The Herald (Zimbabwe)

Cabinet opens doors to innovative power generation


THE determinat­ion by the Government, as seen in the report from Cabinet this week, to keep moving faster and harder on building up both the electrical generation capacity of Zimbabwe and on making the services more efficient, is crucial to ensure our productive sectors can produce more, and that ever more of our population can have a good life with uninterrup­ted supplies.

The Cabinet wants to see electricit­y imports end by 2025, just over two years from now, so there is some very hard work required at Zesa and all its subsidiari­es, as well as some longterm planning.

We all saw with the Hwange Thermal extension, the two 300MW Unit 7 and Unit 8 that this work cannot be instantane­ous, even when contractor and customer, that is us, are pushing as hard as they can.

While the two units are still going through their final checking routines after some months of running, they are completed and all we are seeing is some contract requiremen­ts. But fairly obviously the timing for greatly improved delivery of power, means that the next major convention­al hydro or thermal station is for medium term and longer term planning.

The report from Cabinet did, however, present quite a lot of good news.

For a start it appears that transmissi­on losses within Zimbabwe are at a very bad 20 percent, compared to around 4 percent in say China, and that gives Zesa and subsidiary ZETDC a lot of room to manoeuvre.

Getting the present loss rates down to more acceptable levels should mean at least another 200MW, with zero rise in operation costs or finding extra water at Kariba South or fixing something extra at Hwange.

Since ZETDC and Zesa can sell everything that they generate and transmit, the money from selling those 200MW should be more than enough for both replacing dodgy transmissi­on equipment and for upgrading the grid.

Transmissi­on losses are inherent in any system, but engineers have long known how to reduce them.

This is the main reason why for longer distances electricit­y is transmitte­d at ever higher voltages, to reduce the transmissi­on losses.

The high voltage is then stepped down in a sequence of transforme­rs until it comes right down to the 220 volts consumers want in factory, shop and home.

Obviously ZETDC engineers and technician­s need to study their system and see what combinatio­n of new equipment and new practice is needed, but this must not be delayed.

Even if the 20 percent loss rate has to be reduced one percent at a time, chipping off 1 percent of losses does at another 20MW plus to the supply reaching consumers and that is useful.

There is also a possibilit­y that some of the extra power is theft, users bypassing the metering systems, and that crime needs to be checked and eliminated.

The second plank is to increase generation. In many respects. There are two easier openings for this. The first is pushing faster on the repair and renovation of the older six units at Hwange Thermal, work which has already started on the 210MW Unit 6, now pushing 35-years-old and so in need of some very serious attention.

But as each unit is brought back to full output ZETDC can sell that extra power and energy, and those extra sales are what will be paying for the work. There are some small thermal stations being installed at some of the largest interior dams. None of these are large, but every extra megawatt is still usable, and generation does mean that irrigation water is being released into rivers and canals.

The dams were built for irrigation and that remains their main need, but if the water can do some double work, generate power while on its way to irrigate fields, then we can win twice.

Then we have solar, frequently spoken of at as a major saviour of Zimbabwe by eliminatin­g energy shortages quickly.

One huge advantage of solar is that a solar station is modular, built up as an array of hundreds, even thousands, or panels. But it can be earning money while it is being built and can be built in phases. Even if you install 1MW at a time, each new megawatt can be sold as it goes live.

While some solar power, and in times to come most solar power, will need to be backed by battery packs so that electricit­y can be transmitte­d, sold and used when the sun is not shining, we can also use Lake Kariba and Kariba South hydro station as a sort of battery substitute.

Although Kariba South can generate just over 1000MW, the average is set thanks to river flows at around 400MW to 600MW.

The huge extra capacity means Kariba South can handle the early morning and early evening peaks, and then cut back sharply at other times, but it also means it could cut back to just idling during the day if there were several hundred megawatts of installed solar taking the load, keeping the water in the dam for the peaks and for the night.

We may well need, as Cabinet noted, to start adding the battery farms for storing some and in the end most solar, but the raw materials are readily available in Zimbabwe to build batteries and the continual breakthrou­ghs in design mean that the costs are continuall­y falling even as miners, including the Zimbabwean miners, are able to charge more for lithium and the trace elements.

The other area where Cabinet now sees the need for serious action is with the three old small thermal stations at Harare, Bulawayo and Munyati.

The latest equipment in these three was installed in the 1950s, and by now some has already passed its 70th birthday and the rest is heading there soon. Expecting them to work is not realistic. And decommissi­oning is the only answer.

Cost accountant­s will need to work out if the stations can be re-equipped using some of the surviving civil engineerin­g, such as the cooling towers, or whether it makes more sense to just build new somewhere else.

Moving out of the mindset of preserving them is an advance. With already 38MW from private power stations reaching the grid we are seeing the start of another revolution, so the sites could even be sold.

At the same time we need to be thinking hard, and innovative­ly, about the medium longer term. Batoka Gorge has been seen as the next major hydro-scheme, but in light of climate change even this might need a rethink and a recosting of its power output if Zambezi River flows remain below historic levels.

The original thinking of a hydro dam downstream of Kariba and the Kafue confluence might be better, with modern design minimising ecological damage, especially as regular daily flows from Kariba and the two Kafue dams minimise the need for downstream storage.

The Second Republic has been noted for its innovation, and innovation in a changing climate and changing world conditions.

Sometimes plans from decades ago are seen as a solution; they may well be, such as the Matabelela­nd pipeline from Gwayi-Shangani, but at other times they just reflect the investment made in planning then and that might not be the best now.

The Government’s position outline this week, which includes checking up on the whole Zesa operation and seeing if there better and more efficient ways of running generation and distributi­on in Zimbabwe, even if that means rebundling, is also an outline that will some of our best brains to work out the gaps and details.

Here the other elements, including the most innovating thinking and the most businessli­ke calculatio­ns, need to be brought into play.

Newspapers in English

Newspapers from Zimbabwe