the energy sector uses to gather threat intelligence. Advanced Grid in Colorado In 2016, Xcel Energy announced the Advanced Grid Intelligence and Security (AGIS) initiative, a long-term effort related to power reliability, distributed generation, and information sharing with customers. Through the initiative, Xcel would build an "intelligent grid" in Colorado in order to improve grid security. The company filed a request for permission with the Colorado Public Utilities Commission for the program, which would cost $500 million. Programs Since 1998, Xcel Energy's Windsource program has allowed customers to designate that part or all of their electricity comes from a renewable energy source. In 2015, about 96,000 people were enrolled in Windsource. In 2011, more than 2.3 million electric and 261,800 natural gas customers took part in Xcel Energy's energy efficiency programs for homes and businesses. Xcel Energy also offers customers incentives to install solar panels. At the end of 2011, more than 10,600 photovoltaic systems had been installed, with a capacity of about 121 megawatts (DC). In early 2011, Xcel Energy suspended the solar rebate program before reaching a settlement a month later with representatives of solar power companies to restore the solar incentive program until it is fully reviewed by the Public Utilities Commission. Controversies On August 1, 2002, Xcel Energy Inc. was sued because of engaging in "round-trip" energy trades that provided no economic benefit for the company, and because the company lacked the necessary internal controls to adequately monitor the trading of its power. Xcel paid $80,000,000 in a settlement. The Cabin Creek Fire occurred on October 2, 2007, at Xcel Energy's Hydropower Generation plant in Georgetown, Colorado. On June 1, 2011, Federal prosecutors opened their charges that Xcel Energy was criminally liable for the deaths of the five RPI workers. On June 28, the jury found Xcel Energy not guilty. On December 19, 2011, RPI Coating pleaded guilty to workplace safety violations and paid $1.55 million in a cash settlement. The company took responsibility for the deaths of five workers and the injuries to three. The U.S. Chemical Safety and Hazard Investigation Board conducted an investigation of the incident. Its report can be found on the CSB website. It is considered one of the worst unmitigated incidents to occur in a permit-required confined space. The parent company to Xcel Energy, and later Xcel Energy itself have operated the Prairie Island Nuclear Power Plant since 1973. Over