Project FORTRESS: demonstrating resilient decarbonisation pathways for protected sites
Client Challenge
The SSEN FORTRESS project (Flexibility and Optimisation for Resilience in Energy Systems) is an innovation initiative led by Scottish and Southern Electricity Networks (SSEN) Distribution. It aims to support the decarbonisation of sites with significant resilience requirements, such as hospitals, airports, and military bases, by helping them transition from fossil fuel-based energy systems to electrified heating and power, while maintaining high levels of resilience. These sites are protected under the grid code and are therefore referred to as Protected Sites.
Protected Sites like hospitals are major energy users, but much of their demand has historically been hidden from Distribution Network Operators (DNOs) due to using gas or other fossil fuels for heating, and often on-site electricity generation from gas combined heat and power (CHP). As these sites move toward electrification of heat, their demand on the grid will increase significantly.
The FORTRESS project was initiated to addresses the challenge of how to:
- Maintain resilience during this transition
- Avoid uncoordinated and costly network upgrades
- Enable flexible energy use to reduce peak demand and optimise grid capacity.
Hospitals were chosen for the study due to their significant energy needs and need for resilience.
Ricardo Solution
SSEN Distribution collaborated with Ricardo and NHS Tayside and the electricity network, to explore innovative heat flexibility strategies. Ricardo’s approach included:
- Site survey –assessment of Ninewells Hospital’s heating and power infrastructure to identify requirements for low-carbon transition.
- Energy modelling and peak lopping analysis – simulation of future energy demand and evaluation of flexible operation strategies to reduce network constraints and operating costs.
- Cost-benefit analysis – comparison of multiple scenarios to understand financial impacts for both DNOs and hospitals.
- Stakeholder engagement – Consultations with similar resilient sites (airports, ports, defence) and DNOs to identify barriers and shape implementation strategies.
Key findings included:
- The year-round energy demand for hospitals is potentially useful to networks for flexibility services and could significantly benefit hospitals
- It is important for sites to have a costed plan for decarbonisation so that they can communicate their needs to network operators and other stakeholders
- Planning a site trial is important to demonstrate the benefits of flexible energy connections and give confidence to hospitals and network operators of their suitability.
Client benefit
SSEN Distribution gained an understanding of the magnitude of hospitals’ growing demand for electricity using the Ninewells Hospital example, and of the potential benefits of the sites being able to communicate their future needs so that networks can forecast their future demands; as well as an understanding of the potential for flexibility to accelerate the transition of these sites by limiting or overcoming impacts on networks.
Through Project FORTRESS, NHS Tayside gained guidance on next steps to develop a clear and actionable pathway toward decarbonising Ninewells Hospital without compromising its critical energy resilience. The collaboration with Ricardo provided not just technical insights, but a strategic framework for change.
Perhaps most importantly, the initiative laid the groundwork for a subsequent alpha trial to demonstrate the potential for this to be scalable and benefit electricity bill payers.
The insights from FORTRESS are not limited to Ninewells and the learnings were shared with NHS and network stakeholders through a public show-and-tell engagement session.