SharePowering urban sustainability: how electricity import capacity shapes heat pump adoption and thermal storage
A recent study published in Energies evaluated two scenarios modelling the relationship between electricity import and technologies implemented in urban areas to meet the demands for heating, assuming the electrification of transportation and other industries.
According to IEA, urban areas contribute to over 70% of annual global greenhouse gas emissions [1]. Therefore, cities have a significant role to play in addressing climate change. In that regard, electrification, the process through which electricity replaces fossil fuels, has been identified as one of the main potential mitigation options.
In a study published in Energies, the authors examined how varying electricity supply capacities affect cities’ optimal way of supplying heat [2].
Two main scenarios, low and high electricity import capacities, have been modelled using data from six urban areas in Sweden. In the scenario with high import capacity, researchers assumed that the electricity import capacity is the sum of the electricity peak demand recorded in the year 2019 (adjusted for projected city growth) and the additional average load from electric vehicles and new industrial establishments. In the low import capacity scenario, the import capacity is limited to 60% of the value in the high import capacity scenario and represents a future scenario with limited additional grid expansion.
The results highlight the following:
In high electricity import capacity scenarios, electricity primarily originates from imports, which outcompete most local electricity production. Large-scale heat pumps combined with thermal energy storage and biogas boilers dominate the heating sector in all the modelled cities. Based on the assumptions outlined in this study, this assertion holds true for cities where the maximum import capacity is utilised up to 5000 h annually.
In situations where electricity imports are more restricted, the properties of each individual city assume a more crucial role in determining the most cost-effective energy system configuration:
- Cities with a large heat demand relative to their electricity demand (low electricity-to-heat ratio) tend to favour a heating system that incorporates both heat pumps and combined heat and power (CHP).
- In contrast, cities with a high electricity-to-heat ratio tend to incorporate a heating system that is based primarily on CHP in conjunction with high levels of thermal energy storage.
- High electricity demand flexibility within a city, in which loads are shiftable over seasons, enables the synergistic use of solar PV and stationary batteries as a cost-efficient alternative.
Although the model input is based on data from Sweden, the authors aimed to represent any urban environment with an existing district heating network and a seasonal heat demand, such as Northern and Eastern Europe and parts of North America.
This study underscores the critical role of electricity import capacity in shaping urban energy strategies, highlighting the need for tailored solutions to optimise heating systems and reduce emissions in diverse city environments.
For more information, the study is available in open access on Energies and FRIDOC.
Sources
[1] IEA (2021), Empowering Cities for a Net Zero Future: Unlocking resilient, smart, sustainable urban energy systems, OECD Publishing, Paris, https://doi.org/10.1787/7a222c8b-en
[2] Bertilsson, J.; Göransson, L.; Johnsson, F. Impact of Energy-Related Properties of Cities on Optimal Urban Energy System Design. Energies 2024, 17, 3813. https://doi.org/10.3390/en17153813