The US Department of Energy wants to increase the number of commercial properties with solar panels on their roofs. The federal agency has requested ideas from the public on how businesses can use their rooftops more efficiently to generate energy. A statement from the DOE said “Areas of key interest center on technical, economic, administrative, and legal barriers and opportunities to reduce costs of capital, lower operational risks, protect consumers, and increase efficient market activities.” The Solar Industries Energy Association reports that big-box retailers have made significant progress in deploying rooftop solar systems in recent years. Wal-Mart leads the retail sector as the company’s stores produced 105 megawatts of power last year. Target recently announced plans to have rooftop solar projects on up to 30 stores in North Carolina by the end of this year. The company is working towards 500 stores nationwide employing rooftop solar panels by 2020. [BIZ]