The role of end-use energy conversion efficiency as a climate mitigation tool

Abstract

Historically, conversion efficiency improvements have revolutionised the energy system, yet to reach climate targets, the scientific community agrees that even higher levels of energy efficiency improvement are required. When focusing on technical options there are two classes of technologies: conversion devices and passive systems. This thesis explores the role that the former can have in reducing energy demand with the aim of providing advice on the prioritisation and differentiation of policy action among these devices. The analysis is divided into three main chapters. First, issues with data quality were identified a cause for the marginalisation of end-use efficiency measures compared to supply-side ones. For the first time, the uncertainty of end-use statistics is quantified by drawing from methods developed in the field of Material Flow Analysis using the United Kingdom as a case study. The majority (85%) of the Useful energy balance uncertainties are below an acceptable (±25%) threshold. Therefore, end-use statistics are deemed sufficiently reliable for the development of policy-relevant indicators. Second, the technical efficiency limits for six widely used conversion devices are determined stochastically based on a combination of engineering models and review of the technical literature. The resulting limits are used to calculate the energy saving potential of each conversion device, and each design parameter for the United Kingdom. It is shown that 25% of the UK’s Final energy demand could be avoided if all conversion devices reached their technical limit. On the other hand, 15% savings could be achieved by applying available technology. Nonetheless, improvement margins vary substantially among devices meaning that strategies involving different balances of R&D and technology adoption incentives are required for each technology. Third, the International Energy Agency’s Energy Technology Perspective’s modelling results are used to assess the saving potential of seven conversion devices in three emission scenarios. Between 3.2% and 4.2% of cumulative energy demand between 2014 and 2060 can be saved thanks to improvements in conversion efficiency. Most savings come from improved internal combustion engines in all scenarios. Carbon emission savings from conversion efficiency are highest in the baseline scenario and lowest in the most ambitious climate scenario due to negative emissions in electricity generation nullifying the effect of improvements in electricity-using devices. No technology was found to breach the technical efficiency limit in the IEA’s assessment meaning that expected efficiency improvements technically realistic. Current innovation activity in energy conversion devices is quantified by means of patent counts and it’s compared to the distribution of saving potentials. It is found that innovation in air coolers and heat pumps is low when compared to the expected efficiency savings from these technologies. The thesis results are useful for directing policy and investment priorities for conversion devices as function of the ambition of the climate scenario. The analysis of technical efficiency limits for conversion devices, help improve energy system models. The novel uncertainty method provides a powerful tool for supporting energy planning and decision making.