Multi-scale energy system optimisation for efficient, affordable and secure net-zero transitions
File(s)
Author(s)
Mersch, Matthias
Type
Thesis
Abstract
This thesis presents a robust analysis of optimal and near-optimal net-zero transition pathways for integrated energy systems. It combines technology-level optimisation and whole-energy system optimisation for a comprehensive assessment of transition pathways and the role of individual technologies. Aspects of all three dimensions of the energy trilemma are considered: affordability, energy security, and sustainability. The focus is explicitly on integrated energy systems, particularly interactions between the electricity, heating, hydrogen, and carbon dioxide removal sectors. To conduct the research, a clean energy technology model library and an integrated whole-energy system model have been developed, which are both presented in this thesis.
The results show that the optimal transition of the power sector is not qualitatively affected by uncertain fuel prices and technology costs. In all cases, renewables account for most of the power generation in 2050, while nuclear power is also an important contributor. Bioenergy with carbon capture and storage provides valuable negative emissions, while gas turbines remain in the system as dispatchable generation capacity. The heating sectors on the other hand are strongly affected by uncertainties. Natural gas prices, which determine the trade-off between gas boilers and heat pumps, are particularly important. Hydrogen is never used for low-temperature heat provision in the cost-optimal scenarios. However, many near-optimal solutions exist which show that, encouragingly, a multitude of different pathways to net-zero are possible at only marginally higher cost.
The analysis further highlights that emission reduction and energy security are not conflicting targets. Domestic renewable energy generation and heat pump deployment have co-benefits of reducing emissions and fuel imports. Furthermore, fuel imports can be diversified at only marginally higher costs. Finally, it is shown that technology-level optimisation is crucial to maximise the potential especially of novel technologies, which can then make an important contribution to the decarbonisation of the whole energy system.
The results show that the optimal transition of the power sector is not qualitatively affected by uncertain fuel prices and technology costs. In all cases, renewables account for most of the power generation in 2050, while nuclear power is also an important contributor. Bioenergy with carbon capture and storage provides valuable negative emissions, while gas turbines remain in the system as dispatchable generation capacity. The heating sectors on the other hand are strongly affected by uncertainties. Natural gas prices, which determine the trade-off between gas boilers and heat pumps, are particularly important. Hydrogen is never used for low-temperature heat provision in the cost-optimal scenarios. However, many near-optimal solutions exist which show that, encouragingly, a multitude of different pathways to net-zero are possible at only marginally higher cost.
The analysis further highlights that emission reduction and energy security are not conflicting targets. Domestic renewable energy generation and heat pump deployment have co-benefits of reducing emissions and fuel imports. Furthermore, fuel imports can be diversified at only marginally higher costs. Finally, it is shown that technology-level optimisation is crucial to maximise the potential especially of novel technologies, which can then make an important contribution to the decarbonisation of the whole energy system.
Version
Open Access
Date Issued
2024-07-26
Date Awarded
01/02/2025
License URL
Advisor
Markides, Christos N.
Mac Dowell, Niall
Publisher Department
Department of Chemical Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)