Our way of life requires almost three times as much energy as was needed by our parents' and grandparents' generations. Today's energy supply is still based on the use of fossil fuels. The consequence of this is the emission of sulphur compounds, various particles and carbon dioxide into the atmosphere. Emissions cause climate change, air pollution and also problems with water. It is therefore essential that we switch to renewable energy sources. New technologies mean that we can already obtain energy relatively cheaply not only from hydropower and biomass but also from the wind and the sun and from geothermal energy.