Advancing Irish energy system modelling to inform residential policy
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Full Text E-thesis
Date
2023
Authors
McGuire, Jason
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Publisher
University College Cork
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Abstract
Anthropogenic greenhouse gas emissions are rising, and a lack of action towards climate policy has sparked a renewed determination to act. Energy Systems Optimisation Models (ESOMs) help guide energy policymaking to meet climate goals. This thesis uses a newly developed ESOM, TIMES Ireland Model (TIM), to explore Ireland’s decarbonisation pathways. TIM incorporates empirical internal temperature variations in buildings. Building Energy Rating (BER) assessments in Ireland, based on Energy Performance Certificates (EPC), measure a building’s expected energy consumption. However, it has been observed that standard BER assessments tend to overestimate residential energy consumption in Ireland by as much as 23%. When empirical internal temperatures are used in place of BER temperature assumptions, 6% fewer thermal retrofits are required to achieve the cost-optimal decarbonisation pathway, but energy savings are 114% less in this case. The new methodology better reflects energy consumption without overestimating the effect of thermal retrofits and provides more accurate climate policy insights.
The Danish Energy Agency supported this thesis by exploring the feasibility of district heating (DH) in Ireland. Ireland is a country with low DH deployment, but it has significant surplus heat. Using scenarios that considered different connection rates and maximum annual growth, this thesis consistently showed that DH saturates the heat market before 2050 in all scenarios. If DH is excluded, the average sectoral marginal CO2 emission price over the model’s time horizon is €729/tCO2. However, when DH is permitted, this cost reduces by 13% to 25%, depending on the connection rate and maximum growth constraint.
A policy-focused aspect of this thesis explored Ireland’s current fabric-first policy approach to understand if it is cost-effective. Alternative decarbonisation pathways allow for variations in heat pump subsidy thresholds connected to a dwelling’s Heat Loss Indicator (HLI). The thesis also accounted for sub-optimal heat pumps, which do not achieve peak performance due to high HLIs. The findings suggest that the current fabric-first approach is stringent, requiring a BER rating of B2 or equivalent energy consumption, which is not cost-effective. Significant savings can be made, especially post-2030. For example, post-2030, the fabric-first average sectoral marginal CO2 emission price is €675/tCO2. Simply by allowing sub-optimal heat pump installation, this reduces to €312/tCO2. Adjusting the HLI threshold to 2.3 W/K/m² could further reduce this cost to €273/tCO2.
This research offers a detailed exploration of the Irish residential sector, emphasizing the complex interactions among different energy sectors and advocating for a more coherent energy planning approach. For policymakers, it is essential to better understand residential energy consumption, embrace district heating through spatial energy system planning, and reevaluate the fabric-first approach. By doing so, Ireland could effectively achieve its climate goals more cost-effectively.
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Keywords
Energy System Optimisation Model (ESOM) , The Integrated MARKAL-EFOM System (TIMES) , Ireland , Residential decarbonisation , Open-source model , Heat pumps , Thermal efficiency , District heating , Sector coupling
Citation
McGuire, J. 2023. Advancing Irish energy system modelling to inform residential policy. PhD Thesis, University College Cork.