Storage technologies for renewable energy sources

Renewable energy sources such as wind or solar energy are fluctuating: Since the wind does not blow constantly strong and the sun shines stronger on some days and less strong on others (and not at all at night), both energy sources can only be used continuously and reliably if they are coupled with intelligent storage solutions. In this case, the punctual power surpluses are saved for those phases in which no power is produced. Peak load is the term used to describe the high demand for power within a power grid that occurs for a short period of time. Such unforeseen peak loads are balanced with storage technologies that must be available quickly – sometimes within seconds. 

There are many different storage technologies: One is thermal storage, which stores heat and thus energy primarily by heating water. This method is mainly used in private households for short-term storage of photovoltaic energy. On an industrial scale, there are other approaches using different storage materials such as concrete or liquid salt. In addition to thermal storage, there are also electrodynamic, electrostatic and flywheel storage systems for short-term storage in power plants. For long-term storage, on the other hand, electrochemical storage systems such as accumulators or batteries and pumped storage systems are used. In recent years, a great deal of research has been conducted into lithium batteries, to develop especially powerful mobile storage systems for hybrid vehicles or smartphones. But a lot of research is also currently being done with battery storage systems in the field of electrical grid support. This is because large power grids are subject to strong fluctuations in electricity supply and demand.

In addition to battery storage technologies, compressed air storage power plants are also used to support the power grids and balance out phases of peak load electricity. The first power plant of this type was built in Germany back in 1978. Here, electricity is stored by compressing air in underground caverns and discharged again during peak load demand by heating the air and expanding it in a gas turbine. In its conventional mode of operation, compressed air storage technology is a hybrid technology because natural gas is required. The more advanced technology, on the other hand, works with an additional heat accumulator to be completely climate-friendly.

Sources:

Dr. Rainer Tamme, “Speichertechnologien für erneuerbare Energien – Voraussetzung für eine nachhaltige Energieversorgung”, in: FVS Themen (2006):

https://www.fvee.de/fileadmin/publikationen/Themenhefte/th2006/th2006_03_03.pdf, accessed: 3/12/2022 at 8:30 a.m.

https://www.enbw.com/energie-entdecken/verteilung-und-transport/netzsteuerung/, accessed: 3/12/2022 at 9:30 a.m.