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A multi-megawatt battery, with a capacity equivalent to two million iPhone 6 batteries, has been put into operation at the Dörverden run-of-river hydropower plant in Germany. With pure energy "in a can", renewable energy sources can take on new and important tasks.

Energy from the sun, wind and water – all the renewable sources in our portfolio – will be stored in the battery.

The lithium-ion battery in Dörverden consists of three mobile units, each storing more than one megawatt of power. The battery is the first of its kind in Statkraft.

"Energy from the sun, wind and water – all the renewable sources in our portfolio – will be stored in the battery," says Matthias Holzenkamp, Vice President Business Development in Statkraft's Continental Asset Management and Market Access unit in Düsseldorf, Germany.

While other renewable energy storage systems, such as pump-storage power plants for hydropower, are tied to specific geographical locations, batteries can be moved. For several of the renewable energy types, battery storage can provide good solutions to key challenges related to flexibility and system security.

Matthias Holzenkamp. Vice President Business Development in Statkraft's Continental Asset Management and Market Access unit in Düsseldorf, Germany.

Clean system security

Storage systems are important for developing renewable energy because they help strengthen the system security of the power grid with clean energy. "An increasing amount of energy production in Germany originates from the sun and wind, creating a growing need for stability and security solutions in the power grid," explains Holzenkamp. "Sun and wind are variable energy sources. The amount of energy that can be produced depends on the number of days with wind and sun, and results in unpredictable variations in energy production."

"So we need to make sure we have backup solutions. And they should preferably be clean," says Holzenkamp.

Control reserve

Germany is the European leader in generating energy from variable renewable sources such as sun and wind, and the country has set itself ambitious goals. By 2020, one third of Germany's electricity consumption will be supplied by renewable energy sources, by 2030 half, and by 2050 a full 80 per cent. "It is very important that these energy sources can also deliver stability and system security in the power grid," says Holzenkamp.

"The batteries we have now put into operation, have the potential to play a central role in the power grid's most important balancing act between energy consumption and energy production," Holzenkamp says.

"First, they can deliver positive control reserve, in other words supply energy from the sun and wind when energy consumption is high – without the sun shining or the wind blowing. Second, a battery can react incredibly quickly."

FACTS Statkraft's new battery storage system with a capacity of 3 MW is located at the Dörverden runof-river hydropower plant in Lower Saxony, Germany. The battery system has been developed in close cooperation with the company ads-tec GmbH and is the first multi-megawatt battery in the power grid area of the system operator TenneT TSO GmbH.

Renewable flexibility

"In line with the agreement we have made with the local system operator TenneT TSO GmbH, we have currently set the battery to react within 30 seconds," says Holzenkamp. "But it can react in under a second to fluctuations in the power grid."

This lightning-fast reaction time could mean new business opportunities for Statkraft.

"This flexibility makes it possible to develop a completely new service that will help to keep the system frequency as close to 50Hz as possible during normal operation," says Holzenkamp.

"To achieve this, the technical devices must react within one second, and batteries are currently the most promising technology for services of this kind. Statkraft has a team in the UK investigating the potential business opportunities."

Following the market closely

Whether Statkraft installs these types of batteries elsewhere depends on how the market for battery-based services develops.

"But we are following up new opportunities," says Holzenkamp.

"The most promising right now are two projects where Statkraft can provide important new knowledge, a relevant location and market access for the battery. Naturally, we will also closely follow any opportunities that arise in the UK."

Text: Anette Hjerde
Photo: Sabine Grothues
The article has also been published in Statkraft's magazine People & Power no. 2/2016