Net zero heating: identifying evolvable least-cost system architectures for the UK

Net zero heating: identifying evolvable least-cost system architectures for the UK

Dr Daniel Scamman, UCL Energy Institute
Dr Steve Pye, UCL Energy Institute
Prof Bob Lowe, UCL Energy Institute

The UK’s 2019 commitment to achieving net zero emissions by 2050 has profound implications for all sectors of the UK economy. Good progress has been achieved in decarbonising the power sector, but faster progress is now needed in the harder-to-abate sectors.  One such sector is heating, which faces challenges including the current widespread use of natural gas, thermally inefficient building stock, large daily and seasonal swings in demand, and the costs and disruption of installing and using alternative systems.  At least three options exist for low carbon heating: electrification, hydrogen and heat networks, which individually and in multiple combinations give rise to a range of potential architectures.  It may be possible to de-risk a decarbonisation strategy by understanding how different types of energy system architecture emerge, depending on factors including the existing energy system infrastructure, strategic decisions on energy policy, consumer preferences, and future technology breakthroughs.  This study aims to understand i) what type of systems can effectively deliver heat decarbonisation pathways, and ii) what system architectures exhibit the greatest evolvability for adjusting to currently unknown, future shocks to the heat sector.

We apply system architecture thinking 1,2 to identify features of energy system architectures which determine their ability to achieve system goals including decarbonisation and cost minimisation.  These include evolvability, flexibility, robustness and feasibility.  This study focuses on evolvabilty, which concerns the ability of the energy system to change over the medium to longer term, and the implications of changing course, even after specific choices and decisions have been made. Three core heat decarbonisation pathways with high penetrations of electrification, hydrogen and heat networks achieving 100% decarbonisation are created in the least-cost UK TIMES energy system model (UKTM)3,4 to allow system impacts and synergies to be evaluated.

For this research we use a myopic foresight version of UKTM5, to reduce planning foresight to align more closely with real world decision making.  We also consider the effect of early (e.g. 2020s) versus delayed intervention (2030s and 2040s) in decarbonisation of the heat sector on system objectives, evolvability, and path dependence.6,7

Initial results have indicated significant divergence in energy systems architecture for the three core decarbonisation pathways.  The evolvability of different energy system architectures is quantified in terms of costs, deployment rates, decision points and wider system implications.  Limited foresight is found to increase system diversity and system cost.  Certain early interventions can greatly reduce the system’s evolvability for switching from one architecture to another in response to unforeseen shocks.  But others, including those that increase technological and supply chain diversity and viability within the energy system, can increase it.  Conversely, delayed interventions can also reduce evolvability by failing to sustain and/or enhance technological diversity and supply chain viability, and therefore making it harder to change the technology mix, and the achievement of decarbonisation objectives.  These insights will help system planners identify the energy system architectures best suited to delivering heat decarbonisation in the UK at minimum cost.

Keywords: net-zero heating; energy system architecture; evolvability; myopic modelling; energy system modelling; least-cost optimisation

References:

1. Crawley et al., System architecture, Prentice Hall Press (2015).
2. Scamman et al., Energies, 13(8), 1869 (2020).
3. Pye et al., Nat. Energy, 2, 17024 (2017).
4. Broad et al, Energy Policy, 140, 111321 (2020).
5. Fuso Nerini et al., Energy Strategy Reviews, 17, 19-26 (2017).
6. Gross & Hanna, Nature Energy, 4, 358-364 (2019)
7. Lowe et al. Lost Generation: Reflections on Resilience and Flexibility from an Energy System Architecture Perspective, Applied Energy (in review).