Renewable energy can be produced from a variety of sources such as biomass, hydro, sun and wind. Renewable energy sources often have an intermittent or irregular output depending on weather and wind conditions. An increase in the use of intermittent power in the electricity system often leads to an increased need for regulating power. Energy sources used for regulating power are primarily hydro and combustion plants.
Wind power emits no CO2 and is the fastest growing source of energy in the EU. Wind turbines have an impact on the landscape, which some people find disturbing. Wind power has no fuel costs, though total cost is high due to significant investment costs and the need for network capacity investments for new wind farms. Today, wind power is largely dependent on support systems.
By using biomass instead of fossil fuels, CO2 emissions can be significantly reduced, but supply of larger volumes is currently difficult to secure. Using biomass to produce electricity is also currently more expensive than using energy sources such as coal, gas or nuclear power
Hydro power is the leading renewable energy source and causes almost no emissions. Hydro power plants provide large-scale and stable electricity generation, and also functions as balancing power, since capacity can be rapidly changed. Constructing a new power plant requires a substantial investment, but its economic life is long.
Solar energy is a fast-growing, renewable energy source that generates very low emissions. The potential for solar energy is substantial if the technology is developed for large-scale production, with lower manufacturing costs.
Ocean energy is a renewable energy source, in which electricity can be generated from tidal streams, waves or differences in salinity. The new technologies have great potential, but are still under development.