LIAISE Policy Brief No. 3 on "Re-assessment of CO₂ and SO₂ emissions in energy sector by using LEAP-model: experiences from Estonian energy sector planning" has just been published. The LEAP (Long-range Energy Alternatives Planning) model is a software tool for energy policy analysis and climate change mitigation assessment. In 2012, a re-assessment of LEAP modelling results on CO2 and SO2 emissions in the Strategic Environmental Assessment of the Estonian National Energy Sector Development Plan until 2020 (further referred to as the Energy Plan 2020) was carried out. The aim of this re-assessment was to find out to what extent the LEAP model results for the Energy Plan 2020 were achieved and what were the possible reasons for deviation. The results highlight the opportunities for policy learning through the re-assessment of modelling results and the need to find out how to include into Impact Assessment the uncertainties that remain outside the scope of models.