The Mossel Bay municipality has cut the ribbon on the Hartenbos Waste Water Treatment Works solar PV plant and microgrid project.

Developed in partnership with Solareff and Element Consulting Engineers, the hybrid, grid-tied microgrid is designed to ensure uninterrupted power supply to the wastewater treatment facility, up to and including Stage 6 loadshedding.

Under normal conditions, it operates in parallel with the Eskom grid.

In the event of grid interruptions, the battery energy storage system (BESS) takes over, supported by solar generation during daylight hours.

Standby diesel generators provide additional backup if needed.

Excess solar energy is fed into the municipal grid, thereby reducing the Mossel Bay municipality's long-term energy costs and boosting its sustainability.

The energy project, situated on 3.5 ha of municipal land, was designed with future expansion in mind and can be scaled up to 5 MVA as demand grows.

Current solar generation capacity is 2.112 MVA from 4 536 PV panels. PV inverter station capacity is at 3.2 MVA, with BESS inverter station capacity at 2.75 MVA.

Generator farm capacity is 1.6 MVA.

The new substation tied to the project includes 11 kV switchgear and control systems that can switch seamlessly between solar, battery and diesel backup.

"As a municipal manager, I am proud to say that we are one step closer in making our city and our town sustainable," says Mossel Bay municipality's Colin Puren.

Solareff held the ground-breaking ceremony to kickstart the project in November last year, and reached practical completion at the end of September this year.

"We all know the history of Eskom and energy prices in South Africa, so the Mossel Bay council decided to start investing in energy sustainability," explains Mossel Bay municipality Mayor Dirk Kotzé.

"This [project] means that our bulk infrastructure will be able to cope with extended periods of loadshedding."

"What these types of projects further provide is grid resilience," adds Solareff chief commercial officer DeVilliers Botha.

"You would have often heard that we need to expand the transmission grid in the country to provide power across the country.

"However, if we install more of these types of microgrid systems, we bring resilience and also stability to local grids."