Geothermal potential – why hot rocks are cool

8th September 2021 | Commercial Energy

At the end of April 2021, the UK government reset its own climate goalposts and pledged to enshrine in law the most ambitious climate change targets in the world, committing to reducing greenhouse gas emissions by 78%. However, as the UK commits to leading the way on systemic decarbonisation, this ambition is not currently matched by adequate sources of a renewable energy and heat.

Geothermal energy has the potential to significantly contribute to the country’s net-zero goals alongside, of course, a variety of other energy solutions – but currently, its potential as source of both heat and baseload electricity is not being taken advantage of. It is highly dispatchable, renewable, and capable of sustaining projects for lifespans of over 50 years. With November’s COP26 calling the attention of the world to the UK’s climate action, the country cannot be seen to be wasting, undervaluing, or ignoring the natural resources that can accelerate its plans.

The UK is home to a number of locations suitable for deep geothermal energy drilling, as well as several hundred defunct oil and gas wells that could be modified and converted. As well as electricity, geothermal energy can provide large quantities of renewable heat from underground to the surface. The heating of homes and district heating is a challenge for decarbonisation, but geothermal heat provides a viable zero-carbon alternative to gas.
Agriculture and other industries can benefit too; for example, the United Downs Deep Geothermal Power Plant in Cornwall is to deliver a rum distillery with zero-carbon heat and power.

A recent report from engineering consultants Arup states that by delivering up to 12 deep geothermal projects per year over the next 30 years, the UK could host 360 plants that together would be able to generate between 200 and 400GWh of electricity per year, and up to 15,000GWh of heat. The benefits of investing in geothermal energy are not restricted to renewable electricity and heat: it is estimated that enough projects would create 10,000 direct jobs and 25,000 indirect jobs, generating £1.5 billion ($2bn) of investment.

These jobs would clearly be concentrated in areas with promising geological conditions such as Northumberland, Durham, Cumbria. Newcastle upon Tyne, Staffordshire, and Cornwall – several of which are areas that the government has pledged to ‘level up’. The development of 10 to 12 projects over the next five years in these areas would lead to 500 to 500GWh of heat per year, which would supply the equivalent of up to 50,000 homes with investment in the order of £10 million to £15 million ($13.9 – $20.9 million) for each project.

At the same time, the development of these types of projects would lead to a carbon savings of up to 80,000 – 100,000 tonnes, purely through the decarbonisation of district heating.

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