The UK has an ambitious target of an 80% reduction in carbon dioxide emissions by 2050, to be reached using a
series of ‘carbon budgets’ to aid policy development. Current energy systems modelling methods do not explore,
or are unable to account for, physical (thermodynamic) limits to the rate of change of infrastructure. The power
generation sector has a variety of technological options for this low-carbon transition. We compare physically
constrained scenarios that accentuate either carbon capture and storage, fastest plausible nuclear new build, or
fastest plausible build rate of offshore wind. We set these in the context of the UK’s legislated fifth carbon
budget, which has a comprehensive range of carbon reduction measures with respect to business-as-usual. The
framework for our scenario comparison uses our novel system dynamics model to substantiate the policy’s
ability to meet 2035 emissions targets while maintaining financial productivity and socially expected
employment levels. For an ambitious nuclear new build programme we find that even if it stays on track it is
more expensive than offshore wind generation and delays emissions reductions. This affects the cumulative
emissions and impacts on the UK’s ability to contribute to international climate change targets. If delays or
cancellation occur to the deployment programmes of carbon capture and storage technologies or nuclear new
build, we suggest the electricity and decarbonisation targets can by met by a fast growth of offshore wind
generation with no change to financial and employment levels.Arup’s internal Design and Technical Fun