De Vlei Boerdery is a table grape farm situated in the Hex River valley, with a proud legacy of sustainable farming dating back to 1732. In 2023 they made the decision to invest in sustainable energy supply and lower their carbon footprint by going green! By March 2024, De Vlei’s renewable energy system was operational, just in time to support the peak of their harvest season.
Figure 1: Roof mounted solar PV structure
Figure 2: Battery room
The system
The roofs of two packhouses were fitted with solar panels, and an existing building was converted to house the main distribution board, inverter and batteries. The renewable energy system includes:
- 710 solar panels generating 397 kWp.
- 44 batteries storing 630 kWh.
- A 500 kW hybrid inverter.
Additionally, an underground microgrid spans 6 km, connecting eight grid-supplied points. This setup allowed De Vlei to terminate seven of these Eskom points, significantly reducing both fixed and variable electricity costs.
Figure 3: Single Line Diagram (SLD) of De Vlei energy system
Figure 4: Satellite view of MV network
Grid energy supply
Since the system’s commissioning in March 2024 through January 2025, the area experienced 380 hours of grid downtime, equating to 4% of the year without grid-supplied power. Despite this, De Vlei remained fully operational and had virtually no power outage during the same period. Furthermore, due to the battery energy storage system, De Vlei hardly had to operate their diesel generator, which ran for no more than 50 hours, while the system sustained itself for the remaining 330 hours.
The system is designed to optimize electricity usage by:
- Utilising batteries during peak (expensive) periods.
- Recharging batteries with solar energy whenever possible.
- Recharging batteries with grid electricity only during off-peak periods if necessary.
Figure 5: Total monthly grid (ESKOM) power usage after renewable energy system installation
From the outset, there was a noticeable reduction in total energy supplied by the grid, even during winter months. This improvement reflects only kilowatt-hour reductions, excluding additional savings from shifting to off-peak grid use.
Electrical savings in one year
When developing a proposal, we predict annual savings based on several factors. This year, the primary factors influencing actual costs and savings were:
- Reduced loadshedding in 2024 (ending successfully in March 2024).
- A significant increase in electricity costs.
Regardless of these factors, De Vlei achieved a 12% savings over and above what 2Zero50 predicted they would.
The outcome: A 67% reduction in electricity costs over one year.
Figure 7: Savings on total cost of electricity
Conclusion
De Vlei Boerdery is thrilled with the results of their renewable energy system.
“Danie Rautenbach and his team at 2Zero50 did excellent work at developing a complete solution built around our specific needs and managing all aspects of the project. We can highly recommend them and also RB Electrical (from Kathu) who did the electrical work to a very high standard.” – The Viljoen Family
Figure 8: The Viljoen family
