Some say ZESA is now working on the same off-peak hours as telecoms operators and their bonus data. It’s such a funny statement to lighten up an otherwise dark situation that Zimbabwe finds itself in. Pun intended. The lights are off and they are staying off for 18 hours or more. Why is it this bad?
Demand vs Supply
Zimbabwe’s power demand sits at 2100MW and at the time I am writing this we are producing 501MW of power. Less than 25% of the national demand. Is it a case that we don’t have enough power-generating stations to meet this demand?
No. We have enough capacity, in fact, the total installed capacity for power generation in Zimbabwe is 2210MW. Enough to meet all our energy needs and have a little over as much as Munyati Power Station’s capacity to spare However, not all available power stations are operational and the operational ones are not operating at full capacity.
Of the installed capacity of 2210MW, only 1555MW of it is operational. When we say operational we are talking of power stations that are actually running and how much they can reliably produce. A figure that can be lower than the installed capacity. ZPC at the moment lists 5 power stations.
|Power Station||Installed capacity||Current output|
|Kariba South Power Station||1050MW||200MW|
|Hwange Power Station||920MW||301MW|
|Munyati Power Station||100MW||0MW|
|Bulawayo Power Station||90MW||0MW|
|Harare Power Station||50MW||0MW|
So if everything was running in the most ideal scenario we would have a net positive electricity balance meaning no load shedding plus power exports. But looking at the best-case scenario only 76% of the national demand can be fulfilled by all the power stations combined in their current state. So if in our current state, we can fulfill 76% of the national demand, why is our best effort only getting us 25% of the national demand? The best way is to look at it at the power station level.
Kariba South Power Station – 200MW/1050MW
Kariba can supply half of Zimbabwe’s power demand on its own. It’s a big power station no doubt but right now it’s only producing 200MW and that is after our Minister of Energy had some talks with the Zambezi River Authority to keep the plant running. ZPC had been ordered to shut down operations at Kariba because the lake levels are now dangerously low for power production.
The way this works is this. There is the absolute water level of the lake and the maximum depth that is available for use for electricity generation. This maximum depth is less than the full depth of the lake. So we can run out of water to make electricity without running the lake completely dry to its bed. Live water is what they call the level of water available for power generation and dead water is the remaining water below this level that cannot be accessed for electricity production.
So we are fast running out of this live water which is why power production has been greatly reduced at Kariba from the 1050MW it is capable of producing to the 200MW it is producing now.
Reducing electricity production output also manages the lake’s inflows of water vs its outflows. Water is still flowing into the lake from the Zambezi river at a certain rate. If the rate of water flowing out of the lake via power generation is managed such that it’s less than water flowing into the lake then we can still produce some power and also raise levels of water in the lake. So the Kariba situation is one we can do nothing about till the rains come hopefully in mid-January.
Hwange Power Station – 301MW/920MW
It’s the second-largest power-generating facility in the country and has been undergoing maintenance and expansions. There are 6 units currently operational and capable of producing 920MW however we are only producing less than a 3rd of that. The two biggest reasons are breakdowns and an insufficient supply of fuel (coal) to fire it up to maximum capacity.
To alleviate coal supply challenges faced by thermal power stations, cabinet approved for a long term coal supply agreement which will see coal suppliers getting long term bank financing they need to expand on their production.ZPC Power Column Q2 2022
The period under review saw Zimbabwe Power Company (ZPC) experiencing depressed generation at the thermal stations due to numerous forced outages.ZPC Power Column Q3 2022
Thermal power stations work the same way as your car. Fuel goes into an engine, gets burnt and produces energy that moves the car. In the case of Hwange Power Station the energy produced is used to turn a generator that produces electricity. The less fuel you feed it the less energy it produces and the less electricity that comes out of that.
Then when you are servicing elements of the power station, everything needs to be shut down and in such a case no power is being produced. This then becomes really confusing when ZPC also announces that it is expanding the power station and making it bigger. Unit 7 is expected to come online by the end of this year.
In August 2018, ZPC officially commenced expansion works at Hwange Power Station which will result in a third stage being added to the station with 2 x 300MW units being constructed. The expansion project will increase Hwange’s generation capacity from the current 920MW to 1520MW.ZPC – Hwange Power Station
We are failing to deliver enough coal to fully make use of the available capacity at Hwange and we think making the power station bigger will solve the problem. Not really. But there are cases to be made in favor of this move.
New power-generating units are expected to be more efficient with the fuel they receive meaning that given the same amount of fuel used by older units, the newer ones will be capable of producing more electricity. Also, a new machine will break down less than an old one, and considering the Hwange power station is almost 40 years old, (the designed lifespan of a coal-fired power station), it might be more economical to build it anew than to run maintenance on it.
However, the coal supply issue needs to be looked into otherwise the 1520MW of installed capacity is going to be another nice-looking figure on paper but doing nothing towards lessening load shedding. And these new units are most likely going to be taking over from the old units that are too soon to be too expensive to repair so we may never hear news of Hwange Power Station producing that 1520MW of capacity. The best bet is 900MW if the stars align.
Munyati, Bulawayo & Harare Power Stations – 0MW/240MW
These ones are completely switched off for probably the same reasons as those of Hwange Power Station. Coal is in short supply and they are so old that they are constantly breaking down. Munyati Power station is about 76 years old, Bulawayo Power station is about 75 years old, and Harare Power Station is 67 years old, and this is against an expected life span of 39 years for coal-fired power stations.
We are almost getting to double the expected life expectancy of these power stations and really at this point they are virtually dangerous to operate beyond the point of them being very unreliable now. Harare and Bulawayo power stations were actually derated to try and improve reliability and buy some time but they have not been operational for a while now. ZPC had issued applications to refurbish and revive these 3 plants but progress on that is nowhere to be seen.
We just have to live with the load shedding
In December 2019 or 3 years ago, we were in exactly the same electricity jam, and watching the videos I made back then it’s wild that the situation is still exactly the same. Our electricity producing capacity is the same. Right now we are producing 501MW and in 2019 we were producing 589MW. The only difference is that back then solar backup systems were not as accessible as they are today.