Clean Energy USA (CEUSA) Part of the Schell Brothers family of companies is a Rehoboth Beach-based company which designs and installs solar electric power systems throughout the state of Delaware. Established in 2007, CEUSA has installed approximately 1,000 solar power systems on homes and businesses, making it the largest locally owned solar company in the state. In 2016, CEUSA expects to install over 1.3 Megawatts (1,300 kilowatts) of power.