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Water for thirsty Medupi

I KEEP hearing rumours about Medupi, the coal-fired power station that is turning out to be the most expensive ever built anywhere. The station’s foundations are being built 50% below requirement. No, they’re not. Oh, well, the boiler foundation structure is prejudiced. When I ran a check, the answer was no, it’s not.

Which is right? Given the consistently bad news we’ve been getting about Medupi, it’s easy to shrug and assume the worst — like the latest assessment I’ve heard, that the total cost of the project, interest included, is heading towards R200bn.

What is indisputable, however, is the need to worry about the supply of water to Lephalale, where Medupi is situated. The power station, which will employ a dry-cooling method that doesn’t use evaporation to cool the water, will nevertheless require 6-billion litres of water a year without a flue gas desulphurisation (FGD) plant, and 14-billion litres a year with such a plant.

Those numbers are Eskom’s, and they are at huge variance to those produced by James Blignaut, whose scientific paper was published in the Journal of Energy in Southern Africa (Volume 23, Number 4, November 2012). In his view, once all six units are operational, Medupi will consume 21-billion litres a year (excluding washing coal, but including that very expensive FGD plant).

What this illustrates is the unintended consequence of efforts to mitigate climate change and acid rain. It can be argued these are vital components of any new power station, but if the water isn’t available, then what? Whichever numbers are used, where is this water coming from? Limpopo isn’t exactly the wettest province in the country. The interim plan is to supplement what’s immediately available through the construction (for another R15bn) of the Mokolo Crocodile Water Augmentation Project. It will pump and pipe water nearly 100km from the Mokolo Dam to the Lephalale area.

Sounds good enough, but there’s a problem. The Mokolo Dam’s estimated content when full is 44-billion litres. Allowing for a reserve and irrigation leaves 30-billion litres. Water already allocated to large users (Exarro, Matimba power station and Lephalale municipality) totals 19-billion litres. That leaves only 11-billion litres for Medupi, but Eskom will “borrow” 3-billion litres from Matimba, which doesn’t use its full allocation. When that’s done, the Mokolo Dam is empty and any fish in it are flapping around in the mud.

That’s frankly scary. The only real alternative source available is the second phase of the Lesotho Highlands Water Project, for which the governmental agreement was signed only in May this year. South Africa currently receives 24,600 litres of water per second from the project, and the second phase will add another 45,500 litres a second, virtually tripling the offtake. The project cost is estimated at R12bn (which I don’t believe) and it won’t be completed until 2020.

Assuming that the rule still stands good that the first Medupi unit will come on-stream in, say, October next year, and subsequent units will follow at six-monthly intervals, then Medupi will finally be fully operational in 2017. That leaves three very lean years. What happens if the dreaded El Niño strikes and Southern Africa enters a prolonged period of drought?

None of this includes the requirements of the new Kusile power station. We have left ourselves very little wriggle room.

Source: BD Live

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