Overview

The Multi-scale analysis of low carbon heat supply technologies in urban areas project was led by Dr Christos Markides and Professor Nilay Shah from the Department of Chemical Engineering. The project assessed and compared the challenges and opportunities associated with matching thermal energy demand with different low-carbon heat supply technologies. The project also took into account different spatial scales in urban areas and the impact of new/alternative technologies on current energy systems.

The team's broad aim was to create a knowledge base to support the stakeholders like EDF Energy R&D UK Centre in understanding how cities can, and will, transition towards different heat supply strategies.

The demand for residential and commercial heat in the UK represents nearly half of the total energy consumption. One way to help the UK meet its carbon-emission reduction targets is the adoption of low-carbon heat-supply technologies, such as heat pumps and high quality combined heat and power technologies.

Workplan

The project looked at a number of areas in relation to the broad research aim:

• Simulation and comparison of different conversion technologies in both the residential and commercial sectors
• Assessment and characterisation of the heat demand of the different urban energy processes and possible delivery options
• Development of recommendations about the most appropriate heat conversion technologies to be deployed for different users
• Operational optimisation study based on a mixed-integer linear programming model of an energy centre comprising various combinations of heat supply technologies
• Analysis of the energy demand profile variations created by alternative heat conversion technologies

Outcomes

Important results that were produced during the course of this project, including:

• A detailed characterisation of low-carbon heat-supply technologies with detail added on energy devices at difference sizes/scales
• A baseline energy supply scenario of heat with current technologies
• Energy supply scenarios of heat by introducing different levels of technology adoption
• An assessment of the trade-offs between technical, economic, and environmental impacts of the different supply technologies
• Load duration curves, carbon duration curves and heat supply profiles for different technology configurations
• A carbon and costs analysis that has shown the benefits offered by a combination of CHP units, heat pumps and thermal storage in terms of increased flexibility and lower emissions; this highlights the need for EDF to conduct further investigations in the use of these technologies for the extension of existing district heating schemes

It was also illustrated, using time-dependent carbon factors for the national grid, that when employing heat pumps, heat networks may constitute a more suitable pathway for heat electrification than more distributed individual heat pumps at the building level. It was concluded that further investigations are warranted in terms of the expected required electricity network reinforcements to allow for heat electrification through building level technology. As an alternative, it was proposed that EDF could also consider the use of low-temperature heat networks with booster heat pumps at the building level.

Furthermore, the results highlighted the differences between various combinations of CHP engine or plant sizes (2 CHP units of the same size or a set of two asymmetrical CHP units for baseload and load tracking). While the results are case-dependent they demonstrate the importance for EDF of carefully formulating a capacity expansion strategy for existing district heating networks. Further work is currently being conducted through an MSc research project, conducted on behalf of EDF Energy R&D UK Centre, to include the phasing aspect of capacity expansion using multi-period optimisation approaches.