(7e) A Study of Emissions from Domestic Solid Fuel Stove Combustion in Ireland

The emissions study was carried out at the School of Mechanical & Materials Engineering building in University College Dublin (UCD) between April and July 2019. In total, 22 experimental runs were performed on 2 domestic stoves (stove 2 conforming to EU Ecodesign 2022 emission standards); using 5 domestically available solid fuels with several repeat analyses. Determination of flue gas composition was carried out in real-time using aerosol mass spectrometry, black carbon aethalometer, particle filters and gas analysers. The average emission factors of PM2.5 particulate matter in grams per Kg fuel burned in stove 1 were; wood logs 1.5, smoky coal 1.05, sod peat 0.63, biomass briquettes 0.25 and smokeless coal 0.1. For stove 2, the respective emission factors of biomass briquettes and smokeless coal were 0.1 and 0.1 g kg^-1 fuel burned. Generally, black carbon (BC) emission factors from fuels other than smoky coal were relatively low (0.007 – 0.027 g kg^-1), with a large proportion of this figure potentially arising from firelighter combustion. The proportion of BC emitted from smoky coal was 57 %, up to 80 times greater than manufactured smokeless coal. The manufactured smokeless fuel emitted the least amount of particulate at 0.10 g kg^-1 in both stoves which is in agreement with the governmental regulations. From this study it can be demonstrated that, in terms of particulate mass generated, briquettes made from torrefied olive stones produce 6 times fewer than wood logs when burned in stove 1 and 15 times fewer in stove 2. Torrefaction and subsequent densification of biomass via briquetting produces a consistent product with predictable combustion characteristics and has not only the potential to vastly reduce particulate and aerosol pollution, but also to mitigate Irish carbon emissions from the residential heating sector. Finally, the life cycle assessment was conducted to estimate the emissions released nationally for the next decade.