The abundant higher-elevation sunshine of Pueblo has resulted in another major solar farm. Xcel Energy and Lightsource bp have announced the development of a 298-megawatt project to be called Sun Mountain Solar.
San Francisco-based Lightsource bp—the renewable energy partner of British Petroleum—will finance, build, own, and operate the facility and deliver the solar energy it generates to Xcel Energy under a long-term power purchase agreement. Construction of the project is expected to begin before the end of 2021.
This comes just as Lightsource bp wraps up work on a slightly larger, 300-megawatt solar farm called Bighorn Solar. That solar farm is located on 5,000 acres of land owned by Evraz, the owner of the steel mill that has been at the core of Pueblo’s economy for 140 years. It’s the largest behind-the-meter solar project in the country. It allows Evraz to claim to be the only solar-powered steel mill in the world.
With these two projects, Lightsource bp will have made a cumulative investment of $500 million in Colorado. Both are within the city of Pueblo and will contribute $48 million in property tax payments to Pueblo over their lifespan.
The Pueblo area has a solar resource that ranks 8 or 9 on a scale of 10, Kevin Smith, the chief executive of Lightsource bp, Americas, said at a recent ceremony marking the near completion of the solar project for the steel mill.
The new project will create 300 jobs during construction, which Lightsource expects to be filled mostly by locals.
“This collaboration is a win for Pueblo and for the State of Colorado and demonstrates our commitment to the communities as we lead the energy transition. We will continue to explore new and innovative projects that benefit our customers,” said Alice Jackson, president of Xcel Energy’s Colorado division.

Kevin Smith, chief executive of solar developer Lightsource bp, talks with Mike Kruger, chief executive of Colorado Solar and Storage Association, at an Oct. 13 celebration of the Bighorn Solar project. Above, Bighorn Solar panels and the Comanche Generating Station in the background. Photos/Allen Best
For Xcel, the solar farm will help replace power generation lost by the retirement of Comanche 1 and 2 in 2022 and 2025 respectively. The two coal plants being retired in the next several years together have 779-megawatt generating capacity. The two big solar farms will together deliver 598 megawatts of generating capacity – when the sun is out. Other solar projects are also being built in Pueblo County along with wind farms farther to the east, and storage is being added to the mix near Pueblo and metro Denver.
Looming before Pueblo but also Xcel and state regulators is when Comanche 3 will be retired. Xcel wants to retire it in 2040 while operating it at only a third capacity. Environmental advocates have been calling for a retirement of between 2027 and 2035.
In filings with state regulators, Pueblo County calls for Comanche 3 to remain in operation until 2040 or for Xcel and its minor partners—Holy Cross Energy and Core Electrical Cooperative—to pay the taxes in lieu. But Pueblo County also supports converting the coal plant to a nuclear plant, to ensure the property tax base.
About 200 people attended a hearing before PUC commissioners held in Pueblo on Oct. 28. A majority of the 40-plus people who testified called for Comanche 3 to be closed early and opposed construction of a nuclear power plant.
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