Energy use contributes 79% to total greenhouse gas emissions in Slovenia. The biggest sources of emissions are electricity and heat production and transport. With the introduction of the EU Greenhouse Gas Emissions Trading Scheme (EU-ETS) Member States targets for GHG's covered only emissions from nonETS sources. Transport is by far the largest source of on nonETS emissions in Slovenia with 47%, while  emissions from energy use contribute 73%. The 2020 target has been achieved. Target for the following years are significantly more ambitious.

The intensity of SO2, NOx and CO2 emissions from electricity and heat production in public thermal power plants in 2021 was significantly lower than in 2005, with SO2 emissions intensity 94% lower, NOx  71% lower and CO2 28% lower. Compared to the EU-27 average, the intensity of CO2 emissions in Slovenia in 2021 was higher, NOx emissions slightly lower and SO2 emissions significantly lower.

Although electricity and heat generation increased by 30% between 1990 and 2021, CO2 emissions decreased by 31.5%, mainly due to the increase in generation efficiency, as well as to the increase in RES and nuclear generation. SO2 emissions decreased by almost 99%, mainly due to the installation of desulphurisation, the increase in generation efficiency and share of RES and nuclear generation.

The amount of waste from coal combustion is decreasing as a result of the reduction in the use of coal for electricity generation. In 2022, the amount was 15% lower than the previous year. By far the largest source is the Šoštanj thermal power plant. Most of the waste is used as fill material in mines.

Over the period 1990-2022, the amount of spent nuclear fuel, the only high-level radioactive waste, increased at an average rate of 5% per year. In the absence of a satisfactory permanent storage solution, there are concerns about the accumulation of this waste.

Air pollutant emissions have decreased in the period 2005−2020 to the levels that enable Slovenia achievement of its 2020 targets. But to reach 2030 targets additional decrease is needed. Reduction of emissions contributed to lower impact on ecosystems and human health, as emissions of pollutants that contribute to acidification, ozone precursors and particles, decreased by half compared to 2005.

Final energy consumption amounted to 4,719 ktoe in 2021 and increased by 7.1 % compared to the previous year. The increase was mainly a result of a economic recovery after the coronavirus pandemic and a colder year 2021. There was an increase in all sectors. Final energy consumption was 177 ktoe (3.6%) lower than the indicative target value for 2021 from the currrent National Energy and Climate Plan (NECP). The annual indicative target from the proposal for the NECP update was also achieved. In the period 2000‒2021, final energy consumption increased by 3.9 %.

Slovenia has a fairly high level of energy intensity that is decreasing, especially in the last few years. Average yearly decrease rate in the period 2005-2021 was 2.7 %. Compared to EU-27 Slovenia had 37 % higher intensity in 2020, being 11 % points lower than in 2005.

The intensity of final energy consumption as well as sectoral intensities in Slovenia have decreased over the period 2005-2022. Most in industry, least in transport. Comparison with the EU-27 shows that Slovenia is worse than the EU-27 average, but the gap has almost halved over the period 2005-2021, with contribution of all sectors except transport.

Primary energy consumption amounted to 6,470 ktoe in 2021 and increased by 2.7 % compared to the previous year. The increase was a result of an increase in the final energy consumption due to the economic recovery after the coronavirus pandemic and a colder year 2021, while the electricity production decreased compared to the previous year. Primary energy consumption was 258 ktoe (3.8%) lower than the indicative target value for 2021 from the currrent National Energy and Climate Plan (NECP), while it slightly lagged behind the annual indicative target from the proposal for the NECP update.