Environmental lifecycle assessment of buildings in Ireland A move towards nearly zero energy buildings

Directives in the European Union are ensuring that buildings in this region are moving towards nearly zero energy buildings (NZEB). That is, all new buildings or buildings receiving significant retrofit from 2020 must have a very high energy performance, where the nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby. As a consequence, for countries like Ireland, which has a temperate oceanic climate, a key to achieving NZEB is to have high thermal and air tightness performances of the building envelop. Consequently, as the operational energy of the building reduces the embodied energy (and embodied carbon) typically increases as a proportion of the lifecycle energy of the building due to increased embodied energy of the building envelope and the lower operational energy. This paper presents the outcomes of a number of case study buildings in Ireland, which focuses on the full environmental lifecycle assessment of buildings using (embodied and operational) energy usage and greenhouse gas emissions as indicators. The case studies are divided into two categories (1) new residential buildings constructed to various building regulation standards, and (2) existing residential buildings receiving upgrades. This paper clearly highlights that future building regulations and legislation need to focus on reducing the environmental impact of construction materials and practices, and not just solely focus on operational aspects of buildings.