Green powers for cars

According to studies, car exhaust are found to be one main cause for global warming. Since cars' invention, they bring us amazing transportation convenience. Now they need a change. Some new green power are being developed, like solar batteries and less polluted chemical powers. Solar power, in the form of battery, is used as engine power in some cars. So far, it is seen as most safe power which does not send harmful substances to the air or contribute to climate change. The problem is that car batteries are more expensive than gas. However, we will never stop striving for transportation efficiency as well as environmental adaptation.