1.A.1.a Public Electricity And Heat Production

Last updated on 10 Dec 2013 11:53 (cf. Authors)

Short description

Kraftwerk_Lippendorf.png

Source category Public Electricity and Heat Production (1.A.1.a) comprises district heating plants and electricity and heat production of power plants. Waste incineration is also included.

NFR-Code Name of Category Method AD EF Key Source for (by)
1.A.1.a Public Electricity and Heat Production T2 NS CS SOx & NOx (L/T), CO (L), TSP, PM10 & PM2.5 (L/T), Pb (T), Hg (L/T), Cd (L/T), PCDD/F (L/T), HCB (L/T)

Method

Basically a Tier 2/3 method is used for emission reporting. This means the use of country-specific data at a more detailed level. Emission factors and activity data are available for different fuel types, different technologies, plant size, etc. The use of plant-spezific data for a bottom-up approache is not possible. Although there is a database (POSO) with fuel data including NOx , SOx and TSP emissions for large combustion plants available. But the database is not complete and data quality is not always satisfactory. Therefore only measured and verified data were used.

Activity data

Conventional fuels
Key source of all conventional fuels is the National Energy Balance. The fuel input for electricity production is given in line 11 ("Public thermal power stations") of the National Energy Balance. The fuel inputs for public heat production are given in lines 15 ("combined heat and power stations") and 16 ("district heating stations"). Line 14 ("Hydroelectric, wind-power, photovoltaic systems and other similar systems") comprises all systems/ plants that generate electricity from biogas, landfill gas, sewage-treatment gas or solid biomass and feed the electricity into the public grid. Since no cut-off limit applies for such systems, this catagory includes very small sytems too. German statistic provides only electricity generation data of those biomass plants, who feed into the public grid. But the Renewable Energy Act (EEG) does allow a full registration of electricity generation from renewable energies. However, the calculation of fuel data is connected with high uncertainties, since an average generation efficiency is necessary for the conversion.
Above-mentioned data provided by the Energy Balance are summarised fuel consumption data. To get technical details which are needed for calculating emissions additional statistical data were used. All the data result in the calculation model "Balance of Emission Sources" which is part of the central database (CSE). The aim of the database is to produce more detailed fuel consumption data which are adjusted to the special technical characteristics of electricity and heat production. As a result, fuel-specific and technology-specific emission factors may be applied to the relevant activity rates. As a result, 142, so called time series, were implemented in the database CSE. The year 1990 required a different structur whithin the database with 154 additional time series, since this was the year of the reunification in Germany with two different statistical offices and two data systems.
When the calculations for submission 2013 were done, the Energy Balance 2011 was not yet available. Insofar for the year 2011 preliminary data are used. These data are also provided by the Working Group on Energy Balances which compiles a priliminary energy balance. That's the reason why Germany has to done recalculations for the previous year.
For waste incineration plants both energy and waste statistics are used. That way, completeness is ensured and double counting avoided.

Biomass
The database for the calculation model consists of the National Energy Balance. Line 14 ("Hydroelectric, wind-power, photovoltaic systems and other similar systems") comprises all systems/ plants that generate electricity from biogas, landfill gas, sewage-treatment gas or solid biomass and feed the electricity into the public grid. Since no cut-off limit applies for such systems, this catagory includes very small sytems, too. German statistic provides only electricity generation data of those biomass plants, who feed into the public grid. But the Renewable Energy Act (EEG) does allow a full registration of electricity generation from renewable energies. However, the calculation of fuel data is connected with high uncertainties, since an average generation efficiency is necessary for the conversion.

Waste
Activity data from waste incineration plants are given by the waste statistics of the Federal Statistical Office (Statistisches Bundesamt, Fachserie 19, Reihe 1). Waste quantities are available at a very detailed level for different economic sectors. Municipal and industrial waste were classified in keeping with the Ordinance on the European Waste Catalogue (AVV), with industrial waste including all waste with waste-classification numbers beginning with the numbers 01 through 19.

Emission factors

Large and medium combustion plants
The underlying data for the emission factors used is provided by the report on the research project "Ermittlung und Evaluierung von Emissionsfaktoren für Feuerungsanlagen in Deutschland für die Jahre 1995, 2000 und 2010" (Determination and evaluation of emission factors for combustion systems in Germany for the years 1995, 2000 and 2010"; RENTZ et al, 2002). The values for the intermediate years 1996-1999 and 2001-2008 are obtained via linear interpolation. That project, along with the linear interpolation for the intermediate years, has also provided the underlying data for the source catagories 1.A.1.b, 1.A.1.c and 1.A.2.f i, where the factors include power plants, gas turbines or boilers for production of steam and hot/ warm water. The research project was carried out by the Franco-German Institute for Environmental research (Deutsch-Französisches Institut für Umweltforschung - DFIU) at the University of Karlsruhe and was completed in late 2002. The project's aim was to determine and evaluate representive emission factors for the years 1995, 2000 and 2010 for the main air polluntants produced by combustion plants and gas turbine plants in Germany that are subject to licensing requirements. This process consists primarily of analysing and characterising the relevant emitter structures, and the pertinent emission factors, for the year 1995, and then of updating the data for the years 2000 and 2010. This procedure systematically determines emission factors for the substances SO2, NOx, CO, NMVOC, dust and N2O. The process differentiates between 12 coal fuels, 4 liquid fuels, 7 gaseous fuels and firewood. In addition, the available data relative to emission factors of other substances are also compiled; these other substances include PAH, PCDD/F, As and Cd for combustion systems subject to licensing requirements.
As part of another research project, completed in February 2007, for updating the National Programme in the framework of directive 2001/81/EC on national emission ceilings for certain atmospheric pollutants ("NEC Directive"), induvidual emission factors for the components SO2, NOx and dust were revised in keeping with recent findings.
The current emission factor data status of large and medium combustion plants is basically the result of a research project, which was completed in 2011 (Fichtner et al. 2011).
Heavy metal emission factors are mainly the result of a comprehensive study of PRTR data, which provide an information about emissions and the quality (measurement/ estimated/ calculated data) of large combustion plants. The combination of emission from PRTR and the relevant fuel data from a database called "POSO", which contains additional data of large combustion plants, allows the determination of plant-specific emission factors. Due to the fact, that only some plants do really measure heavy metals, the determined emission factors were used for the hole sector (1.A.1.a).

Engines
Emission factors for gas engines were determined by the project: "Processing of data in emissions declarations pursuant to the 11th Ordinance on the Execution of the Federal Immission Control Act". Additional data were provided by the local authorities (results of emission monitoring). All emission factors used for reporting are derived from plants which are subject of licensing and reviewed by the competent authorities. However, a large part of the 7,500 biogas plants in Germany does not require a license. In order to meet the quality requirements, a new reporting structure is necessary. Furthermore, there is a need for additional data from small biogas fired engines.
Emission factors for liquid fuels are given by the project: "Determination of the state-of-the-art of emission control techniques for stationary internal combustion engines", Müller-BBM 2010.

Waste incineration plants
Data source for emission factors of waste incineration plants is the project: "Review of the emission factors for waste incineration", ATZ 2010. The aim of the study was to determine emission factors for municipal waste, industrial waste, hazardous waste, waste wood and sewage sludge incineration. Emission factors for 25 pollutants are available. The different fuel categories are consistent with the waste statistic. The fuel category "industrial waste" has different meanings: substitute fuel originate from municipal or industrial waste or untreated production waste. This kind of fuels were basically incinerated in so called waste-to-energy-plants (in German EBS-Kraftwerke). Compared to conventional municipal waste incineration plants, "EBS-Kraftwerke" are mostely smaller and more efficient. There are also some technical differences. All these plants have to comply with the same limit values. Nevertheless emission factors are different due to different abatement technology and operating conditions.
Furthermore it was necessary to develope a method to calculate emissions from co-incineration systems. In Germany there is a large number of, basically, coal fired power plants, which use also a relevant amount of different waste fuels like sewage sludge, industrial waste (for example from papaer industry), conditioned municipal waste etc. Since plant-specific data cannot be used, it's necessary to calculate emissions at a more aggregated level. Fuel data are availabel from ETS. Furthermore the information about the coal qualities is available. Therfore it's possible to calculate specific emission factors for co-incinerated waste fuels.

Table: Implied emission factors for public electricity and heat production

Pollutant SOx NOx TSP CO Pb Hg Cd
Fuel [kg/TJ] [g/TJ]
Hard Coal 61 61 3 9 3.57 2.12 0.49
Lignite 65 73 3 60 2.8 2.54 0.37
Natural gas 0.5 56 0.3 33 NA 0.01 NA
Mineral oil products 76 70 5 15 9.56 1.82 0.15
Biomass (excluding Waste) 39 142 6 102 2.47 0.07 0.06
Municipal Waste 3 49 0.5 5 2.7 1.1 0.36

The table gives an overview of the implied emission factors. In reality the German inventory compiling process is very complex and includes the use of a considerable number of emission factors, which cannot be published completely in the IIR. Actually there are different emission factors available for diverse fuel types, various techniques and licensing requirements. However, the implied emission factor may give an impression about the order of magnitude.
PM 10 and PM 2.5 emission factors are calculated as a fraction of TSP. The share of PM 10 is 90 % and the share of PM 2.5 is 80 %. This is a simple but also conservative approache, knowing that, in reality, PM emissions depend on fuel, combustion and abatement technologies. PM emission reporting starts in 1995, since no sufficient information about the dust composition of the early 1990th is available.

Trend discussion for Key Sources

The following diagrams give an overview and assistance for explaining dominant emission trends of selected pollutants.

Fuel Consumption

The first graph shows that the total energy consumption of fossil fuels for public electricity and heat consumption didn't change very much since 1990. The main reasons are the rising electricity demand and a great number of industrial power plants whose emissions are now reported in source catagorie 1.A.1.a. From 1990 to the present time, fuel swich changed slightly from coal to natural gas. In 2009 fuel consumption of all fossil fuels decreased remarkable as a result of the economic crisis. The economic recovery in 2010 led to an increasing fuel consumption because of the increasing electricity demand. From 2003 biomass consumption rises considerably due to the government aid of renewable energies.

Sulfur Oxides - SOx

SOx emission trend shows the big dominance of lignite due to high Sulphur content of lignite fuels. However SOx emissions decrease more than lignite consumption does. Before the german reunification in 1990, lignite fired public power plants in eastern germany didn't use flue gas desulphurisation plants. The implementation of strikter regulations in the New German Länder resulted in considerably decreasing emissions. From 1999 onwards emissions remain stable at a very low level.

Nitrogen Oxides - NOx

Nitrogen oxides emissions decreases due to declining lignite consumption in the early 1990s and due to NOx emission reduction measurements in the New German Länder. After 2002 the increasing consumption of natural gas biogas, wood and other biomass in the public sector gain influence and increases NOx emissions. The upward trend was only interrupted by the economic crises in 2009.

Particulate Matter - PM2.5 & PM10 & TSP

Similar to SOx emissions, Particulate Matter emissions decreases considerably since 1990 due to stricter regulations in eastern Germany. After 2002 PM10 and PM2.5 emission trends were influenced by the increasing use of biomass for public electricity and heat production.

Priority Heavy metal - Pb & Hg & Cd

Emission trends of all priority heavy metals are mostly influenced by the emissions from lignite use. The reasons of the declining emissions are on the one hand the decreasing lignite consumption and on the other hand the implementation of stricter regulations in eastern Germany. Due to the fact, that heavy metal emission factors for waste incineration plants are constant, emission trends solely depend on coal consumption. In reality emission trends of all heavy metals would be more influenced by the emissions from waste fuels, since the emission factors for waste incineration plants in 1990 are expected to be high. In recent years emissions from Biomass combustion gain more and more influence on the trend.

Persistent Organic Pollutants

HCB emission factors of hard coal are given by the CORINAIR Guidebook 2006. While emission factors of municipal waste are derived from a measurement project initiated by the industrial association. The 1990 value for waste incineration plants is an expert judgement derived from the developement of legislative regulation. Insofar emission trend depends basically on the technical developement of waste incineration plants as well as fuel consumption of hard coal and its annual fluctuations. Regarding to HCB emissions the German inventory is not yet complete. Large source catagories are not yet reported since uncertainties of emission factors are very high due to unavailable measurements. Therefore source catagory 1.A.1.a is key catagory in level for HCB.
Main driver of the dioxin emission trend is by far waste incineration with high specific emissions in the early 90s and considerably decreasing emissions due to stricter regulations in Germany. In recent years emissions remain stable at a very low level.

Recalculations

Recalculations were necessary for the latest reference year (2010) due to the availability of the National Energy Balance. Germany has a federal structure which causes a time lack of the National Energy Balance. Therefore recalculations are always necessary.
Further recalculations due to a comprehensive evaluation of measurements which necessitated a revision of SOX emission factors of coal fired power plants. A revision of the waste calculation model led to recalculations of all pollutants.

For pollutant specific information on qualitative and quantitative impacts on 1990 and 2010 emission estimates see chapter 11. Recalculations.

Planned improvements

Currently the reporting structure of biogas and liquid biomass is under revision. That means methodological changes as well as changes of activity data and emission factors. A big step is necessary to follow the fast developement of reniewable energies during the last years. This is also a change from a central energy supply system, which is easy to calculate to a decentralised energy supply, which is more demanding regarding the inventory compilation process.
It´s planned to revise CO emission factors for all combustion plants, since CO emission factors of lignite and gas fired power plants seem to be too high.
Furthermore there are plans for POPs and heavy metal measurements for large combustion plants in order to get a better understanding of these "exotic" pollutants. At the moment there are only a few measurement data available, which show a wide range. Therefore more frequend measurements are necessary.
There are also plans to evaluate and analyse BREF-data in order to determine or to improve emission factors for different pollutants.
Moreover we plan to improve the emission factors of waste incineration plants for the year 1990 in order to provide a more realistic trend for these kind of plants.
A medium-term goal is the revision of TSP and PM emission factors.


Bibliography
1. National energy balance and Satellite balance for renewable energy: http://www.ag-energiebilanzen.de/viewpage.php?idpage=216
2. Stationary engines: FKZ 3707 42 103/01 "Aufbereitung von Daten der Emissionserklärungen gemäß 11.BImSchV aus dem Jahre 2004 für die Verwendung bei der UNFCCC- und UNECE-Berichterstattung/ Teilbericht Stationäre Verbrennungsmotoren" IZT 2009, Melanie Degel, Wolfram Jörß http://www.umweltdaten.de/publikationen/fpdf-l/3887.pdf
3. Large and medium combustion plants, including gasturbines: FKZ 3708 42 301, "Fortschreibung der Emissionsfaktoren für Feuerungs- und Gasturbinenanlagen nach 13./17. BImSchV und TA Luft" DFIU, KIT, EIFER 2011, W. Fichtner, U. Karl, R. Hartel, D. Balussou: not published
4. Waste incineration: FKZ 3708 49 1075 "Überprüfung der Emissionsfaktoren für die Abfallverbrennung" ATZ Entwicklungszentrum 2010, Robert Daschner, Prof. Dr. Martin Faulstich, Prof. Dr. Peter Quicker, Samir Binder: not published
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