Evaluation of the embodied carbon of insulation in achieving a national retrofit plan in Ireland: Probono case study and the national perspective

Abstract

Overall, the building and construction sector, in Ireland, was responsible for 23 % of final energy use and 37 % of carbon dioxide (CO2) emissions in 2021. Ireland boasts some of the most ambitious targets for Greenhouse Gas (GHG) emission reduction to 2030 in the world. In Ireland, emissions related to the operation of the residential sector receive particular attention, and the government have introduced a National Retrofit Plan that aims to retrofit 500,000 (~25%) of the national housing stock by 2030. However, carbon emissions related to the achievement of this retrofit have not been quantified. This paper aims to outline the initial steps in evaluating the embodied carbon input of achieving a national retrofit plan of this unprecedented scale. Also, it aims to assess the relative carbon savings resulting from the production of materials to achieve retrofit plan. In the first stage, a case study of social housing, used in Probono project within the Dun Laoghaire Rathdown (DLR) local authority of Dublin City in Ireland is investigated as a best practice template for future retrofit projects. The embodied carbon of retrofit is evaluated. Then, a large housing sample set of DLR is evaluated in terms of Building Energy Rating (BER). This sample set is compared with the BER ratings of national stock to evaluate its representativeness. The results indicate that most of the dwellings on the sample set of DLR, in line with the national stock, are C and D rated and need to be retrofit to achieve B rating or better. In the final section, four types of nominal dwellings in Ireland are selected to evaluate the required volumes of thermal insulation and the added embodied carbon of retrofit to reach the national retrofit plan. The results demonstrate that ~30 million m3 of thermal insulation will be required for the national retrofit plan and it will add ~2 MtCO2 of the embodied carbon.