Harnessing the heat of the earth
Geothermal resources are reservoirs of hot water that exist or are human made at varying temperatures and depths below the Earth’s surface. Wells, ranging from a few feet to several miles deep, can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface for use in heating and cooling.
A pair of wells (known as a doublet) up to 5km deep are drilled into underground reservoirs containing brine (very salty, undrinkable, water).
One of the wells is used to tap into the geothermal resource by pumping the hot water to the surface where the heat is transferred to the surface system through a heat exchanger. The brine is then returned to the reservoir through the second well.
The water in the surface system, after being heated by passing through the heat exchanger, can be utilised for a district heating network or for directly connecting to other customers networks.
An ideal solution to the urban deployment of renewable energy, geothermal energy…
…has the smallest surface footprint of any energy source and it runs 24 hours a day, whatever the weather
…is low in visual impact, with no buildings higher than 10m and it removes the requirement for expensive building retrofits
…is dispatchable with wide temperature applicability, storage potential and can be used for cooling as well as heating
…has high public acceptance – development of geothermal has the backing of business, academics and NGOs
Geothermal is an indigenous source of sustainable energy
Embracing it would decarbonise heating, reduce our reliance on imports and help to safeguard Britain’s energy security. As a non-extractive, renewable energy source, geothermal heat can play a key role in reducing the UK’s carbon emissions and meeting the targets set at COP 26.
Unlike other forms of renewable energy like wind and solar, geothermal heat is constant, switchable and not susceptible to the weather, meaning the energy derived from it is predictable and stable.
Geothermal energy offers a major opportunity for the UK to bolster its energy security with proven green technology, saving money on costly imports while creating jobs as part of a just transition from fossil fuels.