Making the most of it

There are two main kinds of solar energy - solar photovoltaic (PV) and concentrating solar power (CSP). PV directly converts solar energy into electricity using a PV cell made of a semiconductor material, while CSP devices concentrate energy from the sun's rays to heat a receiver to high temperatures. This heat is transformed first into mechanical energy (by turbines or other engines) and then into electricity - solar thermal electricity (STE). Over the period 2000 11, solar PV was the fastest growing renewable power technology worldwide. Cumulative installed capacity of solar PV reached roughly 65GW at the end of 2011, up from only 1.5GW in 2000. In 2011, Germany and Italy accounted for over half the global cumulative capacity, followed by Japan, Spain, the United States and China. In its SunShot strategy the US Department of Energy predicts that when the price of solar electricity reaches about $0.06 per kilowatt-hour over its lifetime, it will be cost-competitive with other non-renewable forms of electricity. This in turn will enable solar-generated power to grow. The drive to reduce costs encompasses the entire value chain from the efficiency of individual cells to manufacturing costs as well as complimentary technologies such as energy storage and effective planning.