Rosemount oil refinery considers building its own large solar farm

Flint Hills Resources is contemplating the construction of a large on-site solar farm to generate electricity for its sprawling Pine Bend oil refinery in Rosemount.

Flint Hills said Tuesday it is reviewing bids from developers for a plant that would be built just west of the refinery on 200 to 300 acres of farmland owned by the company. Flint Hills, an arm of Wichita, Kan.-based Koch Industries, will decide on whether to proceed by midyear.

"There is not really any project like this in Minnesota," said Jake Reint, spokesman for Flint Hills.

Indeed, the Flint Hills solar farm would stand out nationally, and it would be the latest effort by the refinery to significantly cut its power bill with self-generated electricity.

"We are in a highly competitive commodity business where many of our competitors pay far less for the energy required to power their operations than we do," Geoff Glasrud, Flint Hills' plant manager, said in a statement.

Flint Hills is one of the Midwest's largest oil refineries with a production capacity of 345,000 barrels per day. It supplies more than half of the motor fuel sold in Minnesota and around 40% of it in Wisconsin.

The refinery's solar farm could produce up to 30 megawatts of power, complementing the 50-megawatt on-site generator Flint Hills opened in 2019. That generator, part of a combined heat power system, is fueled by natural gas and waste heat and provides about 40% of the plant's electricity.

The solar plant could raise the refinery's self-generation to 50% of its electricity demand, Flint Hills said.

Refineries consume huge amounts of power, and historically Flint Hills has been one of Minneapolis-based Xcel Energy's largest customers in Minnesota.

"The self-generation element of the [Flint Hills solar] project is really cool," said David Shaffer, executive director of the Minnesota Solar Energy Industries Association, a trade group.

While companies often contract with utilities for large solar-power purchases, a big, on-site project dedicated to one company is rare, he said. "They will be able to look out at their solar panels and see their electricity demand [from Xcel] fall."

The largest on-site commercial solar plant in Minnesota can generate 3 megawatts, Shaffer said. Most commercial solar projects in Minnesota are 1 to 5 megawatts.

A megawatt is 1 million watts.

The two largest solar plants in Minnesota — both of which supply electricity to Xcel Energy — have the capacity to generate 100 megawatts and 62 megawatts when the sun is fully shining.

Two other solar plants on tap for Minnesota — one for Xcel and another for Otter Tail Power — would generate up to 80 megawatts and 50 megawatts, respectively. Xcel is also planning a massive solar farm in Becker with a capacity of at least 400 megawatts.

The Flint Hills solar plant wouldn't need approval from the Minnesota public utility regulators, though grid interconnection agreements with Xcel likely would, Reint said.

Reint declined to disclose the solar plant's estimated cost.

If it goes forward, the project would be eligible for federal investment tax credits for solar power. "Obviously, the incentives contribute to the project's economics," Reint said.

Mike Hughlett • 612-673-7003