This indicator analyses trends of past CO₂, SO₂ and NO_x 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 NO_x 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 NO_x into ground level ozone, while this gas, the same as SO₂, contributes to the acidification of the atmosphere and emission of (secondary) dust particles.

In 2007, the electricity and heat production sector contributed 32 % of total CO₂ emissions, 59 % of total SO₂ emissions and 28 % of total NO_x 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 NO_x emissions making it the largest source of CO₂ and SO₂ emissions and the second largest source of NO_x emissions (the largest being transport). In the 1990-2007 period, SO₂ and NO_x emissions reduced by 95 % and 27 % respectively, while CO₂ emissions increased by 10 %. In 2007, CO₂ emissions increased by 4 % and SO₂ and NO_x 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 NO_x 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 NO_x 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 NO_x emissions. One of the most common forms of combustion modification is to use low NO_x 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, NO_x emissions were 27 % lower than in 1990 as a consequence of:
• implemented abatement techniques, such as the replacement of burners with low NO_x 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.