Specified generator: comply with permit conditions
The emission limit values (ELVs) and air quality standards specified generators must meet, including the deadlines for complying.
Applies to England and Wales
If your generator’s capacity is more than 1 megawatt thermal you may also need to comply with the medium combustion plant ELV requirements.
Deadlines for complying with ELVs
You must make sure your specified generator complies with the appropriate ELV by the required date. These are, for:
- Tranche B specified generators – from 1 January 2019 or when the new specified generator is commissioned
- Tranche A specified generators – either 1 January 2025 or 1 January 2030 depending on the site’s total capacity
For a specified generator site, each individual generator must meet the conditions that relate to that generator by the required date.
You must demonstrate you can comply with all of these permit conditions before you apply for your specified generator permit.
Standard ELV the specified generator must meet
You must meet this ELV by the required date.
For engines and turbines the standard ELV for nitrogen oxides is 190mg/Nm3 at a temperature and pressure of 273.15K and 101.3kPa. With a correction for the water vapour content of the waste gases to dry gas, standardised to O2 concentration of 15%.
This is equivalent to 500mg/Nm3 at 5% O2. This ELV is achievable by most gas fired generators.
For:
- solid fuels it’s 475mg/Nm3 at 6% O2
- gas and liquid non-gas turbine or engine it’s 570mg/Nm3 at 3% O2
If you operate a generator with a diesel engine, you’re likely to need to fit secondary abatement to achieve this ELV.
Where the generator needs secondary abatement, for example by using selective catalytic reduction, the standard ELV must be met within:
- 20 minutes of starting operation if it’s a Tranche A
- 20 minutes of starting operation if it’s a Tranche B that was previously a Tranche A
- 10 minutes of starting operation if it’s a Tranche B
You must keep records of the effective continuous operation of secondary abatement in accordance with your permit. This may include reagent dosing rates or post catalyst continuous process emissions monitoring data (or both).
You must monitor emissions at least every 3 years where secondary abatement is fitted.
You must monitor your emissions every 1,500 hours if you are operating under the 500 hour per annum exemption.
Air quality standards
Your specified generator must not cause a breach of an air quality standard. You must ensure it protects:
- human health – known as sensitive receptors
- conservation sites – known as habitats
You must make sure your generator can comply with the rules in a standard rules permit on sensitive receptors and habitats.
If it cannot, you must quantify the impact on sensitive receptors and habitats, for example by air dispersion modelling.
Read the detail in the guide Specified generators: dispersion modelling assessment.
As a result of your assessment the regulator may set the following stricter permit conditions. These could require you to:
- meet a lower ELV
- better disperse emissions
- reduce hours of operation
You must meet these conditions from the date the permit is required.
Protecting habitats
See the guidance on the requirements to protect habitats.
Dark smoke
The generator must not persistently emit dark smoke. See the guidance on how to identify dark smoke.
Apply for a specified generator environmental permit
See the guidance Specified generator: apply for an environmental permit.
Contact your regulator
England
Contact the Environment Agency
General enquiries
National Customer Contact Centre
PO Box 544
Rotherham
S60 1BY
Email [email protected]
Telephone 03708 506 506
Telephone from outside the UK (Monday to Friday, 8am to 6pm GMT) +44 (0) 114 282 5312
Monday to Friday, 8am to 6pm.
Wales
Contact NRW.
Updates to this page
Published 15 July 2019Last updated 28 December 2022 + show all updates
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Updated to state that operators must keep records of the effective continuous operation of secondary abatement in accordance with their permit.
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First published.