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Geothermal Power :hotsprings: - Coggle Diagram
Geothermal Power
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Radioactive decay of isotopes in earths mantle releases heat
Thorium
Uranium
Potassium
Harnessing
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Low temperature
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Geothermal springs
Groundwater that has been heated by hot rocks underground
Comes to the surface in hot springs
Used for district heating
Geothermal aquifers
Hot groundwater may be pumped to the surface from underground aquifers
Used for district heating scheme
High temperature
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Geothermal steam systems
Ground water at very high temps may be bought to the surface
By extraction boreholes
Produces high temp steam at the surface used for making electricity
Hot dry rock systems
Hot rocks near the surface but no borehole
Two boreholes are used
Water is pumped down an injection borehole
Steam is recovered from the second
Fracturing the rocks underground may increase the permeability/surface area exposed for heat absorption
Locational constraints
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Geothermal power stations that use steam turbines need a heat source above 150 degrees
Requires relatively recent volcanic activity
hot rocks are near the surface
In other areas hot rocks are so deep down
Its uneconomical
Environmental impacts
:evergreen_tree:
Very few if carefully developed
Infrastructure
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Steam and hot water pipes can provide obstacles to the movement of large mammals
Gaseous emissions
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hot water is extracted from the ground and can release gases
Small amounts of carbon dioxide
hydrogen sulphide
Waste water
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can contain salts and heavy metals
New technologies
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Low temperature fluids
use liquids that boil and turn turbines at lower temps
water can cool as 60 degrees can boil butane and pentane
Allow areas with low temp rocks to be used for electricity generation
Areas in the UK
Heat may be moved towards the surface of the crust by molten magma or hot water
The heat may be exploited for space heating, hot water or electricity generation