Frequently asked questions on renewable energy
What is renewable energy?
Renewable energy is energy from sustainable sources such as water power, wind energy, solar energy, biomass and geothermal energy. Unlike fossil the energy sources; oil, natural gas, coal and lignite coal as well as uranium ore, renewable energy does not use up these energy sources.
Bioenergy: Bioenergy is extremely diverse. Heat, electricity and fuels can be produced from solid, liquid and gaseous biomass. Vegetable and animal wastes are used just as much as regrowable raw materials, e.g. energy crops or wood. In Germany bioenergy's greatest significance is in heating – although biomass is also used for electricity generation and as a biofuel.
www.unendlich-viel-energie.de/de/biomasse
Solar energy: Both heat and electricity can be produced from the sun's radiation. Photovoltaic modules on the roof or in open spaces use semi-conductors such as silicon to convert the sunlight into electrical energy. Solar collectors, in which liquid circulates, are used to obtain heat for space heating and for heating water as well as for cooling buildings. A third technology makes it possible to generate electricity, process heat and cooling by concentrating and amplifying the sun's rays. The sunlight is concentrated via reflectors and is converted into steam with which a generator or a heat and cooling machine is operated.
www.unendlich-viel-energie.de/de/sonne.html
Wind energy: Use of the wind as a drive power has a long tradition. Windmills were used to grind grain or as a saw and oil mill. Modern wind turbines produce electricity from the power of the wind. They utilise the lift produced by the wind when it flows past the rotor blades.
http://www.unendlich-viel-energie.de/de/wind.html
Water power: Water power was already being used to drive machines such as flour mills in Ancient Egyptian and in the Roman Empire. In the Middle Ages, water mills were used in Europe for saw and paper mills. Electricity has been produced from water power since the end of the 19th century. Today water power (hydroelectric power) is a fully developed technology and, after traditional biomass use, is the most used renewable energy source worldwide.
www.unendlich-viel-energie.de/de/wasser.html
Geothermal energy: Geothermics (geothermal prospecting) is the use of the earth's heat to produce electricity, heat and cooling energy. The temperatures inside the earth heat the earth's outer layers and underground water reservoirs. This energy is tapped with the help of wells. For utilisation of geothermal energy up to 400 metres deep ("near-surface"), a heat probe combined with a heat pump utilises the different temperature level between the soil and the ambient air. In deeper strata, hot water and steam are obtained to produce electricity and for district heating networks.
How are Renewable energies promoted in Germany?
The Federal Government has internationally obligated itself to reducing the emission of greenhouse gases by 40 percent by 2020. To achieve this, renewable energy should account for a 30 percent share of the electricity sector, 14 percent of the heat sector and 12 to 15 percent of fuels. Various instruments are used to promote and implement these climate objectives.
In the electricity sector the Renewable Energy Law (EEG) is the most important basis for the development of renewable energy. It guarantees the purchase of electricity from water power, wind and solar energy, biomass and geothermal energy and for a period of 20 years pays a fixed amount for each kilowatt-hour fed into the grid. Incentives for innovation and increased efficiency are set through the annual reduction in the rates paid for this electricity. The remuneration is made by means of a consumption-dependent contribution, which all consumers pay. For an average 3-person household, the additional costs for this subsidy of environmentally friendly and import-independent energy are around 2.10 euro per month.
Heating with renewable energy is promoted by the Market Incentive Programme . A so-called "climate premium" is paid to all who install a solar heating system, a wood pellet or firewood stove or a geothermal energy probe. This investment costs grant varies depending on the size and quality of the system. Low-interest loads are issued by the "Kreditanstalt für Wiederaufbau" (KfW - Reconstruction Bank). At present, a "Renewable Energy Heat Law" is being planned, which specifies a certain heat share of 15 percent from renewable energy in a new building.
The use of biofuels in the transport sector is currently promoted by a blending obligation requiring the addition (blending) of renewable fuel to conventional fuels. The tax incentive to date for pure biofuels will be gradually withdrawn. Since January 2007, the Biofuel Quota Law has obliged suppliers of fossil fuels to add a minimum proportion of biofuel: In 2008, 4.4 percent (in energy terms) of conventional diesels must be replaced with biodiesel and 2 percent bioethanol must be added to petrol. In addition to the two minimum fractions, a total biofuel quota has been set for the whole fuel market which must be fulfilled, for example through pure fuels. For example, farmers who use pure vegetable oil as a fuel can have the tax on oil reimbursed.
What will future houses look like?
- Foto: Agentur für Erneuerbare Energien
The house of the future will ideally produce all the energy it needs itself - or even more than it needs. This is already possible today in so-called "Plus Energy Houses".
This type of house is well-insulated and is highly efficient with respect to energy use. The low residual heat requirement is covered by a solar heating system, geothermal energy or wood pellets. In office and other commercial buildings air conditioning with renewable energy also will play an important role. Part of the facade surface and the roof will ideally be used to generate electricity by means of photovoltaics.
The terms which describe the most modern and sustainable houses are: Passive house, zero energy house and plus energy house. The low energy house is already the standard for today. These concepts are primarily realised in new build projects, but old buildings can also be modernised to the relevant standard.
Further information:
http://www.passivehouse.co.uk/
http://www.passivehouse.org.nz/
http://www.netzeroenergybuildings.com/
German links:
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