Dr. Oliver Kinnane:

I thank the committee for inviting me to present today. The evidence I will give is based on findings from research projects funded by the Sustainable Energy Authority of Ireland, SEAI, Research Ireland and the European Commission and undertaken by an excellent team of researchers at UCD's school of architecture, planning and environmental policy. This includes industry relevant projects focused on conservation and reuse, concrete innovation, MMC, building performance analysis and compact urban growth.

On the built environment and carbon budgets, Ireland is constructing while at the same time trying to reduce its carbon emissions to meet its ambitious carbon budgets. However, construction is inherently carbon intensive. More buildings will add carbon emissions in the short-term through the emissions embodied in the materials they are constructed with and in the longer term through a life cycle of operation. Ireland is projected to overshoot its carbon budgets. Although progress has been made in improving building efficiency, the operation of the built environment sector will slightly exceed its first carbon budget period of 2021 to 2025, but is forecast to overshoot its second carbon budget for the period 2025 to 2030 by 20% to 25%.

The built environment category accounts only for operational emissions and is split between residential and commercial with public buildings subcategories. Quantifying all other carbon emissions associated with the built environment is a challenge. The varied categorisation of emissions is a barrier to achieving real progress. Additionally, in our system of accounting, only production-based emissions are reported, but in Ireland we import considerable quantities of metals and other materials for construction. To get a clearer picture of the real carbon impactors in construction, we propose a consumption-based accounting approach also be used. This would provide essential information about the most carbon-intensive materials, where they are coming from and what fuel was used in their production.

In 2022, we undertook an accounting and modelling study of the Irish built environment and construction sector that included all these emissions, thereby presenting a holistic picture. We baselined carbon-related current activity and projected emissions out to 2030 and 2050 for different scenarios. One of the primary results of the forecasting study showed that carbon reductions due to operational efficiency gains, if achieved through retrofit and efficiency improvements, would be cancelled out by the carbon emissions associated with the construction of housing. Since that study was compiled, housing targets have increased from 33,000 per year to over 50,000 per year. This increase will bring considerable additional embodied carbon as a result of the use of current methods of construction.

On materials and embodied carbon, a success story in the context of carbon emissions in the built environment is evident in a reduction in cement related emissions in the industrial process category, although this is primarily related to a reduction in production levels. More sustainable gains are achievable through cement innovation and replacement, as well as fuel switching in the production of clinker. In the longer run, moving towards a performance-based approach to green procurement and away from a fully prescriptive-based approach can bring considerable carbon savings. Restrictive carbon standards are currently a barrier to entry and usage of low-carbon cement alternatives. A revision of standards is required along with new systems that enable accelerated approval processes.

Updates to existing regulations are also required to enable greater usage of timber particularly for mid-rise buildings. Although the increased use of timber in low-rise residential construction is welcome, the full potential of embodied carbon savings will not be achieved while substructure, cladding and roofing elements remain as heavy embodied carbon components. The climate action plan 2025 calls for a 30% reduction in embodied carbon of construction materials, but more detailed and measurable targets are required along with clear implementation pathways as has been called for by the CCAC.

On the construction of housing, modern methods of construction can be part of the solution to increase housing output through improved construction sector productivity delivered by an expanded workforce. MMC enables a diversification of the workforce, drawing a wider range of workers ,including those from manufacturing industries, into construction. However, upskilling of a new MMC workforce in construction is required. Decisions to support and knowledge sharing platforms that enable access to key information about product viability, cost and sustainability are required for architects, engineers and specifiers. Recent research we have undertaken has questioned the often repeated sustainability credentials of MMC, showing wide variation between different systems of different materials.

MMC schemes we have analysed in detail from a life-cycle analysis perspective highlight the reduced embodied carbon of MMC components in construction, but traditional build elements, such as the high-embodied carbon-brick cladding offset these gains. The planning preference for brick-clad buildings should be reconsidered, particularly as other cladding materials offer embodied carbon savings. A financial model to support MMC manufacturers that reduces the risk for product producers is required. Recasting of standards and regulations is key to enabling greater MMC innovation and market penetration. Enhancing capacity to support an efficient agrément certification process is required. Over 50% of the embodied carbon in any building is within the building structure, and there is an onus is on structural engineers to optimise their structural designs. An increased focus on embodied carbon metrics is needed in the engineering profession and in third level education.

The housing programme is critically important to climate targets, not only in new housing construction but also because the design, form and location of new housing dictate new infrastructure demands, new transport demands, future operational costs and if poorly designed or built, future replacement costs. Sustainable communities need to be considered more broadly than the energy use in construction. Apartment construction embodies higher carbon per square metre of floor area than scheme housing, primarily due to greater concrete usage in the building structure, but represents a more sustainable construction type when evaluated in terms of land use and lifecycle carbon. This raises key questions about how we measure and interpret embodied carbon metrics, which from 2027 will become mandatorily reported when the new energy performance of buildings directive, EPBD, is transcribed into national regulations. There are growing calls to set embodied carbon targets per bed space, not per metre squared, house or apartment so that the optimum resources are used to house the most people most efficiently.

On reuse over new build, the renovation and reuse of existing buildings carries a fraction of the embodied carbon cost of new build. Our modelling works shows that retrofitting 100,000 of our vacant homes could slice over 1 megatonne of CO2 emissions off the embodied carbon bill to 2030. The reuse of existing buildings in existing cities, towns and villages is an opportunity to add to the housing stock where existing structures, infrastructure and services are already provided, saving more than 30% additional embodied carbon. Regulatory barriers mean that the process to conversion and reuse is often cumbersome and inefficient. This includes separate processes for planning, conservation, fire safety, disability access, etc. These administrative systems need to be streamlined to support building owners and reduce costs. Uptake of grant support is low. The process needs to be revised to reduce administrative burden and upfront costs for building owners. Savings are also available in the commercial sector where the demolition of existing buildings and replacement with new claimed and more sustainable buildings is common.

Fifteen per cent of our commercial buildings nationally are estimated to be vacant. Those buildings should be reused as a priority.

Care needs to be taken when retrofitting, particularly with traditional builds. The risk of long-term damage to buildings and the development of poor environmental quality is high due to moisture trapping, as we have highlighted through SEAI-funded research. Retrofit rates and heat pump installations are well below target. To maximise the benefit of moving homes to electrical power, a more rapid reduction in the carbon intensity of the electricity grid is essential through either renewables or other clean means of generation.

Much work is required across the construction sector to achieve more sustainable practices that can set us on a path to meeting our carbon budgets. A holistic perspective of the built environment is necessary and faster evolution of regulatory frameworks are required to support innovation in concrete, MMC and bio-based alternatives.

We need to save the buildings we have and retrofit first. We need to legislate to limit unnecessary demolition. Going beyond new regulations for embodied carbon reporting, nationally we should penalise demolition, perhaps through setting of carbon caps for new development that subtract any wasted embodied carbon of demolition.

More and better data is required to get a clearer picture of the built environment's impact. This can benefit academic research which is essential to providing an evidence base and objective critical review of strategy and policy. Increasing research funding is critical to allow universities to work alongside industry and policymakers to achieve a more sustainable built environment for Ireland. I apologise for running so much over time.