Clean coal
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Range of technologies to pre-treat coal to reduce emissions, burn it more efficiently, or capture and store carbon emissions. |
Most abundant and widely distributed fossil fuel. Preserves existing industry and makes use of existing infrastructure.
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Uses more coal per kWh than normal coal power. Produces some pollutants, such as heavy metals. Coal is a finite resource.
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Small-scale trials under way. Huge investment(c $3trn) needed by 2050. Estimated cost: 5-13 cents/kWh (double normal coal).
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Geothermal
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Uses naturally hot rocks, or temperature differences, beneath Earth's surface to heat water directly or drive turbines. |
Constant renewable energy source in some locations. Highly efficient for heating living spaces. Long hardware lifetime.
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Underground heat only available in some locations. Energy can "dry up" for years. Can in some locations release toxic gases.
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Currently less than 1% of global capacity. US and Australia investing in new technologies. Estimated cost: 5-11 cents/kWh. |
Nuclear
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Harnesses energy from the controlled splitting of atoms, releasing heat that is harvested to drive turbines. |
Significant historical experience and technology developed. Can provide heat and electricity. Plentiful fuel supplies.
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Perceived as risky. Strong opposition from green campaigners. Creates radioactive waste. Fuel can be weapons security risk.
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Set for a comeback after years in shadow. New reactors behind schedule. Disputed cost. One estimate: 4-8 cents/kWh.
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Marine
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Exploits energy of shifting tides, underwater currents, or shoreline and offshore waves. |
Large and infinitely renewable resource. Tidal energy very regular. Can be exploited on small or large scale.
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No consensus on best means to capture energy. Large projects may disrupt natural water flow, tides and ecosystems.
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Little expected before 2030. Technology uncertain, so wide cost range: 15-30 cents/KWh (double or triple coal).
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Wind
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Using the wind, on land or at sea, to drive turbines. |
Significant experience and mature industry and infrastructure. Infinitely renewable resource. Can be deployed in range of project sizes.
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Intermittent resource. Not efficient for all locations. Windfarms interrupt radar signals, can be noisy and regarded by some as unsightly.
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Currently about 1% of global supply. Onshore cheaper than offshore. High energy storage costs are handicap. Quite low cost: 7-14 cents/kWh.
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Solar
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Gathers energy from sunlight, using light to generate electricity directly (photovoltaic) or to heat liquids to drive a turbine. |
Infinitely renewable and most abundant zero-carbon resource. Silent and no effects on local environment.
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Like wind and marine, intermittent. Current photovoltaic designs complex; if widely used, chemicals could become scarce.
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US investing heavily, EU planning plant in Africa. Cost still high (13-35 cents/kWh) but expected to fall. Price of solar panels falling.
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Hydroelectric
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Generates electricity by damming water and constraining flow through turbines. Most widely deployed renewable strategy.
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Well-established as a large-scale energy source. Can also be used for energy storage if run in reverse.
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Dams disrupt ecosystems and are a public health risk if they burst. Can trap decaying matter that creates pollution.
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One of the cheapest forms of electricity. Development focusing on small hydro-electric power. Estimated cost: 2-6 cents/kWh.
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