Medium combustion plant and specified generator activities

What is a medium combustion plant or specified generator activity?

These are burning or power generation activities that create air pollution, and may cause harm to human health and the environment. We need to control harmful emissions of sulphur dioxide (SO2), nitrogen oxides (NOx) and dust into the air.

A simple explanation of a medium combustion plant and specified generator follows, or you can read full Medium combustion plant and specified generator guidance on Gov.uk.

Medium combustion plant:

This is any plant or equipment used to burn (combust) materials, including waste, with a rated thermal input between 1 and 50 megawatts.

Specified generator:

These are any medium combustion plant used to generate electricity, on a site where the total (aggregated) megawatt thermal input is less than 50 megawatts. They are divided into Tranche A and Tranche B categories, depending on their operational start date or the type of electricity supply contract.

Do I need a medium combustion plant or specified generator activity permit?

You may not need a permit if:

• the rated thermal input (th) of your combustion plant is less than 1 megawatt thermal
• you are already operating a combustion or specified generator activity and can benefit from a transitional period
• you can comply with the conditions in Regulatory Decision 075 when operating a Schedule 25B, specified generator with one or more tranche B generators for research and development testing

You must apply for a permit if:

• the rated thermal input (th) of your combustion plant is equal to or greater than 1 megawatt thermal and less than 50 megawatts thermal, regardless of the fuel type, and
• you are not already operating a combustion or specified generator activity, as transitional periods do not apply to you

Am I covered by a transitional period?

If you are already carrying out a medium combustion plant or specified generator activity, you may have some time before you need to comply with the new requirements.

If you operate under standard rule sets SR2009 No.4, SR2012 No.9, SR2012 No.10, SR2012 No.11 or SR2012 No.12, you can carry on operating under your current permit until the relevant transition period comes to an end. This is either 2024 or 2029.

If you want to start operating a new medium combustion plant or specified generator activity, you must apply for a new permit if you don’t have one already. Or apply to change your current permit, so that you can meet the new requirements.

If you’re unsure whether you can benefit from a transitional period, or which transitional period applies to you, please ask us for help.

What type of permit do I need?

We offer eight standard rule permit options for medium combustion plant or specified generator activities. If you can meet the criteria set out in the relevant rule set and accompanying generic risk assessment, you can benefit from a standard rule option. 

If you can’t meet the criteria for a standard rule option, you must apply for a bespoke permit.

Please note we have reduced the screening distance to 5km to determine when an assessment is required of aerial emissions on Habitat’s sites from MCP/SG fired on natural gas or low-sulphur diesel.

When using fuels such as biogas and landfill gas the screening distance remains unchanged at 10 km.

Can I qualify for a standard rule permit?

To qualify for a standard rule permit you must be able to meet:

• the rules (conditions) of the relevant rule set or sets, and
• the ways of working set out in the Generic Risk Assessment that goes along with the relevant rule set or sets

You must also be confident that you can follow the guidance on how to comply with your environmental permit.

To see if there is a suitable option for you:

• Look at the standard rule options at the bottom of this page
• Read carefully through the full standard rules set and the associated generic risks assessment

You must pay attention to the location and operating restrictions.

If you’re happy you can meet the requirements, you can apply for the standard rule permit using the application forms and guidance at the bottom of this page. Remember to also look at ‘Things to consider before you apply’.

If you cannot meet all the limitations and requirements, you will need to apply for a bespoke permit.

What should I know before I apply?

The application forms and guidance tell you what reports, plans, assessments and other information we need. Our environmental permit guidance documents will help you put these things together.

Make sure you read all relevant environmental permitting guidance on medium combustion plant or specified generator activities on Gov.uk before you apply, and how to comply with your permit.

If you’re still not sure about whether you need a permit, or what you must do, we can help.

How do I apply?

You must:

• Complete all relevant application forms from the document download section at the bottom of this page
• Include the correct application fee with the application
• Make sure you send us all the supporting information we need to assess your application

The application form guidance will help you. Please make sure you read it when filling out the forms. If you don’t send us all the information we need, it will take longer to assess your application.

How long does a permit application take to process?

The legal guide to assess standard rule applications and surrenders is three months. It is four months for bespoke applications, and two months to transfer the permit holder. It can take longer if we need to ask you for more information.

Time starts when we tell you we have all the information we need. The information we need is set out in the application forms and accompanying guidance.

Look at our service levels for more information on what you can expect from us.

How can I get help and advice?

Read the application form guidance before you fill out the forms. This will help you understand the information we need.

Read the relevant environmental permitting guidance on medium combustion plant or specified generator activities on Gov.uk before you apply.

If you have a general query about medium combustion plant or specified generator activities, or if you’re unsure whether you can benefit from a transitional period, or which transitional period applies to you, send us an email at mcpd.queries@naturalresourceswales.gov.uk

If you want more help, you can use our pre-application advice service. There may be a charge for this. You can talk to your permit compliance officer if you already have one. If you’re not sure who this is, or you don’t already have one, please get in touch with us.