The system used to clean subway cars at the Coney Island Maintenance Facility in New York City is not your typical solar hot water heater. The roof-mounted system, which works even on cold and cloudy days, heats the water up to 140 degrees. The hot water is then used to power wash subway cars. Each month, this solar system heats almost 60,000 gallons of water. While the system only prevents 84 tons of carbon emissions, it will be used as a stepping-stone to other projects in the future.

Photo: Otto Yamamoto/Flickr