First Solar Inc. (FSLR), the world’s largest maker of thin-film solar panels, may sell electricity at a lower rate than new coal plants earn, according to a regulatory filing from a project it purchased in New Mexico.

El Paso Electric Co. (EE) agreed to buy power from First Solar’s the 50-megawatt Macho Springs project for 5.79 cents a kilowatt- hour, according to a Jan. 22 procedural order from the New Mexico Public Regulation Commission. That’s less than half the 12.8 cents a kilowatt-hour for power from typical new coal plants, according to models compiled by Bloomberg.

First Solar, which said in a statement yesterday that it bought the Macho Springs project from Element Power Solar, didn’t disclose any of the state and federal incentives that will boost the company’s revenue from the project.

The Macho Springs rate would be “the lowest solar power purchase agreement price we have ever seen,” Aaron Chew, an analyst at Maxim Group LLC in New York, said in an e-mail. It’s less than half the rate that First Solar will get for its Antelope Valley, Topaz, and Agua Caliente projects, he said.

Federal and state incentives will probably supplement First Solar’s revenue from the project. That support includes a 30 percent federal business energy investment tax credit, according to Anthony Kim, an analyst for Bloomberg New Energy Finance said today in an interview.

Incentives vary widely by location and aren’t included in the London-based research company’s levelized pricing models.

“When you add in the incentives, the PPA value becomes more comparable to rates we’ve seen signed in California,” said Kim.

El Paso Electric must submit additional information by today on how renewable-energy credits related to the project may affect the utility’s costs.

Alan Bernheimer, a spokesman for Tempe, Arizona-based First Solar, wouldn’t confirm the rate in the regulatory filing. “That information is usually confidential,” he said.