Emissions of air pollutants from large combustion plants

Indicator Assessment
Prod-ID: IND-427-en
Also known as: INDP 002
Created 21 Feb 2017 Published 19 Apr 2017 Last modified 19 Apr 2017
15 min read
Large combustion plants are responsible for a significant proportion of anthropogenic emissions. In 2014, large combustion plant emissions of sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) contributed 45 % and 15 %, respectively, to EU-28 totals. Since 2004, emissions from large combustion plants in the EU-28 have decreased by 74 % for SO 2 , 47 % for NO x and 73 % for dust. The largest plants (> 500 MWth) account for only 24 % of large combustion plants but are responsible for around 80 % of all large combustion plant SO 2 , NO x  and dust emissions. In 2014, of a total of 3 446 large combustion plants, 50 % of all emissions came from just 42, 82 and 31 plants for SO 2 , 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 2014 for all sizes of large combustion plants.

Key messages

Large combustion plants are responsible for a significant proportion of anthropogenic emissions. In 2014, large combustion plant emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx) contributed 45 % and 15 %, respectively, to EU-28 totals.

Since 2004, emissions from large combustion plants in the EU-28 have decreased by 74 % for SO2, 47 % for NOx and 73 % for dust.

The largest plants (> 500 MWth) account for only 24 % of large combustion plants but are responsible for around 80 % of all large combustion plant SO2, NOand dust emissions. In 2014, of a total of 3 446 large combustion plants, 50 % of all emissions came from just 42, 82 and 31 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 2014 for all sizes of large combustion plants.

What progress is being made towards reducing emissions from large combustion plants in the European Union?

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

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Emissions from large combustion plants in the European Union

SO2
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NOx
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Dust
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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), sulfur 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 repealed); 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 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.

Large combustion plant contributions to total anthropogenic 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 2014, LCP emissions of SO2 and NO­x contributed 45 % and 15 %, respectively, to EU-28 totals (see Air pollutant emissions data viewer (LRTAP Convention) under data sources.

Changes in large combustion plant emissions

Between 2004 and 2014, emissions of SO2 from LCPs reduced by 74 %, NO­x by 47 % and dust by 74 % (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 the largest LCPs with a rated thermal input above 500 MW (24 % of all LCPs).

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 (10 %) 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 rather stable but decreasing emission patterns until 2014.

Latest year (2014) large combustion plant emissions

The largest plants (rated thermal input above 500 MWth) account for only 24 % of all LCPs but are responsible for the vast majority of LCP SO2, NOx and dust emissions. In 2014, these largest plants emitted 80 % of of all LCP SOemissions,  76 % of NOx emissions and 81 % of dust emissions.

A small number of the largest LCPs are responsible for a disproportionally large proportion of LCP emissions. In 2014, from a total of 3 446 LCPs, 50 % of all emissions came from just 42, 82 and 31 plants for SO2, NOx and dust, respectively. Conversely, the 1 107 LCPs in the lowest capacity class (50-100 MWth) emitted only 4 % of SO2 and dust emissions and 6 % of NOx emissions in 2014.

Has the environmental performance of large combustion plants in the European Union improved?

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

SO2
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NOx
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Dust
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Evolution of the environmental performance of large combustion plants in the EU-28, expressed as implied emission factors for SO2, NOx and dust

SO2
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NOx
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Dust
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As an indicator for assessing the environmental performance of a combustion plant, the ratio of the emissions and the fuel consumed (also referred to as the implied emission factor (IEF)) can be used.

Environmental performance for 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).

IEFs decreased most in the 301-500 MWth capacity class, namely by 75 % for SO­2, 33 % for NOx and 71 % for dust between 2004 and 2014.

A higher proportion of small LCPs use less polluting natural gas as a main fuel rather than solid fuels (i.e. coal and lignite). In 2014, ‘other solid fuels’ represented 12 % of fuel consumption in 50-100 MWth plants, compared with 70 % for > 500 MWth plants. This results in smaller LCPs having lower overall IEFs. However, when calculated for each fuel and capacity class, the smaller capacity classes have consistently higher IEFs. For example, the SO2 IEF for the combustion of other solid fuels (i.e. mainly coal and lignite) in 2014 was 0.30 t/TJ for 50-100 MWth LCPs and 0.14 t/TJ for > 500 MWth LCPs. This is likely to be because of the higher operating efficiencies possible for larger plants.

Environmental performance for different fuel types

Overall, the environmental performance of LCPs improved for all fuel types between 2004 and 2014 (Fig. 4) for single-fuel plants , i.e. those with at least 95 % of fuel consumption from one fuel type (see Indicator Specifications for further methodological details). For the combustion of biomass, the IEF decreased the least in that period of time. There was even a slight increase for NOx by 2 %. This increase was observed in 7 of the 13 countries which reported suitable data for multiple years. Other solid fuels showed the largest improvements in environmental performance. The SO2 IEF for solid fuels decreased by 69 %.  

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 (0.0005 t/TJ for natural gas compared with 0.157 t/TJ for liquid fuels and 0.148 t/TJ for other solid fuels, in 2014). 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.

Indicator specification and metadata

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 2004-2014 (most recent year with officially reported LCP emissions and fuel use; EEA LCP database v1.0 (see Data sources))

Units

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

Total fuel consumption — terajoules (TJ)/year

Implied emission factor — tonnes (t)/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 is being negotiated at the moment, and an implementing act will set the aspects that will entail a legally binding character.

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.

Targets

No targets have been specified

Related policy documents

Methodology

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 2004-2014 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 72 % of the plants, 78 % of SO2 and NOx emissions and 77 % of dust emissions. 

Methodology for gap filling

Some data are considered outliers, reporting very high quantities for single years, and have been modified accordingly. The modifications made are available to view on the Eionet forum (1). If there is an erroneous spike in data between years, the data are interpolated between adjacent years or set to be equal to the closest year if at the end of a time series. In some instances, a unit error is assumed.

Methodology references

No methodology references available.

Uncertainties

Methodology uncertainty

This indicator covers the EU-28 countries. However, there are no data for Croatia for 2004-2009. Croatia data have not been gap-filled; in the years for which data for Croatia have been reported, the data account for less than 1 % of total EU-28 emissions and fuel consumption. This is, therefore, considered to cause only 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

Generic metadata

Topics:

information.png Tags:
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DPSIR: Pressure
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
Indicator codes
  • INDP 002
Temporal coverage:

Contacts and ownership

EEA Contact Info

Bastian Zeiger

EEA Management Plan

2017 1.2.2 (note: EEA internal system)

Dates

Frequency of updates

Updates are scheduled once per year
European Environment Agency (EEA)
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Phone: +45 3336 7100