District heating is a better means to decarbonise heat supply than electrification.

The decarbonisation of heat will require zero-emission heat sources irrespective of whether heat is delivered via district heating or produced onsite. In fact, electrification and district heating are likely to increasingly be used in combination to try and realise the benefits of both.

A decarbonised energy system will need a decarbonised supply of heat. Although district heating can be useful in making use of otherwise wasted heat, the widespread use of district heating will rely on the ability to generate zero-carbon heat, often for use in densely populated urban areas where air pollution concerns are critical. Electrification can, therefore, be expected to play an important role in the future of district heating for several reasons.

First, modern heat networks do not distribute heat at high temperatures. Doing so is expensive, both because more heat tends to be lost in transit and because the infrastructure costs involved in combatting these losses are greater. Rather they distribute heat at low temperatures that is then used by electric heat pumps to supply higher temperature heat to end-users. As such, incorporating heat pumps directly into the network infrastructure can improve the flexibility and efficiency of the heat network.

Second, large-scale heat pumps are already used as a source of initial heat supply by some heat networks. Doing so enables useful heat to be gathered from ubiquitous low-temperature sources of industrial waste heat. Using these pumps, excess power generation can effectively be stored as heat in the heat network for later use.

As a result, electrification and district heating are natural complements and can usefully be applied in tandem where conditions support the use of heat networks.

References:

Simone Buffa et al., “5th Generation District Heating and Cooling Systems: A Review of Existing Cases in Europe,” Renewable and Sustainable Energy Reviews 104 (April 1, 2019): 504–22, https://doi.org/10.1016/j.rser.2018.12.059.

Helge Averfalk et al., “Large Heat Pumps in Swedish District Heating Systems,” Renewable and Sustainable Energy Reviews 79 (November 1, 2017): 1275–84, https://doi.org/10.1016/j.rser.2017.05.135.