Promises and realities of renewable energies

By focussing on electricity production, the author proposes an analysis of renewable energies (wind, solar, hydraulic, biomass, geothermal) as part of sustainable development, and tries to clarify their role within the energy mix. The first part addressed hydraulic energy: present hydroelectric installations, hydraulic energy in Europe, marine renewable energy projects concerning tidal, wave, sea current, thermal, or salinity gradient osmotic energy. The second part addresses wind energy: general presentation, first steps of development, operation description, status of development in Europe and in the world. The third part addresses solar energy: contribution of solar radiation on the Earth, photovoltaic solar electricity production, thermal solar power plant. The fourth part addresses biomass and geothermal energy. The last part discusses the role of renewable energies within the current context: with respect to sustainable development and to other primary energies (fossil and nuclear energy)