Project Summary
Emergency services must plan to remain operational during power outages, even as they transition to fully electric fleets. Currently, there is no clear picture of how much energy these services will require under crisis conditions in a net-zero future, nor how much of a role intermittent renewable generation can play in it. We propose to build an integrated modelling framework that quantifies both the future energy demands of decarbonised emergency vehicle fleets and the potential for on-site renewable energy and battery storage to meet these needs during grid outages. By combining vehicle-level energy modelling with site-specific renewable energy capacity assessments and assessments of the readiness and viability of both ‘Vehicle to Grid’ and micro-grid technologies, we will identify how and where West Yorkshire’s emergency services can remain functional during a grid outage. This project provides a vital foundation for future investment and resilience planning for emergency services across the UK and will unlock the viability of the decarbonisation agenda for those services.
Project Achievements
The Civil Contingencies Act requires emergency vehicle fleets to remain operational under crisis conditions including power outages. Existing contingency models built around diesel bunkered fuel systems need to adapt to the transition towards zero-emission fleets, thus presenting new challenges for resilience planning. To address the challenge that faces blue light services, we developed a pioneering modelling approach that maps how emergency vehicles maintain operations when the national grid is down. Starting with operational requirements we determined the infrastructure required to maintain continuity during power outages, prioritising critical system performance. We focused on a case study of Leeds Ambulance Station and quantified the energy demand of EV ambulances between 2025-2035 across three power outage scenarios (1 hour, 1 day and 20 days). We assessed the feasibility of renewables, energy storage and V2X microgrid technologies in meeting fleet demand during each outage scenario.
Conclusions
Our project evidenced the resilience challenge faced by blue light services as they transition to zero-emission fleets. We identified significant on-site energy storage would be required to maintain critical operations during a 20 day outage. The cost of such infrastructure is not economically feasible for blue light services, highlighting the need for wider conversations at policy and organisational level to re-develop contingency planning expectations. The traditional 20 day bunkered fuel approach cannot be met using on-site zero-emission technologies alone and if these requirements are to remain in place, organisations will need to adopt wider collaborative strategies and co-ordinate with local governments and national bodies to acquire shared charging facilities during a long-term outage. Our project found that on-site resilience is feasible with battery energy storage for short-term outage scenarios of between 1 hour and 1 day. We recommend that blue light services invest in on-site energy storage combined with renewable energy generation such as solar PV and vehicle-to-grid bidirectional charging to meet contingency requirements.
Next Steps
The next phase of this work will focus on extending the modelling framework through closer integration with live operational data and real-world site conditions. While the project established a robust feasibility-level assessment, further refinement using measured charging behaviour, vehicle dwell times, and site-specific load profiles would strengthen confidence in infrastructure sizing and cost estimates. In addition, changing energy demands of fleets during grid outage scenarios could be integrated into the modelling framework, rather than assuming business-as-usual. A priority next step is the application of the framework to additional ambulance stations and other blue light service estates, enabling comparison across urban, suburban, and rural contexts. This will test the transferability of assumptions and support the development of generalised guidance for resilience planning. Further work is also required to assess implementation pathways, including procurement models, spatial constraints, planning considerations, and integration with existing estate strategies. It is also necessary to understand additional technologies, including diesel generators and whether these can fit with organizational net zero targets.
