Drilling to begin at UK’s first geothermal power plant

Posted: November 6, 2018 by oldbrew in Energy, geothermal, News
Tags: ,

Credit: ukcampsite.co.uk


It seems unlikely that hordes of angry protesters would rush to this project to complain about any alleged dangers of deep drilling – but you never know.

Drilling will start this week at what could become the UK’s first deep geothermal electricity plant in Cornwall, reports ITV News.

Two wells will be drilled through granite rock near St Day, the deepest of which will reach 4.5 kilometres.

Geothermal Engineering Ltd says the aim of the project is to demonstrate the potential of geothermal technology to produce electricity and renewable heat in the UK.

It is believed that the plant at the United Downs Industrial Estate has the potential to supply up to 3MWe (Mega Watt electrical) of electricity, enough to power 3,000 homes.

Once drilling at the site is complete, water will be pumped from the deepest well at a temperature of approximately 190C.

This water will be fed through a heat exchanger at the surface and re-injected into the ground to pick up more heat from the rocks in a continuous cycle.

The extracted heat will be converted into electricity and supplied to the National Grid.

Geothermal technology is described as a “continuous” energy source because it does not suffer from peaks and troughs experienced by other sustainable power sources.

Continued here.

Comments
  1. Neil Hampshire says:

    Does anyone know if the geothermal well has to be fracked to help with the flow of water from inlet to outlet?

  2. oldbrew says:

    The ITV report only says:
    Once drilling at the site is complete, water will be pumped from the deepest well at a temperature of approximately 190C.

    This water will be fed through a heat exchanger at the surface and re-injected into the ground to pick up more heat from the rocks in a continuous cycle.

    Drilling 4.5 km. through granite sounds quite tough.
    – – –
    Fracking Geothermal

    Seriously folks you read it right… fracking (an actual technical term for hydraulic fracturing) hot dry rock reservoirs — a technique that is already pretty well understood and is widely used in the oil and gas sectors to squeeze out extra production from low permeable deposits – has the potential to open up vast hot dry rock “heat” reservoirs for use as a reliable geothermal energy source. According to a 400 page MIT study The Future of Geothermal Energy sponsored by the Department of Energy (DOE) and published in 2007 the economically recoverable potential for “Heat Mining” in the US could grow to a cumulative installed generating capacity of 100GW in less than fifty years.

    Read more: http://greeneconomypost.com/fracking-geothermal-4804.htm

  3. oldbrew says:

    When you’re not below ground it can get windy…

  4. spetzer86 says:

    Since geothermal plants are associated with earthquakes, it is rather amusing the protestors aren’t out and about on this one. https://phys.org/news/2018-04-evidence-geothermal-pohang-earthquake.html

  5. oldbrew says:

    spetzer – great link.

    Quote: Last year, on November 15, a 5.5-magnitude earthquake struck the South Korean city of Pohang, causing structural damage and numerous injurious to citizens.
    . . .
    Data from the sensors indicated the earthquake was centered directly below the geothermal plant

  6. Graeme No.3 says:

    190℃ is a low temperature for electricity generation. Low efficiency usually means higher cost electricity.
    As for continuous operation, have they checked the actual history of geothermal stations? Those in NZ have had to be throttled back as too much extraction leaves the rocks cooler, and they have to drill new holes regularly. In Australia the attempt at geothermal energy collapsed because of the amount of ‘gunk’ getting into the working fluid. Salts dissolved from the granite at high temperatures becoming insoluble at lower temperatures.
    And lastly, the heat in granite rocks comes partly from uranium (don’t tell the Greenies).

  7. oldbrew says:

    Re 190℃ – the next line says:
    This water will be fed through a heat exchanger at the surface and re-injected into the ground to pick up more heat from the rocks in a continuous cycle.

  8. craigm350 says:

    Reblogged this on WeatherAction News and commented:
    Keep it in the ground 😁

  9. tom0mason says:

    Hopefully these people have also considered the problems other geothermal site have had — like bring up subterranean hazardous material such as arsenic, boron, and mercury to the surface? Or what they’ll do if they hit a large gas pocket of methane, hydrogen sulfide, or any other noxious gas?
    Contamination from the rising hot water was a problem in New Zealand — https://www.niwa.co.nz/our-science/freshwater/tools/kaitiaki_tools/impacts/chemical-contaminates/causes-of-chemical-contamination/geothermal-energy-and-chemical-contamination
    Radon a known hazard from the rocks around Cornwall (see https://www.cornwall.gov.uk/environment-and-planning/environmental-protection/environmental-protection-radon/ ).

    “The £18m project has received £10.6m from the European Regional Development Fund, £2.4m from Cornwall Council and £5m from private investors.” 36 million initial costs, how much to keep it running – maintenance, etc., and for what sort of productive time span — 20 years, 40 years? The Norwegians (at http://www.renewableenergyfocus.com/view/12469/drilling-10-000-m-deep-geothermal-wells/ ) say “The normal lifespan for a deep geothermal well is around 30 years, after which the rock has cooled down too much from the cold water injected into the well. However, if left for 25-30 years, the geothermal well will have heated up again.”

    The EU reports problems such as micro-seismic events, alteration to the water table, CO2, methane, and hydrogen sulfide outgassing, heavy metal (including mercury), and high chloride contamination (so high costs maintenance ). http://www.geothermalcommunities.eu/assets/elearning/8.1.GE%20vs%20Environment.pdf
    But overall the EU is fully behind such power generation, so it must be suspect.

  10. Graeme No.3 says:

    oldbrew:
    They aren’t cascading heat upwards; 190℃ is obviously their top temperature and heat is transferred to their generation side fluid. If water, then their top pressure will be about 161 p.s.i. Hell! marine steam engines built in 1910 needed more pressure (in the first stage).
    If they’re using an organic volatile … well, lotsaluck with that but stand well away.
    Perhaps they’re using Drayton cycle compressed CO2 above its triple point?????

  11. oldbrew says:

    Graeme: OK, understood.

    It’s a demonstration project so let’s see what problems they run into.

  12. hearle says:

    I wonder if they did their homework on the Geodynamics project in South Australia that has closed see https://www.abc.net.au/news/2016-08-30/geothermal-power-plant-closes-de
    emed-not-financially-viable/7798962

  13. oldbrew says:

    How relevant is geothermal power?

    Report: UK power capacity ‘to drop by a third without new nuclear’

    Trade union Prospect warns this generation shortfall could occur by 2030

    https://www.energylivenews.com/2018/11/07/uk-power-capacity-to-drop-by-a-third-without-new-nuclear/

  14. oldbrew says:

    BBC: Radon gas linked to granite geology, study finds
    24 September 2012

    Radon occurs naturally in areas with a large amount of granite

    https://www.bbc.co.uk/news/world-europe-jersey-19686157

  15. Adam Gallon says:

    The Eden Project uses geothermal & fracks for it!
    https://www.edenproject.com/eden-story/behind-the-scenes/eden-deep-geothermal-energy-project
    Note the spin. “Fracking the rock to create a geothermal heat exchanger is not the same as fracking for shale gas. “

  16. oldbrew says:

    From Adam’s link:

    What about radiation?
    Radon and background radiation is naturally produced by the granites and clays of Cornwall.

  17. oldbrew says:

    Environmental Impacts Of Drilling For Geothermal Energy
    NOVEMBER 9, 2018
    By Paul Homewood

    Cornwall County Council have actually published a fact sheet for geothermal, which outlines potential environmental issues

    https://notalotofpeopleknowthat.wordpress.com/2018/11/09/environmental-impacts-of-drilling-for-geothermal-energy/

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