CHEYENNE, Wyo. (AP) — The first major solar energy plant in the nation's top coal-mining state cleared a significant regulatory hurdle Tuesday when the U.S. Bureau of Land Management determined it will cause no environmental harm.

As a result, the Sweetwater Solar LLC plant could begin producing electricity by the end of the year on BLM land outside Green River in western Wyoming.

BLM officials made the determination after completing a study required by federal law.

The BLM did not return a call seeking information on when construction might begin on the plant expected to generate 80 megawatts of electricity, enough for about 17,000 homes.

The plan calls for as many as 250,000 solar panels, each measuring about 6 by 3 feet (2 by 1 meters), and other equipment to span more than a square mile (2.5 square kilometers) of remote high desert.

Wyoming gets plenty of sunshine but has no large commercial solar facilities.

Around 40 percent of coal mined in the U.S. comes from Wyoming and 85 percent of all electricity generated in Wyoming comes from coal-fired power plants.

Rocky Mountain Power, a subsidiary of Portland, Oregon-based PacifiCorp, has agreed to buy the new solar plant's electricity.

The utility chooses its power sources based on affordability for customers, said Rocky Mountain Power spokesman Dave Eskelsen.

"Renewable energy — particularly solar and wind power — have been increasingly attractive. Wind particularly, since 2005-2006," Eskelsen said.

Rocky Mountain Power in recent years has added to its portfolio about 1,800 megawatts of wind power and plans 850 megawatts of solar, with much of the solar already installed in Utah.

Sweetwater Solar is a subsidiary of Irvine, California-based 174 Power Global. The company has told Rocky Mountain Power the plant will be online by the end of 2018, Eskelsen said.