Emissions of pollutants into the air

The term emission means the process of emitting i.e. inserting pollutants into the air. In Croatian legislation, emission is presented as the mass of pollutants in milligrams (mg) per cubic meter of standardized air (m_n³), i.e. mg/ m_n³.

During 2018, the emission of air pollutants from HEP’s thermal power plants (TPP), combined heat and power plants (CHP), biomass fired power plants (BE-TO Sisak and BE-TO Osijek) and city heating boiler facilities did not exceed emission limit values.

In 2018, emissions of nitrogen-oxide (NO_x) from HEP’s TPPs and CHPs decreased by 50 %, that of sulfur-dioxide (SO₂) by 73 %, carbon-monoxide (CO) by 28 % and solid particles by 43 % compared to 2017 levels. The decrease of these emissions is the result of the use of natural gas as primary fuel and reduced operating hours of coal-fired thermal power plants.

Emissions of pollutants into the air – NO_x, SO₂, CO and solid particles from thermal power plants and combined heat and power plants:

Year	NO_x t/year	SO₂ t/year	CO t/year	Solid particles t/year
2017	2,779	1,444	225	69
2018	1,391	386	162	39
2018/2017 (%)	50	27	72	57

In 2018, NO_x emissions at BE-TO Osijek CHP and BE-TO Sisak CHP remained at the same level as in 2017, with SO₂ emissions decreasing by 92% and emissions of suspended particles by 83% as a result of higher quality fuel purchases. An 83% reduction in CO emissions was achieved by optimizing the fuel combustion system.

Emissions of pollutants into the air – NO_x, SO₂, CO and solid particles from biomass fired power plants – BE-TO Osijek CHP and BE-TO Sisak CHP:

Year	NO_x t/year	SO₂ t/year	CO t/year	Solid particles t/year
2017	26.74	3.56	29.7	56.77
2018	26.87	0.27	5.2	9.54
2018/2017 (%)	100.48	7.58	17.51	16.80

NO_X and CO emission measurements were conducted in city heating boiler facilities during 2017, and the calculation of these emissions was carried out based on measurement results. The measured emission values are mostly lower than the emission factors. In 2018, the measurement was not conducted, since it has been scheduled for every other year in accordance with the applicable regulations, so that the calculation of NO_X and CO emissions was based on emission factors (EMEP / EEA - 2016 method). The same applies to SO₂ emissions, for which calculation was made by mass balance. For these reasons, there were no major differences in the amount of CO₂ and SO₂ emissions in 2017 and 2018 as regards city heating boiler facilities, but there was a difference in NO_X and CO emissions.

Emissions of pollutants into the air – NO_x, SO₂, CO and solid particles from city heating boiler facilities:

Year	NO_x t/year	SO₂ t/year	CO t/year	Solid particles t/year
2017	17	6	2.5	0.5
2018	43	5	5.2	N/A*
2018/2017 (%)	253	83	208

_{* Below the level of emissions obligatory to report to the Environmental Pollution Register}

Measuring emissions

Measuring of pollutant emissions into the air is carried out by initial, intermittent, continuous and special measurements at the outlet/stack. The frequency of measuring pollutant emissions into the air from an individual outlet/stack is regulated by law.

Pollutant emissions into the air from HEP's thermal power plants and combined heat and power plants are measured continuously by automatic metering systems (AMS), and data are transmitted via a computer network to the Information system for monitoring pollutant emissions from stationary sources, maintained by the Ministry of the Environment and Energy (MoEE). Emissions from city heating boiler facilities are measured periodically.

Supervision and reporting

If pollutant emissions at site exceed threshold values, information on the types and quantities of pollutants in the air and the type and characteristics of fuel used to generate electricity and heat and process steam from HEP's sources (with the capacity exceeding 100 kW), are entered once a year into the Environmental Pollution Register (ROO) kept by the Croatian Agency for the Environment and Nature (HAOP).