Indicator Assessment

Emissions of air pollutants from large combustion plants

Indicator Assessment
Prod-ID: IND-427-en
  Also known as: INDP 006
Published 05 Dec 2017 Last modified 11 May 2021
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  • Large combustion plants are responsible for a significant proportion of anthropogenic pollutant emissions. In 2015, large combustion plant emissions of sulphur dioxide (SO2) and nitrogen oxides (NOx) accounted for 44 % and 14 %, respectively, of EU-28 totals.
  • Since 2004, emissions from large combustion plants in the EU-28 have decreased by 77 % for SO2, 49 % for NOx and 81 % for dust.
  • The largest plants (greater than 500 megawatt thermal (MWth)) account for only 24 % of large combustion plants but are responsible for around 80 % of all large combustion plant SO2, NOx and dust emissions. In 2015, of a total of 3 418 large combustion plants, 50 % of all emissions came from just 40, 89 and 47 plants for SO2, NOx and dust, respectively.
  • One indicator of the environmental performance of large combustion plants is the ratio between emissions and fuel consumption (i.e. the implied emission factor). The implied emission factors for all three pollutants decreased significantly between 2004 and 2015 for all sizes of large combustion plant.

Indexed SO2, NOx and dust emissions from large combustion plants in the European Union


Emissions from large combustion plants in the European Union, by capacity class


Large combustion plants (LCPs) have been regulated in the EU through:

  • the LCP Directive (Directive 2001/80/EC; fully repealed by Industrial Emissions Directive (2010/75/EU) by 1 January 2016), which imposed minimum requirements for emissions of nitrogen oxides (NOx), sulphur dioxide (SO2) and dust;
  • the Integrated Pollution Prevention and Control (IPPC) Directive (Directive 2008/1/EC; repealed by Industrial Emissions Directive (2010/75/EU) by 7 January 2013) and its Reference Document on Best Available Techniques (BREF) for Large Combustion Plants (EC, 2006b; in the process of being updated (EC, 2016)); the IPPC Directive required the establishment of integrated permits taking into account the principle of best available techniques (BATs) and local considerations;
  • the Industrial Emissions Directive (IED, Directive 2010/75/EU; see Indicator Specifications and Metadata for details); from 7 January 2013, minimum requirements for new LCPs are set by this directive.

The National Emission Ceilings Directive (2016/2284) is another driver for pollutant emission reductions, where LCPs account for a large fraction of emissions in Member States (e.g.: SO
2, NOx and particulate matter).

The collective aim of these policies has been to reduce the environmental impacts of LCPs and, in particular, the emissions from acidifying pollutants, particulate matter and ozone precursors to which NOx, SO2 and dust contribute.

Emission reductions occur not only as a result of implementing policies, but also because of other factors including broader economic and societal changes, e.g. economic conditions, international fuel prices and industry initiatives.

LCPs vary significantly in size. Four capacity classes have been established for this indicator:

  • Small LCPs, with a thermal input between 50 and 100 MWth;
  • Medium-sized LCPs, with a thermal input between 101 and 300 MWth;
  • Large LCPs, with a thermal input between 301 and 500 MWth;
  • Very large LCPs, with a thermal input greater than 500 MWth.

Large combustion plant emissions

Emissions from LCPs constitute a significant proportion of total anthropogenic emissions and are considered to be among the main environmental pressures from LCPs. In 2015, LCP emissions of SO2 and NOx accounted for 44 % and 14 %, respectively, of EU-28 totals (see the Air pollutant emissions data viewer (LRTAP Convention) under data sources).

Between 2004 and 2015, emissions of SO2 from LCPs decreased by 77 %, while those of NOand dustdecreased by 49 % and 81 %, respectively (Fig. 2). Emissions have decreased for LCPs in all capacity classes; however, the majority of emission reductions in absolute terms has been achieved through environmental improvements in very large LCPs with a rated thermal input above 500 MW (24 % of all LCPs by number and representing 70 % of the installed capacity).

Between 2007 and 2009, emissions of SO2, NOx and dust declined significantly. Although the entry into force (on 1 January 2008) of the emission limit values for existing plants under the LCP Directive occurred in this period, a potentially more significant factor is the general economic downturn in Europe that commenced during 2008. A corresponding decrease in fuel consumption between 2007 and 2009 (9 %) suggests that the decrease in emissions may have been due to a decrease in the activity of LCPs, rather than a substantial improvement in environmental performance. This significant emission reduction was followed by a period of more stable but nonetheless decreasing emissions until 2015.

Very large LCPs account for only 24 % of all LCPs but are responsible for the vast majority of LCP SO2, NOx and dust emissions. In 2015, these largest plants emitted 84 % of all LCP SO2 emissions, 79 % of NOx emissions and 82 % of dust emissions.

In fact, only a small number of very large LCPs are responsible for the majority of emissions. In 2015, from a total of 3 418 LCPs, 50 % of all emissions came from just 40, 89 and 47 plants for SO2, NOx and dust, respectively. Conversely, the 1 094 small LCPs emitted only 2 % of SO2 and dust emissions and 4 % of NOx emissions.

Evolution of the environmental performance of large combustion plants in the EU-28, expressed as implied emission factors for SO2, NOx and dust (by capacity class)


Evolution of the environmental performance of large combustion plants in the EU-28, expressed as implied emission factors for sulphur dioxide, nitrogen oxide and dust, by fuel type


The ratio of emissions to fuel consumed (also referred to as the implied emission factor (IEF)) can be used as an indicator for assessing the environmental performance of a combustion plant.

Environmental performance of different capacity classes

The environmental performance of LCPs has improved significantly in all capacity classes (Fig. 3). The largest decline in IEFs can be observed for the 2006-2010 period. One possible reason for this is the introduction of improved abatement measures to comply with the LCP Directive (entered into force in January 2008) and the IPPC permit (taking into account the LCP BREF from 2006). It is possible that improvements in environmental performance in 2015 could be reflecting investment made to comply with the IED, which entered into force in January 2016.

Between 2004 and 2015, IEFs decreased most for large  LCPs (301 to 500 MWth capacity), namely by 75 % for SO2, 39 % for NOx and 83 % for dust.

Fossil fuels are a concern due to their contribution to climate change. Coal and lignite (included in 'Other solid fuels') are considered the worst fuel option in terms of climate change and air pollution impacts. Although natural gas is considered a 'cleaner option' (less SO2 and dust emitted), there are still concerns from a climate-change perspective. A higher proportion of small LCPs use the less polluting natural gas as their main fuel rather than solid fuels (i.e. coal and lignite). In 2015, 'Other solid fuels' represented 8 % of fuel consumption in small LCPs, compared with 68 % for very large plants. This resulted in small LCPs having lower overall operating IEFs. However, when calculated for each fuel and capacity class, small LCPs have consistently higher IEFs. For example, the SO2 IEF for the combustion of other solid fuels in 2015 was 0.17 t/TJ for small LCPs and 0.13 t/TJ for very large LCPs. This is likely to be caused by the higher operating efficiencies possible in larger plants.

Environmental performance for different fuel types

Overall, the environmental performance of LCPs improved for all fuel types between 2004 and 2015 (Fig. 4) for single-fuel plants, i.e. those one fuel type accounting for at least 95 % of their fuel consumption (see Indicator Specifications for further methodological details). Other solid fuels showed the largest improvements in environmental performance. The 'Other solid fuels' IEF for SO2 decreased by 72 %, for NOx by 38 % and for dust by 79 % across the time series.

The environmental performance of liquid fuels and other solid fuels is consistently worse than for the other fuels across the three pollutants. Natural gas has the lowest IEF for all three pollutants, most notably for SO2 (0.0006 t/TJ for natural gas compared with 0.142 t/TJ for liquid fuels and 0.132 t/TJ for other solid fuels, in 2015). At the beginning of the time series, the NOx IEF for other gases was similar to that of natural gas, but the environmental performance did not improve over time as much as it did for natural gas.

Supporting information

Indicator definition

This indicator tracks trends since 2004 in emissions of SO2, NOx and dust, as well as the environmental performance of LCPs. LCPs comprise combustion plants with a total rated thermal input equal to or greater than 50 MW.

The geographical coverage comprises the EU-28 Member States (Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden and the United Kingdom).

The temporal coverage is 2004-2015 (most recent year with officially reported LCP emissions and fuel use; EEA LCP database v1.0 (see Data sources))


SO2, NOx and dust emissions – kilotonnes (kt)/year

Total fuel consumption – terajoules (TJ)/year

Implied emission factors – tonnes/terajoules (TJ)

Rated thermal input – megawatt thermal (MWth)


Policy context and targets

Context description

The EU has had a policy on emissions from combustion plants since the 1980s. Between 2004 and 2013, two pieces of EU law were in place: the LCP Directive (Directive 2001/80/EC) and the IPPC Directive (Directive 2008/1/EC). EU law imposed specific emission limit values on emissions of NOx, SO2 and dust from plants with a rated thermal input equal to or greater than 50 MW. Since 1 January 2016, this legislation has been replaced by the IED (Directive 2010/75/EU).

The aim of EU policy on LCPs is to reduce emissions to air, water and land, including measures related to waste, in order to achieve a high level of protection of the environment as a whole. The focus for LCPs is to reduce the emissions of acidifying pollutants, particles and ozone precursors.

The Large Combustion Plant Directive

The EU (then the European Economic Community (EEC)) started to regulate combustion plants by means of Directive 84/360/EEC. This directive established a framework for permitting installations and the criteria to do so, but did not establish specific limitations that were applicable across Member States. During the 1980s, the European Communities became party to the Convention on Long-range Transboundary Air Pollution which requires more harmonised action and the establishment of clearer operational criteria and emission limit values.

These precedent directives were replaced by Directive 2001/80/EC, known as the LCP Directive, which imposed limits on the emissions of NOx, SO2 and dust from plants with a rated thermal input equal to or greater than 50 MW. The aim of the LCP Directive was to reduce the emissions of acidifying pollutants, particles and ozone precursors

The Integrated Pollution Prevention and Control Directive and the 2006 Reference Document on Best Available Techniques for Large Combustion Plants

Combustion plants were also regulated by the so-called IPPC Directive, a piece of EU law which tackled LCPs in an integrated way and not only with regard to their emissions to air. Under the IPPC Directive, a BREF on LCPs was agreed in order to establish a reference for the permits of LCPs.

The Industrial Emissions Directive

As of 2016, all combustion plants have been regulated by Directive 2010/75/EU, the IED, which simultaneously establishes minimum requirements (Chapter III) and an integrated permitting system (Chapter I). A new BREF document for LCPs under the IED has been negotiated, and an implementing act will set the aspects that will entail a legally binding character (EC, 2016).

Under the IED, permit conditions, including emission limit values, must be based on BATs. The term ‘best available techniques’ refers to the most effective, economically and technically viable methods of operation which reduce emissions and the impact on the environment.

The European Pollutant Release and Transfer Register

An additional EU regulation is the Regulation on the European Pollutant Release and Transfer Register (E-PRTR) (Regulation (EC) No 166/2006): plants with activities over certain thresholds must report to the E-PRTR on releases of pollutants and off-site transfers of waste and pollutants in wastewater.

The European National Emission Ceilings Directive

The National Emission Ceilings Directive (NECD, 2016/2284) sets mandatory national emission ceilings for a number of air pollutants. This in turn is a driver for emission reductions in a variety of sectors including the energy sector and large combustion plants


No targets have been specified.

Related policy documents



Methodology for indicator calculation

Queries are applied to the LCP database (EEA, 2016a) for the calculations necessary in this analysis. For each plant, total fuel consumption (a sum of fuel consumption from all fuel types) and capacity class (based on a plant's rated thermal input (MWth)) are calculated. Plants are grouped into five capacity classes: > 500 MWth, 301-500 MWth, 101-300 MWth, 50-100 MWth and < 50 MWth. The last of these (< 50 MWth) is excluded from calculations involving capacities in this indicator.

Figure 1: to create an index graph of the pollutants, disaggregated by capacity class, an index for each pollutant and capacity class is calculated for 2004-2015 as follows: (emissions in the capacity class for the current year/emissions for all capacity classes in the base year) * 100. The base year is 2004.

Figure 2: for each capacity class and year, emissions and total fuel consumption are summed, and an IEF is calculated as follows: emissions (tonnes)/fuel consumption (TJ).

Figure 3 and 4: IEFs are calculated for each pollutant separated by capacity class (Figure 3) and fuel type (Figure 4) at the EU level. The sum of emissions for a given pollutant in a given year is divided by the total fuel consumption, for each capacity class and fuel type.

LCP emissions are reported at plant level if a plant can use different fuels. For the calculation of fuel-specific IEFs, only single-fuel (i.e. plants for which one fuel represents more than 95% of the total fuel input in TJ) are included. All emissions of the plant are attributed to the single fuel, resulting in a coverage of 71 % of the plants, 78 % of SOemissions, 79% of NOx emissions and 73 % of dust emissions

Methodology for gap filling

For the earlier years in the time series some plants had missing MWth capacity data. Where possible, the MWth from an adjacent year’s reporting for that plant was used to gap fill.

Methodology references

No methodology references available.



Methodology uncertainty

This indicator covers EU-28 countries. However, there is no data for Croatia for 2004-2009. Their data has not been gap-filled, and in the years of reporting contributes less than 1% of emissions and fuel consumption to the EU-28 total. It is thus considered a minor distortion of the overall trend.

Data sets uncertainty

Although the reporting requirements began in 2004, it is possible that the data for the first reported period (2004-2006) contain some gaps.

Rationale uncertainty

No uncertainty has been specified.

Data sources

Other info

DPSIR: Pressure
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • INDP 006
Frequency of updates
Updates are scheduled once per year
EEA Contact Info


Geographic coverage

Temporal coverage


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