Johannesburg may use 'zoo poo', sewage to fight loadshedding

Johannesburg is considering generating power from sources ranging from sewage to the city’s water pipes in a bid to end power cuts that shutter shops and cause traffic gridlock.

The options, along with solar power and tripling output from a coal-fired plant on the city’s eastern outskirts, are among those being explored as a national electricity shortage threatens to subject the city, home to 8 million people including surrounding areas, to power cuts for years.

The power situation is a “national issue” and must be approached in new ways, Sol Masolo, a spokesman for City Power, the city’s power distribution company, said in an interview. “Now we have a clear focus on projects that we do to mitigate load shedding,” he said, using the local term for electricity cuts.

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Because the government has delayed a decision on whether to allow Eskom  to build new power plants more than a decade ago electricity is now rationed to businesses and city dwellers with areas of the city often blacked out for four hours at a time. Lynne Brown, the public enterprises minister, has said the country can expect the situation to persist for another three years as generating plants are built.

The cuts shut businesses, leave residences without lighting and disrupt transport with traffic lights taken offline. That has a cost.

Eskom cuts power in three stages, according to the severity of the shortage on a given day. Stage 1 cuts 1,000 megawatts nationally, stage 2 reduces supply by 2,000 megawatts and stage 3 up to 3,000 megawatts. Stage 4 is the reduction of 4,000 megawatts.

A full month of Stage 1 costs businesses nationally about R6 billion a month, Mike Schussler, chief economist at Johannesburg-based research group Economists.co.za, said in a May 20 interview. Eskom has reached Stage 3 on three days this year and regularly announces stage 2 cuts.

Johannesburg Mayor Parks Tau this month announced plans to use in-pipe turbines to create energy from the citywide water system, similar to a system used in Portland, Oregon, and to convert sewage to gas by using bio-digesters. The city zoo has a system installed that uses anaerobic bacteria to convert “zoo poo” into gas.

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City Power has over two years installed about 30,000 “smart meters,” which warn customers to reduce consumption before potential blackouts and can limit the power they use. Consumers can then prioritize what to unplug to help curb the cuts implemented by Eskom. It plans to double the number, Masolo said. Already that has allowed the city to reduce the scope of some outages.

City Power also has a control system that allows it to switch off hot water heaters in certain areas of Johannesburg and is looking to curb the installation of new units, Masolo said.

 “By installing solar water heaters you’re basically killing demand for the regular ones,” he said.

While renewable energy is favored some of the most effective solutions seen by cities are more traditional ones.

The coal-fired Kelvin Power Station, owned by Nedbank Group Ltd. and Investec Ltd., is currently supplying about 200 megawatts to City Power, or about 7% of the city’s needs.

“We are engaging with the private sector to secure investment in Kelvin to push its capacity to at least 600 megawatts,” Tau said in a May 6 address.

Tshwane has similar plans to revive two coal-fired plants and plans a 40 megawatt solar power facility.

- Bloomberg