Zesa needs fixing so Zimbabwe copes

09 Aug, 2019 - 00:08 0 Views

eBusiness Weekly

BusinessWeekly Last Word

Zimbabwe’s electricity supply is in a dreadful mess after more than a quarter century of misplanning and mismanagement and while the measures announced in the Supplementary Budget last week are about the best on the table, they can be a little more than a band aid over the next few months while some real graft is put in properly over the next few years.

The saddest side of all this is that the engineers, to be precise that core of competent Zimbabwean power engineers, have been carefully explaining since the mid-1980s exactly what needed to be done and the order that new generating capacity should be brought on stream and when. And they were ignored until the new dispensation actually listened and started work last year, almost 30 years late, on the Hwange Thermal Extension, which includes fixing design problems on the original station plus accelerating the necessary refurbishment.

Zimbabwe started off well at independence. The messy management structure that had grown up in bits and pieces for decades in colonial times was obviously not a decent planning authority and needed change.

There were four power stations, all with a different owner. Kariba South, with two thirds of installed capacity, was still owned by Capco, set up when colonial Zimbabwe and colonial Zambia shared the station as well as the dam and the lake. The newest of the three small thermals, Munyati, and that was mostly more than a quarter century old, was owned by the then Electricity Supply Commission. Harare and Bulawayo City Councils each owned the station in their city, with the last equipment bought around 30 years before. Between the four, Zimbabwe could generate just under 1 000MW flat out though, more than it manages now. So one of the first decisions of the new Government, after careful consultation and planning, was to amalgamate the four generator owners, plus Mutare and Gweru municipal distribution, and hive off Capco’s management of the lake and dam into the new two-country Zambezi River Authority. It made sense and it worked.

The three old thermals were expensive to operate. By the time coal reached Harare it was around six times the price it cost to mine. Bulawayo and Kwekwe coal was cheaper, but not spectacularly so. Mixed with very cheap Kariba South power, and with the dam wall basically paid for that was cheap, it was manageable. But refurbishing those stations would be costly with modest gain. However the UDI authorities had started building a proper large thermal in 1973 at Hwange. Sanctions enforcement stopped work in 1975 but independent Zimbabwe’s new Zesa inherited a lot of work, including most of the civil works, plus the plans for mining the extra coal very nearby so it could be delivered by conveyor with almost zero transport cost.

New consultants were brought in, they recommended continuing with now upgraded technology and so work started in 1983. By 1986 the four 120MW units of the first phase were feeding the grid and two years later the two 220MW generators of the second phase were on line. Theoretically Hwange was rated at 920MW but could not generate much over 800MW because the consultants missed climate inadequacies of the cooling system, but still that meant Hwange had no excuse not to pull out a boiler-turbine-generator set at a time for maintenance since it made no difference.

Meanwhile everyone recognised that if Zimbabwe was to keep developing properly, more stations would have to be brought into line at regular intervals. Four schemes were proposed: Kariba South Extension, Hwange Extension, Sengwa Thermal (in two phases) and Mupata Gorge Dam. A powerful side issue saw Mupata being dumped on environmental grounds but replaced with Batoka Gorge Dam, so the mix of options was the same.

The intense argument then started. Kariba South Extension was the cheapest option since the dam wall was already there and there were no fuel costs. This was pressed hard by the overseas consultants who said there was enough water flowing into the dam. The Zimbabwean energy experts said this was not so. Long-term records showed that the consultants’  use of a decade of very good seasons was chancing it and that the long-term pattern showed otherwise. Although records had not been kept at Kariba for that long, they had been kept at Victoria Falls and as almost all Lake Kariba’s water comes from first eastern Angola and then western Zambia, the records at the Falls are a close approximation of how the Zambezi flows into Lake Kariba.

The Zimbabwean engineers noted that Kariba South Extension would not add any energy to the grid, although it would allow that energy to be varied, with the bigger station going flat at peak periods but cut back sharply at other times so the same daily water ration was used as before. And they were worried about those drought dips in the graphs and the wisdom of putting too many eggs in the Kariba basket. But in any case they saw the first priority was more energy, rather than more peak power.

They wanted, as a matter of urgency, Hwange Extension, units 7 and 8, installed first to build up the energy supply while using the last few years of the old thermals to help cope with maximum demand for a few hours a day. Then they wanted at least the first pair of units at Sengwa coal field, putting out another 600MW and preferably all four putting out 1 200MW, before we then really had to extend Kariba South, with Kariba now being the peak power supply station, not the base station on the grid. Droughts would be a nuisance, rolling blackouts at peak periods, but nothing dramatic. They were not opposed to Kariba South Extension. They just wanted it in the right place in the sequence when it moved from potential white elephant to an essential component on the grid.

Batoka would now also make sense. This lake will be fairly small, at least by Kariba standards. So Batoka needs a pair of double-sized stations on each bank to go flat out while the river is in flood and while Lake Kariba is filling up with its two stations on reduced supply. Then at low water when Batoka is forced to cut right back the two oversized stations at Kariba go flat out, draining the lake faster than they would have been allowed before because there was more water to start with. And with at least half Zimbabwe’s power being thermal we are not going to crash in a regional drought.

As we all know, for almost 30 years, none of the four schemes was added. During the 1990s instead of generating more, Zimbabwe imported ever more, because then there was a sharp surplus in the region and people were prepared to make good prices. And then when Zesa started adding capacity it chose Kariba South Extension. Admittedly circumstances had changed. A lot of heavy industry, the sector with 24-hour processes, had been wiped out in the last days of ESAP and the hyperinflation with battered survivors smashed by dollarisation, so the gap between peak demand and 1am demand was wider. And secondly the tightening of imports meant foreign supplies were dodgy at peaks but okay at other times, so again converting Kariba South to a peak power supply was not totally daft. But Zesa was still gambling that there would be no droughts until the second expansion step, Hwange Extension, was finished. And Zesa gambled badly.

If Zesa had even kept Hwange in proper order, we would have an extra 350MW or so right now, about 50 percent more than we are getting. There are social media-type comments that a thermal station has a design life of 25 years. Original mechanical and electrical equipment might be lucky to last that long with heavy use but people replace this regularly if they are running a proper power station. Zesa does this itself at Kariba South where it is highly unlikely that any original electrical and mechanical equipment survives from 1961 and some must have been replaced more than once. But even routine maintenance was dodged so right now the station is operating at just over half its effective capacity.

And if Zesa had managed to get the solar power running then that would be another 100MW in daylight, allowing more Kariba water at night, because we would use less Kariba day water.

Zesa has a surprising record of bad management, surprising because it still retains some good engineers and technicians. Now there is a gap, because no big choices need to be made while work is in progress on Hwange Extension. The Government has the needed time for a detailed investigation into Zesa and its organisational and management weaknesses and getting these fixed. With an efficient authority the pricing formulas can then be tackled properly, on the basis that tariffs will be collected (not always true right now) and used efficiently to generate electricity with the right power stations being built in the right sequence.



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