50Hertz and ENERTRAG SE, a major operator of renewable energy plants, have launched a joint pilot project for the provision of reactive power through renewable energy near Bertikow in Brandenburg, Germany.
At Bertikow, wind power and other generation plants based on renewable energies with a total capacity of over 500MW are connected to the nearby 50Hertz substation.
In the future, they will provide the reactive power that is important for voltage maintenance and thus grid stability, even if little wind feed-in is available.
The provision of sufficient reactive power is the basis for a stable power grid.
Reactive power ensures the smooth transport of electricity over longer distances.
It can be used to compensate for voltage losses during transport so that as much active power as possible reaches the consumer and the grid functions safely.
50Hertz said that, according to current regulations, renewable energy plants do not have to deliver reactive power during periods when they provide little or no active power (less than 10% of their active power).
This presents the power grid operators with the challenge that they have to compensate for the necessary reactive power with other technical systems to maintain voltage during these times.
However, modern wind turbines are also technically capable of providing reactive power, even if there is little or no wind.
In the pilot project, ENERTRAG and 50Hertz also want to test how reactive power retrieval works technically in practice and can be contractually designed, also with a view to a future reactive power market.
Ground-mounted photovoltaic systems can also provide reactive power via their inverters if, for example, there is no sun at night.
Managing director markets and system operations at 50Hertz, Dirk Biermann said: “In the course of the energy transition, innovative solutions for reliable power grid operation are absolutely necessary.
“We at 50Hertz are testing various possibilities.
“The permanent provision of reactive power by renewable energy plants is new technological and regulatory territory.
“Grid operators at the distribution grid level, where the majority of renewable energy plants are directly connected, will therefore also benefit from the knowledge we are gathering here.”
Thorsten Leske, head of the Electrical Grids Department at ENERTRAG, added: “In the course of the energy transition, renewable energy plants (EEA) will have to provide the entire system service that is still supplied to the grid by conventional power plants today.
“In the pilot project, different EEAs provide reactive power to stabilize the transmission grid – even when there is no wind.
“At the same time, this is an example of subordinate distribution grids in which the technical possibilities of the EEA have not yet been exhausted.
“The next step should be to establish a market model for the provision of reactive power.”