RENEWABLE ENERGY
Paving the way for
a more sustainable city
The City of Cape Town has become the first municipality in South Africa to own a floating power plant.
I
n its efforts to pave the way towards a more sustainable city, the City of Cape Town has installed a floating solar photovoltaic (PV) system at the Kraaifontein Wastewater Treatment Works. The City hopes the project will help to determine evaporation savings and energy generation per formance of floating solar farms. With the project, the City aims to achieve total renewable energy generation of 300 MW through both City-owned and private power generation. The floating solar farm is part of a research study involving private company Floating Solar, the Water Research Commission and the University of Cape Town. Data will be collected from sensors over a 12-month period to potentially inform the design of larger utilityscale floating solar PV projects over the next few years through competitive bid processes. The farm includes a floating solar panel array as well as a ground-mounted solar panel system to determine evaporation savings and relative energy generation per formance of floating solar PV technology.
The systems The floating system consists of: • a 3.51 kWp floating solar PV system: nine
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390 W peak (Wp) PV panels mounted on a floating solar island, with panels installed at a 12-degree tilt • two identical tanks (20 m in diameter) including a water supply system: one reser voir is covered by a floating solar PV system and the other is uncovered as a control • o ne reser voir is covered using the Hydrelio Air technology with a four-per-row configuration • water levels in each reser voir are 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 reser voir • a three-phase inverter. The ground-mounted system consists of: • t wo land-based solar PV systems each with an installed capacity of 3.51 kWp: comprising nine 390 Wp solar PV panels at the same tilt as the floating solar PV system (12 degrees) and nine 390 Wp solar PV panels installed at the optimal South African tilt of 32 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)
• i nstruments installed on the solar PV panels (energy generation monitoring system and temperature sensor).
Future-fit city Phindile Maxiti, MMC: Energy and Climate Change, City of Cape Town, says the City has a target to achieve 300 MW of renewable energy generation by 2030, with 50 MW of this comprising 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,” she says. “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.” The project will not only look at the amount of energy that can be generated by floating panels, but will also investigate how much can be generated compared with the groundmounted panels. The other important pillar of the research will be to determine what impact the floats have on water evaporation.
