Electricity sector decarbonisation is widely seen as a fundamental step in the global fight against climate change. The need to secure this transition is compounded by the prospective use of electrification to deliver economy-wide carbon reductions, especially in harder to address sectors like heat and transport. No agreement has yet been reached on the best decarbonisation approach. Empirical evidence is required to guide a transition that not only succeeds in delivering a ‘truly’ low carbon electricity source, but also prevents wider environmental issues being exacerbated. This research portfolio examines the low carbon transition of electricity systems in a UK context. The energy and environmental implications in response to different decarbonisation approaches were evaluated using Life Cycle Assessment (LCA) and related methods. Potential UK low carbon electricity systems were investigated via three socio-technical energy scenarios, known as the Transition Pathways. Key factors were identified, which may impact the future environmental performance of UK electricity, such as supply chain dynamics, policy shifts, and new entrant technologies, were investigated to assess their consequences on decarbonisation targets. This research exemplifies the guiding principles of LCA as a valuable proactive tool in shaping superior future decarbonisation and wider environmental policies. A key finding of this thesis was the importance of whole life cycle accounting of power sector GHG emissions, including upstream impacts which are often overlooked by governmental bodies. Hence, current decarbonisation policies may lead to a shift in practices and the adoption of production routes with unintended negative effects upstream. In this work, the upstream gas emissions for future supplies increase significantly (rising 2.7 to 3.4 times current mix per MJ supplied) and are foreseen to be highly influential on the future electricity systems analysed. Increased influx of biomethane leads to a substantial reduction in direct fossil emissions (up to 10.6 million tonnes of CO2eq), and is found to be critical in offsetting rising upstream emissions. The roll-out of carbon capture and storage was also found to be instrumental in the success of the pathways. The electricity system transitions assessed achieved differing, yet significant, levels of decarbonisation (between 75-85% reductions on 1990 levels on a lifecycle basis). Nevertheless, these were often achieved at the expense of wider environmental impacts, suggesting trade-offs were unavoidable. The civic-led energy transition resulted in the greatest associated environmental benefits, realising the greatest reduction in 13 of 18 environmental categories assessed, compared to the 2008 levels. It was also the only pathway to decouple electricity supply from fossil fuel use. Reliance on metal resources was seen to steadily increase in response to a developing renewable energy sector, rising 23-75% from the 2008 baseline system. The presented results, models and data are transparently presented for others in the field to build upon, and scrutinise their implications for wider decarbonisation strategies within and outside of the electricity sector.
|Date of Award||23 Nov 2016|
|Supervisor||Sally Clift (Supervisor) & Geoff Hammond (Supervisor)|