Royal United Hospital Bath Decarbonisation Strategy for Royal United Hospital Bath

The Royal United Hospitals Bath NHS Foundation Trust commissioned a comprehensive study to explore pathways for transitioning its estate toward a low-carbon future. The strategy considered a wide range of technical and operational options, enabling the Trust to understand how different decarbonisation scenarios would affect service continuity, infrastructure demands, long-term investment requirements, and resilience across a complex, 24/7 acute hospital environment.

Working collaboratively with the Trust, the study focused on three overarching priorities that would shape the decarbonisation roadmap:

• Reducing Overall Energy Demand - The first priority involved identifying opportunities to lower consumption through improvements to existing systems, upgrades to plant, and optimisation of controls. Reducing demand formed the essential baseline step for making any future low-carbon technologies viable and cost-effective.

• Expanding On-Site Renewable Energy Generation - The strategy assessed how the estate could generate a greater proportion of its own power through renewable technologies-most notably solar PV-helping to reduce reliance on external energy sources and improve long-term sustainability.

• Transitioning Away from Fossil Fuels - A central challenge was developing a credible route to eliminate the use of natural gas across a site that relied heavily on a 2MW gas-fired combined heat and power (CHP) plant, as well as gas-powered boilers for space heating and hot water. Moving to electric alternatives, such as heat pumps and other low-carbon systems, would require not only replacement of major plant but also substantial reconfiguration of the hospital's existing steam-based distribution network.

Key Technical and Infrastructure Challenges

A series of significant constraints needed to be addressed as part of the strategy:

• Legacy steam systems: Replacing gas-based infrastructure with electrically-led systems required extensive redesign of pipework and distribution networks, particularly given the age and complexity of existing hospital buildings.

• Electrical capacity limitations: The hospital was already operating close to its available grid capacity. Transitioning to electric heating, upgraded HVAC plant, and new EV charging facilities would increase demand beyond what the current network could accommodate, making an upgrade to the local distribution network essential.

• Operational resilience: As a major acute healthcare site providing emergency and intensive care services, maintaining uninterrupted operation was paramount. Any proposed decarbonisation interventions needed to safeguard resilience and ensure the hospital could continue functioning around the clock without exposing critical services to unacceptable risks.

All potential pathways were assessed with these constraints in mind, resulting in a realistic and phased strategy that supported decarbonisation while prioritising patient safety, regulatory compliance, and long-term estate resilience.

The work described was undertaken by a member of our team during their previous employment. Responsibilities included supporting the development of the decarbonisation strategy, advising on the cost and feasibility implications of different technical pathways, and helping evaluate the financial and operational impacts.