Renewable Energy: an Overview

Why do we need renewable energies?
Wind and solar energy, hydro power, geothermal energy and bioenergy are available in almost limitless supply. In contrast to energy sources such as oil, coal, uranium and natural gas, the use of renewable energies protects the climate and environment, is safe, resource-efficient and environmentally friendly. It ensures greater independence from energy imports, greater security of supply and strengthens the domestic economy. Renewable energies contribute to sustainable energy supply, support innovation and create a constantly increasing number of jobs.

The fossil fuels oil, coal and gas have two major disadvantages: their availability is not infinite and their combustion generates climate-damaging emissions, causing considerable subsequent damage and costs. Uranium, too, is a finite resource. The increased use of renewable energies is therefore not only appropriate from an environmental perspective, it also has macroeconomic benefits. For example, in 2009 the use of renewable energies in Germany prevented the release of about 107 million tonnes of climate-damaging CO2.

Germany and the EU therefore aim to strongly increase their use of renewable energies. There are also international efforts to this end; Germany actively supports stepping up these efforts.

Renewable Energy Sources Act
Windpark Enlarge image (© dpa - Bildfunk) The Renewable Energy Sources Act (Erneuerbare-Energien-Gesetz, EEG) obliges operators of power grids to give priority to purchasing electricity from renewable energies and to pay fixed prices for this. The amended EEG 2009 entered into force on January 1, 2009.

The EEG is an important driving force in the expansion of renewable energies in the electricity sector. The goal is to increase the share of renewables in total electricity consumption to at least 30 percent by 2020, after which date a continuous increase is prescribed.

Since the adoption of the Electricity Feed Act in 1990, wind power has developed strongly and hydro power has been maintained at a high level. The entry into force of the Renewable Energy Sources Act in 2000 led to a similar boom in biomass and photovoltaics. The use of geothermal energy for electricity generation has also developed considerably. The Renewable Energy Sources Act has thus proved to be a model and successful instrument.

Wind power still sailing ahead
At the end of 2009, there were around 21,164 wind turbines for electricity generation in Germany, with a capacity of around 25,777 megawatts. Thus in 2009, wind energy once again made the biggest contribution to electricity generation from renewable energies. However, there is still considerable potential to be tapped, suitable sites are now also being developed in Germany's southern states at an increasing rate and small-scale old turbines are being replaced by larger new turbines (re-powering). The establishment of first pilot offshore wind farms will be a start into tapping the enormous offshore wind potential in the future (offshore wind energy).

Hydro power
With the Electricity Feed Act and the Renewable Energy Sources Act, electricity generation from hydro power has been maintained at a high level. Hydro power plants are a climate-friendly form of electricity generation, and in 2009 led to savings of around 16 million tonnes CO2 in Germany. There are still suitable sites that can be used for reactivating small hydro power plants. The modernisation of outdated technologies in existing plants and in some cases new construction, especially at transverse structures, is also an option. The German government's goal is to link increased hydro power capacities to improved aquatic ecology.

Biomass storage tank Enlarge image (© © The Renewable Energy Sources Act also promotes electricity generation from biomass. Biomass is defined as renewable raw materials such as wood but also plant and animal wastes. Within the framework of the Renewable Energy Sources Act, the 2001 Biomass Ordinance regulates which substances and technical procedures can be used and which environmental requirements have to be met. Additional measures such as the market incentive programme for renewable energies give support to increasing the energy exploitation of biomass, in particular for heat production.

Together with landfill gas, sewage gas and the biogenic share of wastes, more electricity was produced from biomass in 2009 again, round about 35 TWh, than from hydro power The share in gross electricity consumption was 5.2 percent. The contribution of biomass to heat supply in 2009 totalled around 101 TWh, thus accounting for 91 percent of renewable energies in this sector.

With a share round about 3.5 million tonnes, biofuels covered 5.5 percent of the total fuel demand in 2009.

Solar energy
As a lasting and secure source, the sun provides us with enough energy every year to cover Germany's energy needs 80-fold. Options for exploiting solar energy in Germany include solar thermal heat use through solar panels, passive solar use and electricity generation using photovoltaic installations.
Siemens solar installation in the Mojave desert Enlarge image Siemens solar installation in the Mojave desert (© Siemens) In 2009, approximately 13 million square metres of collector area were installed in Germany; solar heat is thus being increasingly used. With the new Renewable Energies Heat Act (Erneuerbare-Energien-Wärmegesetz - EEWärmeG), which entered into force on January 1, 2009, more heat will be generated from renewable energy sources in future. Solar energy, geothermal energy, ambient heat and biomass are particularly suited. Electricity generation from solar energy has also expanded through the promotion of renewable energies and is causing a boom on the jobs market.

Geothermal energy
Heat from the Earth's interior can be used to heat buildings, fed into local heat grids, and used to generate electricity. Over 30 geothermal installations and more than 400,000 heat pumps are currently contributing to Germany's heat supply.

At this stage geothermal energy only plays a very minor role in electricity generation, but more installations will go into operation in the years to come.

Renewable energies as an economic factor
Renewable energies are increasingly becoming an important economic factor in Germany. The domestic turnover in 2009 totalled around 33 billion Euro. The sector with the largest turnover was biomass for energy, followed by the solar energy and wind energy. Linked to this, there is also significant growth in employment. According to an ongoing BMU research project, the number of people working in the renewables sector in Germany increased to around 300,500 in 2009. Compared with around 160,500 in 2004, approximately 140,000 new jobs were created in only five years.

The share of renewables in gross electricity consumption is to be increased to at least 30 percent by 2020, followed by a continuous increase. Other goals are a 14 percent share of renewable energies in total heat supply by 2020. Furthermore, by 2020 the share of biogenic fuels is to be increased to a level of 12 percent (energy related). This is to achieve a 7 percent decrease of greenhouse gas emissions against the use of fossil fuels.

In the long term, i.e. by the middle of this century, around half of the energy supply is to be met by renewable energies.

Renewable Energy: an Overview

Spillway of the hydroelectric dam at Manantan. Kayes, Mali