Electrical energy can be created if a magnet passes close to a metal wire. This is the method used by a generator. The biggest generators are in power stations. Electrical energy can also be released by combining chemicals in a jar with two different kinds of metal rods. This is the method used in a battery. Static electricity can be created through the friction between two materials - for instance a wool cap and a plastic ruler. This may make a spark. Electrical energy can also be created using energy from the sun, as in photovoltaic cells. 