The shift to clean energy promises a major change to the St. Croix River Valley later this decade when Xcel Energy's coal-fired Allen S. King Power Plant in Oak Park Heights shuts down, potentially in 2028 — a closure that would open a large tract of land with nearly a mile of riverfront for new uses.

It's not immediately clear what could end up on the site after the plant closes. Xcel will continue to have easements on the property even if it sells the land, and there are likely other height and shoreline restrictions that could prevent some types of future uses, said Oak Park Heights Mayor Mary McComber.

The 170-acre site, including its 4,500 feet of riverfront, falls within the protections of the federal Wild and Scenic Rivers Act. Understanding how those restrictions and protections will guide future land use is one of the primary goals of an Oak Park Heights City Council advisory panel formed this summer. The group expects to hold its first meeting next month as it begins an intensive yearlong study of the King site.

Members include local citizens; city officials from Oak Park Heights, Bayport and Stillwater; business leaders and environmentalists, and representatives from Xcel, the state Natural Resources and Transportation departments, and the National Park Service.

The 511-megawatt King plant, built in 1968, will close in 2028 pending approval by the Public Utilities Commission. But Oak Park Heights is eager to get started now on long-term planning for the site, said McComber.

"2028 seems like a long way away, but it's really not," she said.

Even if the plant does shutter in 2028, it could be much longer before everything gets removed from the site, including the soaring smokestack visible up and down the river valley, McComber said.

The plant's closure also carries with it some peril for Oak Park Heights. The plant is the city's largest taxpayer by far, with annual collections making up about 39% of the tax base, the mayor said. There's no future use of the King site that could fully make up for the lost revenue, she said, and the city has begun exploring ways to mitigate some of it.

This year's federal census could hold at least a small bonus for Oak Park Heights. If the 2020 count finds more than 5,000 people living there, the city will be eligible for some state road funds that it hasn't gotten before, McComber said. The city's population was 4,339 in 2010.

Closing the King plant is part of Xcel's transition to clean energy, a move that sets the utility on course to deliver 100% carbon-free electricity by 2050. All coal plants in the region will be shut down by 2030, according to Xcel spokesman Randy Fordice.

Xcel's transition includes investment in low-cost renewable energy and the continued operation of nuclear plants, which don't produce carbon pollution. The utility plans to use natural gas "to provide reliability and integrate the increasing amount of renewable energy we're adding," Fordice said.

Xcel will work with Oak Park Heights to plan for the transition, he said, as the utility has done with other communities that saw the closure of large power plants, such as the Sherco plant in Becker, Minn.