IS A CLIMATE SOLUTION JUST BENEATH OUR FEET?
IS A CLIMATE SOLUTION JUST BENEATH OUR FEET?
Professor Dave Healy discusses whether a solution to our energy problems may lie just 100 metres underground.
I believe the answer has been beneath our feet all along.
Before I was interviewed for my role at Leeds, there was talk that the University was going to investigate geothermal heat for the buildings on campus. I was a bit sceptical – because no major UK university had ever been so bold. I asked about it at interview, and they told me drilling would start on Monday!
That’s when I knew Leeds was the place for me.
Decarbonising the UK’s domestic heating sector is crucial for the country to meet net zero ambitions by 2050. Heating accounts for about one third of the UK’s energy consumption and is still primarily powered by natural gas.
The UK has focussed on several ways we might transition to clean energy, chiefly wind and solar power.
But there are issues with these options. They rely on the UK’s fluctuating weather, which leads to surges and lulls – and there are further challenges of rising electricity demands, inefficiencies in renewable energy conversion and the need to improve the pylon, cable and grid infrastructure.
Geothermal heat can help overcome many of those issues, and Geosolutions Leeds is showing what’s possible. We aim to meet the challenges of the climate crisis through world-class subsurface research – and it all started here on campus with those holes, the Monday after my interview.
Walk about some familiar campus landmarks, and you might see the drill holes, though you might also miss them because they’re quite discreet. There are ten in total drilling down to between 100 and 200 metres.
Testing has shown that conditions beneath campus are suitable for replacing the current gas heating system with a geothermal alternative. That’s thanks to sandstone aquifers under the city which hold large quantities of flowing groundwater. A combination of age-old radioactive decay in the Earth’s subsurface and solar energy from above has warmed this water to around 12-14 degrees centigrade.
We’ll pipe this warm water into a new energy centre, which is currently being built on campus, where heat pumps will use a small amount of green electricity to boost the temperature. The water will pass into the radiators in our engineering buildings and the Henry Price halls of residence.
It’s an open-loop system, so once used, the now cool water will be carried back into the ground through a different borehole, where it’s heated underground once more. En route, that cool water can even be used to extract heat from large data centres in Engineering – a process which usually uses air conditioning. This excess heat is returned to the ground where it is stored in the aquifer for extraction in winter.
The whole process is clean, constant, and almost infinitely renewable. The geothermal site is operating as a Living Lab for testing and teaching. We’ll continue to work our way down campus in sections, taking with us what we have learned, and switching off the gas as we go. We were one of the first institutions in the country to do it, and other UK universities are looking to Leeds for guidance as they follow suit. They may not have identical ground conditions to Leeds because of varied geology across the UK – so they may have to drill deeper, for example – but the principle is the same.
Many countries are making good use of geothermal energy already. In Paris and Munich, apartments and tower blocks are heated this way. In the Netherlands, farmers have been using geothermal energy in greenhouses for over 20 years. We’re showing that local heat is secure, cost effective, viable and sustainable here too. The next step is to expand beyond campus and into the city.
Currently, an incinerator facility provides some heat across Leeds through the PIPES heating network. This piping infrastructure could be connected to geothermal heat sources instead, and we’re collaborating with Leeds City Council to help make this happen.
Of course there are still challenges to overcome. Upfront costs can be high – although we know from our forecasting that these will be offset over time.
People may worry about earthquakes and fracking because we're digging into the ground, but this is actually the opposite process. By taking water out of the earth at this shallow depth, we’re not adding pressure, and if anything, we’re reducing the risk of earthquakes and slippage. We’re also using fibre optic systems to monitor seismic signals, which means we can pick up on subtle changes underground and ensure the geothermal system operates efficiently and safely.
Regulation issues are non-trivial. Designs must ensure the boreholes are in the right places with the right spacing – and we’d need to stop people drilling down to steal other people’s heat. The use of heat pumps in the system also means reliance on other green sources of energy, highlighting that it will still take a combination of solutions to reach net zero.
That's why our experts – across geology, engineering and social sciences – are providing support to those other areas, too. We're investigating more efficient and environmentally friendly approaches to the exploration and extraction of key elements needed to build wind turbines, solar panels, and electric vehicles. We’re supporting projects to lock carbon dioxide and nuclear waste within rock formations. Our researchers analyse and model the sea floor to help mitigate the risk associated with wind farm development upon mobile sediments, and improve the lifespan of offshore infrastructure.
However we do it, the need to accelerate our pioneering work and transition away from fossil fuels has only increased in the current geopolitical climate, with issues around energy security and the pricing of fossil fuels.
But that's another benefit of geothermal heat; it’s unaffected by the world outside. We’ll always have it – it's right beneath our feet.
Dave Healy is Professor of Geomechanics and Director of Geosolutions Leeds, an interdisciplinary research centre bringing together experts across geology, engineering, and social sciences to lead the way towards a clean-energy future. He says a solution to our energy problems may lie just 100 metres underground.
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