Storage and Grid Technology
Different applications in which a large number of innovative storage and grid technologies are being used or tried out in Germany are:
• Modernisation of transport and distribution networks in order to collect electric power generated by decentralised plants across the country and transport it from the points of generation to the load centres;
• Grid-compatible and grid-interactive behaviour of decentralised energy plants in order to ensure stable and secure operation of the grid;
• Development, use and optimisation of storage systems to balance fluctuations in residual demand, to make balancing control energy and other system services available, to avoid black-outs and to maintain a safeguarded energy supply, as well as to absorb the occasional significant surpluses from renewable energies and balance longer slack periods in the long term.
Use of electricity storage and load management
As the share of renewable energies in the electricity supply increases, the flexibilities provided by storage capacities and load management take on greater importance.
Compressed air and liquid air storage
Compressed air storage plants use excess energy, such as energy produced from volatile renewable energy sources, to compress air, which is then stored in underground chambers. When electricity is required, it is produced in a gas turbine using the compressed air.
Batteries are especially well suited to the storage of electrical energy. These batteries consist of galvanic elements that generate voltage through a combination of two different electrodes and an electrolyte in an electrochemical process.
Power to gas
The idea of power to gas is to convert renewable electricity into hydrogen or methane. The gas can be transported and stored in the gas infrastructure and then used by the various areas of application. At need, it is converted back into electricity. By the same token, the hydrogen can be used directly, for instance, in the mobility sector. Power to gas is thus a cross-system solution for integrating renewable energies into the energy system.
With the growing share of renewable energies comes the need to utilise flexibilities in relation to demand in order to balance fluctuations in the generation of energy. In the industrial sector, shiftable loads can be harnessed at a comparatively low cost by using existing measurement and control solutions together with process and automation technology in order to respond to the situation with regard to supply on the electricity market. The same results can be achieved in private households by using smart meters in combination with building automation technology, controllable devices and time-of-use tariffs.
Grid integration via virtual power plants
A virtual power plant is a combination of decentralized electricity generators using renewable energy sources – such as biogas, CHP, wind power, solar power and hydropower plants – for the purposes of joint electricity marketing and in order to take over responsibility for the grid, for example in order to provide controllable energy. All controllable plants networked into the virtual power station are accessible from a central control station.