Unlocking thermal energy: Executive summary

Half of the energy used in UK industry is wasted, primarily through heat loss due to system inefficiencies. There is an opportunity to improve thermal energy efficiency in industry and to re-use surplus heat elsewhere, re-imagining the role of heat in a net zero future. Utilising the latest UK science and engineering can improve the efficiency and performance of heat capture, transport and storage systems; these opportunities are summarised in this report. Doing so can advance decarbonisation, support UK industrial productivity and competitiveness, and unlock new sources of heat for domestic consumers.

Heat loss is particularly notable in the UK’s foundation industries, which includes steel, cement, chemicals, glass, paper and ceramics, where materials are typically heated to temperatures in the range of 400 – 2,000°C and then cooled. Switching to clean energy sources as part of the UK’s journey to net zero, alongside efficiency measures like improved design, will reduce some of these losses, but a significant amount of energy will continue to be lost as heat. New sources of waste heat will also emerge, including from electrolytic hydrogen production, carbon capture and storage, and data centres.

This report proposes an approach to thermal energy re-use, where heat is cascaded from high-temperature point sources to lower temperature end-users. Heat could first be used on-site, then in industrial clusters with co-location of different industries, and finally for low-temperature uses including space heating in the built environment.

This will require i) efficient systems for heat capture and exchange; ii) heat networks to transport thermal energy at a range of temperatures; and iii) thermal energy storage to balance supply and demand over time and to build system resilience and reliability. Heat re-use systems could be integrated alongside wider energy efficiency and fuel switching measures, capturing unavoidable waste heat and putting it to productive use.

Finally, to implement systems for heat re-use, there is a need for the valuation, trade and measurement of surplus heat, appropriate regulation and planning, and support to overcome the high costs of technology development and deployment. Co-ordination and collaboration between government at national and local levels, industry, regulators, communities and researchers would help to overcome some of the challenges in establishing and operating these systems.