5. Nuclear: Perhaps the most controversial form of renewable energy is nuclear energy. Electricity is produced from the energy released by nuclear reactions. While fission (splitting) is the main source used today, interest continues in developing cold fusion. Currently, though, power plants generating power using nuclear fission are among the safest plants. They also generate power without emitting pollution. In Europe, France benefits greatly as its nuclear energy produces the cheapest electricity (according to 60 Minutes).