“Occupiers share similar green ambitions, so the putting in place of contractual agreements that help both sides is a win-win. But it’s something that we’re yet to see become mainstream.”

Securing green onsite energy supply could equally help existing buildings to compete for the best tenants.

“Occupiers will continue to seek the best and latest on offer in terms of renewable energy to help them meet their own sustainability commitments,” says Readhead.

While there are still some feasibility issues for landlords and their tenants to overcome, the focus on cutting carbon will only increase amid tightening regulation and growing peer pressure.

“Investors are aware that just a few years from now their buildings could be overshadowed by greener newbuilds that are more energy efficient or have cutting-edge technology - and this has clear implications for future property valuations,” says Readhead.

In the short-term, improvements in accurately forecasting the benefits achievable from commercial rooftop space will be needed.

“There are increasingly more sophisticated ways of assessing potential solar capacity, for example through specialist software using satelite imagery,” Readhead says. “That can help landlords cost effectively gain a more accurate picture of what’s possible and where.”

In the meantime, growing interest in and knowledge of the area is helping to drive progress. “Discussions are certainly more finessed now in terms of addressing those practical issues,” says Readhead. “The trajectory that both investors and occupiers are now on points towards greater collaboration on delivering onsite green energy supply and achieving wider sustainability goals.”