Energy source
In the energy industry and energy technology, an energy source or an energy converter is referred to as an energy source that is used to generate useful energy .
Differentiation of terms
Colloquially and in non-scientific literature, the terms energy , energy carrier and energy source are often used as synonyms, but they have different meanings in the scientific field of energy technology. In a closed system, the energy source is the element that makes the energy available through conversion from another form of energy. The energy carrier, on the other hand, is the means that can be balanced in terms of quantity that contains and transfers the energy. This can be illustrated by the sun , which, with its nuclear fusions, represents the most important energy source for the earth and provides the energy by means of the energy carrier radiation.
Earthly energy balance
Most of the energy sources that can be used on earth come from radiation from the sun. The solar radiation can be converted directly (solar collector). Mostly, however, the use takes place indirectly, as an interaction of the solar radiation with the earth's surface takes place an energy conversion. Biologically converted energy is created in the long term through plant growth in different periods of time ( biomass , wood , peat , coal , petroleum ). Weather effects are short and medium term ( wind , hydropower ).
In terms of the light spectrum of the solar radiation falling on the earth, the earth corresponds approximately to a black body . In relation to the mean surface temperature of the earth, the Carnot factor is 0.95, so that the radiation energy can be regarded as almost pure exergy . In order for energy sources to be used, there must be a temperature sink that represents the earth's surface. This in turn emits thermal radiation. The components of the atmosphere influence the reflection through absorption ( global warming ). The space itself is also almost black when viewed over the entire spherical space area, so that the terrestrial infrared heat radiation can be emitted from the earth into space . The solar radiation incident on the earth and the emitted thermal radiation must be the same on average so that the temperature equilibrium of the earth is given. The energy sources, which are ultimately based on solar energy, are converted into energy that is useful for humans using machines, and the energy is ultimately emitted into space as entropy with a time delay .
Forms of energy sources
Humans have always needed different forms of energy to survive. With industrialization, mankind's energy needs have increased and changed. The main source of energy on earth is the sun. Solar energy is also the driving force for many other energy sources such as ocean currents and the water cycle .
The various forms of energy sources are in detail:
- Fossil energy ( hard coal , lignite , peat, natural gas , petroleum)
-
Regenerative energy
- Solar energy (usable solar energy radiation : light, heat)
- Biomass
- Wind energy (atmospheric currents)
- Hydropower, including
- Tides ( tidal range )
- Wave power ( wave power plant )
- Ocean current ( ocean current power plant )
- Geothermal energy (geothermal energy)
- Nuclear energy ( fission and fusion )
Share of the individual energy sources in Germany
- Share of the individual energy sources in total energy consumption, differentiated according to the primary energy used :
2005 | 2010 | 2012 | 2018 | |
---|---|---|---|---|
mineral oil | 36.0% | 33.6% | 33.0% | 34.0% |
natural gas | 22.7% | 21.8% | 21.5% | 23.4% |
Hard coal | 12.9% | 12.1% | 12.9% | 10.9% |
Brown coal | 11.2% | 10.7% | 12.0% | 11.3% |
Renewable energy | 4.6% | 9.4% | 11.6% | 13.8% |
Nuclear energy | 12.5% | 10.9% | 7.9% | 6.3% |
Others | 1.5% | 1.3% | 0.4% | |
total | 14,244 PJ | 14,057 PJ | 13,757 PJ | 13,106 PJ |
- Share of the individual energy sources in electricity generation in Germany:
Energy source | 1990 | 1995 | 2000 | 2005 | 2010 | 2015 | 2018 |
---|---|---|---|---|---|---|---|
Hard coals | 140.8 | 147.1 | 143.1 | 134.1 | 117.0 | 117.7 | 83.2 |
Brown coals | 170.9 | 142.6 | 148.3 | 154.1 | 145.9 | 154.5 | 145.5 |
mineral oil | 10.8 | 9.1 | 5.9 | 12.0 | 8.7 | 6.2 | 5.2 |
natural gas | 35.9 | 41.1 | 49.2 | 72.7 | 89.3 | 62.0 | 83.4 |
Nuclear energy | 152.5 | 154.1 | 169.6 | 163.0 | 140.6 | 91.8 | 76.0 |
Wind power on land | k. A. | 1.5 | 9.5 | 27.9 | 38.9 | 72.2 | 92.2 |
Wind power at sea | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 8.3 | 19.3 |
Hydropower | 19.7 | 21.6 | 24.9 | 19.6 | 21.0 | 19.0 | 16.6 |
Biomass | k. A. | 0.7 | 1.6 | 11.5 | 29.1 | 44.6 | 45.7 |
Photovoltaics | k. A. | 0.0 | 0.0 | 1.3 | 11.7 | 38.4 | 46.2 |
Geothermal energy | 0.0 | 0.0 | 0.0 | 0.0 | 0.0 | 0.1 | 0.2 |
rubbish | k. A. | 1.3 | 1.8 | 3.3 | 4.7 | 5.8 | 6.2 |
Other | 19.3 | 17.7 | 22.6 | 23.8 | 26.6 | 27.3 | 27.0 |
(Data in TWh)
Fossil energy sources
Fossil fuels are substances made from biomass, which - sealed off from the atmosphere by layers of sediment - rotted in the absence of oxygen and thus obtained their chemical energy . Fossil fuels are coal , natural gas , oil and methane hydrate . All fossil fuels have in common that they are only available to a limited extent and their use is associated with more or less high CO 2 emissions (see greenhouse effect , climate change , climate protection ).
Coal power plants
Stone and brown coal formed in the Carboniferous and Tertiary of dead plants , which in mud sagged and were compressed slowly. The process in which dead organic material is first converted into peat, then into lignite and finally into hard coal is known as coalification and is characterized by an increase in the relative carbon content. Therefore, hard coal has a higher calorific value than lignite.
In Germany , hard coal is mined underground in tunnels and shafts , while the lignite lying further above can be mined in open-cast mining after the surface layers ( overburden ) have been removed.
Coal is burned to generate electricity in steam power plants. Furthermore, hard coal is used in steel production and to a lesser extent, like lignite, for the operation of living space heating systems (coal stoves).
Coal is a domestic energy source, so it secures jobs and reduces dependence on imports . In addition, electricity from coal-fired power plants can be called up as required, so no shadow power plants are required to compensate for fluctuations. However, this only applies to a very limited extent to lignite power plants, as these are operated at the base load , i.e. with constant output. Domestic hard coal is very expensive compared to imported coal and must be heavily subsidized in order to remain competitive.
As a fossil fuel, coal is only available to a limited extent and as a raw material for the chemical industry it is actually too good to burn. Moreover, which is combustion of coal, compared with other fossil fuels with relatively high CO 2 - emissions connected as coal essentially of carbon consists. The combustion of coal is also - due to the impurities it contains - associated with relatively high pollutant emissions ( sulfur compounds , nitrogen compounds , dust ), which are reduced in modern coal-fired power plants with high technical effort. The open pit mining of lignite initially caused enormous environmental damage through the use of the land. After decades, planned recultivation creates areas with similar or better soil quality than before. In addition, with the settlements standing on the brown coal, cultural assets are destroyed. After incineration, ash and filter dust remain , which are properly disposed of, as well as gypsum from flue gas desulphurisation , which is now used in the building materials industry.
Even during normal operation, a coal-fired power plant emits radioactive substances through the release of the natural radioactivity contained in the coal ( 40 K , uranium , thorium ) with the exhaust air . So far, however, no harmful pollution has been found in the immediate vicinity.
Oil power plants
About 70 million years ago crude oil was created from dead aquatic animals and plants through sedimentation of microorganisms in connection with suspended mineral matter . It essentially consists of hydrocarbons . Typical impurities are sulfur compounds, hydrogen sulfide and nitrogen compounds. Crude oil is used to generate electricity in steam power plants , as a raw material for fuels ( gasoline , diesel ), in oil heating systems and as a raw material in the chemical industry.
Electricity from oil-fired power plants can be called up as required, so no shadow power plants are required to compensate for fluctuations. To a lesser extent than coal, crude oil from the North Sea is a domestic energy source, thus securing jobs in a structurally weak environment. However, the occurrences in the North Sea are very limited.
As a fossil fuel, crude oil is only available to a limited extent, and as an essential and versatile raw material for the chemical industry (raw material for lubricants , plastics and much more), it is far more valuable than coal. The combustion of crude oil produces more CO 2 per unit of energy gained than the combustion of natural gas, but less than the combustion of coal. It is associated with relatively high pollutant emissions (sulfur compounds, nitrogen compounds), which can only be reduced with great technical effort. Petroleum is an environmental pollutant ( oil spill ). The extraction of crude oil leads to environmental pollution, both with normal extraction ( leaks ) and with tanker accidents (see e.g. Exxon Valdez , Amoco Cadiz and others). After the incineration, filter dust remains for disposal as well as gypsum from the flue gas desulphurisation .
In addition, there is a problem in the maximum delivery time called peak oil . Once the peak is reached, the delivery rate begins to decrease. If consumption remains the same or increases, this leads to price increases and possibly to supply bottlenecks.
Burning natural gas
Natural gas was created together with crude oil , it is the gaseous part of the conversion products under normal temperature conditions. Natural gas mainly consists of methane (CH 4 ). Typical impurities are sulfur compounds, hydrogen sulfide and nitrogen compounds. Natural gas is used to generate electricity with gas turbines , for heating and also as motor vehicle fuel ( CNG ). Natural gas is also the raw material for synthesis gas that is used in the chemical industry ( methanol , hydrogen and ammonia ).
Compared to coal and crude oil, natural gas contains considerably fewer impurities (e.g. sulfur compounds), so it releases fewer pollutants when it is burned and is therefore a comparatively environmentally friendly fossil fuel. From a chemical point of view, natural gas also contains a higher proportion of hydrogen than coal or crude oil and therefore releases less greenhouse gas CO 2 with the same energy yield . However, unburned methane, the main component of natural gas, is itself a very effective greenhouse gas (see Global Warming Potential ). Natural gas from leaks also promotes the greenhouse effect .
Today, natural gas is mainly used to generate electricity in gas turbine or combined cycle power plants (gas and steam power plants). These power plants achieve very high efficiencies , 55 to 60%, and, in contrast to coal or nuclear power plants, can deliver electricity at very short notice if required, so they are suitable for peak loads and can be used to compensate for load fluctuations, power plant failures or power fluctuations, e.g. B. of wind turbines can be used.
Combustion of methane hydrate
Methane hydrate ( methane clathrate , methane ice ) is an intercalation compound ( clathrate ), a substance reminiscent of milky ice , which consists of methane that is physically stored in water . The water molecules completely enclose the methane.
Methane hydrate was first discovered in the Black Sea in 1971 . Methane hydrate forms on the bottom of seas or deep lakes, where the pressure is high enough around 20 bar and the ambient temperature is low enough at 3 to 4 ° C.
At lower pressure, methane hydrate is unstable and decomposes into water and free methane, which theoretically could be used in a similar way to natural gas . The largest deposits of methane hydrate were found on the slopes of the continental shelves .
With an estimated twelve trillion tons of methane hydrate, more than twice as much carbon is bound there as in all oil , natural gas and coal reserves in the world. The possibilities for the economic dismantling of the methane hydrate fields are currently being investigated in several test projects. a. tested for feasibility in Canadian and Japanese coastal waters. A commercial breakdown of methane hydrates is considered possible from 2015 to 2020. In March 2013, the Japanese research vessel Chikyu succeeded in offshore production of methane hydrate in gas form for the first time.
Little is known about the extent of the unintentional release of methane during production. The combustion of methane hydrate releases about the same amount of CO 2 emissions as that of natural gas, so that this also contributes to global warming , but to a lesser extent than coal or petroleum. Furthermore, methane itself is a powerful greenhouse gas that is far more effective than CO 2 (see Global Warming Potential ). During the dismantling process, high demands would have to be made in terms of avoiding leakages and other methane releases.
The exploitation of methane hydrate deposits on continental shelves requires extensive investigations into the slope stability. Landslides on continental shelves, for example, can lead to tsunamis due to their size of several hundred kilometers .
Waste incineration plants
In waste incineration plants , part of the energy contained in waste is converted into heat and / or electrical energy. Sometimes waste incineration plants are classified as renewable energy sources; however, this would only be correct if biomass waste were used. But because mostly both fossil and regenerative materials are burned, the classification is problematic.
Renewable energy sources
Renewable energy sources bear their name because, in contrast to the limited availability of fossil fuels, they are constantly direct (sunlight) or indirect (wind, water power , wave energy , biomass , muscle power ) from the sun or from other, non-fossil sources (geothermal energy: radioactive decay in the earth's interior , tidal power plants : movement of the moon and earth). They are therefore never running out by human standards. Renewable energy sources have been used by mankind for thousands of years. In industrial terms, however, apart from hydropower plants, they are currently still unattractive due to high initial investments and inconsistent energy flow. That is why the use of renewable energy sources is promoted by the governments in many countries through subsidies . This should make the use attractive and promote further development. The generation of renewable energy is - apart from the construction of power plants - CO 2 -free and does not release any other pollutants .
Wind turbines
Different warm air layers lead to a displacement of air , which is called wind. Today wind turbines use the kinetic energy of the wind to convert it into mechanical energy with the help of propellers and finally into electrical energy in a generator . Wind energy has been used in windmills to grind grain since the 10th century .
The energetic amortization period is extremely short, it is a few months to a year. The use of wind energy does not involve any significant safety risks. A wind turbine is very reliable, the technical availability is between 95 and 99%, the energetic around 70 and 85%. All installed wind turbines together cannot fail at the same time, nor is it likely that they will supply no or maximum electricity at the same time. In addition, wind energy is independent of fuels and their price development; the electricity costs arise almost exclusively from the costs of financing the necessary investments . This factor means that with conventional energy prices rising further, the generation of electricity from wind energy becomes more competitive. As a purely domestic energy source, it reduces dependence on the global price increases of other energy sources.
Wind turbines are directly dependent on the prevailing wind conditions, so the generation fluctuates. If there is no wind or if the wind is too strong, they do not generate any electricity. The start-up speed of typical wind turbines is 2-4 m / s, while the shutdown speed for most systems is approx. 25 m / s. Sometimes only 20 m / s. However, with certain wind turbines it is possible to continue to operate them with reduced power even at higher wind speeds of up to more than 30 m / s, which on the one hand increases the electricity yield, but on the other hand also reduces the need for control energy, since only part of the Power goes from the network. The integration of larger amounts of wind energy requires the use of controllable power plants such as fossil or biomass-fired power plants or, in the long term, electricity storage. So far, conventional power plants have primarily served to compensate for fluctuations in wind energy. Due to the fact that the wind supply can now be forecast quite well, the necessary proportion of required control energy drops to less than 10% of the wind energy capacity and can be generated by existing power plants within their normal control activity. The majority of the balancing energy, on the other hand, is provided by medium-load power plants within the existing power plant schedules. The reduction in efficiency is just a few percentage points, as is the case with regular activity due to changing requirements.
Direct use of solar energy
For direct use of the energy from the sun's radiation, it can either be converted directly ( photovoltaics ) or indirectly ( solar thermal ) into electricity or used directly as solar heat. There are no fuel costs, but a solar power plant does require a certain amount of maintenance.
The supply of solar energy is linked to daylight and therefore fluctuates (day / night, weather, season), therefore the generation of solar power is associated with the use of controllable fossil or regenerative ( shadow power plants ) or long-term storage power plants. Solar thermal power plants are planned in many climatically more favorable regions (Southern Europe, Africa, America etc.), but not economical in Central Europe because of the insufficient direct solar radiation.
Photovoltaics
In photovoltaics, sunlight is converted directly into electrical direct current using solar cells .
The energetic amortization period is relatively short, it is a few years. The solar energy supply roughly follows the current electricity demand, during the day and especially at midday the solar energy reaches its maximum supply, it is therefore very well suited for medium load coverage and therefore a component in the energy mix . In addition, photovoltaics is independent of fuels and their price development; the electricity costs arise exclusively from investment and (low) maintenance costs. This factor enables the cost of electricity from photovoltaics to fall continuously as conventional energy prices continue to rise. Solar energy is a purely domestic energy source, but cannot prevent dependence on global price increases for other energy sources. A photovoltaic system is very reliable and practically maintenance-free . All installed systems together cannot fail at the same time. They do not provide any electricity in the dark, but then the electricity demand is lower. In Germany, photovoltaics is mainly implemented as a decentralized technology.
Use of solar thermal energy
With solar thermal energy (solar heat utilization), the heat generated by absorption when sunlight hits a surface is collected in solar collectors via a carrier medium (e.g. water) and used for heating or domestic water heating. Use for electricity generation is not economically feasible in Central Europe.
The supply of solar energy is linked to daylight and therefore fluctuates (day / night, weather, season); However, fluctuations in the time of day and the weather can now be largely compensated for when using solar heat using heat storage technologies (e.g. latent heat storage ). The seasonal fluctuations are more serious, since solar heat is least available for heating purposes exactly when it is needed. Long-term storage of heat from summer to winter is technically possible despite the thermal losses, but only economical in some cases.
Solar thermal power plants and solar thermal power plants
In solar thermal power plants , the sunlight is concentrated on a collector via a large number of mirrors , which means that the temperatures required for a power plant with a steam cycle are reached. The cooling of the steam downstream of the turbine causes problems because there is usually a lack of water in the sunny areas.
With a suitable construction (an inverted funnel), updraft power plants generate a strong thermal updraft , which can be used with turbines . Due to insufficient solar radiation, these power plants cannot be used in Germany.
Hydropower plants
Hydroelectric power plants utilize the energy from the gravity or kinetic energy of continuously flowing water to therefrom by means of hydraulic turbines and in turn to obtain mechanical energy electric energy. Since the natural water cycle is powered by the sun, hydropower is indirectly a form of solar energy. Hydropower is mainly used to generate electricity, the direct use of mechanical work (water mills) is rather negligible. Electricity from hydropower plants can be called up as required, so no shadow power plants are required to compensate for fluctuations.
The reservoirs usually required for hydropower plants are dependent on suitable terrain structures that are only available to a limited extent. Hydropower is therefore very limited in terms of the amount that can be extracted; the possibilities in Germany are largely exhausted. In addition, the construction of reservoirs requires a lot of space. If forests are flooded when creating reservoirs, the subsequent rotting of the organic material produces a large amount of methane , which acts as a greenhouse gas . In addition, oxygen is consumed in the process, so that in this phase (which can take many years) the reservoir is rather hostile to life for water dwellers.
Tidal power plants
Tidal power plants use the kinetic energy of the ocean currents associated with the tides to generate electrical energy. For this purpose, dams with turbines are being built in suitably shaped estuaries or on similar coastlines with a strong tidal range . One of the most famous tidal power is the tidal power Rance in the mouth of the Rance in Saint-Malo , France.
Tidal power plants are only profitable in places that have a suitable coastline with a strong tidal range; such places are very limited. The constant corrosion from the salt water results in high maintenance costs. In addition, tidal power plants can, under certain circumstances, significantly interfere with what are sometimes very sensitive ecosystems .
Ocean current power plants
An ocean current power plant uses the kinetic energy from the natural ocean current to provide electricity.
Currently (as of 2004) there are some ocean current power plants in the test stage:
- Seaflow
- Leprechaun (Strait of Messina)
- Hammerfest (Norway)
The Seaflow was designed by the University of Kassel and built with the support of a British Ministry off the coast of Cornwall in the Strait of Bristol in south-west England. It is currently being tested.
Wave power plants
Wave power plants use the energy of the waves generated by the wind on the surface of the sea . The development is still at the beginning. The world's first wave power plant with a pneumatic chamber that feeds electricity into a commercial power grid has existed since 2000 . Instead of the expected annual average output of 500 kW, however, only 21 kW was achieved in 2005/2006.
Wave power plants with floats are still in the test phase. At the end of 2007, the first 3 plants off Portugal should go into operation. They use the wave movement in serpentine form to hydraulically transfer the movement between several links to generators. Many test facilities were destroyed by winter storms, which deliver around a hundred times as much power as the wave movement during the other seasons. As there is therefore insufficient experience with wave power plants, we know about the ecological effects, e.g. B. on marine life, so far little.
Osmotic power plants
Osmosis power plants are hydropower plants that can generate energy from the different salt content of fresh and salt water. According to the principle of osmosis, an ion-poor liquid (e.g. fresh water from a river) penetrates a membrane in the direction of a more ion-rich liquid (e.g. sea water), whereby an osmotic pressure builds up. With a suitable structure, the liquid flow can drive a turbine and generate electricity in the process.
In Scandinavia there are already test facilities at estuaries, but the process is still far from being profitable. An unsolved problem is the rapid contamination of the membrane. The main advantage (in contrast to wind and sun, for example) would be the constant availability of energy as long as both fresh and salt water are available.
Use of geothermal energy
The geothermal energy is in the form of thermal energy stored (colloquially heat) energy below the earth's surface. In the interior of the earth, immense amounts (around 1,011 terawatt years) of thermal energy are stored, some of which have been preserved from the time the earth was formed, but mainly arise from the decay of natural radioactive isotopes . The temperature in the earth's core is estimated at 6000 ° C, in the upper mantle still 1300 ° C. 99% of the globe is hotter than 1000 ° C, only 0.1% is cooler than 100 ° C. The temperature increases by 3 ° C per 100 m depth on average. However, some areas have a higher temperature gradient , for example areas in the USA , Italy , Iceland , Indonesia or New Zealand . If open cycles are used, the use of geothermal energy to generate electricity can release pollutants such as salts and gases dissolved in the water. Therefore closed circuits with a heat exchanger are usually used.
Conversion of biomass
Biomass is one of the renewable raw materials , i. In other words, it is not available indefinitely (like wind energy, for example), but can (in contrast to fossil fuels) be produced again naturally within a short time after harvesting. Biomass is created by converting energy from solar radiation with the help of plants through the process of photosynthesis into organic matter. Biomass thus represents stored solar energy. The difference between biomass and other types of use of solar energy is its independence from the times of solar radiation. Biomass can be used in many different ways, e.g. B. by:
- the direct combustion of wood and other biomass (the oldest use of biomass for energy production),
- Conversion by microorganisms into biogas , which can be used for power plants, as fuel or for heating as well
- Conversion through chemical processes, e.g. B. in biodiesel or alcohols .
The biological substances suitable for use are also diverse, so in addition to vegetable oils and fruits for biodiesel, the remaining parts of the plants, such as wood, straw, etc. for z. B. BtL fuel and animal excrement for biogas and biological municipal waste ( landfill gas ) can be used to produce heating fuels .
Biomass makes sense as a niche energy source as long as it uses waste products from agricultural and forestry processes or biodegradable municipal waste and helps to dispose of it. A large-scale use with specially generated biomass, z. B. for large-scale conversion from diesel to biodiesel, largely fails due to the enormous amount of space required to generate the biomass. In addition, the ecological pollution caused by intensive agricultural use is problematic. Last but not least, the resource biomass is limited by the generation capacity of the earth (energy contribution from the sun, available area) and is already used to a considerable extent by humans.
Nuclear energy sources
Nuclear power plants
The nuclear fission of uranium or plutonium produces energy and neutrons , which in turn trigger further fission. This energy released in this chain reaction is used in a controlled manner in a nuclear reactor .
The operation of a nuclear power plant does not release any CO 2 or other harmful substances .
Apart from annual maintenance, nuclear power plants are highly available (more than 90% ), are particularly suitable for constant power output and are therefore classic base load power plants . Nuclear power plants have a long service life, and some in the USA have had their operating licenses extended to a term of up to 60 years.
The marginal costs of electricity generation in nuclear power plants are well below those of a coal-fired power plant. However, the macroeconomic average costs are likely to be significantly higher, since the use of nuclear energy will result in very high costs for the complex dismantling of the radiologically contaminated power plant and the permanent safe storage of the spent nuclear fuel. The repository problem in particular has not yet been resolved worldwide, which means that the exact costs cannot yet be foreseen.
Even during normal operation, a nuclear power plant releases small amounts of radioactive substances with exhaust air ( noble gases ) and waste water into the environment. The radiation exposure of the population caused by this is far below the fluctuation range of natural radiation exposure and is also around 50 times lower than the radiation exposure that a coal-fired power plant emits by releasing the natural radioactivity contained in the fuel ( 40 K , uranium , thorium ). Nevertheless, according to a study, the result of which is confirmed by the Federal Office for Radiation Protection , cancer is more common in children near nuclear power plants.
Radioactive decay
In radionuclide batteries , the radioactive decay of unstable nuclides is used to generate thermoelectric power and for heating purposes. In relation to the mass, the electrical power and the total energy yield are low compared to other energy sources. However, radionuclide batteries are very robust, maintenance-free and long-lasting. Because of these properties, they were used for cardiac pacemakers . They are also used in space probes for the outer solar system , where the solar radiation is not sufficient for an energy supply with solar cells .
See also
Web links
- Electricity generation from renewable energies
- Climate protection and energy supply in Germany 1990–2020 . (PDF; 3.16 MB) Study by the German Physical Society (DPG) ; Analysis 1990–2005 and outlook 2005–2020 with individual analysis of the energy sources. (3.16 MB)
- Renewable and non-renewable energy sources
- Innovative approach to using biomass
Individual evidence
- ↑ Working Group on Energy Balances
- ↑ Working Group on Energy Balances ( Memento from May 13, 2012 in the Internet Archive )
- ↑ Preliminary figures. (PDF) Federal Ministry of Economics
- ↑ Energy data: Complete edition. Federal Ministry for Economic Affairs and Energy, October 2019, accessed on February 19, 2020 .
- ↑ Energy in Germany . ( Memento from July 12, 2016 in the Internet Archive ) (XLS; 0.1 MB) BMWi
- ↑ Federal Ministry for Economic Affairs and Energy: Complete edition of the energy data - data collection of the BMWi. Retrieved February 19, 2020 .
- ↑ Scientific Advisory Council of the Federal Government on Global Change: Special Report 2006 . Archived from the original on June 11, 2008. Retrieved October 17, 2010.
- ↑ Japan harbors methane hydrate from the deep sea. In: tagesschau.de. March 13, 2013, archived from the original on March 15, 2013 ; Retrieved March 23, 2013 .
- ↑ Japan extracts gas from methane hydrate in world first. In: BBC News. March 12, 2013, accessed March 23, 2013 .
- ↑ Renewable Energies 2010. ( Memento of March 16, 2012 in the Internet Archive ) (PDF; 1.22 MB) BMU, as of: Feb 2013
- ↑ Enercon storm regulation (PDF)
- ^ Islay Limpet Project Monitoring Final Report. ( Memento of September 28, 2007 in the Internet Archive ) (PDF) wavegen.co.uk (English)
- ↑ The salt in the soup of renewable energies: Osmosis power plants use the different ion content of river and sea water. On: Wissenschaft.de from April 14, 2006.
- ↑ Humans already use a quarter of all biomass . Retrieved September 7, 2019 . Wissenschaft.de
- ↑ BfS opinion on the KiKK study ( Memento from August 29, 2013 in the Internet Archive )