[EN06]
Emissions (CO2, SO2 and NOx) from public electricity and heat production
Assessments published: [ 2014 2012 2009 2008 ]

This indicator analyses trends of past CO2, SO2 and NOx emissions from electricity and heat production from the viewpoint of implementing different measures and enables estimates to be made of the contribution of various measures aimed at reducing CO2, SO2 and NOx emissions.

CO2 is the most important greenhouse gas that causes warmth to be trapped in the Earth’s atmosphere thus causing the surface temperature to increase. This will have numerous direct (more common and longer lasting heat waves) and indirect (greater frequency of extreme meteorological events, rise in sea level, etc.) effects on the ecosystem and the human population. A chemical reaction converts NOx into ground level ozone, while this gas, the same as SO2, contributes to the acidification of the atmosphere and emission of (secondary) dust particles.

Image EN6-1: A breakdown of CO2 emissions trends in the 1990-2010 period

Source: Statistical Office of the Republic of Slovenia, 2012; Slovenian Environment Agency, 2012; Jožef Stefan Institute, 2012.


Image EN6-2: A breakdown of SO2 emissions trends in the 1990-2010 period

Source: Statistical Office of the Republic of Slovenia, 2012; Slovenian Environment Agency, 2012; Jožef Stefan Institute, 2012.


Image EN6-3: A breakdown of NOx emissions trends in the 1990-2010 period

Source: Statistical Office of the Republic of Slovenia, 2012; Slovenian Environment Agency, 2012; Jožef Stefan Institute, 2012.


- an 8 percent reduction in greenhouse gas emissions in the 2008-2012 period (CO2 emissions from heat and electricity production are determined by allocated allowances pursuant to the National Plan for the Allocation of Emission Allowances) and a 20 % or 30 % reduction of greenhouse gas emissions by 2020 from the base year (1986);
- in the 2008-2012 period, average greenhouse gas emissions can amount to no more than 18,726 kt CO2 equiv. or 20,046 kt CO2 equiv. including sinks;
- reduction of NOx emissions to target values of 45 thousand tonnes;
- reduction of SO2 emissions to target values of 27 thousand tonnes.

The amendment of Directive 2001/81/EC on national emission ceilings for certain atmospheric pollutants will determine new targets for SO2, NOx, NMVOC, NH3 and PM2.5 emissions for 2020.

Data for Slovenia

Objectives summarised by: Resolucija o Nacionalnem programu varstva okolja 2005-2012 (Resolution on the National Environmental Action Plan 2005-2012, Official Gazette of the Republic of Slovenia, No. 2/06), the proposal of the climate and energy package, Protocol to the 1979 Convention on long-range transboundary air pollution to abate acidification, eutrophication and ground-level ozone and Directive 2001/81/EC of 23 October 2001 on national emission ceilings for certain atmospheric pollutants (the NEC directive).
Source database or source:
CO2 emissions: greenhouse gas emissions records, the Environmental Agency of the Republic of Slovenia, (see EN01).
SO2 and NOx emissions: records of emissions of air pollutants, the Environmental Agency of the Republic of Slovenia, (see ENO9).
Electricity and heat production: Energetska bilanca Republike Slovenije (Energy Balance of the Republic of Slovenia).
- Electricity production by fuels (nuclear energy, fossil fuels, RES): 1990-1999 data provided by the Jožef Stefan Institute regarding electricity production in public thermal power plants and public combined heat and power plants (conversion of data from the Joint Annual Questionnaire). For the period following the year 2000, data as published on the website of the Statistical Office of the Republic of Slovenia on 6 October 2008 in the SI-STA online application were used. Electricity production of auto-producers has not been considered.
- Heat production: 1990-1991 data provided by the Jožef Stefan Institute for heat production in transformations. Heat production of auto-producers was estimated as 10 % of total production. 1992-1999 data provided by the Jožef Stefan Institute for production of heat in public thermal power plants and combined heat and power plants, from the year 2000, data as provided by the Statistical Office of the Republic of Slovenia for the same items in energy balances.
Fossil fuel consumption: 1990-2007 period, data provided by the Environmental Agency of the Republic of Slovenia, greenhouse gas emissions records (see EN01).
Emission factors: 1990 data provided by the Environmental Agency of the Republic of Slovenia.
- CO2 – greenhouse gas emissions records, (see EN01).
- SO2 and NOx – calculating records of emissions for the year 1990.
Data administrator: For GHG emissions records: the Environmental Agency of the Republic of Slovenia – Tajda Mekinda Majaron, for records of emissions of air pollutants: the Environmental Agency of the Republic of Slovenia – Bojan Rode and for energy balances: the Statistical Office of the Republic of Slovenia – Mojca Suvorov.
Data acquisition date for the indicator: 8 December 2009
Methodology and frequency of data collection for the indicator: Data are prepared on an annual basis. Energy balances for the previous year are available at the end of the current year and records on emissions for the previous year at the beginning of the next year.
Data processing methodology:
Reference emissions (Ref_emissions): These are calculated by assuming the situation had remained the same as in 1990 and that emissions increased at the same rate as electricity and heat production.

Ref_emissions (year) = electricity and heat production (year) x emissions (1990) / electricity and heat production (1990)
Electricity and heat production – total electricity and heat production

Emissions reduction due to the increased share of nuclear and renewable energy: The division of total reduction into RES and nuclear energy was conducted in the following manner:

Em_fossil (year) = Share Fossil (year) / Share Fossil (1990) x Ref_emissions (year)
Share Fossil – share of electricity and heat production from fossil fuels

Emissions reduction due to fossil fuel switching: The implied emission factor for all fuels was calculated on the basis of the emission factor for individual fuels (solid, liquid and gaseous) in 1990 and the share of individual fuels in total use in transformations in a specific year.

Em_fossil mix (year) = Implied EF (year) /Implied EF (1990) x Em_fossil (year)
Implied EF – the implied emission factor for all fuels

Emissions reduction due to efficiency improvements: Efficiency is determined as the ratio of energy and heat production from fossil fuels and the use of fossil fuels

Em_ efficiency (year) = Efficiency (1990) /Efficiency (year) x Em_fossil mix (year)
Efficiency – efficiency of electricity and heat production

Reduction due to abatement technologies: This reduction is assumed to be the residual difference.
The indicator utilises an approach based on the multiplicative IPAT and KAYA identities:
- IPAT Identity: Impact = Population x Affluence x Technology
- KAYA Identity: CO2 emissions = Population x (GDP/Population) x (Energy/GDP) x (CO/Energy)
For the CO2 explanatory factors the identity used is:
- CO2 emissions from electricity and heat production =
Total electricity and heat output
x electricity and heat fossil fuels / total electricity and heat output
x fossil fuel input / electricity and heat from fossil fuels
x CO2 emissions from electricity and heat production / fossil fuel input.

The KAYA Identity is an accounting method enabling the impact of an individual factor to be estimated by addition and subtraction. It is important to be aware of the limitations of this method, as the estimated impacts of individual factors do not represent the exact impact of each factor due to being dependent on each other and the existence of interaction (different methods estimate the impact of individual measures differently). Despite its limitations, the method is useful as it provides indicative information about the importance (success) of different measures in explaining changes in CO2, SO2 and NOx emissions.

Annual growth is occasionally shown in percentage points. The percentage point is a unit used in comparing different percentages. In percentage points, we are dealing with an absolute comparison calculated using the following formula: (nthis year) – (nlast year) = 16 % – 15 % = 1 pp (e.g. if there was a 15 % growth last year and a 16 % growth this year, then this year growth is 1 percentage point higher). The difference in growth can also be expressed by relative comparison using the following formula: [(nthis year / nlast year) * 100] – 100 = [(16 % / 15 %) * 100] – 100=6.7 %. In this case, growth is expressed as a percentage.
Information concerning data quality:
Advantages and disadvantages of the indicator: The reliability of CO2 emissions estimates is very good, as internationally recognised methodology has been used (IPPC). Furthermore, national emission factors have been used for lignite and these depend on coal carbon content. Emission records are also subject to regular UNFCCC reviews. The reliability of SO2 and NOx emissions estimates is good, as data from records have been compared to data from emission measurements conducted at thermal power plants. In addition, internationally recognised methodology has been used (CORINAIR). As regards the manner of origin, SO2 emissions records have a higher reliability, as the quantity of emissions without flue gas treatment directly relates to the fuel’s sulphur content while NOx emissions depend on both the nitrogen amount in the fuel and the combustion process (combustion temperature, ratio between oxygen and fuel) which is specific for each boiler.
As regards fossil fuel consumption, data from greenhouse gas emission records provided by the Environmental Agency of the Republic of Slovenia have been used in the calculations so as to enable the correct estimate of the changed carbon content in coal. This consumption is not completely consistent with data provided by the Statistical Office of the Republic of Slovenia, hence the differences in the production efficiency of electricity and heat.
- Relevance, accuracy, robustness, uncertainty:
Reliability of the indicator (archival data): The indicator is reliable.
Uncertainty of the indicator (scenarios/projections): scenarios and projections are not available.
- Overall assessment (1 = no major comments, 3 = data to be considered with reservation):
Relevance: 1
Accuracy: 2
Completeness over time: 2
Completeness over space: 1

Other sources and literature:

- EEA, 2011. Emissions from public electricity and heat production - explanatory indicators (ENER 009) .

- Ministry of the Environment and Spatial Planning, 2006. Operativni program zmanjševanja emisij toplogrednih plinov do leta 2012 (Operational Programme for Limiting Greenhouse Gas Emissions by 2012).
- Ministry of the Environment and Spatial Planning, 2007. Operativni program doseganja nacionalnih zgornjih mej emisij onesnaževal zunanjega zraka /Revizija operativnega programa doseganja nacionalnih zgornjih mej emisij onesnaževal zunanjega zraka iz leta 2005/ (Operational Programme for Complying with National Emission Ceilings for Atmospheric Pollutants – Revision of Operational Programme for Complying with National Emission Ceilings for Atmospheric Pollutants from 2005/).
- Šoštanj Thermal Power Plant, 2008. BilTEŠ 2007 - Poročilo o proizvodnji, vzdrževanju in ekoloških obremenitvah okolja TE Šoštanj v letu 2007 (Annual reports – Report on the Production, Maintenance and Environmental Strains for the Šoštanj Thermal Power Plant in 2007).

15 November 2012
Matjaž Česen, Institut Jožef Stefan