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ENERGY

Wind power could be stored in water under the Harz mountains

Plans are being developed to store energy generated by wind turbines in water pump storage facilities to be built in former mine shafts under the mountains of the Harz region.

Wind power could be stored in water under the Harz mountains
The Hexentanzplatz in the Harz mountains. Photo: DPA

The project would be a world first – putting a pumped-storage hydroelectricity plant into an old mine, thus avoiding potential planning objections.

As Germany seeks ways to make renewable energy more reliable, one of the major questions is how to store energy generated by solar on sunny, or by wind turbines on blustery days.

Pumped-storage hydroelectricity plants work by using power from solar or wind turbine sources to pump water from one tank to another above it. When the sun goes in or the wind stops blowing and electricity is needed, the water from the top is released to the bottom tank – pushing through turbines as it goes and generating power.

Marko Schmidt, an industrial engineer for the Energy Research Centre of Lower Saxony (EFZN), has carried out a study on building such a plant in the abandoned Wiemannsbucht mine shaft in Bad Grund, a town in the western Harz mountains which he said could be done for up to €200 million.

Several potential pitfalls remain – including as-yet unfound investors – but he says the plant could stimulate the economy and provide urgent energy relief to the region.

“The Harz is one of the most outstanding regions where an underground pumped-storage plant is possible,” Schmidt told news agency DAPD.

A total of six such projects have been proposed for the West Harz region. The storage capacity of the proposed plant in Bad Grund is 400 megawatt hours – enough to provide more than 40,000 households with electricity for a whole day.

While the proposed plant would store energy generated by local wind turbines, future larger projects could also be used as storage for offshore wind power from the North Sea.

Above-ground storage plants, already in use throughout Germany, act as energy reservoirs to overcome intermittent energy shortages common with renewable sources such as wind.

The new subterranean proposal in the Harz would make use of elevation differences between old tunnel crossings in the mines, which can be as deep as 900 metres.

For Schmidt, the underground plant idea’s attraction lies in its minimal impact on the landscape. He said he did not expect Harz residents to protest its construction as they had previously opposed wind turbines and above-ground power lines.

Policy makers have yet to throw their full support behind the project, one of 16 proposals to stimulate the economy of the Harz region, but their rhetoric is optimistic.

The government of Lower Saxony supports the project and is following it with “interest and excitement,” said a spokeswoman for the Ministry of Economic Affairs.

Pending legal approval, the plant could be built in between three and five years, providing the region with up to 150 new jobs, while the plant’s daily operations would employ up to seven people.

Wolf-Rüdiger Canders, professor of electrical machinery at the Braunschweig University of Technology, believes in the project and said it was “not unrealistic” that investors would be found.

DAPD/The Local/adn

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ENERGY

Could the Norwegian government introduce a cap on energy prices? 

Due to soaring prices, the Norwegian government is mulling over several solutions, including a potential price cap for electricity and limiting energy exports abroad. 

Could the Norwegian government introduce a cap on energy prices? 

High energy exports in the last 12 months, low filling levels in Norwegian reservoirs and an uncertain energy situation around Europe have led to soaring electricity prices in southern Norway. 

Last year the government introduced a scheme whereby it covers 80 percent of consumers’ energy bills where the price rose above 70 øre/kWh. The portion of the bill under 70 øre is paid in full by households. The portion the government covers will increase to 90 percent in October. 

Critics have argued that the current scheme still leaves households struggling with their bills. As a result, Norway’s government has said it is mulling its options to curb energy bills.

Norway primarily depends on hydroelectric dams to help it meet its energy needs. Still, reservoirs in southern Norway have been at the lowest level for ten years, public broadcaster NRK reports. 

Low reservoir filling over the past year has conceded with record exports with higher prices on the continent, making sending power abroad an enticing proposition.

Recently, exports have fallen significantly, and the government is considering introducing a limit to reduce the possibility of energy rationing being introduced this winter. 

“Restrictions on the export of electricity to Europe may be one of the measures that is needed,” Elisabeth Sæther, state secretary at the Ministry of Oil and Energy, told NRK. 

Earlier this week, Prime Minister Jonas Gahr Støre ruled out completely shutting off exports to the continent. 

“It is a dangerous thought and will not serve us well. It could give us more expensive power and lack of power in given situations. We will hardly be able to import power when we need it without contributing to other countries when they need it. There is a reciprocity in this,” he told the newspaper Aftenposten earlier in the week. 

Sæther also told NRK that the government was weighing up putting a maximum price on energy but warned that it could have unforeseen consequences. 

“We are afraid that a maximum price means that more water is drawn into the reservoirs, which we need for the winter. It is a serious situation. We must prevent ourselves from getting into a situation where we lack enough power this winter,” she told the broadcaster. 

At the end of May, the state-owned Statnett announced that the supply situation in Norway might be under strain – in some scenarios – all the way up to and through the winter, especially if Southern Norway experiences drier than usual weather in the second part of the year. 

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