Load-shedding has become like an opera that has gone on for too long. The overture is over, the arias have been sung and the swan has died quite a few times. The audience is starting to fidget a bit.
Into this arena, I hope, will arise something I suggested some time back: pay those consumers that have standby generators to run them at times of generation shortage. This was mooted by Eskom some time back and the State-owned electricity utility stated: “Capacity payment for hours scheduled to be on standby the following day; energy payment of R1.25/kWh for energy not consumed; standby notification by 15:00 for the day ahead; minimum 30-minute notification to reduce load; one- to two-hour reduction request per scheduled day; up to 150 load reduction events per year; R3/kWh energy consumed.”
Translated, this means that: (a) Eskom, by 15:00 the day before, will notify you that you will be on standby to start your generator; (b) if the utility does not actually ask you to generate power, it will pay you R1.25/kWh that you kept on standby; (c) on the day, the utility will give you 30 minutes’ notice to start your generator; and (d) you will be asked to run your generator for one to two hours. For example, let us say that a firm called, say, New Mutual, has an installed standby generator capacity of 5 000 kW. It will be notified before 15:00 on, say, Monday, to have 5 000 kW available for two hours on Tuesday. If the genset starts and runs, it will produce 10 000 kWh, for which New Mutual will be paid R3 × 10 000, which is R30 000. If the genset is not called on to start, New Mutual will be paid R1.25 × 10 000, or R12 500.
This sounds like a no-brainer for New Mutual, but consider this: in general, 1 ℓ of diesel fuel will generate 4.5 kWh. To produce 10 000 kWh, you will need about 2 222 ℓ of diesel, which will cost about R33 000. Thus, if the standby genset starts and runs to schedule, New Mutual will lose money.
It’s not all bad news, however – there is the potential R12 500 if it does not start and run. Further, the genset will at least be run at full load from time to time, which is always a good idea for a diesel generator.
The original Eskom idea was that this would apply only to generators of 1 000 kW or more (this was in 2015). There is no reason, with fibre optics, why this should not be applied to generators as small as 250 kW. Yes, before you smart cookies out there start making noises about how to synchronise and load the genset, and what about fault levels, these days this is all covered. There are a number of very good automatic synchronising and loading devices, easily fitted.
I do think the scheme will work well. It will cost Eskom money when it buys private power but this is very much offset by the alternative, which is to run gas turbines, which use diesel fuel and are more expensive than diesel generators. There is a lower limit to the size of the generator that could be used in this scheme – certainly, small solar panels (say, 800 W) pose more dangers than benefits. One would expect that organisations that own gensets of 250 kW and above do keep them secure and in good order. One potential problem is that many organisations that have gensets are not supplied directly by Eskom but from municipalities, which would have to buy into the scheme.
But there are still enough Eskom-supplied consumers who have gensets of some magnitude. I calculate that there is at least 1 800 MW that could be supplied by participating consumers. Perhaps, watch this space.