Even though electricity and heat production increased by 21 % in the 1990-2006 period, CO2, emissions increased “only” by 10 %, predominantly due to a greater efficiency of production. SO2 emissions reduced by 95 % due to the installation of desulphurisation devices and a greater production efficiency, and NOx emissions by 27 % due to the implementation of primary measures on installations used for the reduction of NOx emissions (installation or replacement of burners, etc.), the improved methodology of calculating emissions and a greater production efficiency.
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.
Statistical Office of the Republic of Slovenia, 2009; Environmental Agency of the Republic of Slovenia, 2009.
|Reduction due to % of RES and NE||kt||0||585||-82||-307||198||71||138||-125||14||285|
|Change in the share of RES||kt||0||454||412||134||309||105||443||-144||97||503|
|Change in the share of NE||kt||0||130||-494||-441||-111||-34||-306||19||-83||-218|
|Change due to fossil f. switching||kt||0||6||-74||-61||-59||-39||-2||-40||-46||-27|
|Improvement of efficiency||kt||0||231||100||411||482||489||917||888||572||722|
|Change of the quant. of C in coal||kt||0||186||241||214||377||233||184||204||309||253|
|Reduction due to % of RES and NE||kt||250||168||-160||-481||93||-91||-238||-264|
|Change in the share of RES||kt||565||318||-200||-413||554||-202||-98||-337|
|Change in the share of NE||kt||-314||-150||40||-68||-461||112||-140||73|
|Change due to fossil f. switching||kt||-38||-21||-53||63||11||39||24||29|
|Improvement of efficiency||kt||716||662||822||1008||990||1123||1130||896|
|Change of the quant. of C in coal||kt||172||15||70||93||52||55||127||40|
Statistical Office of the Republic of Slovenia, 2009; Environmental Agency of the Republic of Slovenia, 2009.
|Reduction due to % of RES and NE||kt||0||15||-2||-8||5||2||4||-3||0||7|
|Change in the share of RES||kt||0||12||11||3||8||3||12||-4||3||13|
|Change in the share of NE||kt||0||3||-13||-11||-3||-1||-8||0||-3||-6|
|Change due to fossil f. switching||kt||0||1||-5||-4||-4||-3||-1||-3||-3||-2|
|Improvement of efficiency||kt||0||6||3||11||12||12||24||23||15||18|
|NOx emi. reduction measures||kt||0||5||2||0||-1||44||40||45||47||50|
|Reduction due to % of RES and NE||kt||6||4||-5||-13||1||-3||-7||-7|
|Change in the share of RES||kt||13||7||-6||-11||8||-6||-3||-9|
|Change in the share of NE||kt||-7||-3||1||-2||-7||3||-4||2|
|Change due to fossil f. switching||kt||-3||-2||-4||3||0||3||3||3|
|Improvement of efficiency||kt||19||18||22||26||26||27||27||21|
|NOx emi. reduction measures||kt||62||106||111||108||118||130||157||161|
Statistical Office of the Republic of Slovenia, 2009; Environmental Agency of the Republic of Slovenia, 2009.
|Reduction due to % of RES and NE||kt||0||1.7||-0.2||-0.9||0.6||0.2||0.4||-0.3||0||0.8|
|Change in the share of RES||kt||0||1.3||1.2||0.4||0.9||0.3||1.3||-0.4||0.3||1.4|
|Change in the share of NE||kt||0||0.4||-1.5||-1.3||-0.3||-0.1||-0.9||0.1||-0.3||-0.6|
|Change due to fossil f. switching||kt||0||0||-0.3||-0.2||-0.2||-0.1||0||-0.2||-0.2||-0.1|
|Improvement of efficiency||kt||0||0.7||0.3||1.2||1.3||1.4||2.6||2.5||1.6||2|
|NOx emi. reduction measures||kt||0||0.9||0.1||-0.3||-0.3||-0.2||-1.2||0.1||0.5||0.3|
|Reduction due to % of RES and NE||kt||0.6||0.4||-0.5||-1.4||0.2||-0.3||-0.7||-0.8|
|Change in the share of RES||kt||1.4||0.8||-0.6||-1.2||0.9||-0.7||-0.3||-1|
|Change in the share of NE||kt||-0.8||-0.4||0.1||-0.2||-0.8||0.4||-0.4||0.2|
|Change due to fossil f. switching||kt||-0.1||-0.1||-0.2||0.2||0.1||0.2||0.2||0.2|
|Improvement of efficiency||kt||2.1||2||2.4||2.9||2.9||3.1||3.1||2.3|
|NOx emi. reduction measures||kt||0.9||1.4||1.4||1.4||1.5||3.3||5.4||6.6|
- 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):
Completeness over time: 2
Completeness over space: 1
Other sources and literature:
- EEA, 2008. EN09 Emissions (CO2, SO2 and NOx) from public electricity and heat production - explanatory indicators.
- 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).
In 2007, the electricity and heat production sector contributed 32 % of total CO2 emissions, 59 % of total SO2 emissions and 28 % of total NOx emissions, making it very important for achieving national targets. Information on which measures yield the anticipated results and which are failing is therefore crucial for a timely adaptation of our strategy for reducing emissions.
In 2007, electricity and heat production contributed 6565 kt of CO2 emissions, 8.35 kt of SO2 emissions and 12.47 kt of NOx emissions making it the largest source of CO2 and SO2 emissions and the second largest source of NOx emissions (the largest being transport). In the 1990-2007 period, SO2 and NOx emissions reduced by 95 % and 27 % respectively, while CO2 emissions increased by 10 %. In 2007, CO2 emissions increased by 4 % and SO2 and NOx emissions decreased by 14 % and 5 % respectively. In 2007, electricity and heat production was 21 % greater than in 1990 and 2 % smaller than in 2006, especially due to a lower demand for heat.
The reduction or slowdown in emissions increases as regards increases in electricity and heat production arising in the implementation of measures that can be classified into four groups:
• Increase in the share of non-fossil fuels, such as power production from renewable energy sources and nuclear produce. As regards renewable energy sources, it needs to be said that wood biomass produces SO2 and NOx emissions, but is generally stated to have zero net CO2 emissions. Therefore, when considering emissions of CO2, biomass is regarded as a renewable energy source and when considering SO2 and NOx emissions, as part of fossil fuels.
• Increase in the efficiency of electricity and heat production from fossil fuels. This can be achieved both by improving production efficiency at existing plants as well as constructing new ones and by increasing production of electricity in combined heat and power plants.
• Change in the mix of fossil fuels used for electricity and heat production. Coal (brown coal and lignite) and fuel oil contain significant amounts of carbon, sulphur and nitrogen, which react with oxygen during combustion to form emissions that cause damage to the environment. Natural gas contains significantly less of these chemicals and is therefore more environmentally acceptable.
• Introduction of emissions abatement techniques:
- Flue gas desulphurisation (FGD) substantially reduces SO2 emissions. The most common is the wet calcite flue gas desulphurisation method based on the absorption of sulphur dioxide from flue gases using slurry where it forms a stable product together with the calcite.
- Primary (combustion modification) or secondary measures (flue gas treatment) can be used to reduce NOx emissions. One of the most common forms of combustion modification is to use low NOx burners.
- In the future, carbon capture and storage (CCS) will undoubtedly play an important part in reducing CO2 emissions from coal-fired thermal power plants. The technology is however still in the process of being developed.
- Part of this group is also methodological improvements for calculating emissions records and changes in emission factors due to changes in fuel properties.
In 2007, CO2 emissions from electricity and heat production were 10 % higher than in 1990. If the situation in transformations had been the same in 2007 as in 1990 (the same fuel mix, the same efficiency rates of thermal power plants, etc.), emissions would have been 21 % higher – the same increase as that of electricity and heat production.
In 2007, emissions per unit of electricity and heat produced were 10 % lower than in 1990. This reduction is the result of the following measures being implemented:
• As evident from Figure 1, emission reductions were mostly the result of improvements made to the efficiency of devices for electricity production which was achieved by optimising the operation of existing devices. In 2007, production was 14 % more efficient than in 1990 but 3 percentage points less than in 2006. The lower efficiency result was mostly due to a lower demand for heat. In the future, the construction of new devices is expected to substantially improve efficiency rates.
• In 2007, the quantity of produced electricity and heat from renewables (RES) and nuclear power was 18 % higher than in 1990 (117 ktoe), which is less than in 2006, when production was 20 % higher (135 ktoe). As electricity and heat production from fossil fuels increased by 25 % (143 ktoe), the share of production from fossil fuels was 3.7 % higher than in 1990. Due to the increase in the share of fossil fuels, the impact of this measure was a negative one – emissions increased. In all the years, this share changed, as electricity production from RES depends on river capacity while annual production of electricity in a nuclear power plant depends on the duration of overhauls and partially also river capacity due to cooling. The year 2004 was a record year as regards electricity production in hydroelectric power plants and the year 2005 in the nuclear power plant at Krško. After the construction of the chain of hydroelectric power plants on the lower Sava river and completed refurbishment of existing power plants, the capacity of hydroelectric power plants will increase but not sufficiently to present a substantial growth in the share of RES in electricity production, as the fast growth of electricity consumption causes growth in production from fossil fuels.
• In 2007, coal was still the main energy source in thermal power plants and the minimal reduction in CO2 emissions due to fossil fuel switching is the result of exchanging liquid fuels for gaseous fuels. In 2007, CO2 emissions per unit of fossil fuel used were 0.4 % lower than in 1990. In the future, the construction of new gas-fired thermal power plants to replace coal-fired ones is expected to generate a better impact of this measure on reducing emissions.
• In addition to factors related to fuel consumption, emissions are affected by changes in emission factors for lignite that depend on the carbon content of lignite. In the 1991-2000 period, this emission factor was lower than in 1990, while in the 2001-2005 period, it was approximately the same as in 1990. In 2006, it was substantially lower and in 2007 again almost the same as in 1990. In 2007, emissions reduced by 0.6 % due to changes in the emission factor.
Multiplying the impact of individual measures provides us with the change of emissions in 2007 as regards the year 1990. 1.213 (increase in electricity production) x 0.881 (efficiency improvement) x 1.036 (fossil fuel switching) x 0.996 (emission reduction per unit of used fossil fuel) x 0.994 (change of emission factor) = 1.096 (increase in CO2 emissions in 2007 from 1990).
Linking the reduction in emissions to specific policies is difficult. The results as presented above show estimated impacts of individual groups of measures. The implementation of individual measures is facilitated by different instruments. The increase in the share of RES is for example facilitated by the feed-in tariff system, financial stimulations (subsidies, loans) and the certification of energy sources. Furthermore, other standards for implementing individual measures of course also play an important part, especially in electricity and heat production (e.g. reliability of supply and market conditions since the natural gas and electricity markets opened).
In 2007, SO2 emissions were 95 % lower than in 1990 and 96 % lower per unit of electricity and heat produced. The separation in the connection between emissions and production was achieved by implementing the following measures:
• The most important contribution is that of abatement techniques, i.e. flue gas desulphurisation, replacement of high sulphur content coal with coal with a lower sulphur content and a reduction of sulphur content in liquid fuels. This caused a 95 % reduction in 2007 from 1990.
• The second group of measures with regard to the quantity of the impact is the increased efficiency of devices. Efficiency of electricity production increased by 11 %, but was lower than in 2006.
• Impacts of the other two groups of measures were small. In 2006, the share of fossil fuels and wood biomass was 3.7 % bigger than in 1990. The increase in the share of cleaner fossil fuels affected the reduction of emissions by 1.7 %.
The overall multiplicative impact of these groups of measures and increased electricity production again provides us with the total reduction of emissions in 2007 compared to 1990 levels. In a similar manner to CO2 emissions, future investments in new capacities allow us to anticipate further increases in the efficiency of production and a reduction of SO2 emissions per unit of used fossil fuel.
In 2007, NOx emissions were 27 % lower than in 1990 as a consequence of:
• implemented abatement techniques, such as the replacement of burners with low NOx burners, reconstruction of boilers and improved methodology of calculating records of emissions achieving a 34 % reduction,
• an improved efficiency of devices for electricity and heat production (by 11 %),
• using fossil fuels with lower nitrogen content (from liquid fuels to natural gas) – a 0.9 % reduction.
The 3.7 % increase in the share of fossil fuels and wood biomass resulted in a minor reduction of emissions. In the future, it is anticipated that new investments will result in further reductions of emissions, both for SO2 and CO2.