TenneT, a transmission grid operator, has selected Fluence Energy GmbH, a subsidiary of Fluence Energy Inc, to build grid boosters with a total capacity of 200MW in Germany, cutting down the need for grid interventions and expansion measures.

Fluence will deploy its Ultrastack energy storage system at two strategically located grid nodes – Audorf Süd in the Schleswig-Holstein region and Ottenhofen in the state of Bavaria.

The grid boosters will allow TenneT to integrate more electricity from renewables, enabling the existing grid to operate at higher transmission loads.

As the energy transition picks up pace, the balance between energy production and consumption can be disrupted. Expansion of the grid becomes necessary to transmit energy from decentralised locations, sometimes over long distances.

Traditional grid expansion simultaneously needs to be supplemented with newer technologies such as grid boosters.

Fluence chief business operations and transformation officer Roman Loosen stated: “Germany faces new challenges in a rapidly transforming power sector, including growing renewable generation capacity being situated far from load centres. Grid boosters can be deployed faster, more cost-effectively and more flexibly than traditional grid infrastructure.

“Combining Fluence’s leading energy storage products and services with TenneT’s forward-thinking approach to grid management, the grid boosters play a critical role in strengthening the transmission system and symbolise the significant investment we are taking to advance cleantech innovation in Germany.”

Germany’s high-voltage grid has been operating in accordance with the “n-1 principle”, in which not all power lines are completely utilised. This leaves spare capacity that can be brought in to ensure safe system operation in case of power failure.

With the addition of grid boosters, the transmission capacity of existing lines can run at almost full capacity, thereby reducing the need for preventive grid interventions.

TenneT chief operating officer Tim Meyerjürgens stated: “We will not be able to adapt the transmission grid to the new challenges of the new energy system with grid expansion alone. The integration of electricity from renewables into the transmission grid will also depend to a large extent on operating resources, with which we can flexibly control the transmission grid.

“We are therefore pleased to have won Fluence as a strong and competent partner with many years of experience in the field of storage solutions. Grid boosters are important and tangible solutions for a secure and affordable electricity supply.”

Under the grid development plan, published in 2019, the boosters are pilot projects. The concept will be tested on a small scale with 100MW/100 megawatt-hour energy storage systems at the Audorf Süd and Ottenhofen substations.

The second draft of the grid development plan for 2037 to 2045 confirms the transmission system operators’ plan to add large energy storage systems totalling up to 54.5GW to the German grid by 2045.