Deep decarbonization scenarios for Ireland to 2050 using a new scenario ensemble tool
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University College Cork
In response to the threat of climate change, countries of the world have signed the Paris Agreement aimed at limiting global warming to well below 2 degrees Celsius above pre-industrial levels and with an ambition to limit global warming within 1.5°C. As a member country of the European Union, Ireland is currently not on track to meet its carbon reduction targets and lacks climate policies leading towards a 1.5°C energy future. The purpose of this thesis is to develop methods, evidence and insights from energy systems modelling that can contribute to addressing the challenges of deep decarbonisation of Ireland’s energy system by 2050. While scenario analysis and energy systems modelling has been widely used globally to project 2°C-consistent energy pathways, a comprehensive literature review carried out in this thesis shows that single energy system projections may result in limited or even biased insights. This thesis presents an ensemble of scenarios method, which under a wide range of assumptions captures a broader range of solution space and can better address the challenges of deep decarbonization targets towards 1.5°C. The VEDA-SET (VEDA scenario ensemble tool) system is first developed based on the user shell of the TIMES model VEDA (VErsatile Data Analyst), and allows generating, queueing and analyzing large numbers of scenarios in an efficient manner. Using the VEDA-SET system, scenario ensembles are developed to explore deep decarbonization feasibilities and pathways towards the 1.5°C target set by the Paris Agreement. The results indicate that 1.5°C compatible targets are extremely challenging in terms of cumulative emissions from now to 2050. A more realistic target is midway between 1.5°C and 2°C targets and requires much stronger mitigation efforts between 2020 to 2030 than suggested by the current Nationally Determined Contribution (NDC). The thesis then focuses on mitigation measures by deriving marginal abatement cost curves (MACCs) using scenarios with varying carbon reduction targets. The MACCs are used to identify key mitigation options with significant mitigation potential and rank them based on cost effectiveness. Compared to existing MACCs for Ireland, MACCs based on the TIMES model better capture intertemporal dynamics and interactions across different sectors. Finally, an analysis is carried out to explore pathways that achieve decarbonization through 100% renewable energy. The analysis finds that 100% RES can be achieved through variable renewable energy (VRE) or abundant supply of bioenergy. A global sensitivity analysis using 500 scenarios reveals that energy pathways relying on bioenergy is more susceptible to uncertainties in investment costs, import costs and global bioenergy supply potentials. The scenario ensemble method adopted in this thesis enhances energy systems modeling by improving model transparency, addressing uncertainties and providing more robust policy insights. Besides journal publications and conference presentations, the findings and insights are disseminated through invited talks, policy briefs and online visualization platforms. Analysis on feasibilities of deep decarbonization is referenced by the IPCC special report on 1.5°C, providing evidence base for national mitigation pathways.
TIMES model , Decarbonization , Energy systems modelling , Uncertainty analysis , Renewable energy
Yue, X. 2019. Deep decarbonization scenarios for Ireland to 2050 using a new scenario ensemble tool. PhD Thesis, University College Cork.