  Delivering low-carbon heat will require the substitution of natural gas with
low-carbon alternatives such as electricity and hydrogen. The objective of this
paper is to develop a method to soft-link two advanced, investment-optimising
energy system models, RTN (Resource-Technology Network) and WeSIM
(Whole-electricity System Investment Model), in order to assess cost-efficient
heat decarbonisation pathways for the UK while utilising the respective
strengths of the two models. The linking procedure included passing on hourly
electricity prices from WeSIM as input to RTN, and returning capacities and
locations of hydrogen generation and shares of electricity and hydrogen in heat
supply from RTN to WeSIM. The outputs demonstrate that soft-linking can improve
the quality of the solution, while providing useful insights into the
cost-efficient pathways for zero-carbon heating. Quantitative results point to
the cost-effectiveness of using a mix of electricity and hydrogen technologies
for delivering zero-carbon heat, also demonstrating a high level of interaction
between electricity and hydrogen infrastructure in a zero-carbon system.
Hydrogen from gas reforming with carbon capture and storage can play a
significant role in the medium term, while remaining a cost-efficient option
for supplying peak heat demand in the longer term, with the bulk of heat demand
being supplied by electric heat pumps.
