A coal-mine that powered German industry for almost half a century will get a new lease on life when it's turned into a giant battery that stores excess solar and wind energy. This German coal mine will be converted into giant `battery station' to store enough renewable energy to power some 400,000 homes.

The Prosper-Haniel pit in the state of North Rhine Westphalia near the Dutch border, has produced the fossil fuel for almost half a century. But now it will find a new purpose as a 200- megawatt pumped-storage hydroelectric reservoir, which acts like a battery and will have enough capacity to power more than 400,000 homes.

Researchers from a number of German universities are working alongside private engineering companies and the government on the project. They believe the elevation provided by the pit will provide an opportunity for hydroelectric storage. It is thought that water will be able flow downwards, powering turbines and generating electricity, with water pumped back up again during periods of low demand.

Work will begin when the mine closes in 2018. The project will mean the western city of Bottrop, where people have worked the 600-metre deep mine since 1974, will continue to contribute to playing a key role in providing the country with continuous energy (uninterrupted power).

It is hoped that the project will pave the way for similar facilities across the country, since Germany has doubled its commitment to clean energy and is in need of new sites to store excess power.

Around 26 kilometres of shafts in the complex have the potential to accommodate a million cubic metres of water, which will flow quickly through them.

If the project is a success, other mines may also be converted because the state needs more industrial-scale storage as it seeks to double the share of renewables in its power mix to 30 percent by 2025.Thus, it is hoped that the facility will help Germany reach its goal of 30 per cent of its energy coming from renewables by 2025.

Pumped Storage Plan

The crucible of Germany's industrial revolution, North-Rhine Westphalia generates a third of the nation's power much of using aging coal plants. But as Europe's biggest economy continues its so-called Energiewende, German for energy transition, the need for bigger and better storage has become more glaring.

North-Rhine Westphalia, Germany's most populous state, contributes a fifth of the nation's economic output and is home to utilities  RWE AG, EON SE, Steag GmbH, Uniper SE and Innogy SE  that highlight its traditional links to coal and power generation.

Sustained low wholesale power prices are speeding the closure of Germany's older coal plants owned by the utilities. Applications have been made to shut 27 mainly older coal- and gas-fired generators with a combined capacity of 6.6 gigawatts, or enough power for 13 million average homes, data on the Bnetza regulator's website shows.

Germany's decision to turn a coal mine into a pumped-hydro-storage station may solve two of the most intractable challenges created by its shift to clean power. On a local level, it provides new economic activity in a region where generations of workers have relied on fossil fuel for their livelihoods. On a regional level, it catalyzes the expansion of renewable energy by helping to maintain electric capacity even when the wind doesn't blow or the sun doesn't shine. 

Sources:

The Independent newspaper, UK

Bloomberg

University of Duisburg-Essen