The City of Cape Town is forging ahead with sustainable solar projects to place less responsibility on Eskom. On Wednesday it became 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.
According to the City, 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 solar 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)
Future-fit city
The City’s Mayoral Committee Member for Energy and Climate Change, Councillor Phindile Maxiti said, 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 aim is 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,” he said.
Over 60 high potential projects – with a combined capacity of over 450 MW – have been identified. According to the City, one of the key target markets is the approximately 1000 water treatment works across South Africa, which are well suited to this project 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.
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