Solar cell energy, one of alternative energy. Their source is solar which mean will be unlimited energy resource. This kind of energy using Photovoltaic or generally called Solar Cell’s panel. This equipment changes solar become electric power with Positive and negative electron flow inside of the panel with their differentiation of electron,   results of electron flow is DC electric which fullfil battery. Problem using this kind of energy is their price. Their equipment not so easy to produce and their size too large. But i think it still good enough to starts save our environment. And the main reason is solar cell is free and unlimited energy resource.