Energie transition is the road to a future of the bioeconomy – towards an industrial society that is committed to the idea of sustainability and responsibility towards future generations. At the same time, our electricity will reach 27 percent by 2030 and at least 75 percent renewable energy sources by 2050. The expansion of renewable energies is therefore the central pillar of the energy demand. Renewable energies are to take over the main share of energy supply in Germany.
Renewable energies must therefore be continuously integrated into the power supply system in order to replace conventional energy sources more and more. This requires a fundamental rebuilding of the energy supply system. Ensuring a reliable, environmentally compatible and economically efficient power supply is one of the major challenges of power generation.
The objectives of the system integration of the renewable energies listed below are in particular:
- A safe grid operation with high proportions of renewable energies
- The flexibility of electricity generation and demand
- Intelligent interplay of power generation, consumption and modern networks
- Efficient use of existing network structure
Solar power
The solar energy can also be used directly in many ways. Solar cells in photovoltaic plants, solar thermal power plants and solar collectors use the solar radiation without detours and convert the radiation energy into electricity or heat.
Solar cells directly convert sunlight into electrical current. The core of each solar cell is a semiconductor, which mostly consists of silicon and uses the “photovoltaic effect”. In certain semiconductor layers arranged one above the other, free charges are generated under the influence of light (photons), which can flow off as electrons via an electrical conductor. The resulting direct current can be used directly for the operation of electrical devices or stored in batteries. If it is converted to alternating current, it can also be fed into the public power grid. This is today the most common way of using solar power.
Wind energy on land
Wind energy strongly influences the success story of renewable energies. For centuries, people have been able to exploit the power of the wind, but only with the help of recent experiences and technical possibilities has it been possible to exploit the enormous potential reliably.
Wind turbines use the moving energy of wind caused by different air pressure ratios in the vicinity of the earth’s surface. Modern wind turbine systems use the boost principle instead of the resistance principle. They do not oppose the wind; instead, the wind generates a buoyancy on the wings of the plant, causing the blades of the plant to rotate. While in other parts of the world wind energy is also used to propel pumps, wind turbines in Germany today are exclusively used for the grid-coupled generation of electricity.
Wind energy at sea
At the level of the European Union, overarching climate and energy policy objectives and guidelines are formulated. However, the specific configuration of the energy mix and the implementation of the expansion of renewable energies to achieve these goals still fall within the competence of the individual national states.
The guidelines for European energy policy have also been included in the Treaty of Lisbon, in the form of the cornerstone of the principles of profitability, security of supply and environmental compatibility. The implementation of the European guidelines in German law was mainly based on the Energy Industry Act in 2005.
Bioenergy
Biomass has hitherto been the most important and versatile renewable energy source in Europe. To this end, a comprehensive strategy is being developed to establish the Danube region as an optimal and sustainable biomass source. This very fertile region of Europe was called the Green Chemistry Belt. In addition, the use of bioenergy in the heat, transport and electricity sectors is to be further expanded. Biomass is used in solid, liquid and gaseous form for generating electricity and heat and producing biofuels. Just over two-thirds of the total final energy from renewable sources of energy was provided in 2013 by the various energetically used biomass.
In addition to the biomass provided for agricultural and forestry purposes, residual materials and biogenic waste are available for energy use. These include, in addition to the old and used timber, biowaste (for example biotone), manure / feeder and grain crops. The exploitation of this largely untapped potential will continue to be a priority in the future. The energetic use of biogenic residues and waste materials contributes to avoiding or reducing possible conflicts of use between the energetic and the material use of biomass. In the case of new plants in the electricity sector, waste and residual materials are to be used in the future.
Geothermal
Also known as geothermal energy – is a source of energy that is inexhaustible according to human standards. As we penetrate the earth’s surface, we find an almost constant temperature of about 10 ° C at the first 100 m depth. Then, the temperature rises by an average of 3° C every 100 meters, the deeper you get. This is called geothermal energy (geothermal energy) and can be used to generate energy using various technical processes.
For this purpose, there are three different methods: geothermal energy (up to 400 m depth) as well as geothermal systems that use warm, subsoil water (up to 4,500 m depth) and systems that use heat from the deep rock for electricity generation ( also referred to as “petrothermal geothermal energy” in specialist circles), which are currently reaching to a depth of 5,000 m.
Hydropower
Hydropower has already been used to drive mills, sawmills and hammer works in pre-industrial times. The kinetic and potential energy of a water flow is converted into mechanical rotational energy by means of a turbine wheel, which can be used to drive machines or generators. Today in Europe, hydropower is almost exclusively used for the generation of electric power. Hydropower is a mature technology that generates the largest share of renewable energy worldwide, second only to the traditional use of biomass.
The greatest potential for the use of hydropower is in the Alps and Alpine regions, where there is a favorable gradient. The essential potentials of hydropower lie in the replacement, in the modernization and reactivation of existing plants as well as in the new construction of existing transverse structures. All environmental concerns must be balanced. The goal is an increase in the performance, combined with the improvement of the water-ecological situation.