What is coal?
Coal is a fossil fuel formed from plants that were buried millions of years ago. The high-temperature, high-pressure conditions underground transformed the plants physically and chemically, forming coal.
Coal contains energy that the plants absorbed from the sun millions of years ago. Burning coal releases this energy. It can then be used to heat water to generate steam, which is then used to drive a turbine to generate electricity.
Coal is generally considered to be a reliable energy source for generating electricity: over 40% of the world's electricity is generated using coal, and in 2009, coal-fired power stations supplied about 28% of the electricity used in the UK.
Coal is abundant but finite. Generating electricity using coal is currently relatively inexpensive, but the cost is affected by world coal prices, which may increase in the future as a result of increasing global demand and as resources deplete.
Burning coal also produces high levels of greenhouse gas emissions. Carbon capture and storage (CCS) technology could present a possible solution, though it has not yet been proven to work on an industrial scale.
CCS is also expected to increase the cost of constructing a coal-fired power station, and reduce its efficiency. However, to meet emissions reduction commitments, the UK Government's policy is not to approve new coal-fired power stations unless they incorporate CCS.
How electricity is generated through coal
See how electricity is generated in a coal-fired power station.
Is it plentiful?
Coal is a finite fossil fuel, although it will not run out until the 2120s at current usage rates. But the UK's climate change commitments mean it cannot build more coal plants without technology to reduce their carbon emissions.
Is it secure?
The UK imported 79% of the coal used for electricity generation in 2009, and the majority of that came from one source, so coal has security of supply issues. To address that challenge, the UK is diversifying its energy mix with other energy sources to be less reliant on coal for electricity.
Is it predictable?
UK coal-fired power stations have an assumed availability at peak of 90%. The UK relies on coal-fired power stations to generate consistent levels of electricity. But the Government's climate change commitments mean no more coal-fired plants will be built until the technology is available to bring down their carbon emissions.
Is it affordable?
By 2020 the cost of generating electricity using coal with carbon capture and storage (CCS) technology to reduce emissions should be about 11.3p/kWh. CCS is coal's biggest affordability challenge but the technology should get cheaper as more plants are built.
Is it clean?
Coal-fired power stations have a carbon footprint of 870gCO2e/kWh. With carbon capture and storage (CCS) technology to reduce emissions, that could be brought down to 190gCO2e/kWh.
EDF Energy's approach
Coal is part of EDF Energy's mix of generating technologies in the UK.