Lights on for investors

30 Mar, 2018 - 00:03 0 Views

eBusiness Weekly

Zimbabwe’s well-oiled campaign to attract investment has to be backed by infrastructure and in particular by being able to guarantee the new investors in mining and industry that we can supply them with adequate electricity; an unpowered factory or mine is useless and just a white elephant.

So the commissioning this week by President Emmerson Mnangagwa of the 300 megawatt extension to Kariba South is timely, telling investors that we can provide the basics and that we are prepared to invest our share in infrastructure so that business can do business. If we are to be open for business, we need to ensure the lights are on.

Just as important was the recent announcement that the 600MW extension to Hwange Thermal Station, delayed by well-understood doubts over Zimbabwe’s commitment to proper finance, was now back on track with the main Chinese contractor and financier now ready to accept that Zimbabwe will be paying its interest and finance bills. The seriousness of the new administration has obviously helped overcome doubts in this regard.

Both projects are vital if Zimbabwe’s economy is to take off properly, although until the Hwange extensions are commissioned Zimbabwe will still be reliant, perhaps over-reliant, on imports, basically from Mozambique and South Africa although the commissioning of Kariba Extension will at least make it possible to import enough for a few more years.

Kariba South Extension sorts out the most pressing problem, the peak power demand. Southern Africa is generally close to maximum utilisation of its generation capacity and it would be very difficult to find anyone able to increase supplies early in the morning or in the evenings, when commercial and domestic demand tends to overlap. So load shedding was looming at peak times; Kariba South pushes that danger back. At the same time it helps cut the import bill since the most expensive imports are precisely those at peak demand.

The extra 300MW now available from Kariba South takes care of the extra expected peak requirement. But although Kariba South is now rated at 1050MW, it cannot push that out all day and all night 365 days a year. The entire flow of the Zambezi already goes through the two Kariba power stations, rather than the flood gates, so while Zesa can crank out 1050MW at Kariba South at say 5pm, it will have to cut back to about a third of that at 1am.

But neighbours are in the same time zone so their demand is also sharply down at 1am and most will be quite happy to supply at the off-peak hours, although Zimbabwe needs to recognise that they are also battling to grow their economies and so will at some stage need to cut back on exports to supply their own factories and mines.

This is where the Hwange Extension comes into play. The two giant boiler-generator sets planned for Hwange III will push out 600MW, and fixing the coal supply will mean that this can be pushed out 24/ 7. At the same time Zesa has finally started revamping the two older sections of Hwange, with the new civil works required in the extension finally resolving a cooling deficiency, so even with the higher maintenance times and outages of a thermal plant it is likely that the extended Hwange will be able to supply a minimum of 1200MW pretty continuously. And that will cope with all the 1am demand for a few years, plus a bit in reserve.

Fortunately the Hwange deal is going ahead just in time to have the extra energy available before our neighbourly suppliers have to write the letters telling us that they have to cut back because of local rising demand.

Kariba South Extension will also be vital when Zimbabwe and Zambia finally Batoka Gorge Dam and add two more stations to the regional grid. This is because Lake Batoka, unlike Lake Kariba, will have little storage. The dam wall which is basically there is a vertical drop so water can generate power rather than as a big storage battery.

But by operating Batoka South and the extended Kariba South as an integrated pair, Zimbabwe can maximise both power and energy generation. When the Zambezi comes down in flood Batoka South can be going flat out and the Kariba station can be eased back, letting the Kariba water levels rise. As floods subside the Batoka output will go down, with low-water output probably about half the high water output. But that water that went through on the floods is now safely in Lake Kariba, ready to be used again and Zesa will have a 1050MW station able to go flat out for say 20 hours a day rather than just 12 hours a day.

And even though Batoka is what is called a run-of-river dam, it can still store enough so that Zesa can use it as peak demand supplier during low water periods and a base-load supplier in the floods, while Kariba South does the exact opposite, being a peak demand supplier in the floods, and taking over more base load during low-water months.

And meanwhile the now reliable Hwange will be there, taking up its share of base load. Generating team managers will be tracking multiple data, everything from the Angolan rainfall to detailed demand graphs. And we will all have to be careful how we talk about generating capacity. We might well have 3,5 gigawatts installed from all three main stations, but actual output will probably vary from 2GW to 3GW depending on the time of day and time of year. So we will need to start talking about maximum base load, that 1am summer night figure, and maximum peak output, that 6pm dark winter day maximum demand.

For almost three decades Zimbabwe has paid lip service to doing something about power-station expansion. The debate over Kariba South Extension started in the early 1980s and went through multiple studies before finally ending up in the document store until dusted off as the most vital of the three required upgrades to the system. And the Government has pushed for the next one that can come on stream, Hwange III and done enough walking the talk to get that project back on the tracks.

So we now can promise the investors we hope will be moving in, hiring lots of Zimbabweans, that we can keep the lights on.

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