Abstract
Scenarios play a central role in helping policymakers envisage pathways
to limit global warming to well below 2°C. We demonstrate that the most
recently assessed set of climate stabilization scenarios still favors
fossil fuels, and in particular coal, and bioenergy. In contrast to
insights from empirical innovation studies, scenarios are optimistic on
deployment of lumpy, energy-systems technologies, such as carbon capture
and storage, while insufficiently reflecting innovation dynamics in
granular technologies. Our analysis shows that two pathways for rapid
decarbonization remain systematically undersampled in models that
underpin IPCC scenarios: A) strong growth in intermittent renewables, in
particular solar PV, together with electrification of sectors; and B)
widespread adoption of efficient end use technologies, digitalization,
and new service provisioning systems enabling low energy demand. A
combination of continued PV growth and sector coupling with low to
medium energy demand (a corridor of 250 to 500 EJ of primary energy)
would make fossil fuels obsolete by 2050, thus enabling near-term cost
effective climate change mitigation and reducing the need for carbon
dioxide removal in the 2nd half of the century. These pathways are
realistic, target inclusive well-being, but remain underrepresented in
the modelling literature. We see three modeling innovations that would
improve resolution of near and mid-term dynamics: 1) updating of
renewable energy cost assumptions and fuller representation of
technological learning curves, 2) more explicit modelling of sector
coupling and specifically power-to-X technologies, and 3) including
insights from hourly resolution modelling of energy systems.