Environment Agency
You can fit post-combustion carbon capture (PCC) plants to new or existing power plants to capture the carbon dioxide (CO2) in the flue gas. This is so the CO2 can be either:
- stored in permanent underground geological storage facilities
- used as a product
BAT means the available techniques which are the best for preventing or minimising emissions and impacts on the environment.
Except where stated, this BAT guidance is not a regulatory requirement but identifies important environmental issues to address and best practice.
1. Who this guidance is for
This guidance covers PCC plants that use amine-based technologies to capture CO2 from the flue gases of power and CHP plants fuelled by natural gas and biomass.
In the UK these installations are permitted under the:
- Environmental Permitting Regulations (England and Wales) 2016
- Pollution Prevention and Control (Scotland) Regulations 2012
- Pollution Prevention and Control (Industrial Emissions) Regulations (NI) 2013
For environmental permitting purposes, a PCC plant is a Part A (1) 6.10 activity in its own right when the CO2 is being captured for geological storage. It could also be a directly associated activity with a combustion activity installation when the CO2 is captured and used for other purposes.
This guidance is for:
- operators when designing their plants and preparing their application for an environmental permit
- regulatory staff when setting conditions in environmental permits
- any other organisation or members of the public who want to understand how the environmental regulations and standards are being applied
The guidance covers both new plants and retrofits to existing plants.
The guidance is supported by a BAT review on the same topic which summarises the available evidence. This guidance refers to relevant sections in the BAT review.
The guidance does not include carbon capture for use, though much of this BAT guidance is relevant where you use amine capture solvents.
Current BAT identifies carbon capture as an emerging technique in the large combustion plant (LCP) BAT reference document (BREF) but does not address all the potential effects of carbon capture. This situation is addressed by Article 14(6) of the Industrial Emissions Directive (IED) where regulators must set permit conditions covering emission limit values (ELVs) together with other permit conditions. These conditions must be based on their own determination of BAT using the criteria listed in Annex III of the IED. They should also consult with operators during this process.
Permit conditions must also protect the environment by setting conditions to ensure no environmental quality standards are breached (Article 18 of the IED).
If you operate a large combustion plant, you will need to comply with the:
- IED Chapter III Annex V ELVs
- BAT associated emission limits (AELs) identified in the LCP BREF
You can apply for a temporary derogation of BAT AELs for up to 9 months, on the basis that carbon capture is testing and using an emerging technique (see Article 15(5) of IED).
When you apply for an environmental permit for this activity, you must tell us whether youre going to follow this guidance or propose an alternative.
UK regulators have worked with the UK CCS Research Centre, Carbon Capture and Storage Association and other stakeholders to develop this BAT guidance for PCC.
2. Power plant selection and integration with the PCC plant
2.1 Efficiency of fuel use in power and CHP plants with PCC
You must maximise the thermal energy efficiency of the power plant and of the supply of heat for the associated PCC plant.
You should refer to the LCP BREF which gives BAT definitions that include thermal efficiencies for new and existing power plant technology. Also refer to section 4.13 of the IED environmental permitting regulations guidance on Part A installations.
For natural gas power plants, lower heating value efficiencies of 60% or above without CO2 capture are reported in the LCP BREF to be achievable for large-scale new combined cycle gas turbine installations.
New biomass power plant efficiencies will depend on:
- the size and type of boiler
- whether you use sub- or super-critical steam conditions
You can reduce the impact of adding PCC by using power plant technologies that give highest thermal efficiencies without CO2 capture, since these have low specific CO2 emissions (tonnes CO2 per megawatt hour).
If you expect to use more fuel to help meet the heat or power needs of the PCC plant, you should also integrate the most efficient power plant technologies for that fuel capturing additional CO2.
You should apply fuel input, electricity output and CO2 emission metrics in the same way as you would to a power plant with fully integrated PCC (see section 2.3 on supplying heat and power for PCC operation).
2.2 Dispatchable operation
In line with the needs of a UK electricity system with a large amount of intermittent renewable generation, all thermal power plants, including those with CO2 capture, are likely to be dispatchable.
This means that the power plant operator can, within technical limits on rates