Using the UK energy system modelling environment to investigate the market need of high temperature gas-cooled reactors

High Temperature Gas-Cooled Reactors (HTGRs), a type of advanced nuclear reactor, have been identified as an attractive solution for decarbonising hard to abate sectors through the combined production of heat and electricity. To understand the potential market need for high temperature steam from HTGRs, the UK Energy System Modelling Environment (ESME) has been deployed to calculate HTGR deployment for a given range of scenarios and sensitivities. The range of sensitivities explored include variations on HTGR capital expenditure, applications of HTGR steam in industry, and the availability of alternative solutions including biomass resources and Carbon Capture and Storage (CCS) capture rates. In the most techno-optimistic scenario for biomass availability and CCS capture rates, the resulting HTGR capacity is 0.5 GWth, corresponding to 2 (nominal 250 MWth) units. This demonstrates that the development of a HTGR demonstrator programme in the UK can be considered a ‘no regrets’ option as two units of HTGRs are still valuable even in the best-case scenario for competing solutions. In the case where biomass availability is limited, CCS capture rates are assumed to be low and the steam potential for industry is high, the resulting HTGR capacity is 7.8 GWth, corresponding to 31 units. The use of high temperature steam from HTGRs can be extended to applications including hydrogen production, industrial processes and Direct Air Capture (DAC). In this study it was found that the preferred application for HTGR steam was hydrogen production.