FORTRESS ( Flexibility and Optimisation for Resilience in Energy Systems)

Hospitals and military bases still rely on fossil fuels for backup heating, and switching them to electric heat pumps could overload local power grids. The FORTRESS project tests whether coordinating heat demand across a hospital site—from intensive care to office blocks—can cut the need for expensive grid upgrades. Distribution Network Operators currently face a choice: spend heavily on new cables and transformers to support electrified heating at protected sites, or find smarter ways to manage demand. By analysing how different hospital buildings use heat at different times, the researchers aim to design flexibility strategies that shift non-critical loads without compromising life-support systems. If successful, the approach could reduce infrastructure costs for grid operators while allowing hospitals to decarbonise their heating without sacrificing resilience. The work focuses on a single hospital case study, so the immediate output is a proof-of-concept for coordinated heat flexibility, not a ready-to-deploy system. The real change would come if DNOs adopt similar demand-side strategies for other protected sites, avoiding billions in capital investment while keeping critical services running during grid stress.