In a move to curtail the impact of load shedding, the City of Joburg municipality in South Africa is exploring technology to harness electricity from hydropower in the city’s water pipes.
The city, through its water utility Johannesburg Water (JW), could install turbines in existing water pipes to generate additional power to avoid load shedding, The Star reported.
JW estimates that by doing this between 1 and 2MWs could be generated – or about 10% of the agency’s current 21MW requirement.
This technology would complement JW’s biogas-to-energy programme under way at its wastewater treatment plants and augment its renewable energy generation footprint.
Hydropower pilot project
A city delegation, led by City of Joburg mayor Parks Tau, recently returned from a three-day visit to US city Portland, Oregon, during which it evaluated the feasibility of an in-pipe hydropower system.
The delegation met with Portland officials, including mayor Charles Hayles, representatives of the US based Lucid Energy, a provider of in-conduit hydropower technology, and other experts linked to the installation of the hydrokinetic in-pipe turbine system in the state of Oregon.
Lungile Dhlamini, managing director of JW who accompanied the delegation said: “I was initially a little sceptical, but I am now convinced it can work. We are looking at starting a pilot project that could give us about 10% of our current needs”.
A pilot project of this technology will promote renewable energy generation, mitigate greenhouse gas emissions and load shedding, and take advantage of low-cost energy.
Added benefits from hydropower
Currently the city’s water network requires the installation of new pressure-reducing valves. By installing the turbines within the water pipes, the utility will be able to avoid the installation costs of the valves and be able to harness renewable energy to produce electricity as an added benefit.
The hydropower turbines are installed inside the pipes and turn as the water flows through them, generating electricity as they do, but they must be installed close to an electricity grid connection.
Dhlamini told The Star that the water utility would engage Eskom and City Power to help it locate these connection points.
He said: “We are planning to start small to see how it goes and will be calling for either expressions of interest or requests for proposals, depending on our initial feasibility study. We are in the process of obtaining further technology clarifications from our counterpart, the Portland Water Bureau.”
Further adding that: “Johannesburg Water has estimated it would cost about R23 million/MW ($1.8 million/MW). When compared to other renewable energy sources, the in-pipe turbine is comparable to the cost of solar power.”
City’s blue economy
In terms of the hydropower project development and implementation, the utility is planning to start with actual construction in the second or last quarter of the 2015/16 financial year following engineering, design and procurement processes.
“With help from internationally renowned systems engineer Professor Gunter Pauli and a network of 130 international experts, the idea of in-pipe turbines emerged from the city’s basket of Blue Economy initiatives designed to transform local resources’ scarcity to abundance, while creating business and job opportunities for small to medium enterprises and its job-seekers respectively”, said Dhlamini.