Directing the energy transitions : systematic analysis of the role of renewable energy and electrification in IPCC AR6 scenarios achieving safe climate targets

Abstract

Reaching the ambitious climate targets outlined by the Paris Agreement necessitates a swift defossilisation of the energy systems. The Intergovernmental Panel on Climate Change (IPCC) is prominent in navigating this transition through assessment reports and policy recommendations. Integrated Assessment Models (IAM) and related scenarios are the key components of these assessments. This thesis systematically analyses global climate scenarios in the IPCC Sixth Assessment Report, focusing on those aiming for the lowest warming target of 1.5°C and assessing the penetration of renewable energy and electrification in their mitigation strategies. Notably, the safe and just climate planetary boundaries of 1.0°C/350 ppm, which are critical for preserving a stable climate for humanity, approached by only 8.5% of scenarios analysed. Most of the IAM scenarios, however, overstate the potential of bioenergy and fossil fuels with carbon capture and sequestration, while underestimating the expected growth of renewable energy technologies, particularly solar photovoltaics and wind power, which is caused by the lack of power-to-X considerations in modelling practices. Only 30% of the 143 scenarios assessed, project the share of primary renewable electricity more than 55% in total primary energy demand and 97% exceed the sustainable potential of bioenergy in 2100. The findings emphasise the critical need for improved transparency in input assumptions of IAMs and the inclusion of insights from different modelling frameworks to ensure credible policy advice and more diverse mitigation strategies. Such improvements can facilitate more accurate investment decisions and expedite the transition to a safe and just climate future.