Flooded mines across the UK could store large amounts of wind energy that would otherwise go to waste by heating up the water within them. The heat could then be extracted to warm homes in winter.
In 2022, enough wind energy to power more than a million homes was wasted in the UK, to the think tank Carbon Tracker. That is largely because infrastructure for wind energy transmission and storage has not kept pace with the boom in wind turbine installations, forcing suppliers to pause production when demand falls below supply.
That has spurred experts to search for new ways to store this energy for long periods in order to maximise how much can be captured when the wind is blowing.
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鈥淭he UK is peppered with mine shafts from the days of coal mining 鈥� we want to turn these holes in the ground into thermal stores to help balance the electrical grid and to decarbonise homes and businesses,鈥� says a group of researchers led by at the University of Strathclyde in the UK in a to explore this idea.
The group 鈥� which includes representatives from several energy companies, as well as the UK鈥檚 Coal Authority 鈥� is now studying the feasibility of the idea, with plans to run tests in a mine in Scotland by mid-2024.
Shipton tells 快猫短视频 this will involve warming the top 20 metres of the water in a mine shaft with loops of steel tubing carrying a heated fluid. The researchers will use the experiment to answer a slew of questions about the safety of such systems, from how the heat affects the water鈥檚 convection in the shaft to how it impacts the integrity of the concrete walls of the mine.
Shipton says they have not yet settled on a site for the experiment, but are considering the Monktonhall Colliery near Edinburgh and the Barony Colliery south of Glasgow, which are among the deepest mines in Scotland.
鈥淭he thing that I really like about this idea is that they鈥檙e trying to take all the infrastructure that has been abandoned and do something useful with it today,鈥� says at Carbon Tracker.
There are around 170,000 mine entrances in the country. Shipton estimates that if just 1 per cent of those were used to store heat, they could provide enough energy to warm 10 per cent of UK homes for a week, even in a worst-case scenario of cold weather and low energy production.
If heated to at least 55掳C (131掳F), Shipton says the mine water could be used directly in district heating networks or industries that use low-grade heat. She says mine shafts are ideal for storing heat because they are well insulated, and the water in them is already kept relatively warm by geothermal energy and chemical processes.
There are more than 40 sites in the country that already use heat extracted from naturally warmed mine water, says at Durham University in the UK. The Dutch town of Heerlen also uses industrial heat to recharge mine water for supplying warmth to the town in winter. But he says Shipton鈥檚 plan to use surplus renewable electricity to heat the water is new and interesting. He thinks the idea could be particularly valuable for communities that lost livelihoods from the closure of the mines. 鈥淲e can rebuild communities around a shared heat facility,鈥� he says.
Gluyas adds that finding ways to reuse heat is a very efficient application of surplus energy. 鈥淵ou can鈥檛 beat the second law of thermodynamics. But you can snuggle up pretty close to it,鈥� he says.
