Actually, we could produce enough power to satisfy all of man's needs with geothermal energy. The problem is that it is not economically feasible to do so. The reason for this is the difficulty of power transmission. In attempting to transmit electricity in a wire grid system, where they exist, we have limits of a few hundred miles, before the losses due to resistance eat up so much power that the economic feasibility falls off entirely. If we tried to produce geothermal energy on a massive scale where it was not readily available to us through geyser activity and other hot spots in the earth's crust, the cost would be staggering. So, in conclusion, it is possible, but not economically feasible to do so. As a result, the worldwide percentage of required power that could be produced with geothermal would be less than ten percent, and probably closer to five percent.

It would depend on whether your region has access to it. Solar energy is a better alternative for countries like Australia, which have no geothermal activity.

Geothermal could provide 100% of mans energy needs. Currently it is not economically feasible. As we reach peak oil in about 2020 it should become more favorable.

one lighting bolt can power london for a day. imagine what we could do if we could gather 100 bolts. it would power most of britain in one storm. there are waves, win, and solar. the only reason we havn't is because the oil people buy the patents for the eco stuff then scrap them.

It depends on the location. Several nations generate a large fraction of their electricity this way (NZ,Iceland). There are many places where hot rock layers are reasonably close to the surface. +3

I think that Brian29's response is very well done. I do believe that geothermal is the answer ultimately and that with more funding and research the economic feasibility issue could be resolved. My "dream" on this matter is as follows: If only we could draw strong wire from superconducting material that would remain superconducting at normal environmental temperatures. We could then transmit electrical energy with minimal loss in transit. I feel that one of the biggest mistakes our country is making is not investing more in superconductivity research. I don't believe that we will ever be able to nullify the second law of thermodynamics but we could come close. Also - more research and experimentation should be done on hot granitic bodies underground. Even in Florida where I live one can reach granite underground if drilling deep enough. Hot granite acquiring heat from beneath it is ripe for exploitation and closed systems using water's phase changes could be employed to provide the heat that could be used to make the steam to turn turbines which, in turn, would turn the generators. In my "dream" we could make so much electrical energy that much of it could be used to disassociate the water molecule into its components (hydrogen and oxygen) and we could use the hydrogen and oxygen as fuel utilizing their proven exergonic reaction with each other! Actually, the oxygen could come from the air just as it does in our current internal combustion engines. As to depleting the heat of the earth. NO way. Heat is constantly generated within the earth's interior via nuclear reactions - mainly Alpha decay but also some beta decay.