South Africa’s commercial property industry has the potential to ease the country’s power crisis, with enough roof space to generate 4.7 gigawatts of electricity, a new study has found.

Retail, office and industrial properties in the country’s five biggest cities have 68.7 million square meters (739 million square feet) of rooftops that have no solar panels, according to the study by Gmaven, a South African real estate software and data services company.

Installing solar panels on two-thirds of commercial properties in those cities’ main nodes would cost as much as 55 billion rand ($3 billion), yet they could generate electricity that leads to 12.3 billion rand of savings each year, Gmaven said. Just 6.4% of the 41,000 properties it surveyed already have panels in place.

South Africa’s government has cited rooftop solar as one of the solutions to a 15-year power crisis that has worsened to the extent that rotational blackouts have been imposed almost every day this year, the worst of them lasting as as long as 12 hours a day.

Properties held by Resilient REIT Ltd., a real estate investment trust, plan to have 68 megawatts of installed solar capacity by the end of this year, while Growthpoint Properties Ltd. is aiming for 46 megawatts by 2026, according to Gmaven.

The study didn’t assess the cost of battery backup to store excess solar power generated during the day.

“Unlike in the residential space, the commercial property sector’s major electricity consumption is during daytime hours,” Gmaven said. “The industry’s peak power needs are broadly matched by peak solar radiation.”