George Eliot Hospital NHS Trust needed a clear pathway to meet the NHS Net Zero target of 2040. With baseline greenhouse gas emissions of 6,662 tonnes CO₂e per year from building operations, the scale of the challenge was significant.

The situation was complicated by a substantial constraint: the hospital's energy strategy was dominated by a gas-fired combined heat and power (CHP) system, operated under a 15-year Energy Performance Contract with an external provider running until 2032. While this arrangement delivered valuable cost savings, the CHP was responsible for approximately 70% of the hospital's building-related emissions. Any decarbonisation strategy would need to work around, and eventually beyond, this contractual commitment.

The Trust also faced the challenge common to many NHS organisations: limited capital budgets competing against clinical priorities. Any proposed measures would need to demonstrate clear economic cases and identify realistic funding routes, including grant opportunities through schemes such as the Public Sector Decarbonisation Scheme (PSDS).

We delivered the work in two phases. The first phase produced an Initial Buildings Decarbonisation Plan, establishing the strategic framework. The second phase comprised detailed Investment Grade Audits (IGAs) to validate the technical and economic case for each proposed measure.

Our methodology followed the Energy Hierarchy, prioritising energy demand reduction before considering renewable energy supply. This sequencing ensures that investment delivers maximum impact and that renewable systems are sized appropriately for reduced loads.

The IGA phase involved extensive site surveys and data collection, including air flow testing of the hospital's air handling units, thermal imaging to identify heat loss, and dynamic thermal modelling of the building envelope. We developed energy profiles using half-hourly consumption data and built an energy model of the hospital to simulate various technology configurations.

Throughout both phases, we worked collaboratively with the Trust's estates and sustainability teams, as well as the existing CHP operator, to ensure that proposals were practical and aligned with operational requirements.

We developed a comprehensive buildings decarbonisation plan covering energy efficiency, renewable generation, heat pump installation, and innovative electricity procurement:

Energy efficiency measures including HVAC system optimisation through variable speed drives and upgraded controls, building energy management system enhancements with automated monitoring and targeting, and fabric improvements to reduce heat loss.

Solar PV and battery storage to reduce grid dependence and optimise energy usage, with voltage optimisation to maximise efficiency. The combined implementation offers projected annual savings of around £180,000.

Phased heat pump installation beginning with the peripheral buildings (which can proceed without affecting the CHP contract) and extending to the main hospital once the CHP reaches end of contract. A £3.4 million heat pump project for the peripheral buildings was developed to grant-funding readiness.

Peer-to-peer renewable electricity supply to provide verifiable green electricity at stable, long-term pricing, supplementing on-site generation and filling the gap left by eventual CHP decommissioning.

The plan also addressed practical considerations including glazing upgrades, insulation improvements, food waste processing, and the resilience of mechanical and electrical systems throughout the transition.

The project delivered a robust roadmap for achieving Net Zero, with the potential to reach this target by 2040 in line with NHS requirements, or as early as 2031 through accelerated adoption of peer-to-peer electricity supply and heat pump technology.

Key outcomes included:

A clear emissions reduction trajectory from 6,662 tonnes CO₂e per year to Net Zero by 2040, with defined milestones and technology interventions mapped against the timeline.

An investment programme exceeding £10 million identified and prioritised, with phased implementation to manage capital requirements and minimise operational disruption.

Grant-ready project documentation for the £3.4 million peripheral buildings heat pump project, prepared to support PSDS funding applications.

Detailed technical validation through thermal imaging, thermal modelling, and HVAC performance assessment, providing confidence in the proposed measures and their projected savings.

A practical framework that works within the constraints of the existing CHP contract, enabling progress on peripheral buildings and energy efficiency measures while planning for the post-CHP transition.