This is pretty sweet – from District of Columbia Department of the Environment:
“DDOE unveils its state-of-the-art rooftop solar analysis tool, with the aim of advancing solar education and promoting rooftop solar adoption in the District. Crisp graphics and a simple but powerful interface make this new solar analysis and mapping tool a welcome addition to the District’s renewable energy toolbox. It reveals the relatively untapped solar potential of over 160,000 buildings, identifying over 2.5 gigawatts of high performance solar photovoltaic potential, or over $10 billion in potential local business. This would be enough to power the homes of 1.5 million American families while offsetting carbon emissions equivalent to planting 37.5 million trees. Explore this powerful new resource here.