The impact of CO₂ capture in the power and heat sector on the emission of SO₂, NO_x, particulate matter, volatile organic compounds and NH₃ in the European Union

Abstract

This study quantifies the trade-offs and synergies between climate and air quality policy objectives for the European power and heat (P&H) sector. An overview is presented of the expected performance data of CO2 capture systems implemented at P&H plants, and the expected emission of key air pollutants, being: SO2, NOX, NH3, volatile organic compounds (VOCs) and particulate matter (PM). The CO2 capture systems investigated include: post-combustion, oxyfuel combustion and pre-combustion capture. For all capture systems it was found that SO2, NOx and PM emissions are expected to be reduced or remain equal per unit of primary energy input compared to power plants without CO2 capture. Increase in primary energy input as a result of the energy penalty for CO2 capture may for some technologies and substances result in a net increase of emissions per kWh output. The emission of ammonia may increase by a factor of up to 45 per unit of primary energy input for post-combustion technologies. No data are available about the emission of VOCs from CO2 capture technologies. A simple model was developed and applied to analyse the impact of CO2 capture in the European P&H sector on the emission level of key air pollutants in 2030. Four scenarios were developed: one without CO2 capture and three with one dominantly implemented CO2 capture system, varying between: post-combustion, oxyfuel combustion and pre-combustion. The results showed a reduction in GHG emissions for the scenarios with CO2 capture compared to the baseline scenario between 12% and 20% in the EU 27 region in 2030. NOx emissions were 15% higher in the P&H sector in a scenario with predominantly post-combustion and lower when oxyfuel combustion (-16%) or pre-combustion (-20%) were implemented on a large scale. Large scale implementation of the post-combustion technology in 2030 may also result in significantly higher, i.e. increase by a factor of 28, NH3 emissions compared to scenarios with other CO2 capture options or without capture. SO2 emissions were very low for all scenarios that include large scale implementation of CO2 capture in 2030, i.e. a reduction varying between 27% and 41%. Particulate Matter emissions were found to be lower in the scenarios with CO2 capture. The scenario with implementation of the oxyfuel technology showed the lowest PM emissions followed by the scenario with a significant share allocated to pre-combustion, respectively -59% and -31%. The scenario with post-combustion capture resulted in PM emissions varying between 35% reduction and 26% increase.