Answer: Solar Energy
Solar energy is the best natural energy resource. There are several reasons behind this. First of all, there are two ways to extract energy from the sun. Photovotalic energy and thermal energy. PV is great for places that get a lot of direct sunlight, but geographic regions that expereience less sunlight can still use an collect thermal heat. In general, the sun has an extreme amount of energy, and by collecting it, we benefit greatly.
Right now, the major downside to solar energy is that great amounts are produced during the day time, but none during the night. Unfortuantely, we don't have strong enough batteries to save all of the energy that we collect from the sun during the day to use during the night. Therefore, the daytime energy is forced to be dumped while the energy at night has to be produced in a different way. Therefore, while solar energy is one of the best optionss we have right now, better batteries could make it even better.