The Medium Combustion Plant Directive

On the 25th of November 2015, the Directive 2015/2193 was published “on the limitation of emissions of certain pollutants into the air from medium combustion plants.” It will pass into UK Law on the 19th of December 2017. Referred to as The Medium Combustion Plant Directive or MCPD it plugs the gap between the Industrial Emissions Directive 2010/75/EU (the IED) and the “Eco-Design” Directive 2009/125/EC.

It will apply to all operators and owners of combustion plant rated between 1 MW and 50 MW thermal input.

A “combustion plant” is “…any technical apparatus in which fuels are oxidised in order to use the heat thus generated” so it will cover boilers, turbines, and engines.  The rules are intended to apply to both new and existing equipment.”

The Directive places limits on the concentration levels of sulphur dioxide (SO2), oxides of nitrogen (NOX), and particulates in exhaust gases from affected plant.  These Emissions Limit Values (ELV’s) vary according to the type of plant and the fuel used but the general aim is to reduce the background levels of these harmful substances.  Furthermore, it will be necessary to monitor (but not limit) carbon monoxide (CO).

  • Medium Combustion Plant Directive
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  • 1. Will I be affected?
     

    The Directive applies to any combustion plant with a rated thermal input of between 1 MW and 50 MW that doesn’t already fall into Chapter III or IV of the IED (essentially installations over 50 MW or those involved in the incineration of waste).  there's a list of other exemptions in Q6.

    A “combustion plant” is “…any technical apparatus in which fuels are oxidised in order to use the heat thus generated” so it will cover boilers, turbines, and engines.  The rules are intended to apply to both new and existing equipment.

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  • 2. I have several appliances that are individually less than 50 MW but the combined input is more than 50 MW. Will MCPD apply to me?
     

    No, you have a Chapter III installation under IED (also referred to as a Part A1 installation in UK pollution permitting and control legislation).

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  • 3. I have several appliances that are individually less than 1 MW but the combined input is more than 1 MW. Will MCPD apply to me?
     

    The UK implementation intends to include all generators irrespective of size.  Other appliances under 1MW will not be covered (even if they add up to an installation of 1MW or more) as they already covered by the “Eco Design” Directive.

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  • 4. I have a mixture of plant, some above 1MW and some below, how will MCPD apply to me?
     

    Assuming that the aggregated total is less than 50 MW, MCPD would apply to apparatus over 1 MW (and all generators) while the “Eco Design” Directive would apply to those below. As an example, an installation consists of a 2 MW engine, a 5 MW steam boiler, and two 500 kW hot water boilers. The hot water boilers fall outside MCPD (they are “Eco-Design” Directive) both the engine and the boiler are within the scope of MCPD and need to meet the individual ELV’s for that type of plant.  Generators, irrespective of size, are expected to be regulated under MCPD in the UK.

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  • 5. What is “aggregation”?
     

    Several Directives lump together all of the combustion plant on a site that already share the same stack (or could reasonably do so) into one total input figure (so two 2 MW input appliances would make a 4 MW installation). This is used in part to decide if you are a Large Combustion Plant under IED and will also determine the monitoring interval for your site under MCPD.

    MCPD is slightly more complicated in that only plant supplied after 20th December 2018 will be subject to aggregation.  Multi plant sites will need to look closely as they replace an individual piece of plant to see how the MCPD will affect them after the change.  One thing to note is that aggregated plant 20MW and below is subject to triennial testing while aggregated plant over 20MW will be subject to annual testing

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  • 6. So what will the new rules be?
     

    All plant (both new and existing) will require a permit from the 20th of December 2018.  It is proposed that installations between 1 MW and 20 MW will be inspected every 3 years to ensure compliance with the ELV’s while installations over 20 MW will be tested annually.  Additionally the carbon monoxide emissions will be recorded for all installations but currently no limit has been proposed.

    There is some debate about the difficulties of a 3 year (as opposed to annual) testing regime so this may yet change.

    Plant operational before December 20th 2018 will not need to obtain a permit until January 20124 if it is over 5MW (2029 for smaller plant) with emissions limits applying from January 2025 (2030 for smaller plant)

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  • 7. What Emission Limit Values (ELV’s) will apply to my plant?
     

    This will depend on the type of appliance you have, the fuel you use and when the appliance was put into service:

    Appliances above 5 MW that have been registered before 19th December 2017 or put into service before 20th December 2018 will have to comply with the following ELV’s from 1st January 2025.  Appliances of 5 MW and below will have until 2030 to comply.

    Where limits already exist in a Local Authority that are more stringent than those laid out below, the more stringent requirement will apply.

    Note that the following figures are normalised to 3% O2 for liquid and gaseous fuels and 6% O2 for solid fuels for plants other than engines and turbines.  Engines and turbines are all normalised to 15% O2.  All figures are in mg/Nm3;

    For EXISTING engines and gas turbines:

    Pollutant

    Type of medium combustion plant

    Gas oil

    Liquid fuels other than gas oil

    Natural gas

    Gaseous fuels other than natural gas

    SO2

    Engines and gas turbines

    120

    15(1)(2)

    NOX

    Engines

    190(3)(4)

    190(3)(5)

    190(6)

    190(6)

    Gas turbines (7)

    200

    200

    150

    200

    Dust

    Engines and gas turbines

    10(8)

    (1)  60 mg/Nm³ in the case of biogas.

    (2)  130 mg/Nm³ in the case of low calorific gases from coke ovens, and 65 mg/Nm3 in the case of low calorific gases from blast furnaces, in the iron and steel industry.

    (3)  1850 mg/Nm³ in the following cases:

    (i)

    for diesel engines the construction of which commenced before 18 May 2006;

    (ii)

    for dual fuel engines in liquid mode.

    (4)  250 mg/Nm³ in the case of engines with a rated thermal input equal to or greater than 1 MW and less than or equal to 5 MW.

    (5)  250 mg/Nm³ in the case of engines with a rated thermal input equal to or greater than 1 MW and less than or equal to 5 MW; 225 mg/Nm³ in the case of engines with a rated thermal input greater than 5 MW and less than or equal to 20 MW.

    (6)  380 mg/Nm³ for dual fuel engines in gas mode.

    (7)  Emission limit values are only applicable above 70 % load.

    (8)  20 mg/Nm³ in the case of plants with a rated thermal input equal to or greater than 1 MW and less than or equal to 20 MW.

    For EXISTING plant other than engines and gas turbines:

    Pollutant Solid biomass Other solid fuels Liquid fuels other than gas oil Gas oil Natural gas Gaseous fuels other than natural gas
    SO2 200 (1) 1100 (2) 350 (5) - - 35 (3)
    NOX 650 650 650 200 200 250
    Dust 30 (4) 30 (4) 30 - - -

    (1) 300 in the case of plant firing straw

    (2) 400 mg/Nm³ in the case of plants with a rated thermal input greater than 20 MW.

    (3) or whichever is the higher of 200 in the case of plant rated 5 MW or less or 170 mg/Nm³ in the case of biogas

    (4) 50 in the case of plant rated 20 MW or less

    (5) 850 mg/Nm³ for plants 5MW<>20MW firing heavy fuel oil until January 1st 2030

    For new plant put into service after 20th December 2018 the following ELV’s will apply

    For NEW engines and gas turbines:

    Pollutant

    Type of medium combustion plant

    Gas oil

    Liquid fuels other than gas oil

    Natural gas

    Gaseous fuels other than natural gas

    SO2

    Engines and gas turbines

    120

    15(1)

    NOX

    Engines

    190(2)

    190(2)

    95(3)

    190

    Gas turbines(4)

    75

    75

    50

    75

    Dust

    Engines and gas turbines

    10(5)

    (1) 40 mg/Nm³ in the case of biogas

    (2) 225 mg/Nm³ for dual fuel engines in liquid mode.

    (3) 190 mg/Nm³ for dual fuel engines in gas mode

    (4) Emission limit values are only applicable above 70 % load

    (5) 20 mg/Nm³ in the case of plants with a total rated thermal input equal to or greater than 1 MW and less than or equal to 5 MW

    For NEW plant other than engines and gas turbines:

    Pollutant Solid biomass Other solid fuels Liquid fuels other than gas oil Gas oil Natural gas Gaseous fuels other than natural gas
    SO2 200 400 350 - - 35(1)
    NOX 300(2) 300(2) 300 200 100 200
    Particulate matter 20(3) 20(3) 20(4) - - -

    (1) 100 mg/Nm³ in the case of biogas

    (2) 500 mg/Nm³ in the case of plants with a total rated thermal input equal to or greater than 1 MW and less than or equal to 5 MW.

    (3) 50 mg/Nm³ in the case of plants with a total rated thermal input equal to or greater than 1 MW and less than or equal to 5 MW; 30 mg/Nm³ in the case of plants with a total rated thermal input greater than 5 MW and less than or equal to 20 MW

    (4) 50 mg/Nm³ in the case of plants with a total rated thermal input equal to or greater than 1 MW and less than or equal to 5 MW.

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  • 8. How will the law be implemented in the UK?
     

    The implementation will be via amendments to the existing permitting laws;

    • Environmental Permitting (England and Wales) Regulations
    • Pollution Prevention and Control (Scotland) Regulations
    • Pollution Prevention Control (Industrial Emissions) Regulations (Northern Ireland)

    These already place emissions limits on installations in the region of 20 MW to 50 MW falling outside of IED (what are known as Part B or Part C installations).  We anticipate that where there is a conflict between the MCPD ELV’s and existing ELV’s that the lower value will apply.

    If you are currently outside the scope of these regulations then the MCPD ELV’s will apply.

    The Clean Air Act will be amended to avoid double regulation.

    Emissions of SO2 are already limited through The Sulphur Content of Liquid Fuels Regulations (SCoLF) so these rules will either need to be updated or repealed to reflect the drop from 1700 mg/Nm3 to 350 mg/Nm3 for plants firing heavy fuel oil.  The existing rules do however allow a means by which the monitoring of SO2 can be avoided; that is by burning fuel of sufficiently low sulphur content and it is most likely that record keeping to show the S content of the fuel used will be simplest method of demonstrating compliance with the SO2 ELV for the majority of operators.

    Biomass boilers installed under the Renewable Heat Incentive since 2013 already have ELV’s in place for particulates and NOX.  The proposed MCPD limits are tighter and also include SO2 which was not included in the RHI ELV’s.

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  • 9. Who will issue the permits?
     

    In Scotland the permits are almost certainly going to be issued by SEPA. In the rest of the UK,  sites over 20 MW will fall under the Environment Agency who will also retain control of sites of 20 MW and below that they already monitor.  DEFRA are currently seeking feedback from industry regarding the permitting body in England and Wales, the Government preference is to use Local Authorities (as they already have first contact with an MCP through planning laws) but industry itself would prefer the Environment Agency (as this is seen as a modification of the current permitting regime and to use LA's would be duplicate work already done for larger plant)

    Permits are currently predicted to cost between £90 and £310 per year for most applicants with the highest risk plants paying up to £800 per year.  There will also be a one off registration fee around £200 for low risk plants, and up to £1600 for the highest risk plants.  A more detailed fee structure is not currently available.

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  • 10. Who will do the sampling?
     

    The details are yet to be established but the Environment Agency are eager to see "low risk" plants (which we take to mean those burning standard fuels complying with a recognised standard such as natural gas, LPG, or light oils to BS 2869) receive a "light touch" approach.  There are two proposed testing regimes;

    random testing which would require the end user to arrange testing and retain records which are made available to the authorities on request or;

    scheduled testing where the testing is performed either in front of the regulator or reports are passed to the regulator at specified times.

    The preference appears to be for the former which, as well as being the lower cost option, is also the most likely to maximise compliance.  The detail of the testing are yet to be thrashed out; will it be MCERTS (as it is for larger plant) or will companies already performing combustion checks as part of annual inspections be acceptable?

     

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  • 11. How do I know if my existing boiler meets the new regulations?
     

    If you operate a Part B or C installation or have a biomass plant registered after September of 2013 you will already have emissions reporting from an MCERTS approved lab so you should only need to compare your most recent test against the MCPD ELV’s.

    Everyone else can get an idea of where they stand from recent service reports which should show NOX and, where relevant, SO2.  While these are not a substitute for an MCERTS approved testing house, it will serve as an indication as to whether or not you may have a problem to address in the coming years.

    If you’re firing a gaseous fuel from a mainstream source such as natural gas or LPG you will probably already comply with the proposed limits for NOX for existing plant.

    Rules controlling the amount of sulphur in liquid fuels will mean that diesel fired plant will automatically meet the proposed ELV’s.

    HFO fired plant will not to meet the ELV’s for SO2 or particulates without abatement.

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  • 12. What do I do if my existing boiler doesn’t meet the new regulations?
     

    Plant over 5MW will need to comply by the 1st of January 2025 while plant in the 1 to 5MW range will need to comply by 1st of January 2030 so you have a bit of time to bring your plant into compliance. Depending on where you are non-compliant, there are a number of things that can be done; the costs will vary and it will obviously be an economic decision if you replace or modify the plant. Note that if you replace the equipment, it must be put into operation before the 20th of December 2018 to be considered "existing plant". Plant registered or put into service after these dates will need to comply with the stricter "new equipment" ELV's

    The following is quick overview of techniques available to you to help in reducing your emissions;

    NOX

    NOX is produced primarily from the heat of the flame reacting with nitrogen in the air.  Liquid and solid fuels generally also contain an amount of nitrogen in the chemical structure which add to the NOX level when burned although this difference is already reflected in the different proposed levels.

    In order of increasing cost, NOX can be controlled by:

    • careful commissioning of the burner,
    • careful matching of a boiler and a burner
    • the design of the burner itself (multi-nozzle heads, premix heads, water injection) and
    • abatement techniques such as flue gas recirculation (FGR) or by chemical treatment in the flue

    SO2

    SO2 emissions are entirely related to the amount of sulphur present in the fuel to begin with.  To reduce the level of SO2 in the flue gas you have only three options;

    • Specify a low sulphur version of your existing fuel (if one is available)
    • Switch to a different grade of fuel (such as switching from heavy fuel oil to diesel or LPG)
    • Apply abatement techniques post-boiler

    Your service provider will advise on the impact of changing fuel grade or sulphur level which could be anything from a simple recommissioning of the existing plant through to infrastructure changes (as would be the case of someone switching to LPG).

    Anyone considering LPG or LNG may find that the fuel supplier is prepared to cover the capital costs of converting existing equipment in return for a longer terms supply agreement.

    Particulates

    Particulates are caused partly through incombustibles in the fuel (ash) and partly by incomplete combustion of the fuel itself (soot).

    • The combustion of solid fuels and heavy fuel oil will unavoidably require filtration of the flue gas in order to meet the emissions targets
    • “other” liquid fuels meeting BS 2869 should be acceptable so long as the combustion equipment is modern and well looked after
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  • 13. Are there any exemptions?
     

    Article 2 contains a list of exemptions:

    • plant already covered by Chapter III or Chapter IV of Directive 2010/75/EC (The Industrial Emissions Directive)
    • non-road mobile machinery
    • combustion plant where the exhaust gas is used for direct heating either of a space (to improve workplace conditions) or for drying or heat treatment of a material (such as grain)on-farm combustion plants with a total rated thermal input less than or equal to 5 MW, that exclusively use unprocessed poultry manure as a fuel
    • post-combustion plants designed to purify the waste gases from industrial processes by combustion, and which are not operated as independent combustion plants
    • any technical apparatus used in the propulsion of a vehicle, ship or aircraft
    • gas turbines and gas and diesel engines, when used on offshore platforms
    • facilities for the regeneration of catalytic cracking catalysts
    • facilities for the conversion of hydrogen sulphide into sulphur
    • reactors used in the chemical industry
    • coke battery furnaces
    • cowpers
    • crematoria
    • combustion plants firing refinery fuels alone or with other fuels for the production of energy within mineral oil and gas refineries
    • recovery boilers within installations for the production of pulp
    • research activities, development activities or testing activities relating to medium combustion plants.
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  • 14. Will there be a limited life derogation like there is for Large Combustion Plant?
     

    Article 6 contains a number of possible exemptions that might make it into the UK application of the Directive

    The UK is likely to allow non compliant plant to run for a maximum of 500 hours per year over a 5 year rolling average with the exception of standby generators.  The 500h will be 1000h in the case of remote islands.  In all of these cases, solid fuelled plant must not exceed 200 mg/Nm³.

    There are also a number of possible time-limited exceptions to the ELV's around larger district heating systems, times of shortage of low sulphur gas-oil, and others.

    which ones do and don't make it into the Statutory Instrument will no doubt be subject to heavy debate in the next few months

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  • 15. I’m planning on buying a new boiler, will it comply with the MCPD?
     

    it is important to note that the responsibility for compliance lies with the user of the plant, not the supplier and that compliance can sometimes only be achieved by control of the fuel or by abatement of the flue gases exiting the plant.  It will however be essential to involve potential suppliers early in the project to ensure that the plant does indeed meet the ELV's applicable to you.

    Some of the issues preventing manufacturers offering off-the-shelf "compliance" with the Directive are:

    • New plant will be subject to "aggregation" while exiting plant will not.
    • Different ELV's may apply in areas of poor air quality
    • The plant may only be compliant when subject to post-treatment of the flue gas (e.g. grit arrestors bought separately and fit to a biomass boiler)
    • The fuel supply can affect certain emissions more than the design of the equipment (e.g. high sulphur fuels)
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  • 16. What uncertainties are there around the proposed directive?
     

    While the Directive has passed through Europe exactly what the finished Regulation will look like in the UK is still to be determined.  A consultation document is currently available here.  The consultation document includes some useful pointers as to where DEFRA see MCPD going in the UK implementation.  It is open for comment until the 8th of February 2017.

    Some of issues still to be resolved:

    Who will run the permitting scheme in England and Wales?

    Will the testing requirements involve MCERTS approved testing houses or heating engineers?

    It is possible that the authorities can require stricter ELV's in areas of poor air quality - what does that mean, in particular in relation to NOwhen most of the UK has unacceptable levels of background NOx?

    What are the penalties for non-compliance?

    Can a triennial reporting regime work?  Will checks be done every 3 years (there's a lot of plant to check and no inspectors) or random testing?

    Users, rather than owners, of hired equipment will be responsible for compliance - is this fair or even practical when equipment moves from site to site on a regular basis?

    how much does an existing piece of equipment have to change before it has to be considered as "new" equipment?  Currently there is no provision for this save for a requirement to report changes to the equipment that might affect the emissions

    It is possible that the approach of the devolved parliaments to these issues could differ.

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  • 17. where can I go to keep up to date with developments with the MCPD?
     

    Keep coming back to this page, we’ll update it as we find out more information.

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Read our Technical Director’s “The Myth of the MCPD Compliant Boiler” post.

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