Specified generator: apply for an environmental permit
Source: gov.uk (2025-01-20)

The types of permit available, how much they cost and how to apply for your environmental permit.

Specified generator 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 permits for specified generators, a:
- standard rules permit – low risk
- simple bespoke permit – low risk
- complex bespoke permit – high risk
Find information on what to do if your specified generator is already permitted, for example, if you have:
- an IED installations environmental permit (https://www.gov.uk/guidance/medium-combustion-plant-and-specified-generators-environmental-permits#ied-chapter-2-permits-affected-by-the-regulations)
- a local authority Part B section 1.1 or 5.1 activity permit (https://www.gov.uk/guidance/part-b-activities-combustion-and-incineration-permits)
Before you apply

Check you have all the information you need, including the deadlines you must meet. Read the guidance ‘Specified generator: when you need a permit’ (https://www.gov.uk/guidance/specified-generator-when-you-need-a-permit) to check:
- if you need to apply for a specified generator permit
- the deadlines for all specified generators and the date you must have a permit in place
You can apply for a site permit if you are operating:
- an individual specified generator
- 2 or more generators for the same purpose
Read the guidance ‘Aggregating generators and deadlines for a specified generator site’ (https://www.gov.uk/guidance/specified-generator-when-you-need-a-permit#aggregating-generators-and-deadlines-for-a-specified-generator-site) to find out how to aggregate the generators and the date you must have a permit in place.

For all types of permit you need to apply in time for the regulator to determine your application.

In:
- England, apply to the Environment Agency using these details and application forms
- Wales, apply to Natural Resources Wales (https://naturalresources.wales/permits-and-permissions/medium-combustion-plants-and-specified-generators) – use their details and application forms
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 (https://naturalresources.wales/permits-and-permissions/medium-combustion-plants-and-specified-generators) guidance.

See the standard rules permits available for low risk Tranche B specified generators (https://www.gov.uk/government/collections/standard-rules-environmental-permitting#medium-combustion-plant-and-specified-generators). Their suitability ranges from small base load combined heat and power systems to peaking abated diesel engines. You can only use them if your site only has Tranche B specified generators, not a mixture of As and Bs.

First, check the standard rule permit you are applying for. You can use the application form (https://www.gov.uk/government/publications/application-for-an-environmental-permit-low-risk-medium-combustion-plant-and-specified-generator) to do this. Select a standard rule set from the ‘application’ tab and complete the ‘details’ tab with information about your generators. The form calculates the figures you entered to check whether you can apply for the standard rules permit you have selected.

Apply for a standard rules permit

You must provide the following information when you submit your application.

About you

You must provide:
- information about the applicant
- the address of the registered office
You must declare if you or any member of your organisation has:
- any conviction of a relevant offence
- current or past bankruptcy or insolvency proceedings against you
About your operation

You must select the standard rules permit you are applying for and provide the site or generator’s:
- location – site name, address and postcode
- the nomenclature of economic activities (NACE) code for the activity
You must also provide:
- generator name
- location – national grid reference (https://gridreferencefinder.com/) or latitude and longitude
- status – Tranche A or Tranche B
- rated thermal input (MWth)
- type of generator – such as diesel engine, gas turbine, dual fuel engine, other engine or MCP (medium combustion plant)
- type and portion of fuels used as set out in the fuel categories in Annex 2 MCPD (Medium Combustion Plant Directive) (https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32015L2193#d1e32-15-1)
- stack height
- expected annual operating hours and average load in use
- whether it’s in an air quality management area (AQMA) or will be deployed to an AQMA
- the distance from places where people live or work (human receptors)
Management system

You must declare the type of management system (https://www.gov.uk/guidance/develop-a-management-system-environmental-permits) you have and that it meets the conditions in the standard rules permit.

Emission limit value (ELV) compliance verification

You must monitor each individual generator as specified in the permit conditions.

As part of your application you must be able to demonstrate that you can meet ELVs using Monitoring stack emissions: low risk MCPs and specified generators (https://www.gov.uk/government/publications/m5-monitoring-of-stack-gas-emissions-from-medium-combustion-plants-and-specified-generators).

Charges for standard rules permits

Find charges for standard rules permits in the Environmental permit and abstraction licensing: tables of charges (https://www.gov.uk/government/publications/environmental-permits-and-abstraction-licences-tables-of-charges): see Table 1.10 (combustion and power) for the application charges and Table 2.10 (combustion and power) for subsistence charges.

Get help with your standard rules application

See guidance on how to get help with your application (https://www.gov.uk/guidance/get-advice-before-you-apply-for-an-environmental-permit) in England.

In Wales, contact Natural Resources Wales (https://naturalresources.wales/about-us/contact-us/general-enquiries) for help.

Complete and submit the standard rules permit application form

The Environment Agency is testing a new online service for medium combustion plant and specified generator permit applications in England. You can sign up to use the new service and give feedback (https://www.smartsurvey.co.uk/s/permissionsignup/).

Or you can complete the spreadsheet application form for a standard rules permit (https://www.gov.uk/government/publications/application-for-an-environmental-permit-low-risk-medium-combustion-plant-and-specified-generator).

Bespoke permits

You must apply for a bespoke permit if you cannot meet the conditions in a standard rules 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
Air emissions risk assessment

You can use the Environment Agency specified generator screening tool (https://www.gov.uk/government/publications/specified-generator-screening-tool) if you operate one of the following:
- a 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
- a single or group of new or existing engines that can achieve the medium combustion plant directive and, or specified generator emission limit values
- a specified generator or generators that have vertical stacks that are not obstructed by cowls or caps
- a specified generator or generators that are fuelled by natural gas, that is, there are insignificant emissions of sulphur dioxide and particulates or, is fuelled by ultra-low sulphur diesel with secondary abatement, used for balancing (no more than 500 hours), and aggregated to no more than 20MWth
If you cannot use the Environment Agency specified generator screening tool, you can use a different method. The regulator will need to check that your choice of method is robust.

If when using a screening tool the emissions screen out as ‘low risk’ you can apply for a simple bespoke permit. You will need to provide a completed copy of the screening tool (https://www.gov.uk/government/publications/specified-generator-screening-tool) you used with your application. This will show you have applied for the correct permit type. You will also need to pay the habitats assessment charge.

If the emissions do not screen out as ‘low risk’ when using the screening tool you will need to apply for a complex bespoke permit. Complex bespoke permits require a site-specific air quality modelling assessment that assesses risks to human health and habitats. See the guidance on how to do detailed air quality modelling for emissions from specified generators (https://www.gov.uk/guidance/specified-generators-dispersion-modelling-assessment). Detailed modelling requires specialist knowledge. You should find a consultant to do it for you.

This guidance is applicable if the specified generator is also a medium combustion plant.

Secondary abatement to meet the ELV

You may configure several generators to exhaust all of their flue gases through a single combined stack to meet the ELV.

The regulators consider this to be an appropriate technique providing the ELV is met on that stack.

You will need to apply for a complex bespoke permit if you use this technique.

ELV compliance verification

Submit monitoring evidence with your application for a bespoke permit that shows your specified generator can meet the ELV.

You can show you are meeting ELVs by using monitoring stack emissions: low risk MCPs and specified generators (https://www.gov.uk/government/publications/m5-monitoring-of-stack-gas-emissions-from-medium-combustion-plants-and-specified-generators) for:
- a specified generator that meets the criteria for a simple bespoke permit
- a specified generator using natural gas with a rated thermal input of less than 5MWth
You can also use this low risk method to do monitoring for diesel back-up specified generators which operate for less than 50 hours per year for testing, even though there is no specified ELV.

For all other applications for a bespoke specified generator permit you must use Environment Agency’s Monitoring Certification Scheme – MCERTS (https://www.gov.uk/government/collections/monitoring-emissions-to-air-land-and-water-mcerts).

Where continuous emission monitoring systems are used on MCPs and specified generators you can use the MCERTS: performance standards for low risk plant monitors (https://www.gov.uk/government/publications/mcerts-performance-standards-for-low-risk-plant-monitors).

Energy efficiency report for specified generator 20MWth or more

If the new MCPs which are also a specified generator have a total thermal rated input of 20MWth or more and produces waste heat at a useful temperature, you must meet Schedule 24 of the Environmental Permitting Regulations (https://www.legislation.gov.uk/uksi/2016/1154/schedule/24/made). This implements the requirements of the Energy Efficiency Directive. You must prepare and submit a report with your application on how your generator meets the requirements (https://www.gov.uk/guidance/energy-efficiency-standards-for-industrial-plants-to-get-environmental-permits).

This requirement does not apply to:
- spark ignition engines
- existing Tranche A and Tranche B generators
Generators located in or deploying to a local authority AQMA

You must provide details of the specific AQMA.

The regulator will consult with the local authority which has responsibility for the AQMA to verify the ambient background NO2 concentration you provided.

Charges for bespoke permits

Find charges for medium combustion plant bespoke permits in table 1.10 of the environmental permits and abstraction licences: tables of charges (https://www.gov.uk/government/publications/environmental-permits-and-abstraction-licences-tables-of-charges).

If the Environment Agency needs to assess the impact of emissions to air on a protected habitats site they will charge you a supplementary charge. Their charge is in table 1.19.2 of the tables of charges (https://www.gov.uk/government/publications/environmental-permits-and-abstraction-licences-tables-of-charges).

Apply for a bespoke permit

The Environment Agency is testing a new online service for medium combustion plant and specified generator permit applications in England. You can sign up to use the new service and give feedback (https://www.smartsurvey.co.uk/s/permissionsignup/).

Or, if you prefer, you can apply for a bespoke permit using the application forms part A, part F1 and part B2.5 (https://www.gov.uk/government/collections/environmental-permit-application-forms-for-a-new-bespoke-permit).

Find the details on how to apply in Wales (https://naturalresources.wales/permits-and-permissions/medium-combustion-plants-and-specified-generators).

Get help with your bespoke application

See guidance on how to get help with your application (https://www.gov.uk/guidance/get-advice-before-you-apply-for-an-environmental-permit) in England.

In Wales, contact Natural Resources Wales (https://naturalresources.wales/about-us/contact-us/general-enquiries) for help.

After you apply

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 (https://www.gov.uk/government/publications/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

If the regulator issues a specified generator permit to a mobile specified generator they will notify the local authority to which it deploys.

Once the regulators have issued your permit they will add your details to the:
- Environment Agency public register (https://environment.data.gov.uk/public-register/view/index) in England
- Natural Resources Wales public register (https://naturalresources.wales/permits-and-permissions/check-for-a-permit-licence-or-exemption) in Wales
See guidance on how to comply with your permit (https://www.gov.uk//guidance/medium-combustion-plant-and-specified-generator-permits-how-to-comply) and how you will be regulated.