Advantages of this compressed air storage
storage systems for electrical energy - why a new storage
Batteries (Li-ion and other accumulator systems) achieve a good storage density, but their lifespan is limited to 8-10 years due to the cycles. Battery storage systems are mainly used as storage systems for photovoltaic systems in the power range from a few kW to 100 kW. Many grouped individual batteries in power packs can already supply entire towns with decentralized electrical energy. e.g. Jamestown in Australia (315 MWh wind farm with 130 MWh in Tesla power packs).
Redox flow storage systems can store large amounts of energy. They offer high cycle stability. The redox flow battery of the Pellworm hybrid power plant has a storage capacity of 1.6 MWh and a charging / discharging capacity of 200 kW. An example of a small household application is the vanadium redox flow battery from VoltStorage, which operates in the power range of 2 kW.
Hydrogen has a very high energy density (triple gasoline, umpteen lithium batteries). There are different storage systems based on hydrogen. Common are compressed gas storage, liquid gas storage, metal hybrid storage, P2G - Power to Gas (electrolysis and methanation). With hydrogen for storing electrical energy, an overall efficiency of approx. 25% can be achieved. In connection with fuel cells, hydrogen is currently being propagated to drive vehicles electrically instead of batteries. Hydrogen filling stations already exist and are constantly being expanded.
Flywheel storage systems are suitable for stabilizing the network frequency in island networks and as short-term compensation storage. The use of this storage system makes economic sense if the energy can be charged and discharged in a short time (a few minutes). The performance of flywheel storage systems ranges from a few kW to a few 10 MW.
Pumped storage power plants store energy in the form of potential energy (positional energy) in a reservoir, which, if required, is converted into electrical energy by means of kinetic energy (by draining the reservoir to drive turbines). Pumped storage power plants can provide high output to cover peak loads within minutes. The overall efficiency of a pumped storage power plant is 75–80%. In Germany there are currently 36 pumped storage plants in operation with a total output of approx. 7 GW and a storage capacity of approx. 40 GWh. Seawater pumped storage power plants are also in operation in Japan and the USA.
Compressed air storage (CAES) is not a new storage technology, but it has only been implemented in large-scale projects so far. There are currently two large plants in operation around the world, namely the Huntdorf compressed air storage power plants in Lower Saxony and McIntosh in Alabama. These provide energy stored in compressed air in the gigawatt range. Both power plants are combined with gas turbines, which prevent cold freezing when the energy is extracted by adding fossil fuels.