reliability in the region stretching between Iowa’s Dubuque County and Wisconsin’s Dane County. The line is promised to connect 161 solar and wind projects to the grid. It is estimated to reduce carbon annual emissions by between 150,000 and 1.1 million tons.

“Additional delays in completion greatly increase the cost burdens and delay the environmental benefits of this project,” Dairyland Power Cooperative and ITC Midwest said in a joint statement shared with the Sun. “The utilities are committed to limiting further delays.” They made clear their plans to begin construction on the acquired land on Monday, May 13, after the land exchange with  U.S. Fish and Wildlife Service was completed last week.

The other backer, American Transmission Company, already finished its segment of the line in December of 2023. “That portion of the project is providing benefits to consumers and generation facilities in the area,” a corporate spokeswoman for ATC, Jody Lau, tells the Sun. “We look forward to the full project going in service and bringing both regional and local benefits to consumers.”

The U.S. Fish and Wildlife Service declined to comment on the matter due to ongoing litigation. 

Delays and high costs are making the construction of transmission infrastructure increasingly challenging. President Biden’s climate goals are 100 percent clean electricity by 2035 and a zero-emissions economy by 2050. That requires expanding transmission systems by 60 percent by 2030 and potentially tripling those systems by 2050, according to the Department of Energy. 

Mr. Biden’s green energy plan is also facing pushback over plans to build two new lithium mines in Nevada. Critics say one proposed mine project at Rhyolite Ridge is home to rare wildlife species, while another project at the Thacker Pass borders a sacred Native American site. Environmentalists and tribal leaders are deriding the mining development plans as “greenwashing” or “green colonialism.”

Correction: A proposed lithium mine at Rhyolite Ridge in Nevada is opposed by environmental critics, while critics say another proposed mine at the Thacker Pass borders a sacred Native American site. An earlier version conflated the two projects.