In this article, comparing four renewable energy sources shows 70% of the electricity generated by the four to come from geothermal with only 42% of the total installed capacity. Wind energy contributes 27% of the electricity, but has 52% of the installed capacity. Solar energy produces 2% of the electricity and tidal energy 1%. Biomass constitutes 93% of the total direct heat production from renewables, geothermal 5%, and solar heating 2%. Conventional fossil energy will not be enough to meet the continuously increasing need for energy in the future. In this case, renewable energy sources will become important. Alternative energy sources are increasing need for energy in the future.