Solar systems on the roof at Tripolia Hospital, Patna. In the foreground are solar thermal hot water heaters, which the hospital uses to create hot water for bathing patients and preparing medicines. In the background is a system that produces steam using the reflected heat of the sun, with which the hospital sterilises all its medical equipment and laundry. Elsewhere, the hospital also has photovoltaic systems, which produce electricity from the sun's energy and power lights and fans and computers. The various solar systems cater for the 200 staff who live on campus, as well as up to 250 inpatients, in combination with electricity from the grid and diesel back up generators.