(373ak) Optimisation of Decarbonisation Pathways for Heat and Power Sectors in the UK

By 2017 UK managed to reduce its greenhouse gas (GHG) emissions by 43% compared to the 1990 levels following the UK’s Climate Change Act, with 75% of these reductions coming from the power sector ^[1]. The need for a sustainable long-term policy towards a low-carbon and potentially carbon-neutral economy, following the latest report from the Intergovernmental Panel on Climate Change ^[2], is becoming urgent. While there is steady progress in decarbonising the power sector, mostly through the deployment of renewable energy sources, the decarbonisation of the heat sector remains a big challenge. Heat is the biggest energy consumer in the UK, accounting for 44% of total energy consumption, while also resulted in 37% of UK’s GHG emissions in 2016 ^[3]. Given the high efficiency and relatively low cost of the gas system, decarbonisation of the heat sector signals a transition that necessitates judicious decision making and potentially high levels of policy intervention. Among the different decarbonisation pathways that have been proposed the most prominent ones involve: (i) electrification of heat through heat pumps, (ii) low-carbon heat networks and (iii) hydrogen-based heating systems ^[3,4].

At the time of writing, the majority of research work examines the problem of heat decarbonisation through electrification by considering aggregate representations of the spatial and temporal scales while also the impact of operational and security constraints on the resulting energy infrastructure has been neglected ^[5-8]. Another impact that has received limited attention is the electricity transmission implications on the design of the resulting national multi-energy system.

In the present work, we propose a spatially explicit optimisation-based approach to study the trade-offs among the different decarbonisation pathways on a national scale. The model simultaneously optimises investment and operational decisions for the power and heat sectors. On the level of investments, capacity expansion and decommission of different technologies are considered with 5-year time steps up to 2050 while the operational level is examined through a unit commitment formulation on an hourly discretisation. Because of the spatial and temporal granularity, the problem is formulated as a large-scale mixed integer linear program which can lead to intractable computational times. To alleviate this issue, we employ data-driven clustering methods and decomposition techniques that preserve the quality of the solutions whilst reducing the computational effort. By considering the whole multi-energy system, economic and policy insights are drawn based on the trade-offs between: (i) flexile and low-carbon technologies, (ii) heat and power generation and storage and (iii) the efficient integration of intermittent renewable energy sources. Finally, results showcase how acknowledging differences in resource endowments at subnational level enables for synergetic decarbonisation of heat and power sectors.

Literature cited:

1. CCC, Reducing UK emissions 2018 progress report to parliament, Committee on Climate Change (2018).
2. IPCC, Global warming of 1.5C, The Intergovernmental Panel on Climate Change (2018).
3. BEIS, Clean growth: Transforming heating- overview of current evidence, Department for Business, Energy & Industrial Strategy (2018).
4. Zhang, G. Strbac, F. Teng, P. Djapic, Economic assessment of alternative heat decarbonisation strategies through coordinated operation with electricity system–UK case study, Appl. Energy 222 (2018): 79-91.
5. Hedegaard, M. Münster, Influence of individual heat pumps on wind power integration- Energy system investments and operation, Energy Convers. Manag. 75 (2013): 673–684.
6. Jalil-Vega, A. Hawkes, Spatially resolved model for studying decarbonisation pathways for heat supply and infrastructure trade-offs, Appl. Energy 210 (2018): 1051–1072.
7. Qadrdan, R. Fazeli, N. Jenkins, G. Strbac, R. Sansom, Gas and electricity supply implications of decarbonising heat sector in GB, Energy (2018).
8. Zhang, X., Strbac, G., Shah, N., Teng, F. and Pudjianto, D. Whole-system assessment of the benefits of integrated electricity and heat system. IEEE Trans. Smart Grid, 10(2019):1132-1145.