08/10/2025
Last month a number of Bevan Brittan colleagues attended the Solar and Storage Live event at the NEC in Birmingham. The event was well attended, and with plenty of industry knowledge in respect of all things related to solar PV and battery storage, with presentations and discussion groups brimming with insight.
One theme which ran through a number of the presentations and discussion groups was the opportunity for significant growth in rooftop solar PV installations on non-domestic buildings (such as warehouses, offices and retail units).
It is understood that at present less than 5% of non-domestic buildings in England have rooftop solar PV systems installed. As the cost of installing systems comes down, and as the cost of electricity (purchased from via grid) increases, there is a real opportunity for landlords, businesses, and solar PV installers and operators to capitalise on the ever-enhancing economics of installing a solar PV system on commercial units, whether via a PPA or whether owned by the building owner.
Retro-fitting rooftop solar PV to existing building stock
Whilst there is no legislation which requires owners of existing buildings to install rooftop solar PV systems on their premises, expectation is that the Minimum Energy Efficiency Standards Regulations will drive landlords to consider installation of rooftop solar PV systems as an integral means of complying with their obligations in respect of their leased spaces. MEES currently requires commercial properties to hold an EPC rating of at least 'E'. However, the government has set a future trajectory, initially aiming for a minimum rating of 'B' by 2030, with interim targets expected. Solar PV is one of the most effective and direct ways to move a property's rating up to meet these future, stricter standards.
This is not to say that retrofitting rooftop solar PV systems into existing buildings can be without its challenges:
Physical
Retrofitting rooftop solar PV systems onto existing commercial roof spaces can be challenging or even unviable, particularly for older buildings, where access to the roof for installation and future maintenance of a system is not readily available without making alterations to the building itself, or indeed where the structural or electrical integrity of the building is unlikely to safely support a PV system. Consequently where space allows it may more economical to install ground mounted solar PV, although the economics can be eroded when installing canopy mounted solar PV over car parks because of the groundworks (including drainage requirements) necessary for hard standing car parks.
Legal
For rooftop solar installations on non-domestic buildings, permitted development rights (PDR) generally allow for installation without needing a full planning application, provided the development meets certain limits and conditions.
Where a commercial unit has a landlord and tenant structure consideration needs to be given to the legal impact of installing a rooftop solar PV system. For example:
- if a tenant that has a lease of a whole building and wants to install a rooftop solar PV system itself, the tenant may require a licence for alterations from its landlord to authorise the installation;
- if a tenant has a lease of a whole building and either the tenant or the landlord intends to procure a third party to install and operate a rooftop solar PV system, then either the tenant's lease will need to be surrendered insofar as it relates to the roof and the airspace above it (together with necessary variations to facilitate access to the roof for cabling and ongoing maintenance), or consent may be required from the landlord in order that the tenant may sublet the roof and the airspace above it for the solar PV installation.
Financial
The installation of a rooftop solar PV system naturally requires a capital outlay and those with an ownership interest in the building may not have the cash necessary to finance an installation. As an alternative to traditional means of securing credit for capital outlay, the use of PPAs via a third party solar PV operator are becoming an attractive proposition for building owners to obtain the benefit of fixed lower cost electricity without the initial capital expenditure.
New Build Units
Currently new non-domestic (industrial / commercial) units are not required to have solar panels installed, but upcoming changes to part L of building regulations will make them a very attractive proposition for new builds. While the standard does not explicitly name solar panels, the performance targets for new non-domestic buildings will be so high that renewable energy sources, such as solar photovoltaic (PV) panels, will be the most practical and cost-effective way to comply.
Having rooftop solar PV systems installed as part of the initial design of new-build commercial units will overcome a number of the challenges which exist for retrofitting rooftop PV systems to existing commercial units. For example, the building can be designed in a way that accommodates the structural needs of a PV system and the access requirements necessary for ongoing operation and maintenance or by system, rather than the building having to be altered to accommodate these needs. Moreover, for a new-build commercial unit, the desired legal structures can be put in place at the outset before an occupational tenant takes its lease of the premises, thereby avoiding the need to unravel existing legal arrangements in order to accommodate an installation.
PPAs
As touched upon above, procuring a third party to own and operate a rooftop solar PV system in combination with a Power Purchase Agreement, is becoming a more commonly used means of rolling out rooftop solar PV installations. When I attended the solar and storage live event a couple of years ago there was relatively little discussion around PPAs, whereas at this year's event the topic of PPAs was ever-present.
Given the potentially high initial cost of installing a PV system, PPA arrangements can be particularly desirable for a landlord or occupier of a commercial unit to obtain the benefit of a prefixed rate for electricity throughout the term of a PPA (which typically lasts for between 10 – 25 years) which is less than that which would be available for electricity purchased via the grid, with the added benefit that the PPA operator has a vested interest in ensuring that the solar PV system is properly maintained to maximise efficiency throughout the term of the PPA, at no cost to the occupier of the commercial unit. There is also often the added benefit that at the end of the PPA term, ownership the solar PV system will be handed over to the building-owner;
Even where the available roof space above a commercial unit would not traditionally make that unit desirable to a commercial solar PV operator, it may be possible to aggregate a number of rooftop installation projects in order that the solar PV operator achieves the necessary threshold to access financing/credit at investment-grade rates, such that a PV project through a PPA can be achieved for a number of smaller units.
Even where an occupier of a commercial unit does not use sufficient electricity for their operations to itself warrant the installation of a PV system, the rooftop of that commercial unit may benefit from renting the roof to a commercial PV operator which can put in place a sleeve PPA, where the premises of the off-taker of electricity is physically separated from the commercial unit upon which the PV system is installed. This may be of particular appeal to intensive electricity consumers whose premises do not have sufficient space to install a PV system with the capacity to generate enough electricity for the consumers' needs.
Landlords
For commercial landlords, where the trend in recent years has been for shorter tenancies, potentially meaning a greater turnover of tenants, installing a rooftop solar PV system, either where the PV system is owned by the landlord (and operated and maintained by a commercial outfit) or where it is operated under a PPA, can make a landlord's building more attractive for prospective tenants looking for the security of lower electricity costs.
EV Fleets
As more and more organisations which operate a fleet of vehicles transitions towards electric vehicles, the appeal both being able to charge those vehicles from electricity generated from the organisation’ premises has a clear economic benefit
Community Energy Companies
The community energy sector is growing. Community energy companies are organisations that develop, own, and/or control energy projects for the benefit of a local community. These projects prioritise local engagement and democratic control, with surplus profits often reinvested back into the community. The number of community energy organizations, volunteers, and members has increased. A 2024 report found 583 organizations with almost 70,000 members in the UK.
Given that community energy companies are not driven by profit they are often able to offer particularly attractive opportunities for solar PV installations.
How Bevan Brittan can help
At Bevan Brittan we have a knowledgeable and experienced team of specialists who can help guide landlords, tenants and commercial solar PV installers and operators through all of the topics discussed above.
Read about our work with Hackney Council on an innovative solar panel pilot project here.
To learn more contact Simon Boyes or our Energy team or Local Government team.
