Decarbonising the UK’s heat infrastructure

According to the UK Government, a heat network is a distribution system of insulated pipes that takes heat from a central source and delivers it to domestic or non-domestic buildings.

Decarbonising heat networks

The UK Government has recognised that promoting new low carbon heat networks can be one of the most cost-effective ways of reducing carbon emissions. The UK’s Climate Change Committee estimates that around 18% of heat will need to come from low carbon heat networks by 2050.

The UK’s more recent ambition for low carbon heat networks has been borrowed from the Nordic vision. The cities of Malmo, Copenhagen and Helsinki have much of their heat supplied by municipally developed heat network infrastructure. This vision was shared by the UK in the 1960s, until the focus shifted to the extraction of sovereign oil and gas resources in the North Sea.

Except for Norway (who pursued an export model), the other Northern European countries did not have access to these resources, and so sought an alternative heat infrastructure model. This led to the deployment of large-scale subterranean heat networks linked back to energy from waste plants and industrial waste heat, mainly led by public investment and a supportive national policy framework aimed at benefitting consumers. For the Nordics, the aggregation of customer demand allowed for greater flexibility in meeting broader socio-economic objectives and controlling the cost of heat to all.

During the equivalent period in the UK, a national gas transmission network was constructed with the promise of cheaper fuel to businesses and residents. Consequently, the UK has arguably the world’s most evolved national gas network. The UK’s utility networks were also privatised through the end of the 20th Century bringing in fragmentation of energy generation, distribution and supply and the introduction of ‘choice’ of energy suppliers to the end customer.

The strategy in both the UK and Scandinavia was to develop heat infrastructure that supported economic growth and provided health benefits to the population – climate change was not on the political agenda.

The advent of the political response to climate change in the UK has recognised that any projections for meeting a 2°C or less global temperature rise necessitate complete decarbonisation of heat by 2050. Heat remains one of the largest sources of carbon emissions, and it is also technically challenging to decarbonise owing to the piecemeal nature of the action required.

The Nordics have realised the opportunities of their heat infrastructure, and by decarbonising their heat source for district heating networks, they were able to decarbonise the heat en masse to the buildings supplied. Although we have seen similar success achieved in the UK on electricity networks, it appears impossible to replicate in the same manner for an extensive gas network. Decarbonising the national gas grid is, at the very best, technically challenging and at worst economically unpalatable. To do so would necessitate the blending of hydrogen with natural gas, currently expected to be technically limited to 20% by 2030.