Combustion Plant

Combustion Plant in Europe

Large Combustion Plant Directive (LCPD)

Sulphur dioxide, nitrogen oxides and particles can travel long distances from their sources before being deposited onto land, surface waters or oceans, or forming ozone (nitrogen oxides form ozone in the presence of organic compounds and sunlight). Emissions from the United Kingdom contribute to pollution problems in other Member States, while Germany, Netherlands, France, Ireland and Belgium are the principal non-domestic contributors to sulphur and nitrogen deposition, and ambient concentrations of pollutants, in the United Kingdom. A Europe-wide approach to reducing these pollutants and their impacts is therefore required.

The revised Large Combustion Plants Directive requires more stringent measures to be introduced to reduce emissions from the sector. Combustion plants contribute very roughly some 25% of nitrogen oxides, 75% of sulphur dioxide, and 25% of particulate emissions in the UK.

The European Commission estimated that the monetised benefits (of the emission limit values for new large combustion plant) in terms of less material damage, morbidity and mortality would amount to 38,444 million (some 25,000m). They did not attempt to monetise the ecosystem benefits. The Commission claimed a benefit to cost ratio of greater than seven for boilers and greater than twenty-six for gas turbines.

Plants subject to the revised Directive are also subject to the provisions in other Community legislation including the Integrated Pollution Prevention and Control Directive (IPPC), the National Emissions Ceilings Directive (NECD), other air quality Directives, and obligations on greenhouse gases.

The revised Large Combustion Plant Directive (2001/80/EC) applies to combustion plants with a thermal output of 50 MW or more.

The Large Combustion Plant Directive aims to reduce acidification, ground level ozone and particles throughout Europe by controlling emissions of sulphur dioxide (SO2) and nitrogen oxides (NOx) and dust (particulate matter (PM)) from large combustion plants (LCPs) in power stations, petroleum refineries, steelworks and other industrial processes running on solid, liquid or gaseous fuel.

These pollutants are major contributors to acid deposition, which acidifies soils and freshwater bodies, damages plants and aquatic habitats, and corrodes building materials.

Nitrogen oxides react with volatile organic compounds in the presence of sunlight to form ozone that can adversely affect human health and ecosystems.

Sulphur dioxide, nitrogen oxides and particles can travel long distances from their sources before being deposited onto land, surface waters or oceans, or forming ozone. Emissions from the UK contribute to pollution problems in other Member States, while Germany, Netherlands, France, Ireland and Belgium are the principal non-domestic contributors to sulphur and nitrogen deposition in the UK.

A Europe-wide approach to reducing these pollutants and their impact is therefore required.

The revised Large Combustion Plant Directive takes into account advances in combustion and abatement technologies.

Reducing Emissions

Combustion plant must meet at least the emission limit values (ELVs) given in the LCPD. For ‘existing’ plants (i.e. those in operation pre- July 1987), Member States can choose to meet the obligations by either:

  • Complying with ELVs for NOx, SO2, and particles.
  • Operating within a ‘National Plan’ setting a national annual mass of emissions calculated by applying the ELV approach to existing plants, on the basis of those plants’ average actual operating hours, fuel used and thermal input, over the 5 years to 2000.


Member States have two options for controlling emissions from existing plants. The choice is between the ’emission limits’ approach, and a ‘national plan’. Either would fully meet the requirements of the Directive:

a. The emission limits approach would apply emission limit values set in the Directive to each ‘existing’ plant from 1 January 2008 for each pollutant. Limits would apply at each individual plant. These would be in the form of a concentration limit.

b. A national plan would establish a national ‘bubble’ for each pollutant. This would be an absolute total limit on emissions to be shared between all the plants in the scheme. Plants would receive an allocation and, within constraints, could trade emission allowances between themselves. The sum of the emissions at plant level would have to add up to the limit at the national level for each compliance period. A national plan would need to include all existing plants in the United Kingdom, and must come into effect no later than 1 January 2008.


Business sectors affected

The sectors affected by the Directive are electricity generation, crude oil refiners, and other operators of large boilers such as chemical manufacturers, car manufacturers, sugar refiners, distillers, the primary and secondary iron and steel producers, aluminium production and paper manufacturers. The dominant impact of the revised Large Combustion Plants Directive will be on the electricity generation industry, and the crude oil refiners. Charities and voluntary organizations are unlikely to be affected directly.

Equity and fairness

The measures will apply equally to all plants within these sectors across Europe in an equitable and fair manner. The cost of reducing emissions from large combustion plants may lead to increased costs to consumers.


The options for ‘existing’ plants have been assessed against an assumed level of electricity generation (the base case) from coal of 84 terawatt hours in 2010, falling to 72 terawatt hours in 2016. The assumption represents a likely future level of generation from coal that is consistent with current Government energy projections; more details are given in the Annex. Sensitivity analysis has been undertaken of 120 and 140 terawatt hours of electricity generation from coal in 2010 across the UK as a whole. The current level of electricity generation from coal is about 120 terawatt hours per year, but the level is expected to fall significantly. By 2010, a coal burn of 120 terawatt hours is not impossible, but a lower burn is more likely.

Assessed benefits

All plants subject to the revised Large Combustion Plants Directive must also comply with the requirements of the Integrated Pollution Prevention and Control Directive, amongst others. That is plants must comply with the requirement to use Best Available Techniques to control emissions. Best Available Techniques are applied in a site specific manner; it will not be possible to say for certain what they require for any specific plant until 2006. Currently all that is available is draft general guidance prepared by the European Commission, which is subject to confirmation in 2004/2005. For the purposes of this assessment, the total benefits and costs for existing plants are shown without attribution between the two Directives.

The benefits from controlling emissions from ‘existing’ plants depend on the implementation option. Both the benefits and the costs are very sensitive to the assumptions made about the future generating load on the existing power plants. Another factor will be the extent to which operators choose to take up the derogations under the Directive.

The level of emissions is lower under the emission limits approach because each plant is required to comply with the emission limits set in the Directive. The measures that need to be adopted to ensure compliance will often deliver greater emission reductions than are required. Under the national plan approach, this is less likely to be the case as emissions trading will allow any ‘over compliance’ to be offset against higher emissions from plants that face higher costs of abatement. This ability to offset ‘over compliance’ will lead to higher emissions under a national plan approach than under the emissions limit value approach overall, but both approaches would meet the requirements of the Directive.


Compliance costs

The Directive will add to the cost of operating some older large combustion plants by requiring additional abatement measures to reduce emissions. The level of cost for ‘existing’ plants depends on whether the emission limits or national emissions reduction plan approach is adopted. While the assumptions underlying the costings are based on a good understanding of energy markets, anticipated life of plants and other influences, they should be recognised as predictions each with an associated uncertainty.

Costs of the emission limits approach can be calculated by determining the cost of additional control equipment required to meet the revised limits. Estimating the costs of a national plan is not so straightforward since the costs will depend on how it is implemented and market influences.

Other costs

Operators already meet the costs of regulation under the existing pollution control regime, and will need to meet the costs of the regime implementing the Integrated Pollution Prevention and Control Directive which is in the process of superseding it. These costs are unlikely to change as a result of the revised Large Combustion Plants Directive and we expect that a single permit will set out the requirements of both Directives at a site.


The Directive has already been transposed by means of domestic legislation, which aimed at incorporating the requirements of the Directive within the existing pollution prevention control regime and require the National authorities to take the necessary steps to ensure that any permit or authorisation relating to a combustion plant include conditions which give effect to the relevant requirements of the Directive. They implement that by incorporating the requirements of the Directive in permits and authorisations.

Monitoring and review

A requirement of the Directive is that the Member States submit an annual report to the European Commission on emissions. The Commission was required to make recommendations to the Parliament by 31 December 2004 on the need for additional measures; the amounts of heavy metals emitted by plants covered by the Directive; the cost effectiveness of additional emission reductions; their technical feasibility; the environmental effects of the Directive; and any national emissions reduction plants submitted by Member States.

In the UK

The Large Combustion Plants (National Emission Reduction Plan) Regulations 2007 (SI 2007 No. 2325) provide the legal basis for the transfer of annual limits between participating Large Combustion Plants within the UK NERP. A register of participating LCPs has been established which will record these transfers.

Large Combustion Plants (National Emission Reduction Plan) Regulations 2007 (SI 2007 No. 2325)

Annex VIII(B) of the Large Combustion Plants Directive requires Member States to establish, starting in 2004 and for each subsequent year, an inventory of SO2, NOx and dust emissions for all combustion plants with a rated thermal input of 50MW or more.

Following the consultation on establishing the operation of the UK National Emission Reduction Plan (NERP) the Large Combustion Plants (National Emission Reduction Plan) Regulations 2007 came into force on 10 September 2007 and on 31 October 2007 the following direction was given to the Environment Agency: The Pollution Prevention and Control (Combustion Plants) (England) Directions 2007

In 2007 Defra held a consultation outlining the proposed operation of the UK National Emission Reduction Plan (NERP) under the Large Combustion Plants Directive (LCPD), and including the Large Combustion Plants (National Emission Reduction Plan) Regulations 2007. The UK National Emission Reduction Plan enables plant operators to trade emission allowances for sulphur dioxide, nitrogen oxides and particulates, while preventing them from emitting an amount of these pollutants that is greater than that for which they hold emission allowances. The documents below are being retained for reference, as they describe the operation of the UK National Emission Reduction Plan, which was established following the consultation.

In December 2010, the directive on industrial emissions (integrated pollution prevention and control) (Recast), was published in the Official Journal and requires transposition into UK law no later than 6 January 2013. It represents a coalescing of seven directives, including the Waste Incineration directive, into one piece of legislation. Certain provisions of the directive follow the implementation dates below:

  • Transposition into UK law by 6 January 2013
  • Implementation from 6 January 2013 in respect of any installation new after that date
    Implementation by 6 January 2014 in respect of installations already in existence before 6 January 2013 (except large combustion plants)
  • Implementation by 6 July 2015 in respect of industrial activities not subject to the current integrated pollution prevention and control directive
  • Implementation from 1 January 2016 in respect of large combustion plants already in existence before 6 January 2013

Medium Combustion Plant Directive

The EU Directive 2015/2193 on Medium Combustion Plants (MCPD) fills the regulatory gap at EU level between large combustion plants (> 50 MW) covered by the Industrial Emissions Directive and smaller appliances (< 1 MW) covered by the Ecodesign Directive.

Medium combustion plants (MCPs) are used to generate heat for large buildings (e.g. offices, hotels, hospitals, prisons) and industrial processes, as well as for power generation. Combustion plants in the MCP range (1-50 MW) are a significant, currently largely unregulated source of emissions of air pollutants (especially nitrogen dioxide (NOx), fine particulate matter (PM) and sulphur dioxide (SO2)) which impact on air quality. The MCPD was brought in to address this issue – it requires all MCPs to be registered or permitted and sets limits on the levels of pollutants that these plants can emit depending on their type, size, age, fuel type and annual operating hours. It also sets periodic emissions monitoring requirements to demonstrate compliance with emission limits. The MCPD will deliver cost effective reductions in pollutant emissions (as outlined in the Impact Assessment referred to under Question 11 of this consultation paper).

The Directive must be transposed into legislation by 19 December 2017, with requirements for new plants coming into force in December 2018. Older plants must comply with requirements from 2024 or 2029 depending largely on size. Full implementation will be achieved in 2030. Whilst many of the requirements in the Directive are set, there are some options for how to transpose it into domestic legislation and that is the focus of this consultation.

Generators with very high NOx emissions

Schemes to increase capacity and provide balancing services for the electricity market are incentivising greater use of (mainly diesel) generators with very high NOx emissions relative to other forms of generators within the MCP size range. In the past emissions from these generators have not been regulated because they have typically been used to provide back-up power in the event of emergencies and therefore run for a very small number of hours. The numbers and use of diesel generators are projected to increase rapidly over the next few years due to domestic energy market incentives. This is likely to lead to an avoidable increase in NOx emissions, which the Scottish and UK Governments are committed to reduce. Ceilings for NOx emissions in 2020 were set in the Gothenburg Protocol, an international agreement under the United Nations Convention on Long Range Transboundary Air Pollution and the National Emission Ceilings Directive.

Modelling indicates that high NOx emitting generators can lead to local NO2 hourly concentrations at levels that, according to the World Health Organisation (WHO), can impact on human health. The UK also has obligations through the EU Ambient Air Quality Directive to ensure that concentrations of NO2 do not exceed WHO guideline levels more than 18 times each year. The MCPD will not provide the controls required to adequately address this problem. Under the MCPD, plant operating for less than 500 hours can be exempt from emission limits. However diesel generators operating for the energy balancing market typically operate for less than 500 hours which means they could benefit from this exemption.

Medium Combustion Plant Directive – General background

The MCPD introduces mandatory registration or permitting of combustion plants with a thermal input capacity of between 1 and 50 MW. In 2030, when fully implemented, it is estimated that it will apply to approximately 2,000 plants in Scotland. Plants must comply with emission limits (set out in Annex II of the Directive) which depend on plant age, size, type and fuel used, and monitor emissions periodically to demonstrate compliance with the Directive. In addition, all plants must monitor emissions of carbon monoxide periodically. It is estimated that approximately 700 MCPs will be subject to emission limits in Scotland; the remaining plants are standby and backup, which operate infrequently. From the plants subject to emission limits, the majority are 1-5 MW gas boilers but there are also plant operating on solid (biomass, coal) and liquid fuels for heat and/or power generation.


The MCPD regulatory approach is designed to be straightforward to apply. However MCPs are very diverse and used for a range of functions, and so the Directive provides for a number of flexibilities to ensure the requirements are proportionate and do not cause risks to energy or heat security. Member States must decide whether to apply some flexibilities. Member States must also determine the appropriate approach to enforcement and permitting in some areas.

Non-Road Mobile Machinery

The MCPD contains an exemption for combustion plants covered by the Non-Road Mobile Machinery Directive (NRMMD)[4], which applies placing on the market emission standards on compression ignition engines with a net power up to 560 KW mounted on non-road mobile machinery. This 560 KW threshold will be removed when new European legislation comes into force in January 2019 but until then, compression ignition engines over the threshold are not subject to NRMMD placing on the market standards. It can therefore be deemed that they are under scope of the MCPD, although this will not apply to engines used for propulsion since these are also exempt from the MCPD.

Non-compliance reporting

The Directive requires Member States to lay down rules for the type, frequency and format of information concerning events of non-compliance with emission limits to be provided by operators to the competent authority. This is required to enable the regulator to meet its obligations, as follows:

  • requiring the operator to take any measures necessary to ensure that compliance is restored without undue delay; and
  • requiring the operator to suspend the operation of the combustion plant where the non-compliance causes a significant degradation of local air quality.

A risk based approach to reporting non compliance will allow operators opportunity to rectify any problems and focus reporting requirements on instances which may result in a threat to air quality.


As previously stated, operators are required to monitor pollutant emissions periodically. The Directive allows Member States to lower frequency of monitoring for plants which operate on average up to 500 hours per annum and benefit from the exemption from compliance with Annex II ELVs. Member States must also decide whether to allow alternative methods for determining SO2 emissions or require continuous monitoring. The less frequent monitoring is justified for these plants because the majority operate for testing and in emergencies only.

Member States must also decide whether to require continuous monitoring. Feedback during the pre consultation process suggests that continuous monitoring is disproportionate, considering the risk posed by MCPs and the additional expense of annual comparison between the automated measuring systems and measurements with the reference methods required by the Directive. However, if an operator chooses to apply continuous monitoring then it will be considered an acceptable alternative subject to meeting the requirements of Part 1 and Part 2 of Annex III of the Directive.

Member States must ensure monitoring is carried out based on methods enabling reliable, representative and comparable results.

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