The outcome of the ANCs long-awaited KwaZulu-Natal conference was a win for the Thuma Mina crowd. (Delwyn Verasamy/M&G)
The Water Research Commission harnessed excess energy within existing water distribution systems to generate hydropower with a potential power output of 22 500MW/h a year across the five large metros.
The project was implemented by the University of Pretoria in partnership with the Tshwane Municipality, Bloemwater and the Ethekwini Municipality.
It uses excess energy in pressurised conduits to produce clean and renewable hydroelectric power. This solution is known as conduit hydropower and uses micro-turbines installed within the conduit system.
Its simplicity is what makes the solution so elegant: harnessing energy that is already present within the existing infrastructure and that would usually be lost through the use of a pressure valve.
“In South Africa we are blessed with large water distribution networks and water transfer schemes, and I believe that there is opportunity to tap into these,” says Jay Bhagwan, executive manager of water use and waste management at the Water Research Commission.
“Hydropower is not a new technology, but conduit or inline pressurised hydropower is, so we initiated a scoping study to explore the potential.”
This study indicated that there was indeed significant potential for the generation of energy through the water supply, and that exploiting pressure at up to 10 water reservoirs in the Tshwane Municipality could produce more than 10 000 000kW/h a year.
There are 284 municipalities and water supply utilities that use the gravity water supply distribution systems needed for the project, and this could provide a potential power output of 22 500MW/h a year over the five large metros.
Since the project’s inception, the Tshwane municipality has generated about 30kW/h per hour at the exit to the Elardus Park reservoir. In Bloemwater, 96kW/h of clean energy is being produced from a pressurised conduit and has become the main source of power at the head office in Pellisier.
“The initial results gave us the confidence to move into a larger pilot with the installation of the 100kW unit at the Elardus Park reservoir,” says Bhagwan. “It was a great moment when we saw the lights go on as the unit lit up the security fences around the reservoir.
“Our success has led to some key decisions by the metro. They have initiated a high-level study to determine the full potential of conduit hydropower and made the decision that all new reservoirs going forward will include a hydro unit as part of the design.”
The project started in April 2011 and concluded at the end of February 2014, but this is not the end of the road. For the Water Research Commission it is the start of a journey that will potentially result in the provision of renewable and low-cost energy to all areas of the country.
“Our next step is to look at low overhead options and see how we can extend this approach to provide off-the-grid electricity to rural communities,” says Bhagwan.