The French food retailer Casino Group, and its renewable energy subsidiary GreenYellow, have signed another deal with SunPower Corporation (NASDAQ:SPWRA, SPWRB) to buy 20 megawatts (MW) of solar panels from the San Jose, California-based manufacturer. According to the press release, the panels in question are SunPower’s E19 solar panels, which are said to offer a world record efficiency of 19 percent.

The panels, which are due to be installed atop Casino Group buildings by the end of 2011, will turn previously under-used roof space into clean energy. The deal brings to 35 MW the cumulative capacity of Casino Group’s solar installations, which include a 15 MW deal inked with SunPower one year ago. All told, Casino Group will have photovoltaic (PV) solar installations at 18 separate company properties, on rooftops and parking lots.

Howard Wenger, President of Utility and Power Plants for SunPower, had the following to say about the deal:

“We are delighted to partner with Casino to further expand their use of solar power in France, increasing their total commitment to more than 35 megawatts. We are confident that, with SunPower’s proven performance and reliability, Casino and GreenYellow will continue to achieve considerable return on investment over the 25-to-30-year lifetime of the solar panels.”

See SunPower’s GetSolar profile.