Presently the bulk of the world's power is provided from fossil fuels. Reserves of fossil fuels are decreasing and will soon be insufficient to support growing energy needs. The most likely replacement for fossil fuels will be nuclear power which already has a significant infrastructure in developed nations. While nuclear power is the most obvious solution, many nations will be turning to other sources such as hydroelectric and geothermal power for their energy needs. Most likely the energy situation in the future will be a combination of nuclear, solar, hydroelectric and other resources, some of which only marginally developed at the present time. So while nuclear power is likely to be the most significant power source of the near future, it is not the only viable power source that will be seen in that future.