Exelon Corp. (EXC) and SunPower Corp. (SPWRA) said Wednesday that the companies will develop the largest urban solar power plant in the U.S. at a former industrial site on Chicago's South Side.

The Exelon deal comes as several utilities expand their solar energy portfolios in an effort to meet state renewable energy requirements and prepare for an expected federal limit on carbon dioxide emissions from power plants that run on fossil fuels. Public Service Electric & Gas Co. (PEG) said in February that it would spend $800 million over the next five years on solar power projects in New Jersey.

The 10-megawatt Exelon plant, scheduled for completion by the end of this year, is contingent on Exelon receiving a loan guarantee under recently passed federal economic stimulus legislation. Exelon is seeking a loan for up to 80% of the project cost, which the company estimates to be about $60 million.

Exelon is "always considering renewables as a way to add low-carbon electricity to the marketplace," Exelon spokesman Paul Elsberg said. He declined to say whether the company has other solar projects in the pipeline.

Chicago-based Exelon will own and operate the plant and market the Solar Renewable Energy Certificates it generates. The certificates are credits for producing a kilowatt-hour of energy from solar power, and can be sold to utilities and other power generators to help them meet state renewable energy requirements.

SunPower, a San Jose, Calif.-based solar panel manufacturer, will design, produce and install the solar plant. The plant will generate enough power to meet the annual energy requirements of about 1,200 to 1,500 homes and will displace about 31.2 million pounds of greenhouse gas emissions annually, Exelon and SunPower said.

-By Christine Buurma, Dow Jones Newswires; 201-938-2061; christine.buurma@dowjones.com