Considerable research and investment has gone into trying to develop alternative sources of energy, such as solar and hydroelectric power, tidal, wave and wind energy, and biomass fuel, But the drawback with all of them (with the possible exception of solar power) is that they are just tinkering with the problem. They are not capable of producing sufficiently large quantities to meet the whole of the world’s existing energy needs, let alone the much larger amounts of electricity that will be needed as economic development progresses in the catch-up countries. They may, together with improvements in energy conservation, represent a useful contribution to the overall problem, especially in the short to medium term, but they are not the ultimate solution, is too far away from being economic to be a clear candidate. This has led to a reassessment of nuclear power as an energy provider.