The UK Government has published its implementation plans for the closure of unabated coal plants by 2025. The decision to close the plants was made in 2015 and was followed by a consultation on how this would be put into effect. The decision has now been made to set a limit on the amount of carbon coal plants can emit, to 450g CO2 per kWh, which is broadly in line with the emissions intensity of an unabated gas generator and is in line with the existing Emission Performance Standard that applies to new build fossil fuel plants. Coal units will be unable to bid into capacity auctions for delivery in 2025/26 and beyond unless they can demonstrate that they will be able to meet this emissions intensity limit. In December 2016, the capacity auction for delivery for 2020/21 awarded secured agreements to 6 GW of unabated coal.
One way that generators could meet the new emissions limit is to co-fire with solid biomass, as is the case at Drax power station, which generates 70% of its electricity from wood pellets. However, the retrofitting of Carbon Capture and Storage (CCS) to existing plants is thought to be inefficient and cost-prohibitive.
The UK is committed to meeting stringent carbon reduction targets under both domestic legislation and international agreements. Because coal emits twice the level of carbon than gas for each kWh of electricity generated, its phase-out is an important element in meeting these targets. Government figures show that the closure of unabated coal plants will yield carbon reductions of 15 MtCO2 (2025 to 2035), in addition to reductions of sulphur dioxide, nitrous oxides, and particulate matter. Coal-fired generation has declined in recent years as a combination of emission limits and carbon taxes have made coal plants uneconomic to run. Support mechanisms for renewables and an increase in gas supply have also played a part. Electricity output from coal fell to a record low of 2% in Q2 of 2017. The UK Government will keep the powers to suspend the coal phase out if there is an emergency shortfall in energy supplies. Although, indications are that any shortfall in generation will be met by existing gas-fired generation plants staying open for longer.