Guidance: Specified generator: apply for an environmental permit

Natural Resources Wales

February 1
14:01 2022

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:

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 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 youre 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 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.


  • England, apply to the Environment Agency using these details and application forms
  • Wales, apply to Natural Resources Wales use their details and application forms

Standard rules permits

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

See the standard rules permits available for low risk Tranche B 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, verify the standard rule permit youre applying for. You can use the application form 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 verify whether you can apply for the standard rules permit youve 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 youre applying for and provide the site or generators:

  • 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 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)
  • stack height
  • expected annual operating hours and average load in use
  • whether its in an AQMA (Air Quality Management Area) 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 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 M5 Monitoring of stack gas emissions from medium combustion plants and specified generators.

Charges for standard rules permits

The charges for specified generator standard rules permits.

Specified generators standard rules permits SR2018 No 1, SR2018 No 2, SR2018 No 3, SR2018 No 4, SR2018 No 5, SR2018 No 6, and SR2018 No 9:

  • application charge 221
  • transfer charge 169
  • surrender charge 125
  • annual subsistence charge 246

SR2018 No 8 mobile plant generator:

  • application charge 221
  • transfer charge 169
  • surrender charge 125
  • annual subsistence charge 273
  • deployment no charge

Get help with your standard rules application

See guidance on how to get help with your application in England.

In Wales, email for help.

Complete and submit the standard rules permit application form

Complete the application form.

Email it to

If you cannot use the form or you have any issues with it, please contact

Bespoke permits

You must apply for a bespoke permit if you cannot meet the conditions in a standard rules permit.

To find out if you can apply for a simple bespoke permit youll need to:

If the emissions screen out as low risk you can apply for a simple bespoke permit. Youll need to provide a completed copy of the screening tool with your application to demonstrate youve applied for the correct permit.

If the emissions do not screen out as low risk youll need to apply for a complex bespoke permit. Complex bespoke permits require a site specific air quality modelling assessment. See the guidance on how to do

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