Energy derived from sources that do not deplete the Earth’s finite and non-renewable mineral resources. Examples include geothermal energy, tidal power, wave power, wind power, solar energy, biomass, biofuels, and hydroelectric power. Many others are currently being investigated due to concerns that fossil fuel reserves are running out, as well as the effects of carbon dioxide emissions from their combustion in terms of climate change. The use of renewable energy is not new. Hydropower uses kinetic energy in water flow to drive a water turbine, which in turn drives an electric generator. The first hydropower plant was open at Niagara Falls in North America in 1899. Tidal power is generated by passing water through a two-way turbine and was first used in the 1900s. Wind turbines generate electricity by using the kinetic energy of the wind to drive a set of turbine blades and thus a generator. There is no atmospheric pollution and no fuel costs. However, there is a visual impact and some noise. Wind turbines were once a common site across Europe for milling grain since the fourteenth century.