Renewable Energies are all possibilities of almost endless resources, as solar and wind energy, waterpower, tidal and wave energy, biomass, heat and cold from air or the upper earth-layers. Furthermore geothermal energy can be used. The Earth is circling around the Sun with an average distance of 150 million km. Hereby the solar radiation that comes on Earth is in average around 1.367 W/m². In Germany on a clear summer day it is around 1.000 W/m². The average of a year in Germany is around 110 W/m², that is around 1000 kWh/m². Such figures are used to project solar energy plants. The solar radiation is also driving the wind energy potentials.

For example, while the solar energy can only be directly used in the day time, wind energy is also possible at night. In the time when the sun doesn’t shine and no wind blows, stored renewable energy in electric batteries could be used. Such kind of concepts should be preferred wherever possible, building decentralized-energy-systems instead of large-scale-power plants and electric transportation over hundreds or thousands of kilometers.