Sign up for daily news updates from CleanTechnica on email. Or follow us on Google News!. Say rooftop solar and most people assume you are talking about putting solar panels on the roof of a private home. But there are thousands of acres of rooftops on commercial buildings and above parking lots that are just perfect for solar energy systems. The beauty part is that using those roofs to generate solar power turns the owners of those properties into prosumers – people who both produce and consume their own locally generated electricity. Part of the reason the idea is becoming more popular is because it allows commercial customers to predict with a high degree of accuracy precisely what electricity will cost them for decades to come. In addition, the cost of solar continues to fall, while state and local incentives often provide a sweetener.