Since the late 1970s, UB has been a leader in energy conservation, completing hundreds of projects designed to increase energy efficiency, leading to savings estimated to be over $100 million. Since 2003, UB has purchased 12 million kilowatt-hours of wind energy. A photovoltaic array on the roof of Norton Hall produces 73,000 kilowatt-hours of electricity annually. The UB Climate Action Initiative includes an inventory of greenhouse gas emissions and recommendations for reducing their impact. UB also uses a 120-kilowatt combined heat and power system to produce energy and heat its swimming pools.