Our power grid operates with 50Hz, which means that the direction is changed 50 times per second. The frequency is affected if generation and consumption fluctuate. When there is too less power, the frequency drops; when there is too much power, the frequency rises. Thus, to keep the frequency stable, generation and consumption need to be in balance.
In case of an imbalance of demand (consumption) and supply (generation), the transmission system operators have to ensure stability. Such transmission system operators are responsible for supraregional supply in the extra-high voltage range.
In the past, the central control of a large power plant was used to achieve this – that was Redispatch 1.0. More and more plants are now feeding renewable energy into the grid on a decentralized basis as a result of increasing environmental awareness. In contrast to the power plant, there is no timetable for these plants. The generated energy depends much more on environmental influences such as solar radiation and wind speed. Now it is also no longer sufficient to shut down the power plant. Instead, the plants that generate renewable energy are now also downregulated – this is referred to as Redispatch 2.0. In comparison to Redispatch 1.0, there are now many more players involved. Previously, there was the transmission system operator, the dispatcher, and the plant operator. Now, various distribution system operators and different plant operators are also involved. The distribution system operators purchase the electricity from the transmission system operator and pass it on to the end consumer at the necessary voltage. Also, plant operators are now no longer defined as power plants, but solar and wind power plant operators. These plant operators are rewarded for feeding electricity into the grid. If the plant is shut down to ensure grid stability, they lose the feed-in tariff. To compensate for this, they are paid a fee for not feeding into the grid, which we refer to as outage work, which is compensated. ¹ Their payment comes at the end of the Redispatch 2.0 processes. For ensuring grid stability, it is necessary to regulate the plants, for which the operator must be compensated. So that this can work, some exchange processes must take place. These are described and defined by the Federal Network Agency. ² The task of ensuring grid stability has increased significantly. Thus, it is not surprising that these are complex processes. Their complexity will not decrease in the future: While the processes of Redispatch 2.0 are being implemented and tested, one already meets the term Redispatch 3.0, where even small potentials are exploited. ³ ⁴
¹ Own illustration
² Bundesnetzagentur 2022, Redispatch https://www.bundesnetzagentur.de/DE/Fachthemen/ElektrizitaetundGas/Versorgungssicherheit/Netzengpassmanagement/Engpassmanagement/Redispatch/start.html, Abruf 17.11.202
³ cf. BDEW Bundesverband der Energie- und Wasserwirtschaft e.V, 2020, BDEW-Leitfaden zur Berechnung der Ausfallarbeit Redispatch 2.0, S.7-8, 38-47
⁴ cf. Bundesnetzagentur für Elektrizität, Gas, Telekommunikation, Post und Eisenbahnen, Anlage 2 zum Beschluss BK6-20-059 – „Kommunikationsprozesse Redispatch“, S.5
⁵ cf. Bundesministerium für Wirtschaft und Klimaschutz 2022, BMWK – Redisptach 3.0, https://www.bmwk.de/Redaktion/DE/Artikel/Digitale-Welt/GAIA-X-Use-Cases/redispatch-30.html, Abruf 18.11.2022
⁶ cf. TransnetBW GmbH, 2022, Studie zu Redispatch 3.0 vorgestellt, https://www.transnetbw.de/de/newsroom/presseinformationen/studie-zu-redispatch-3-0-vorgestellt, Abruf 18.11.2022