Mossel Bay sets benchmark in municipal energy innovation: Hartenbos Waste Water Treatment Works Solar PV Plant and Microgrid

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19-11-2025
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Cape Business News
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Mossel Bay, Western Cape – In a bold step toward sustainable infrastructure and energy resilience, the Mossel Bay Municipality, in partnership with Element Consulting Engineers and Solareff, celebrated the official launch of the Hartenbos Waste Water Treatment Works Solar PV Plant and Microgrid on Wednesday, 5 November 2025. 

“The achievement reflects Mossel Bay’s forward-thinking approach to infrastructure and its dedication to building a greener, smarter future. As a Municipal Manager, I am proud to say that we are one step closer in making our city and our town sustainable,” said Colin Puren, Mossel Bay Municipality Municipal Manager.

Developed in partnership with Solareff and Element Consulting Engineers, this award-winning project is a hybrid grid-tied microgrid designed to ensure an uninterrupted power supply to the wastewater treatment facility, even during 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, reducing long-term energy costs and boosting sustainability for the Mossel Bay area. This solution was designed with future expansion in mind and can be scaled up to 5MVA as demand grows.

“Excess energy from the PV system will obviously be distributed back into the immediate vicinity or the immediate grid that will cater for the other businesses in the area. I’m very excited about this plant. It is the beginning of many good things to happen,” said Dick Naidoo, Mossel Bay Municipality, Director: Infrastructure Services.

“The whole project was basically initiated back in 2020 when the Mossel Bay Municipality appointed Element Consulting Engineers to look at master planning for them, and one of the main aspects that they wanted us to cover as well was also include some renewables, because Mossel Bay, you know, as part of the Western Cape government and so on are very proactive in their approach towards renewables,” said Mr Jako Fourie, Element Consulting Engineers, Project Manager and Owner’s Engineer.

Solareff held the ground-breaking ceremony for the project on 27 November 2024, and reached practical completion for the project in under a year, by 30 September 2025.

The official launch event, held on-site in Hartenbos, featured a ribbon-cutting ceremony, keynote speeches, and a site tour. Speakers included:

• Mossel Bay Executive Mayor, Alderman Dirk Kotzé; 


• Element Consulting Engineers, Owner’s Engineer Mr Hannes Lourens; 


• Element Consulting Engineers, Project Manager and Owner’s Engineer, Mr Jako Fourie;


• Mossel Bay Municipality Portfolio Chair – Infrastructure Services, Alderman Anton Dellemijn; and 


• Solareff Co-founder & Chief Commercial Officer, Mr DeVilliers Botha. 

By investing in clean energy, the Mossel Bay Municipality is safeguarding the environment, reducing reliance on Eskom, and setting a new standard for municipal innovation.

“We all know the history of Eskom and energy prices in South Africa so Mossel Bay Council decided to start investing towards energy sustainability. It is also about delivering services whenever Eskom can’t deliver and we obviously distribute so we are also a taker from Eskom. This will take us off the grid, our bulk infrastructure will be able to cope with extended periods of load shedding and then the main thing is the fact that this solar investment will also enable us to buy energy cheaper and so this is one of those initiatives towards that.” said Mossel Bay Municipality Executive Mayor, Dirk Kotzé.

Project Highlights: A Smart Energy Solution for Critical Infrastructure

• Site Size: 3.5 hectares of municipal land


• Solar Generation Capacity: 2.112MVA from 4,536 PV Panels


• PV Inverter Station Capacity: 3.2MVA


• Battery Energy Storage System (BESS): 4,586kWh


• BESS Inverter Station Capacity: 2.75MVA


• Generator Farm Capacity: 1.6MVA


• New Substation: Includes 11kV switchgear and advanced control systems that switch seamlessly between solar, battery, and diesel backup.

“What these types of projects further provide is grid resilience. 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 distributed around the country, we bring grid resilience and also grid stability to the local grids.” said DeVilliers Botha, Chief Commercial Officer at Solareff.

Award Recognition

The Hartenbos Solar PV Plant and Microgrid project was recently awarded “Top Performing Project” at the AMEU Awards 2025, showcasing municipal energy innovation, and setting a benchmark for sustainable infrastructure in South Africa. The AMEU Awards are a collection of accolades from the Association of Municipal Electricity Utilities (AMEU), a South African body for municipal electricity utilities and their affiliate members, recognising excellence in the electricity sector. The Hartenbos Solar PV Plant and Microgrid project was honoured for its contribution to energy resilience, environmental sustainability, and technical excellence in municipal services. 

Empowering the Next Generation

As part of the launch event, learners from 2 local schools – Sao Bras High School and Lighthouse College – joined for an educational walk-through of the solar installation. Learners explored how solar energy works, the role of microgrids, and how this project supports environmental sustainability.

“At Solareff, we believe in inspiring and equipping young minds to actively shape South Africa’s energy future – because they are the future of energy,” said DeVilliers Botha, Chief Commercial Officer at Solareff. 

A Vision for the Future

The Hartenbos Waste Water Treatment Works Solar PV Plant and Microgrid sets a new benchmark for municipal energy innovation. It demonstrates how clean energy can be reliably integrated into essential infrastructure, reducing carbon emissions and operational costs while enhancing service delivery. Through this solution, we are proud to be setting a precedent for Municipal energy resilience and environmental responsibility in South Africa.

Project Partners

• Mossel Bay Municipality (Client)


• Element Consulting Engineers (Electrical Consultant)


• Solareff (EPC Contractor)