Germany’s 50Hertz opens up reactive power market to renewables, battery storage

German TSO 50Hertz on Tuesday became the country’s first grid operator to tender for market-based reactive power – electricity which flows back and forth in an alternating-current grid to maintain a stable voltage, rather than being consumed by an end-user.

German utilities regulator the Federal Network Agency has charged high- and extra-high-voltage grid operators with securing reactive power on a market basis, by the end of this year and 50Hertz is first out of the blocks.

Tendered reactive power will replace the current system of contracts between grid companies and conventional power plants, opening up its provision to competition. It is expected renewable energy, battery, and electrolyzer sites will compete to provide reactive power as the inverters at such sites can provide the service even when no electricity is being fed into the grid.

TSO 50Hertz held a test tender at the end of January and successfully sourced reactive power from a 600 MW solar plant in Witznitz, Saxony, and a wind farm in Brandenburg.

The tender document states, “Suppliers whose reactive power source is connected to the 50Hertz extra-high-voltage grid, and whose potential exceeds the technical connection guidelines/connection conditions (TAR/TAB) at the time the market-based procurement is announced, can participate in the reactive power market.”

The procurement exercise addresses north, central, east, southwest, and Hamburg sections of the 50Hertz grid as reactive power voltage regulation functions on a relatively small scale.

Successful bidders will receive a payment for non-continuous, “unsecured” reactive power plus a reserve price if the service is continuously provided.

The market-based approach “poses a challenge for system and grid stability because the large generators in power plants automatically regulate voltage and frequency as a byproduct,” said 50Hertz chief executive Stefan Kapferer. With the regulator requiring the new approach, to reduce the cost of reactive power provision, the CEO added batteries, solar and wind power sites, and electrolyzers “are technically capable of doing this. The new market is an incentive to exploit existing and future potential cost-efficiently.”

From pv magazine Deutschland.