Germany: Saft maintenance-free batteries deliver reliable backup power for E.ON’s remote North Sea offshore wind farm

Saft, world leader in the design, development and manufacture of high technology batteries for industry, has supplied its Uptimax nickel battery systems to ensure continuity of power for critical communication and lighting services for sea marking at E.ON’s Amrumbank West offshore wind farm.

The 302 MW capacity wind farm has been inaugurated recently and is located about 40 km from Helgoland, an island off the coast of Germany in the North Sea. It can supply about 300,000 households with renewable energy while helping to reduce CO2 emissions by 740,000 metric tons.

The wind farm’s remote location meant that E.ON required backup batteries that would guarantee reliable and safe operation without the need for regular maintenance visits. 

Benning of Belgium, the power systems supplier for the project, highlighted that Saft’s maintenance-free Uptimax was the only type of battery that would meet E.ON’s stringent technological requirements that included up to four days of backup power, minimal maintenance requirements and long shelf-life.

Saft has provided a total of 80 Saft Uptimax battery systems – one for each turbine. In the event of an interruption to the main power supply, the batteries are designed to deliver peak power for essential safety systems for an initial period of eight hours, followed by a further 88 hours of low power. Each battery is rated at 24 V and has energy storage capacity of 150 Ah or 390 Ah.

The Saft nickel batteries will reduce E.ON’s requirements for costly maintenance visits by helicopter. They will require no topping-up for their entire 20 plus year lifetime.

Benning delivered the battery systems to the offshore construction and engineering specialist Engie Fabricom. The batteries have been built into the modular transition sections of the wind turbine towers, which integrate the structural base section and electrical systems. A lengthy construction and integration process of up to two years meant that the batteries also needed to operate successfully after a long period in storage while fully charged.

“E.ON’s Project team has identified that Saft Uptimax is the only battery system that would meet the stringent technical requirements for Amrumbank West,” said Volker Drescher, Saft’s Germany Sales Manager for Industrial Standby batteries.