Widely used around the world, fracking involves pumping a mixture of water, sand and chemicals underground at high pressure to release natural gas trapped between rocks. 

Former prime minister David Cameron backed efforts to develop the first onshore fracking projects in the UK under a “dash for gas” bid to secure domestic energy supplies.

But tremors triggered during tests by leading player Cuadrilla in Lancashire led to the industry being placed under tight restrictions. It was then banned after the Oil and Gas Authority said it was not “possible to accurately predict the probability or magnitude of earthquakes linked to fracking.”

Cuadrilla, which said it is not part of any potential legal action or correspondence, wrote separately to the Government early this year highlighting that more “red-light” seismic events have been recorded from geothermal work in Cornwall than at its own wells. 

Private company Geothermal Engineering has been testing water flows ahead of plans to develop geothermal power stations using hot water flowing up to 5km underground, from which lithium, used in electric car batteries, would also be extracted. 

Producing energy from geothermal waters is a very different process to fracking as it involves pumping hot water that already flows naturally through rocks, rather than creating fractures. 

Its seismic activity is generally regulated by local authorities based on the vibrations caused at the surface. Frackers, on the other hand, faced strict limits on earthquake magnitude regardless of what was felt at ground level. 

Cuadrilla argues this difference is unfair, since both risk causing earthquakes even if small.  

In its letter to the Government in February, the company said: “It is clear that resolving and lifting the moratorium on hydraulic fracturing should happen in parallel with defining and appropriately mitigating and regulating the risks of induced seismicity associated with comparable operations.” 

This week, the company added that its questions had not been satisfactorily resolved. 

The push from frackers comes as soaring global gas prices trigger a debate about domestic energy supplies.

The prospect of any resurrection for the industry is extremely unlikely, however, given rising hostility to fossil fuels and a push for net zero carbon emissions. Even new oil and gas projects in the established North Sea face huge hurdles to get up and running. 

Last week the proposed Cambo oil field was put on hold following a decision by Shell to pull out.

A Government spokesman said: “All geothermal drilling projects are conducted in the safest way possible, with assessments of likely seismic events made before and during any drilling operation. Seismic activity resulting from current geothermal projects remains extremely low.”

“We maintain our position that fracking will not be allowed to proceed in England unless compelling new scientific evidence is provided.”

Geothermal drilling sparks tensions in Cornwall

Reports of windows rattling heralded the rumblings of a new industrial era in Cornwall. The former mining heartland is once again the focus of prospectors in the rush to green energy and electric cars.

Developers looking to plumb Cornwall’s thermal waters in rocks up to five kilometres underground for clean power, heat and world-class grades of lithium were carrying out tests from Redruth when residents reported shakes above ground.

“I thought the house was going to go down a mine shaft,” wrote one resident on Facebook. “At least I know what it was now.”

Dr Ryan Law, founder and managing director of Geothermal Engineering which briefly paused the tests in late September 2020 to develop a fleet of four geothermal power stations, is keen to reassure residents it’s not a sign of things to come.

“Cornwall is incredibly stable as a rock mass,” he says. “There’s absolutely no possibility we’re ever going to cause anything that’s going to cause any damage to buildings.”

The residents of Cornwall are not the only ones stirred to attention by the tremors, however.

Nearly 400 miles away, Lancashire and its Bowland Shale were until recently at the heart of another rush to secure domestic energy supplies.

Drillers including billionaire industrialist Sir Jim Ratcliffe spent an estimated £500m in the quest for gas trapped between rocks that could be released by pumping in water, sand and chemicals at high pressure – a process known as fracking.

Their dream died before any gas was produced, however. Fracking was banned in England in late 2019 following howls of protest among critics of both the extraction process and fossil fuels, and due to concerns about earthquakes.

Cuadrilla, the largest player, triggered a handful of tremors while drilling in Preston New Road, Lancashire, before the Oil and Gas Authority dealt a final blow in a report saying it was “not possible to accurately predict the probability or magnitude of earthquakes linked to fracking operations.”

Frackers burned by that experience are now looking at the emerging geothermal industry in Cornwall, and crying foul. Some are even threatening to sue, raising a further headache for the Government as it tries to shift away from fossil fuels. 

“With the recent seismicity caused by geothermal development in Cornwall raising no regulatory concerns in Government, it would be remiss of us to not highlight this as further evidence of the asymmetrical approach the [business department] takes to regulation of the shale gas industry,” said Charles McAllister, policy manager at UK Onshore Oil and Gas, the trade group.

“For two subsurface sectors to carry the risk of similar seismicity, yet only one be held to account or best practice for it, is clearly discriminatory,”