Emissions from coal mining include methane released during mining, post-mining activities and from abandoned mines. The calculation is based on the amount of coal extracted, handled or number of abandoned mines and emission factors according to IPCC 2019 Guidelines, taking into account the amount of methane captured or flared. Post-mining emissions are estimated using basic emission factors, as measurements are not performed. Emissions from abandoned mines are calculated conservatively – all are considered to be gassy mines, regardless of their technical condition. CO₂ emissions from mining are based on estimates of concentration in mine air.
Fugitive emissions from oil and natural gas are calculated using a combination of methodologies according to the level of available data. For the transmission and storage of natural gas, direct measurements and modelling according to the OGMP 2.0 methodology, which corresponds to the advanced tier 4 approach, have been used since 2013. The calculations are provided by Eustream and verified by national experts. Leaks from compressors, repairs and accidents are taken into account, and infrared cameras are used for monitoring. Since 2023, emissions from gas distribution have been calculated using the SIMONE model, which allows for accurate and dynamic simulations of gas flow in the network. This tool is certified and used in many European countries. The model outputs have been fully integrated into Slovakia's emissions balance and have replaced the previous calculation method. Emissions from oil and gas extraction and processing, where detailed data are not available, are estimated according to the basic tier 1 IPCC approach.
Projections of emissions from the fugitive emissions subsector are calculated based on outputs on energy needs from the TIMES model for the energy and industry sectors. Calculations use a simple approach based on tier 1 emission factors for both greenhouse gases and pollutants. Emission factors are used according to the methodologies of the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, the 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories and the EMEP/EEA Air Pollutant Emission Inventory Guidebook 2023.