The right strategy for decarbonisation

The NHS estate is one of the largest and most complex public sector property portfolios in Europe, encompassing acute hospitals, laboratories, community facilities, and administrative buildings. While estates teams have delivered numerous efficiency improvements in recent years, achieving Net Zero will require much deeper transformation. Ian Johnson, public sector lead at Ortus Energy, examines the structural challenges facing NHS estates managers and explores how expanded renewable generation, programme-level delivery, and new financing approaches could accelerate progress.

Few organisations manage infrastructure as extensive or operationally critical as the NHS. Across England alone, the NHS estate comprises thousands of buildings delivering clinical care, research, diagnostic, and administrative services.

Hospitals are among the most energy-intensive building types in the public sector. Clinical environments require tightly controlled ventilation systems, sterilisation processes, imaging equipment, and specialist medical technologies operating continuously throughout the day and night. These operational requirements result in substantial and constant electricity demand.

The complexity of the NHS estate further compounds the decarbonisation challenge. Unlike many commercial property portfolios developed under a single strategic framework, NHS buildings have evolved over decades in response to changing healthcare delivery models, emergency capacity requirements, and varying investment cycles.

As a result, estates teams must manage a built environment characterised by:

• Ageing infrastructure.
• Mixed construction types and building vintages.
• Constrained urban hospital campuses.
• Complex mechanical and electrical systems.
• Fragmented estate governance structures.
• Critical 24-hour operational requirements.

These factors make decarbonisation significantly more complicated than in many commercial property portfolios. For NHS estates teams, the challenge therefore involves two parallel objectives: reducing energy demand wherever possible, while also decarbonising the electricity that healthcare facilities must inevitably consume.

The latter challenge increasingly requires new approaches to energy generation and procurement.

Progress to date — valuable but incremental

NHS estates teams have already delivered significant improvements in building energy performance across many facilities.

Common interventions implemented by Trusts include:

• LED lighting upgrades.
• Improved building management systems.
• Plant and boiler replacements.
• Insulation improvements.
• Early-stage heat pump projects.
• Rooftop solar installations.

These initiatives have produced measurable carbon and cost reductions while demonstrating that energy projects can be delivered safely within operational healthcare environments. However, many of these projects fall into the category of relatively straightforward energy efficiency measures.

Typically, they:

• Fit within existing capital budgets.
• Avoid complex procurement processes.
• Minimise disruption to clinical operations.
• Focus on individual buildings rather than estate-wide systems.

Such interventions are essential and represent meaningful progress. Yet they do not fundamentally alter how energy is generated or supplied across the NHS estate.

In many respects, the NHS has already captured much of the ‘low-hanging fruit’ in building efficiency improvements. The next phase of decarbonisation will inevitably require deeper changes to energy infrastructure.

Lessons from the private sector

Large commercial and industrial estates are increasingly addressing similar challenges around energy resilience, carbon reduction, and rising electricity costs. Many organisations with energy-intensive operations, including logistics centres, manufacturing plants, and food distribution facilities, are deploying on-site renewable generation as part of long-term energy strategies.

A useful example comes from the retail logistics sector. Iceland Foods has deployed solar generation at major distribution centres in Deeside and Swindon as part of its strategy to reduce operational emissions and strengthen energy security. The installations, delivered through a solar power purchase agreement, generate more than 2.7 million kWh of electricity annually, reducing the company’s carbon footprint by more than 500 tonnes each year.

While hospital estates differ significantly from logistics facilities, the example illustrates an important principle: major organisations are increasingly treating energy infrastructure as a strategic asset rather than simply a utility cost. For NHS estates teams, this shift in perspective may prove equally important when planning long-term decarbonisation pathways.

Solar PV and battery storage: a strategic opportunity

Among the technologies available to support estate decarbonisation, solar photovoltaic (PV) generation remains one of the most practical options for large building portfolios.

Solar PV offers several advantages for complex operational environments such as hospitals:

• Mature and widely deployed technology.
• Predictable generation profiles.
• Relatively rapid deployment.
• Minimal disruption during installation.
• Low ongoing maintenance requirements.

When combined with battery storage, solar systems can also deliver additional operational benefits, including improved utilisation of locally generated electricity, reduced peak demand, and enhanced resilience during grid disruptions.

Hospitals typically have strong daytime electricity demand profiles, meaning locally generated solar electricity can often be used directly within site operations. Despite this alignment, solar deployment across the NHS estate remains significantly below its technical potential.

Rooftop constraints across hospital estates

One commonly cited barrier to solar rollout is the suitability of existing hospital rooftops. Many NHS buildings present practical challenges, including:

• Structural limitations.
• Complex roof geometries.
• Congestion from existing plant equipment.
• Asbestos presence.
• Heritage restrictions.
• Limited remaining roof lifespan.

In some cases, enabling works may be required before solar installations can be safely deployed. In others, the available roof area is simply insufficient relative to hospital energy demand.

While rooftop solar can make a valuable contribution to decarbonisation efforts, relying solely on rooftop installations is unlikely to deliver the scale of renewable electricity generation required across the NHS estate.

Car park solar canopies: an underused opportunity

A significant yet often overlooked renewable energy opportunity across NHS estates lies within hospital car parks. Across England, NHS organisations collectively manage hundreds of thousands of parking spaces associated with healthcare facilities. Solar canopy structures installed above car parks can transform these spaces into productive renewable energy assets while providing additional operational benefits.

These installations can offer:

• Significant solar generation capacity.
• No competition with rooftop plant space.
• Protection for vehicles from weather conditions.
• Integration with EV charging infrastructure.
• Visible sustainability improvements for staff and visitors.

For constrained hospital campuses, solar canopy systems can often deliver larger solar arrays than rooftop installations alone. They also align closely with the growing electrification of NHS vehicle fleets and the expansion of electric vehicle charging infrastructure across healthcare estates.

Some NHS organisations also control peripheral land that may be suitable for ground-mounted solar installations. This may include rural hospital campuses, estate land banks, or utility areas located within healthcare sites.

Ground-mounted solar systems can offer several advantages compared with rooftop installations, including:

• Lower installation costs per kilowatt.
• Easier access for maintenance.
• Larger potential system sizes.
• Fewer structural constraints.

In some cases, renewable generation located near a hospital site could also supply electricity directly through a private-wire arrangement. For example, a private-wire solar project currently being developed by SSE Energy Solutions to supply the University of Surrey campus demonstrates how large institutional estates can secure dedicated renewable electricity even where building constraints limit on-site installation.

Financial pressures remain one of the most significant barriers to accelerating estate decarbonisation. NHS organisations face multiple competing capital priorities including backlog maintenance, clinical equipment replacement, digital transformation programmes, and major estate redevelopment projects. Energy infrastructure investments inevitably compete against these priorities.

Government grant programmes such as the Public Sector Decarbonisation Scheme have supported early projects. However, the scale of investment required to decarbonise the NHS estate is far greater than the funding available through grant schemes alone.

The role of Power Purchase Agreements

Across the commercial and industrial sectors, many organisations now deploy renewable energy infrastructure through third-party financing structures such as Power Purchase Agreements (PPAs).

Under a PPA model, a developer funds, installs, and operates renewable energy infrastructure while the host organisation purchases the electricity generated under a long-term contract.

Through partnerships between renewable developers and energy suppliers, including collaborations between Ortus Energy and SSE Energy Solutions, organisations can deploy fully funded solar infrastructure without upfront capital expenditure.

In a typical arrangement:

• Ortus Energy develops and delivers the on-site solar installation.
• SSE Energy Solutions provides energy supply expertise and power purchase structures.
• The host organisation purchases electricity generated at an agreed price.
• Operational performance and maintenance responsibilities sit with the infrastructure provider.

For large estates, electricity is increasingly viewed as a strategic input affecting operational resilience, financial planning, and long-term decarbonisation delivery.

Conclusion

NHS estates teams have made meaningful progress in improving the energy performance of healthcare buildings. However, the scale of decarbonisation required across the estate remains significant.

Meeting long-term Net Zero commitments will require a broader strategy that combines energy efficiency with expanded renewable technologies including rooftop solar, solar canopies, ground-mounted installations, and battery storage. It will also require new approaches to financing and infrastructure delivery that bring together estates teams, energy providers, and renewable infrastructure developers.

The NHS estate represents one of the largest built infrastructure systems in the UK. With the right strategy, it has the potential to become a major platform for clean energy generation while improving cost certainty and strengthening operational resilience.

The opportunity is substantial. The next step is moving from incremental progress toward system-wide transformation.

Bibliography

• UK Government. Delivering a Net Zero National Health Service. London: Department of Health and Social Care; 2020.
• NHS England. Estates Return Information Collection (ERIC) Summary Page and Dataset. London: NHS England; 2023.