A photovoltaic stand-alone system run by the Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany, takes care of irrigating a wheat field in Wadi El Natrun, Upper Egypt. Concentrator photovoltaic system (CPV) modules – which, due to their higher degree of effectiveness and their particular construction, require far less space than traditional PV modules – supply the energy, while Fresnel lenses concentrate the rays of the sun onto pinhead-sized multi-junction solar cells. With the aid of a tracking motor, the CPV cells follow the sun precisely to achieve an optimized yield of solar light. They supply the energy for a submersible pump that pumps the water up from a well, for a small desalination unit that satisfies farmers’ potable water requirements, the energy for PV-module trackers, the monitoring and control system, and an air-conditioning unit that cools the utility room of the facility.

By immediately using the largest share of the energy that is generated, expensive storage media capacities are not needed. A sophisticated energy management system monitors the generation of energy and ensures that it immediately goes where it is needed at the moment. Only some of the energy is stored in a relatively small battery to operate the CPV tracker and the measuring system.

^{© Fraunhofer ISE}

• Fraunhofer Institute for Solar Energy Systems ISE, Freiburg, Germany