A $285-million solar energy project will provide most of the power for a major Colorado steel mill, allowing it to produce what it says will be “some of the world’s greenest steel.”

Lightsource BP’s 300-MW Bighorn Solar project, which includes more than 750,000 solar panels, was built on 1,800 acres of land at EVRAZ North America’s Rocky Mountain Steel property in Pueblo in collaboration with utility company Xcel Energy. 

It is the largest U.S. on-site solar power dedicated to a single customer, according to BP, which owns a 50% stake in Lightsource BP.  Bighorn’s capacity may even catapult EVRAZ into the top-10 companies in the U.S. for installed solar capacity, comparing it to those ranked in the Solar Energy Industries Association's latest Solar Means Business Report.

For comparison, Apple is the largest corporate user of on-site solar power, with an installed capacity of nearly 400 MW, according to the ranking, but that is spread across multiple facilities.

In July, EVRAZ broke ground on a $500-million long rail mill expansion of the Pueblo facility that it says will use the site’s solar power. During a press conference at the time, company leaders said the expansion would allow it to better compete with foreign suppliers, since the new long-rail plant will allow the firm to produce steel lengths that are currently only available from overseas producers.

The plant also will improve safety. In May, the facility’s steelworkers’ union local said eight people were treated at a hospital following an explosion.

Bighorn Solar is currently generating electricity, and Lightsource BP expects it to come fully online in November. Lightsource BP is the owner and operator of Bighorn Solar. Xcel Energy will buy the electricity the project generates, and EVRAZ will get fixed-rate energy for 20 years.

“As each new acre of solar panels is installed, we find ourselves closer to our goal of making EVRAZ in Pueblo one of the greenest steel facilities in the world,” Skip Herald, CEO of EVRAZ North America, said in a statement.

EVRAZ is Xcel Energy’s largest retail electric customer in Colorado. Xcel says this project allows it to abate 433,700 metric tons of carbon emissions per year, the equivalent of 92,100 fuel-burning cars.

The solar project is just one component of the facility’s efforts to reduce its environmental impacts. The Rocky Mountain Steel facility, which employs about 1,000 workers, captures nearly all the dust its furnace produces and repurposes it for products such as fertilizer and rubber tires. EVRAZ also recycles scrap metal to use in new steel products. It melts the equivalent of more than 1-million cars each year using an electric arc furnace.

The project complements the Colorado government’s efforts to deliver 55% renewable energy to the grid by 2026 and to reduce carbon emissions by 60%, according to Xcel. The state’s Economic Development Commission approved tax credits of more than $2.8 million to EVRAZ for its expansion.

“The Pueblo plant expansion project embodies the thoughtful and innovative economic advancements that Governor [Jared] Polis champions for a sustainable Colorado,” Betsy Markey, executive director of the Colorado Office of Economic Development and International Trade, said in a statement after EVRAZ announced the expansion plans.

EVRAZ is not the only steelmaker looking to lower its carbon footprint. As ENR previously reported, Nucor Corp. on Oct. 5 announced a new line of net-zero steel products called Econiq, using carbon offsets.

There's potential that other steel producers could find cost-savings through similar solar projects. Energy use accounts for as much as 20-40% of the cost of steel production, according to the World Steel Association. The majority of steel production in the U.S. today—about 70%—comes from electric arc furnaces, which can draw more power from electricity than blast furnaces can, according to the American Iron and Steel Institute.

Kevin Smith, CEO of Lightsource BP, said in a statement that the Bighorn Solar project shows that even hard-to-abate sectors like steel can be decarbonized. “It’s a great example of partners tackling complex issues that U.S. industry is facing today, while at the same time preserving jobs in the manufacturing sector,” he said.

Beyond steel, more businesses have been investing in solar power. On-site solar accounted for just 0.9% of commercial electricity sales in 2020, but that figure was up steadily from about 0.1% in 2011, according to SEIA.