Energy Engineering - Doctoral Theses

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https://hdl.handle.net/10468/2136

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Enhanced modelling of transport decarbonisation and policy pathways for Ireland
(University College Cork, 2023) O'Riordan, Vera; Rogan, Fionn; Daly, Hannah E.; O'Gallachoir, Brian; Climate and Energy Modelling Services
The release of increasing human-induced greenhouse gas emissions and the corresponding global temperature rise has prompted a growing political consensus on a decarbonised future to prevent any sustained economic or environmental harm. Many countries are using energy system modelling tools to develop strategies and policy measures to deliver timely and effective reductions of harmful greenhouse gas emissions across all energy-related sectors. Ireland, with ambitious legally binding carbon budgets, and decarbonisation targets for transport, is a country in the process of assessing and addressing key transport decarbonisation challenges faced by high-emitting countries. This thesis - with its scientific contributions on transport emissions, methodological advancements for transport and multi-sector energy systems simulation modelling, and policy recommendations on how effective measures have been in the past or could be in the future - serves as a small, but novel, piece of this process. The thesis updates the Irish Car Stock Model to investigate the importance of taxation policy using a novel bottom-up stock simulation approach. The simulation model evaluates the 2008 car tax policy in Ireland and finds that while the policy was effective at reducing CO2 emissions, it had a high cost of carbon abatement, between €1,500 – 2,200 per tCO2. The thesis develops the Irish Passenger Transport Emissions and Mobility (IPTEM) model, which for the first time, calculates the overall passenger transport demand in Ireland by trip purpose, trip distance, and mode type. The methodological advancement is in the combination of passenger transport demand from all modes of transport and information from the National Travel Survey, national transport providers, and the Irish Car Stock Model. The study finds that 82% of passenger transport demand is met by cars in Ireland, and the main reason for travel is for work (30%), shopping (19%), and companion journeys (16%). The study also finds that 40% of emissions come from journeys less than 8 kilometres. In Chapter 4, this thesis develops a new model, the LEAP Ireland ASI (Avoid-Shift-Improve) model which projects emissions and demand for passenger and freight transport up to 2030. It is novel in its application of the Avoid-Shift-Improve framework for scenarios focused on reducing the need to travel in the first instance (“Avoid”), then on modal shifting towards increased public transport use and active travel (“Shift”), and then on scenarios focused on improving the fuels used to ones with a lower carbon intensity (“Improve). These scenarios are modelling in combination with one another and the interaction between the policies is also determined. In Chapter 5, the thesis develops a new methodology for simulation modelling to project carbon dioxide emissions, how different scenarios could reduce carbon dioxide emissions, and how these fit in with sectoral emissions ceilings within carbon budgets. The thesis tracks past sectoral emissions and simulates the mitigation potential of a suite of scenarios for transport, residential, electricity, services, and industry sectors. The LEAP Ireland model developed in Chapter 5 can simulate the impact of additional policies, track policy performance, and simulate mitigation potential. The data sources, methodology, and carbon budget analysis are outlined in this novel simulation modelling framework designed to support countries with their carbon budgeting commitments. This thesis also examines the interaction effect between these policy scenarios and discusses their combinations' synergistic and antagonistic effects. The contribution of this thesis is the improvements made to the modelling methods and more robust evidence base for developing sound decarbonisation transport policy measures by shifting the focus beyond car efficiency and electrification.
Connecting the continents. Power system modelling and capacity building for detailed assessments of global power sector decarbonization pathways
(University College Cork, 2021) Brinkerink, Maarten; O'Gallachoir, Brian; Deane, Paul; Energy Exemplar; Science Foundation Ireland
Deep decarbonization of the global energy sector is essential for reaching increasingly ambitious climate change mitigation targets. The momentum on global climate action is gathering speed, hence the need for energy research to accurately inform development pathways and decision making processes for the global energy sector is both critical and urgent. Electricity end use is expected to gain a larger role due to the potential for emission reductions in the electricity sector combined with the ability of electricity to displace fossil fuel use in other sectors. While completely decarbonised power systems based on very high penetrations of wind and solar energy are desirable, the technical and economic feasibility of power systems mostly or fully based on renewables remains a matter of debate. Furthermore, from a continental or global perspective, the role of flexible assets such as large-scale transmission interconnections are poorly understood. This thesis develops, applies, and disseminates a number of key foundation blocks for robust assessments of global power system decarbonization pathways by means of open methods and datasets that can be used with a broad range of modelling tools. The author constructs and uses a detailed global power system model with high technical, temporal, and spatial modelling resolution to assess the technical feasibility of scenarios coming from long-term planning models. The methodological open source soft-link framework presented here is carefully designed to respond to known limitations of Integrated Assessment Models in a manner that allows for iterative model coupling to pinpoint and improve key areas of power system representation within Integrated Assessment Models. The thesis results provide insights that planning models struggle to generate, for example regarding curtailment of renewable electricity, occurrence of unserved energy and the operation of flexible assets at hourly modelling resolution. The research pays particular attention to the potential for intercontinental trade of electricity in context of a globally integrated power grid. The main contributions of this thesis are the development, application and dissemination of new methods, datasets and models that improve power system modelling and capacity building efforts at the global scale. The foundation blocks provided by this research are currently contributing to improved assessments of power system decarbonization pathways and are enriching the evidence base underpinning global climate- and energy policy decisions.
Quantifying the impact of energy technology innovation on cost reductions
(University College Cork, 2019-09) Elia, Alessia; O'Gallachoir, Brian; Rogan, Fionn; Science Foundation Ireland
The alarming global warming risk has pushed for global consensus on the decarbonisation of the energy systems to achieve a low carbon future. In this context, it is necessary to invest in the deployment of emergent renewable energy technologies to accelerate the decarbonisation path of the national energy systems. The recent achievements in technology innovation for two mature renewable energy technologies, onshore wind and solar photovoltaic are generally recognised by decision-makers. However, this is not enough and most of current energy systems remain dependent on fossil-fuel resources to satisfy growing energy demands. Cost reductions are required across many more renewable technologies but the dynamics of how to achieve these cost reductions are poorly understood. Deeper insights into the impacts of energy technology innovation on cost reductions are essential in order to accelerate the development and deployment of emerging renewables energy technologies. This thesis both highlights and addresses the current knowledge gap in our understanding of technology innovation, in the quantification of the drivers of technology cost reduction and in the innovation needs to accelerate technology cost changes. The core of the thesis consists in linking together distinct fields of knowledge in an interdisciplinary manner: on one side the theory of technology cost reduction drivers and the energy technology innovation system framework, and on the other side analytical models to quantify the drivers of cost reduction and identify the innovation needs required to accelerate cost reductions. The thesis firstly develops an understanding of the role of energy technology innovation on technology cost reductions. It explores the impacts of innovation along the different stages of development of a technology and identifies the main drivers of technology cost reductions. In so doing, the thesis also reveals the methods used to quantify multiple drivers of cost reduction and their analytical findings. The thesis then investigates a new method to quantify technology cost reduction drivers based on an advanced bottom-up cost model for onshore wind. The disaggregation in cost components and techno-economic variables developed in this method generates clearer results than current approaches in the literature can provide. This includes improving the causality link between costs components reduction and drivers and providing insights into the impacts of variables related to technical aspects and to manufacturing processes. The thesis highlights the current limitations of attempts to incorporate energy technology innovation impacts into energy system optimization models, the main tools used to inform policy-makers on future climate actions. It further proposes a novel approach to explore technology innovation within current energy system optimization models. This approach links an energy system model with a historical innovation analysis, focusing on the prospects of wave energy development in Ireland. The combination of these two methods generates insightful results regarding the innovation needs required to accelerate technology innovation for wave energy that could not be captured with a single-method approach. The key contributions of this thesis are the enrichment of our understanding of technology innovation, new insights and alternative improved methodologies to quantify technology costs reduction changes allowing to move beyond one-factor analyses, and novel methods to investigate the innovation needs required to accelerate technology cost reduction for emerging energy technologies. Moreover, an example of potential impact on the research community, this thesis lead to discussion between energy modellers and innovation practitioners about the contribution of technology innovation in energy system models.
Performance and power smoothing of innovative closed-circuit oscillating water column wave energy converter
(University College Cork, 2019) Benreguig, Pierre; Murphy, Jimmy; Sheng, Wanan; OCEANERA-NET European Network
Due to the urgency to limit global warming to 1.5◦C, it is necessity to find alternatives to fossil fuel energy to empower human activities. Among the alternative resources of energy, wave energy has a large potential as it could potentially represent 10% of the world electricity demand. Significant progress in this field is however still needed to produce affordable electrical energy. Oscillating-Water-Column (OWC) devices are among the most promising types of wave energy converters because of their relative simplicity. The present work investigates the possibility of improving the performance of this well-established concept by introducing a variation in the working principle. The resulting new Tupperwave concept is equipped with non-return valves and air pressure accumulators to create a smooth unidirectional air flow, harnessed efficiently by a unidirectional turbine. In this thesis, the Tupperwave concept is investigated physically and numerically on a floating structure. In order to assess the relevance of the Tupperwave device against the conventional OWC, wave-to-wire numerical models for both devices are developed, using different thermodynamic approaches and considering the use of the current state-of-the-art turbines for each device. The different power conversion processes of the wave-to-wire models are validated through physical experiments. The wave-to-wire models are then used to identify the benefits of pneumatic power smoothing by the Tupperwave device and assess its electrical power performance. The results demonstrate the potential of the new Tupperwave concept to outperform the conventional OWC concept in terms of electrical power production and quality.
Analysing evolutionary pathways for the European power system resulting from climate mitigation policy
(University College Cork, 2019) Gaffney, Fiac; Deane, Paul; O'Gallachoir, Brian; Bord Gais Energy
The need for robust analysis of decarbonisation pathways has never been as high or as demanding. Globally, climate action is picking up pace. Yet, its momentum may hinge on informed policy decisions being made in a timely manner. Energy research must provide the analysis for these informed decisions. However, the scientific field lags others such as medicine or economics in moving to more open and reproducible science. The fact that this research is directly relevant to the urgent policy challenge of rapid energy system decarbonisation makes reproducibility of results particularly important. Aligning with this belief, all models and datasets used as part of this thesis are made openly available and accessible. The central focus of this thesis is to understand the effects of climate mitigation policy on Europe’s power sector. The approach applied in this thesis looks back in time as well as forward to capture the learnings from previous marketplace evolutions that may help avoid similar pitfalls in the future. Coupled with insights from a power system already having to endure complete market transformation while attempting to remain fit-for-purpose, this knowledge is the basis for analysing proposed decarbonisation pathways for Europe in terms of policy, regulation, economics and system operation perspectives. Today, policymakers and society are confronted by important decisions regarding the balance between cost equality, economic growth, energy security and climate action on a global scale. The key contributions of this thesis to that decision making process are new insights into the effects of policy decisions on cost inequalities stemmed from cross-border subsidisation of renewable energies, the risk exposures associated with over-reliance on technological development/readiness and finally a better, more well-rounded understanding of power system operational concerns in this brave, new decarbonised world.

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