UK commercial roofs could carry around 60 GW of solar against 3-5 GW today, and the barriers named are leases, tax and insurance

A report published on 10 September 2026 estimates that commercial rooftops in the United Kingdom could host around 60 GW of solar generation, against 3 to 5 GW installed today, and argues that the gap is a matter of leases, tax and insurance rather than of technology. The research was commissioned by Real Estate:UK in partnership with the law firm Forsters and Push Power Ltd, and authored by Cushman & Wakefield. It draws on a survey of 70 real-estate organisations that between them manage more than GBP 500 billion of assets. Its central finding is that more than 90% of suitable commercial roof space in the UK is currently unused for solar generation. The barriers it identifies follow directly from the split between who owns a roof and who pays the electricity bill beneath it. The report's seven recommendations include clarifying REIT tax rules so that solar income does not jeopardise a trust's status, standardising the legal furniture (power purchase agreements, lease clauses) so that each installation is not separately negotiated from scratch, establishing consistent insurance standards, improving grid connection times and capacity, raising the 50 kW cap on permitted development, and giving long-term certainty on building efficiency standards. The decentralisation question here is about ownership rather than hardware. A distribution warehouse roof is among the few large, unshaded, already-built surfaces sitting directly above a substantial daytime load. Almost none of them generate. The reason is not that the arithmetic fails; it is that a landlord who pays for a roof array captures value only if the tenant buys the output, the lease permits the arrangement, the insurer accepts the roof penetration, and the tax treatment does not penalise the trust that owns the building. Four separate parties, four separate contracts, no standard instrument. That is a coordination failure, and it is the kind of failure that policy can actually fix. Two cautions on the number. The 60 GW is a conditional technical-and-policy potential rather than a forecast: the report states its projections assume appropriate financial, regulatory and legal frameworks are in place. And this is industry research: commissioned by a real-estate sector body, produced with a law firm and a solar developer, all of whom would transact more if the recommendations were adopted. [UNVERIFIED] The methodology behind the 60 GW figure, and the definition of "suitable" roof space it rests on, were not available to this sweep, and no independent estimate was found to set beside it. The recommendations are more checkable than the headline: the 50 kW permitted development cap is a real number in real regulations, and how many projects sit just underneath it is a question with an answer.