Medium Combustion Plant Directive (MCPD) – 10th April 2024


To comply with the requirements of the Environmental Permitting Regulations (EPR), Schedule 25A & 25B you need a permit from the Environment Agency (EA) for the following:

  • New standalone MCPs between 1-50MWth (before it is commissioned)
  • Existing standalone MCPs between 5-50MWth
  • Tranche A and B specified generators (permitting date requirement varies) 

If you need a permit and have not already submitted an application, you should do this as soon as possible to avoid enforcement action in line with the Environment Agency’s enforcement and sanctions policy.

Online Application & Permissions Service 

In previous briefings the Environment Agency (EA) have referenced their “Apply for and manage environmental permissions service”. This service will support individuals, businesses and their representatives in the digital application process and provides an account to help manage permits and permissions in one place. 

If an individual, businesses or representatives who will be applying for a new Medium Combustion Plant and Specified Generator (MCP & SG) permit and would like to apply using the new service now, please email 

You can complete an application with or without the use of a consultant. If you use a consultant, they will also need to take part in the Private Beta test.

Standard Rules Permit for New/Existing Low Risk Stationary MCPs & Tranche B Specified Generators 

Standard rules permits are available for certain low risk MCP and SG operations, these are the cheapest option available in terms of application charges and on-going subsistence.

To apply for a SR permit you must be able to meet the rules set out in the permit, if you cannot you need to apply for a bespoke permit.

If you already have a SR2018/7 permit and you now want to add some existing MCPs at the same site then you should use the same application form as you would if applying for a new SR permit. The application form will ask you for the details of your current permit and the plant you want to add to that permit. You will pay a charge relevant to the number of plant being added under the application. Following determination of the permit you will be issued with a new Appendix A which will list all the permitted plant at this site.

Bespoke Permits for Existing Standalone MCP 5-50MWth 

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 

The EA have updated their guidance so that you can assess which type of bespoke permit you must apply for and the information you will need to provide. They have updated the air emissions risk assessment process breaking it down into stages:

Stage 1

Stage 1 provides a minimum screening distance to a protected habitat, if you are operating MCP outside of these distances then you can apply for a simple bespoke permit. Please note these screening distances were amended in March 2023 and are now linked to the thermal input and fuel types used.

If you are within the Stage 1 screening distances, then you should move to a Stage 2 assessment

Stage 2

This involves using the simple calculation of atmospheric impact limits (SCAIL) Combustion tool to do an air emissions 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 carry out a Stage 2 air emissions risk assessment, you will need to apply for a complex bespoke permit.

Complex bespoke permits will require you to send us a detailed air dispersion modelling report. You must also include information about any actions you are taking to reduce air impacts to prevent harm to a habitat.

Variations to Bespoke Permits 

The type of variation (minor or normal) depends on the change that is being made. The application charge is based on whether the original permit being varied is complex bespoke or simple bespoke. This extract is from the charging scheme:


We would like to draw your attention to the guidance on aggregation; in summary:

  • You only need to aggregate NEW MCP where they share a common stack.
  • You should not aggregate existing MCPs even if they share a common stack. 

Back-up Generators 

Backup generators (operated for less than 50 hours per year for testing) which are also Medium Combustion Plant DO require permitting at the relevant date.

Bespoke Specified Generator Permit Applications 

You must carry out an air emissions risk assessment for a bespoke application if you operate one of the following:

  • Tranche A or Tranche B specified generator site, or a mix of Tranche A and B specified generator site where all Tranche A generators comply with the Tranche B requirements.
  • Single or group of new or existing engines that can achieve the medium combustion plant directive and, or specified generator emission limit values.
  • Specified generator or generators that have vertical stacks without cowls or caps.
  • Specified generator or generators that are fuelled by natural gas, that is, there are insignificant emissions of sulphur dioxide and particulates or, are fuelled by ultra-low sulphur diesel with secondary abatement, used for balancing (no more than 500 hours), and aggregated to no more than 20MWth. 

The SCAIL Combustion tool should not be used for applications that include Specified Generators.

If you cannot use the specified generator tool, then you can screen the emissions using the air emissions guidance where there are no habitats or carry out detailed air dispersion modelling. 

Calculating Rated Thermal Input Capacity 

The EA have worked with the Combustion Engineers Association (CEA) to provide guidance on calculating the rated thermal input capacity of Medium Combustion Plant (MCP) which is a boiler, this compliments existing AMPS guidance for power generating systems.

EA Review of MCPs which are part of an Industrial Emissions Directive (IED) permit 

For existing MCP between 1-50MWth which are listed as part of an Industrial Emissions Directive (IED) permit the EA will carry out a review of these permits to ensure they are MCPD compliant as a minimum.

Reviews of permits in the industrial food, drink and milk and bio-waste sectors are already underway as part of a wider review programme. Where a review is not already planned, we will send out Regulation 61 notices requiring the necessary Medium Combustion Plant Directive (MCPD) Annex 1 information. 

This will be starting this quarter, and we expect to send out a separate briefing note with details before the end of April 2024.

Existing MCPs that are part of a Part A2 Facility Regulated by the Local Authority (LA) 

For MCPs at Part A2 Facilities regulated by Local Authorities, the EA are still working on preparations to ensure compliance with MCPD of in scope combustion plant at these facilities to determine who the regulator will be.

EA review of MCPs which are part of a Waste Permitted Facility (including closed Landfill). 

For existing MCP between 5-50MWth which are listed as part of a waste permit (non-IED) and the air emissions risks has already been assessed the EA will carry out a review of these permits to ensure they are MCPD and SG compliant as a minimum.

If an MCP and/or SG is absent from the permit, then the operator will need to make an application at the appropriate time. MCP and/or SG which is associated to the waste activities taking place will likely require a variation to the existing permit. MCP and/or SG which is not associated to the waste activity will require a standalone separate permit.

New Contact Point for Standard Rules Permit Holders 

For submitting monitoring returns and correspondence to the EA regarding compliance and billing of standard rules permits only, you should now email

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