A useful reactor of this kind has yet to be developed. Irradiated uranium fuel from commercial nuclear power plants is among the most dangerous radioactive wastes. 30 tons of this stuff is discharged annually from one reactor alone. Total waste generation from all nuclear reactors operating worldwide will exceed 450,00 tons before the middle of the next century. Nuclear energy will gain importance as fossil fuels become more expensive and alternative energy sources are not developed, but without proper waste disposal methods, the costs far outweigh the benefits.
Solar energy is our most important constant energy source.
Solar energy is harnessed and concentrated into panels, converted into electricity, and distributed. This process, though environmentally sound, is quite expensive. Generating 1,000 gigawatt-hours of electricity per year, for example, requires 100 workers in a nuclear power plant, but 248 in a solar thermal facility. Solar powererd cars like these compete in the Winston Solar Challenge race. Biomass Biomass is the energy obtained by using plants and plant products, such as paper, wood, and charcoal as fuel.