When we talk about renewable energy in the UK we tend to think about on- and offshore wind energy, solar power or the recently emerging new tidal and wave developments. And while geothermal energy is often forgotten about it seems that they may receive more attention in the future thanks to renewed interest from developers.
When is geothermal energy efficient?
Geothermal energy is essentially using the heat of the Earth, ‘generated’ by the radioactive decay underneath us. The most ideal places for harnessing this heat depends on the geothermal gradient of the area, the temperature difference between the surface and the core of the Earth. This is on average 25-30C degrees per kilometer increasing with depth, but can be significantly higher in areas near tectonic plate boundaries or in places where the crust is thinner than usual.
Geothermal energy can be used in two ways: the hot water and the hot dry rock found below are used for heating (directly or indirectly) as well as for electricity generation [1].
In the UK
Despite the lack of popularity of geothermal energy projects there are already some successful developments in the UK.
One of the earliest developments exists in Southampton, where a Combined Heat and Power (CHP) station operates, providing district heating, not only used in houses but also in shopping malls and hotels in the city – since 1986. [2]
Also, last year the Department of Energy and Climate Change (DECC) announced the ‘Deep Geothermal Challenge Fund’, which awarded significant funding to three projects in Newcastle and Southampton. [3]
In the Gardens of Eden
The latest large-scale project is probably the planned geothermal power plant of 5MW at the Eden Project in Cornwall. This part of the UK is one of the most suitable places for geothermal energy development thanks to its geology, featuring granite bedrock.
The drilling to the hot dry rocks underneath is expected to start next year [4] after all permissions have been granted, and should reach a depth of 4-5 kilometres. Besides the Eden development it is anticipated to also provide power for 3-4000 homes [5] in the area.
The project seems to be rather promising, which could mean that the whole geothermal energy segment might gain momentum in the UK in the near future.
Reasons could include that geothermal energy is available 24 hours a day; it’s clean, sustainable, but not greatly supported by the government – yet.
[1] http://www.renewableenergyworld.com/rea/tech/geothermal-energy
[2] http://www.southampton.gov.uk/s-environment/energy/Geothermal/default.aspx
[3] http://www.decc.gov.uk/en/content/cms/meeting_energy/geothermal/dgcf/dgcf.aspx
[4] http://www.cornwallbrand.co.uk/news/nid-0061/support-for-uk-geothermal-projects-heats-up-123/
[5] http://www.youtube.com/user/investincornwall#p/a/f/0/eoaxStKTYzM
