Opportunities for rooftop solar
Commercial and industrial rooftops represent a significant opportunity to increase the production of solar energy in the UK, with 350 million sqm of warehouse roof space available (in theory) for utilisation in power production. Earlier this year the government promised to “unleash a solar rooftop revolution” and, more recently. the Prime Minister announced at COP29 that the UK will cut emissions by 81% compared with 1990 levels. With these ambitious targets in place, it is surprising that the adoption of rooftop solar in the commercial property sector is still a long way from reaching its full potential.
In 2022, the UK Warehousing Association produced an investment case for rooftop solar power in warehousing, highlighting that the UK’s 20% largest warehouses could provide 75 million sqm of roof space for solar PVs. Utilising this space would free up land that might otherwise be used by ground mounted solar projects for use in schemes such as housing development and biodiversity projects.
There are significant benefits associated with utilising rooftop solar PVs, some of which are set out below:
- The availability of appropriate roof space is vast given that any building with a sloped or flat roof can generate solar energy and use the power produced onsite in its operations.
- Solar PV is a valuable investment in commercial property, which in itself provides return on investment, creates asset value, and promotes longevity/sustainability for the property.
- Larger warehouses can export their energy generation, increasing returns for the owner.
- In many circumstances, the power produced by solar rooftops can be aggregated and deployed across a whole site (e.g., an entire industrial and logistics park), with participants contributing to their own energy network.
And yet, less than 5% of UK’s commercial and industrial rooftops are equipped with solar PVs. Why is this?
What’s the planning story?
The former Conservative government made changes to the planning landscape in an attempt to make the installation of rooftop solar panels easier. The key changes came with the introduction of the Town and Country Planning (General Permitted Development etc.) (England) (Amendment) (No. 2) Order 2023 (the ‘2023 Order’), which brought most rooftop solar projects into the General Permitted Development regime (and therefore not requiring planning permission). Solar PV equipment on the roofs of non-domestic premises falls within the permitted developments contained within Part 14, Class J(c) of the Town and Country Planning (General Permitted Development etc.) (England) Order 2015 (the ‘2015 Order’).
Crucially, for commercial premises, the 2023 Order removed the 1MW restriction for industrial rooftop solar, which had previously required businesses to apply for planning permission if solar panels would generate more than 1MW of energy. This restriction would capture many of the UK’s largest warehouses and industrial units, with rooftops vast enough to provide many megawatts of energy.
Understandably then, those in the commercial and industrial property sector would be forgiven for thinking that they’re free to install rooftop panels at any scale and at a time that suits them.
What’s the catch?
The 2015 Order sets out the conditions that rooftop solar PV developments are subject to.
Class J(c) developments (non-domestic) are generally permitted, subject to the condition that before beginning the development the developer must apply to the local planning authority (‘LPA’) for a determination as to whether the prior approval of the LPA will be required as to the design or external appearance of the development, in particular the impact of glare on occupiers of neighbouring land.
The LPA can request such information as it may reasonably require in order to determine an application, which could be potentially onerous on the developer, and in any case may refuse an application if it feels the proposal does not comply with any conditions, limitations or restrictions specified in Class J. The application may also be refused where it is considered that the developer has provided insufficient information to enable the LPA to establish whether the proposed development complies with those same conditions, limitations or restrictions.
A recent appeal case demonstrated that insufficient information provided in an application for prior approval will result in rejection if the LPA (and indeed Inspector) cannot conclude that the proposal constitutes permitted development. In the case of Battersea Studios, the submitted plans did not provide sufficient level of clarity or certainty that all of the solar PVs would not be within 1m of the external edge of the roof nor that they would not protrude more than 0.2 from the surface of the roof (as required under paragraph J.1.(a) and J.1.(c) of 2015 Order). As such, the application for prior approval was refused.
In any event, even where prior approval is given, the development must be carried out in accordance with the details approved by the LPA (limiting the ability for design change down the line) and/or subject to any conditions reasonably related to the prior approval.
Final Thoughts
So, whilst there is no requirement for planning permission in respect of the majority of potential solar rooftop projects, it is still possible that a scheme may be refused prior approval by the LPA and halted in its tracks.
No doubt there will be an increasing number of planning appeals on this matter as the commercial and industrial sectors look to take advantage of the benefits of solar PV installation, as is being encouraged from members of the cabinet.
It is important that any company looking to introduce solar PVs at an existing site, or include them as part of a new development, are aware of the potential pitfalls that might postpone works and/or the eventual realisation of the return on the investment in solar power. Seeking up-to-date legal advice is essential to ensure a smooth transition to solar power production.
