Building decarbonisation transition pathways

The problem of decarbonising heating in buildings has been studied for more than 20 years, but there is still no settled consensus on strategy or choice of technology. There is consensus that the problem requires analysis of the whole energy system. Recent literature based on whole system analysis appears to indicate that heat pumps are likely offer the cheapest decarbonisation option overall, achieving an immediate factor of three reduction in emissions, with the promise of close to zero emissions by 2030, as a consequence of a phenomenon that now appears unstoppable – the decarbonisation of electricity generation. Though some dwellings would also benefit from additional insulation to increase health and comfort, the overall role of insulation in decarbonisation is likely to be secondary. High levels of insulation are not essential to the deployment of heat pumps and are only likely to be cost effective in easy-to-treat properties. But technology choice is not an either-or question. Combinations of technology, such as hybrid heat pumps, and deployment of large heat pumps in district heating systems, offer obvious advantages. And if the role of hydrogen as a vector for supplying heat to individual homes appears limited on overall cost grounds, hydrogen or hydrogen-derived fuels are likely to play a strategic role in providing backup for the electricity grid at multiple levels, including the very long-term energy storage that will be needed from about 2040 onwards. Sifting through the multiple combinations and configurations of technologies that are, and will become available over the coming 30 years will be an on-going activity. In this context, a key recent development is an understanding of the need to complement conventional energy modelling with the tools of System Architecture. In addition, there is an ongoing need to evaluate and marshal evidence to establish what works and why, and to enhance learning-by-doing by bridging the gaps between research, innovation and communities of practice.