Construction group Wilson Bayly Holmes-Ovcon (WBHO) is installing large-scale solar panel arrays on the rooftops of three buildings of its headquarters in Johannesburg.

The first of the three buildings will be fully operational this month, with the other two to follow between the end of April and the beginning of May.

WBHO describes the R20-million Going Green project as “ground-breaking” in terms of “the unique model it has developed of the daily, weekly and seasonal load-cycles of the premises to address the challenge of balancing the buildings' unique fluctuations in energy demand and fluctuating solar supply, supported by battery storage”.

The group says this model enables the company to “ensure safe, stable access” to energy throughout the day.

"Being able to define an optimal combination of technologies to meet inconsistent demand is a delicate dance to get it right,” says WBHO project division director Russell Adams.

“We took it hour by hour, day by day, across the seasons on a statistically determined basis, so that it makes technical and financial sense as well.

“Averages don't work well in the world of electricity supply and demand matching. You have to hit the precise point where energy meets economy.”

As a consequence of the solar installation, the buildings can now mitigate up to Stage 5 loadshedding from Eskom.

As the offices remain connected to Eskom, WBHO hopes to eventually supply energy back into the grid.

The Going Green project involves structural changes to the buildings, with concrete blocks placed on the roofs to secure maximum solar panel metreage.

Around 140 t of ballast were placed on the roofs, and 50 t of steel mountings were installed.

The final solar system will have a total capacity of 560 kWp, along with battery storage of 1 576 kWh.

The energy supply mix also includes 750 kW of inverter capacity.

"The investment in the project not only makes environmental sense, but it makes economic sense as well," notes Adams.

“Prior to this project, the company spent in excess of R100 000 a month on diesel to mitigate Stage 6 loadshedding at its head office.”

The Going Green project was preceded in 2016 by an energy audit, replacing all electrical equipment in the buildings with energy efficient alternatives.

In 2022, the company’s large plant and services yard in Midrand began shifting its energy mix towards greater reliance on large-scale photovoltaic arrays by installing a 336 kW system there as well.