Comparative assessment of electrification and low carbon gases for decarbonising heating in buildings

Comparative assessment of electrification and low carbon gases for decarbonising heating in buildings

Pooya Hoseinpoori, Sustainable Gas Institute & Centre for Environmental Policy, Imperial College London
Dr. Richard Hanna, Centre for Environmental Policy, Imperial College London
Prof. Nilay Shah, Imperial College London
Dr. Jeremy Woods, Imperial College London
Prof. Christos Markides, Imperial College London

Around 44% of the final energy demand in the UK is used for heating, and heat-related CO2 emissions account for about 37% of the country’s total emissions. Decarbonising heat is therefore crucial for meeting the 2050 net-zero emission target. Meanwhile, many countries seek policies to reduce fuel poverty by improving the affordability and accessibility of energy services. Since all decarbonisation pathways require changes to the present energy system, changes that come with a cost, these two policy goals are expected to conflict on various issues. The other key policy goal is energy security, which is usually given priority over affordability and decarbonisation. Decarbonising heat while ensuring affordability and security of supply requires a whole systems approach towards heat sector transition in order to achieve a trade-off balance between these policy goals.

In regions where heating is supplied via an extensive gas grid, the pathway adopted for decarbonising heating is primarily tied to the future of the gas grid. This leads to long-running debates about the role of electrification and low-carbon gases, mainly hydrogen, in decarbonising heating, especially in buildings, in these regions. In the UK, the natural gas network supplies about 70% of heat demand and its flexible operation and the availability of cheap underground gas storage play a critical role in balancing supply and demand, especially between seasons. In the UK, the extensive natural gas network is the main unsustainable incumbent in the heat sector, and a transition to low carbon heating is impeded by a number of factors, including the stability and long life of the gas network, the value of stranded assets, and the relatively low costs of central gas heating. UK’s power grid, on the other hand, has had a minor role in supplying heating (less than 9%) and given the low seasonal cooling and air conditioning demand in the UK, the power grid has not been equipped to respond to seasonality and highly fluctuating thermal loads (Load factor of power demand in the UK is about 62% compared to about 17% for heat demand).

There is a range of options for decarbonising heating, and each presents specific challenges and opportunities. The potential of each option for delivering low carbon heat at an affordable cost is dependent on the wider system architecture, and therefore, it is key that their value is evaluated from a systems perspective. In this study, we explore different options for decarbonising heating in the context of different scenarios for the future of the gas grid. Additionally, we discuss how different decisions about the future of the gas grid, aimed at meeting the net-zero emission target, could interact with other policy goals such as energy security.

A novel decision-making framework was developed for the comparative assessment of different pathways for decarbonising heating (Taftan). In this study, Taftan is used to quantify the infrastructure requirements, the investment required and the system-wide implications of different pathways for decarbonising heating in the context of different possible scenarios for the future of the low and medium pressure gas grid in the UK. We examined four sets of scenarios for the future of the low and medium pressure gas grid: a) full electrification of heating in buildings and moving away from the gas grid; b) conversion of the gas grid to deliver hydrogen; c) hybrid heat pump system, and d) a greener gas grid. Such a whole system approach can help better understand the cost-optimal scale of deployment of different decarbonisation options, the likely level of investment required and the trade-offs between end-use heating technologies and infrastructure as well as resource requirements.