At the structure's top, a 4,000-watt wind turbine and 6,500-watt photovoltaic array offers lessons about renewable energy.  Photo 5 of 10 in Sustainability Treehouse by Diana Budds

Sustainability Treehouse

5 of 10

At the structure's top, a 4,000-watt wind turbine and 6,500-watt photovoltaic array offers lessons about renewable energy.