Change description : 2026-02-12 10:00:00: Added links to a new service for applying for a environmental permit online in England. [Guidance and regulation]
Medium Combustion Plant Directive (MCPD) permits are standalone permits. They only cover emissions of SO₂, NOₓ and dust to air. There are no permit conditions for water, land, energy efficiency, odour or noise.
There are 3 types of permit for a stationary or mobile medium combustion plant (MCP):
standard rules permit – low risk
simple bespoke – low risk
complex bespoke permit – high risk
Find information on what to do if your MCP is already permitted, for example, if you have:
You need to apply in time for the regulator to determine your application – check the ‘After you apply’ section of this page for more information.
Standard rules permits
To apply for a standard rules permit in England, you must be able to meet the rules set out in the permit. If you cannot, you must apply for a bespoke permit.
Natural Resources Wales do not issue standard rules permits anymore – only bespoke permits. If your specified generator is in Wales, use the Natural Resources Wales guidance.
If the 500 operating hours per year exemption applies to your MCP, you must provide a signed declaration that the MCP will not operate more than the allowed hours.
Charges for standard rules permits
SR2018 No 7: new and existing, low risk, stationary medium combustion plant and SR2022 No 9: new and existing, low risk, stationary medium combustion plant which is a natural gas boiler
If you cannot meet the conditions in a standard rules permit you must apply for a bespoke permit. There are 2 types:
simple bespoke (low risk) – does not require detailed air dispersion modelling
complex bespoke (high risk) – does require detailed air dispersion modelling
Read the following guidance to see:
which type of bespoke permit you must apply for
what information you must provide in addition to that required for a standard rules permit
You cannot apply for an MCP bespoke permit if the activities are directly associated to an IED installation environmental permit.
Air emissions risk assessment
Stage 1
If each individual MCP is operating outside the minimum screening distances to the habitat sites given in the table then you can apply for a lower risk simple bespoke permit. If any of the MCP(s) are operating inside the minimum screening distances to habitats given in the table then you should move to a stage 2 assessment.
Minimum screening distances to the habitat sites
Fuel type used
Rated thermal input (MWth) of any MCP
Minimum distance from MCP to a site of special scientific interest or marine conservation zone in metres
Minimum distance from MCP to a special area of conservation, special protection area or Ramsar wetland in metres
Natural gas, gas oil or woody solid biomass
1 to less than 2
750
750
Natural gas, gas oil or woody solid biomass
2 to less than 5
1,000
1,000
Natural gas, gas oil or woody solid biomass
5 to less than 10
1,500
1,500
Natural gas, gas oil or woody solid biomass
10 to less than 20
2,000
2,500
Natural gas, gas oil or woody solid biomass
20 to less than 50
2,000
5,000
Gas other than natural gas
1 to less than 2
1,000
1,000
Gas other than natural gas
2 to less than 5
1,500
1,500
Gas other than natural gas
5 to less than 10
2,000
4,000
Gas other than natural gas
10 to less than 20
2,000
5,000
Gas other than natural gas
20 to less than 50
2,000
10,000
Solid and liquid heavy fuel oil
1 to less than 2
2,000
2,000
Solid and liquid heavy fuel oil
2 to less than 5
2,000
4,000
Solid and liquid heavy fuel oil
5 to less than 10
2,000
8,000
Solid and liquid heavy fuel oil
10 to less than 50
2,000
10,000
You can ask for a free habitats (nature and conservation) screening assessment to check if you meet the criteria. Use our pre-application advice service and select the installations form.
Stage 2
If any of your individual MCP are within the minimum screening distances given in the stage 1 assessment, you can use the Simple Calculation of Atmospheric Impact Limits (SCAIL) combustion tool to do an air emission risk assessment.
The output of the screening and subsequent assessment will determine if you:
‘screen out’ and need to apply for a low risk simple bespoke permit
‘screen in’ and need to apply for a high risk complex bespoke permit
If you do not use the SCAIL combustion tool and guidance to do a stage 2 assessment, you will need to apply for a complex bespoke permit. You will need to send us a detailed air dispersion modelling report. You must include information about any actions you are taking to reduce air impacts to prevent harm to a habitat. Detailed modelling requires specialist knowledge. You should find an air quality consultant to do it for you.
If the MCP’s total thermal rated input is 20MWth or more and produces waste heat at a useful temperature you must also meet Schedule 24 of the environmental permitting regulations. This implements the requirements of the Energy Efficiency Directive. You must prepare and submit a report if your plant is:
new or substantially refurbished
operates more than 1,500 hours per year
is over 20MWth (total aggregated net thermal input)
a boiler, furnace, gas turbine or compression ignition engine
If the Environment Agency needs to do extra or unusual regulatory work they will charge you a supplementary charge. For example, if they need to assess the effect of emissions to air on a protected habitats site. Their charge is in table 1.19.2 of the tables of charges.
The regulator may reject your application if, for example you have:
not used the right forms
forgotten to include the fee or sent the wrong fee
not provided important information
Examples of insufficient information include:
an air quality assessment not identifying potential pollutants
emission parameters not being provided
The information required is explained in the application form guidance and depends on the type of application you are making.
Once the regulator has the information they need to start assessing your application, they will contact you and tell you that your application is ‘duly made’. This means they are starting the assessment process.
The regulators may request more information if they need it to complete their assessment.
If the Environment Agency needs any more information from you before your application can be duly made, they will either:
contact you to request it if it seems you could provide the information within 10 working days
return your application with a list of missing information to help you reapply
If the Environment Agency cannot progress your application past the duly made stage, they will return it to you. They may keep part of your application charge if they have spent time reviewing your application. This is explained in the environmental permitting charges guidance.
After an application is duly made, if the Environment Agency needs any more information from you, they will contact you to tell you what information you need to send.
After you get your permit
Once the regulators have issued your permit, they will add your details to the:
Added links to a new service for applying for a environmental permit online in England.
20 January 2025
Added that the Environment Agency is testing a new online service for medium combustion plant and specified generator permit applications in England. Added a link so you can sign up to use the new service and give feedback.
22 July 2024
Added that Natural Resources Wales do not issue standard rules permits anymore – only bespoke permits. In the minimum screening distances to the habitat sites table, added ‘less than’ to clarify the rated thermal input numbers.
16 July 2024
Updated the 'After you apply' section to clarify what happens if the regulators need more information before an application can be 'duly made'.
26 June 2023
Updated section 'Stage 2': If any of your individual MCP are within the minimum screening distances given in the stage 1 assessment, you can use the Simple Calculation of Atmospheric Impact Limits (SCAIL) combustion tool to do an air emission risk assessment.
24 May 2023
The stage 2 screening tool (Simple Calculation of Atmospheric Impact Limits (SCAIL)) for combustion will not be available before 30 June 2023.
27 March 2023
'Charges for standard rules permits' table reflects amended and new standard rules sets relating to MCPs. 'Stage 1': clarified if any of the MCP on site operating outside the minimum screening distances to the habitat sites given in the table then you can apply for a lower risk simple bespoke permit. 'Stage 2': clarified use SCAIL combustion tool for existing MCP applications.
7 March 2023
Clarified types of bespoke permit available and the air emissions risk assessment requirements. Added ‘woody type biomass’ to fuel type used. Added text to the section ‘energy efficiency report of SG 20MWth or more’ – ‘and produces waste heat at a useful temperature’.
4 January 2023
Removed the link to the online application service as people must use the application forms to apply for a bespoke medium combustion plant permit.
1 February 2022
Updated the 'After you apply' section to give examples of insufficient information being provided. Updated how to get advice before applying for a standard rules permit in England.
4 October 2019
Under Bespoke permit, Air emissions risk assessment we have clarified when an assessment is needed by adding the designated site type. We have also removed the link to the specified generator tranche B screening tool, as this guide refers to MCPs not specified generators.
10 September 2019
The Environment Agency's Regulatory Position Statement: Permits for schedule 25B, Tranche B specified generators: RPS 219 for sites in England expired on 31 August 2019.
7 August 2019
The Natural Resource Wales Regulatory Decision has been extended to 31 October 2019.
5 August 2019
Added: In England you can now apply for a bespoke permit online. Also details of when air emission risk assessment and energy efficiency reports are required.