Why rooftop solar
Rooftop solar is one of the most straightforward ways for a business to reduce its emissions. The technology is well established, its output can be measured directly, and the return on investment is well understood. It requires no additional land and uses buildings that already exist.
Because the electricity is generated where it is consumed, comparatively little is lost in transmission, and the building draws less from the grid at times of peak demand. Generating power at the point of use also avoids much of the cost of moving electricity across the network, which is an advantage over larger installations sited further from where the power is needed.
The UK's warehouse roofs alone cover more than 165 million m². Fewer than 5% of commercial and industrial roofs currently generate solar power.
The transparency gap
Two questions that ought to be straightforward remain difficult to answer: how much commercial rooftop solar exists, and who is responsible for it. Many organisations publish net zero commitments, but the renewable generation on the buildings they control is rarely set out in a form that can be compared or verified.
The underlying information sits within official registers, spread across DNO connection data, MCS and REPD. We have brought these sources together and attributed each system to a named organisation.
How the league works
We compile the data from official registers, matching each recorded solar system to the landlord and occupier of the building it sits on.
Ahead of publication, we share each organisation's entry with it directly and invite confirmation or correction.
Once an entry is verified, the organisation can see how it compares with its peers.
The full league table is published on Tuesday 7 October 2026.
Participation is free and reviewing an entry takes only a few minutes. Where solar has been installed but not yet captured in the registers, this is an opportunity to have it recognised.
Built from official registers, open to correction
The league is built entirely from official registers: DNO connection data, MCS, REPD, HM Land Registry and Companies House. Every figure is dated and sourced.
Some estates are held through ownership structures that cannot be confidently resolved from public records. Rather than make assumptions, we record these as unverified, which a brief confirmation resolves. Any organisation that considers its entry inaccurate can submit a correction.