The City of Cape Town has become the first municipality to install a floating solar photovoltaic (PV) system with partners Floating Solar (Pty) Ltd, the Water Research Commission and the University of Cape Town. The floating solar PV pilot, which has been established at the City’s Kraaifontein Wastewater Treatment Works, includes a floating solar PV array as well as a ground-mounted PV system to determine evaporation savings and relative energy generation performance of floating solar PV technology. This is an innovative research study where data is being collected over a 12-month period to potentially inform the design of larger utility scale floating solar PV projects over the next few years through competitive bid processes.
Floating system consists of:
• A floating solar PV system: Nine 360 kilowatt peak (kWp) PV panels mounted on a floating solar island, with panels installed at a 12 degree tilt.
• Two identical tanks (20m in diameter) including a water supply system: one reservoir is covered by a floating solar PV system and the other reservoir is uncovered as a control.
• The one reservoir is covered using the HYDRELIO® AIR technology with a four-per-row configuration.
• Water levels in each reservoir is being monitored with a float switch. When the water level drops below a predetermined point, a pump will be turned on and water fed back into the reservoir. The volume of water will be measured by a flow meter and recorded.
• A three-phase inverter.
Ground-mounted system consists of:
• Two land-based solar PV systems: comprising nine 360 kilowatt peak (kWp) solar PV panels at the same tilt as the floating solar PV system (12 degrees) and nine 360 kilowatt peak (kWp) solar PV panels installed at the optimal South African tilt of between 28 and 33 degrees
• All instrumentation and equipment required for the experiment (ambient temperature and humidity sensor, pluviometry, solar irradiance sensor, data logger, wind speed and direction sensor)
• Instruments installed on the solar PV panels (energy generation monitoring system and temperature sensor)
‘The City has a target to achieve 300 MW of renewable energy generation by 2030, with 50 MW of this comprising of City-owned solar PV plants. The City has been fighting to move away from the sole reliance on Eskom and to diversify the energy mix for cleaner and more affordable and secure power for all. In addition, given that vacant land in the city is very expensive and rooftop solar PV systems are relatively small, Cape Town aims to explore floating solar PV systems for larger scale solar PV installations as part of its pioneering work to diversify the energy mix, to lead by example and to take climate action leadership. Importantly, great things can only be done with great partners. We thank Floating Solar, the Water Research Commission and the University of Cape Town for helping to enable this project and driving it forward with the city.
‘This exciting pilot project not only looks at the amount of energy that can be generated by floating panels, but also investigates how much can be generated compared with the ground-mounted panels. The other important pillar of the research is to see what impact the floats have on water evaporation. Generating clean power and reducing evaporation rates of water bodies could be a great double-win for sustainability. This type of project is a tangible example of how we can build a more sustainable future city and how the green economy can be harnessed for the sustainable, and inclusive, economic recovery we require especially after Covid-19,’ said the City’s Mayoral Committee Member for Energy and Climate Change, Councillor Phindile Maxiti.
Water-sensitive Cape Town
The Water and Sanitation Department continues to explore a range of innovative concepts that could in future enhance water security and sustainability of its operations. City officials are willing to think outside the box, and this is so important for ongoing adaptability and resilience. The more we research and understand, the stronger and better prepared we become,’ said the City’s Mayoral Committee Member for Water and Waste, Alderman Xanthea Limberg.
‘Globally, floating solar has rapidly become the third pillar of the Solar PV industry. In following this trend, we have identified significant potential within South Africa for this promising technology which has the dual benefit of producing power while reducing evaporation and preserving land for other commercial use.
‘From the outset, we have identified over 60 high potential projects – with a combined capacity of over 450 MW – that will be well suited to benefit from Floating Solar development. One of the key target markets is the approximately 1 000 water treatment works across South Africa, which are well suited to floating solar due to significant on site power demand requiring a sustainable energy source, limited available land and water evaporation savings, as well as providing the opportunity to export additional power to the grid.
‘We are extremely pleased that the City of Cape Town is enabling this potential with this pilot project to investigate this potential,’ said Peter Varndell, spokesperson, Floating Solar.
About Floating Solar (Pty) Ltd
Floating Solar (Pty) Ltd was established in 2017 as a Floating Solar PV equipment provider and project developer. They are the distributors for the Ciel and Terre HYDRELIO® floating solar system in Southern Africa.