Context
The NHS is the largest public sector energy consumer in the UK, responsible for approximately 5% of the country’s total carbon emissions. In response to the escalating climate crisis and rising energy costs, the NHS has committed to becoming the world’s first net zero health service, targeting 2040 for emissions it controls directly, and 2045 for emissions it can influence.
Hospitals sit at the centre of this challenge. Operating 24/7, with high electrical loads and limited tolerance for disruption, they require solutions that deliver meaningful carbon reductions without compromising resilience or demanding capital investment. Solar PV represents one of the most effective decarbonisation tools available to NHS estates today.
This case study exemplifies how this ambition can be translated into delivery.
Project Overview
Our client, a large hospital in Surrey undertook a large‑scale solar PV installation across its estate to reduce carbon emissions, stabilise energy costs, and progress its net zero ambitions without incurring upfront capital expenditure.
The project delivered a 1,226.7 kWp solar PV system across more than ten hospital buildings, utilising a mix of standing seam metal roofs and flat roofs.
Due to the size and operational sensitivity of the site, the scheme required a carefully phased approach, detailed technical design, and close coordination with estates and facilities teams.
The system was delivered under a Power Purchase Agreement (PPA). Enabling the hospital to purchase the low‑carbon electricity on‑site at a predictable rate, while construction, ownership, and performance risk sit with the funder and delivery partners.
Technical and Operational Complexity
Delivering infrastructure upgrades in a live acute hospital environment presents a uniquely challenging set of constraints. The hospital operates continuously and spans a complex building estate with varying roof profiles, ages, and access restrictions.
The solar PV arrays were distributed across standing seam and flat roof structures. Each required bespoke design solutions to maximise generation while preserving roof integrity and warranties. Works were sequenced across multiple blocks to minimise disruption and ensure clinical operations were unaffected.
The installation programme spanned four months, including a planned pause over the Christmas period, requiring robust programme management to maintain momentum while respecting site restrictions. The quick installation process meant our client could benefit from cheap, clean energy faster.
Delivery Model and Funding Structure
The PPA funding model was central to the project’s viability. By removing the need for capital investment, the hospital was able to act immediately rather than delaying works until funding became available. Under this structure, the hospital benefits from:
- Long‑term access to lower‑cost, on‑site renewable electricity
- Reduced exposure to volatile grid prices
- Guaranteed system performance and maintenance
- Immediate carbon reductions aligned with NHS net zero targets
For the NHS, this model aligns sustainability objectives with financial prudence, making decarbonisation achievable at scale across stretched estates budgets.
Outcomes and Impact
The completed system provides more than 1.2 MWp of installed capacity, delivering substantial on‑site renewable generation and materially reducing grid electricity demand.
Beyond direct carbon savings, the project demonstrates how complex NHS estates can successfully deploy renewable infrastructure without operational disruption, capital outlay, or additional burden on internal teams.
The hospital now benefits from clean electricity generated on‑site, contributing directly to its net zero pathway.
The hospital also accesses this electricity for less than grid rates – with projected savings of up to £145,000 per year depending on consumption.
Strategic Significance
This project highlights a repeatable model for NHS decarbonisation: large‑scale solar deployed across multiple buildings, funded through PPAs, delivered with minimal disruption to frontline services, and maintained by the funding partner. Contact us to learn how the fully-funded model could work for you.
