Eskom has cunning plan to avoid future load shedding

Aug 11 2017 17:33
Matthew le Cordeur

Cape Town – Instead of decommissioning some of Eskom’s aging coal power plants, the power utility wants to keep some of them in “extended cold reserve” that can be rejuvenated in 10 years should there be any emergency short falls due to new build delays for example.

Acting executive for generation Willy Majola told Fin24 on Friday that it doesn’t make sense to permanently close some of the aging coal stations, whose units could be extended, especially in a time of crisis.

“If we send bulldozers to Hendrina Power Station instead of putting it into extended cold reserve, we might find ourselves in trouble later on,” he said.

Eskom has been temporarily switching off 13 units from eight power stations in times of power surplus, with the idea that some might be switched off for a longer period of time.

This all depends on the Department of Energy’s draft energy plan that will determine what mix of new energy build will be developed in the foreseeable future. This could be a mix of nuclear, gas, renewables and coal. It is expected to be finalised next year February.

If, for example, government decides to build a nuclear power station by 2025, then Majola believes some of the coal power stations not required due to an excess capacity of power could be put on ice and switched on if there was ever a delay in the new build programme.

“In the integrated resource plan, Eskom said excess capacity will peak at 6 500 MW in 2020 and then this will drop to 500 MW in 2025,” he said. “If you have decommissioned these stations (close down permanently), and you are late on new build, you are going to get into trouble.

“If you decommission the stations today, but demand grows and new build is late, then we will go into load shedding. Therefore, we cannot talk about decommissioning the coal stations. We should not decommission stations to ensure we don’t fall into load shedding.”

Majola said Eskom is experiencing “operational excess capacity, which is seasonal”.

As such, he said Eskom has put 13 units totalling 3 700 MW on “cold reserve”: four at Komati, two each at Kriel and Grootvlei, and one each at Camden, Majuba, Arnot, Hendrina and Tutuka. “The call up time ranges from 16 hours to five days,” he said.

Netwerk24 reported on Thursday that Grootvlei and Komati have already been placed in extended cold reserves, which means that it has been scaled down to such an extent that five days are needed before the units can be restarted.

Majola said energy regulator Nersa recently published dispatch rules, which gives Eskom the criteria of which units must be operational, based on a least-cost model. This also takes into consideration the security of the system, the technical capabilities of the units, as well as the transmission stability, he explained.

The aim, interim Eskom CEO Johnny Ddladla said recently, was for the utility to manage the surplus power generation in order to save costs.

“Things can change from day-to-day,” Majola said. “It depends on the criteria set by Nersa. We expect that as we commission more units at Medupi and Kusile, the excess is going to grow.”

“Our projections are that excess will decrease as the load grows. Then, as the excess decreases, you will need more units operational.”

Majola said that during this period of excess capacity, Eskom needs to put some units or the entire plant into extended cold reserve. Eskom previously stated that it will temporarily close the Hendrina, Grootvlei and Komati power stations over the next three to four years, to trim its surplus power and manage power generation costs optimally.

However, Majola said this five-year production plan was based on short run marginal costs. “In this case, those power stations would not be needed and this is largely influenced by coal.”

“However, if you put units in extended cold reserves you have to take into account total cost, which includes a present value analysis, as well as capex and opex costs,”  he said. “We are busy with that study. That will tell us whether it should be units or power stations that are put into extended cold reserves.”

“We know we have to put stations in extended cold reserve because the excess is there,” he said. “We need to justify which coal stations go into reserve. Cold reserve is a risk mitigation with regard to system adequacy.”

“Eskom believes the excess will decrease and we will need new load. The integrated resource plan will tell us when to expect new power and from where.”

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eskom  |  load shedding  |  coal



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