Two power generators out of action on Tongatapu, waiting for parts [1]
Friday, May 20, 2022 - 21:10. Updated on Friday, May 20, 2022 - 21:26.
By Linny Folau
Crucial generator parts are expected to arrive from Germany tomorrow, Saturday. Tonga Power Ltd. has been waiting for the parts needed to fix two electrical generators that went down, forcing some load shedding or rolling power cuts on Tongatapu at peak times since the beginning of May.
Tonga Power Ltd needs eight power generators operating in order to meet Tongatapu's electricity demands, but currently only six are running.
Acting CEO Finau Moa said this week that the parts to fix power generators no. 7 and no. 8 [G7 and G8 Mak] are coming from Germany.
"If parts arrive on 21 May, quarantine and repair works time frame to get power back to normal would be approximately three-weeks, which is second week of June," he said.
But this is highly dependent on arrival of the parts, which were earlier expected to arrive on 16 May.
Tonga Power had planned maintenance for replacement of parts in January this year, but due to COVID restrictions and supplier issues, the delivery of the parts is taking much longer than expected, he said.
The approximate Tongatapu total electricity demand varies from 10MW to 11MW.
He said the power generators no. 1-6 Caterpillar, are currently in operation, supplying a total of 8.4MW to meet total electricity consumer demands for Tongatapu.
However, the two power generators no. 7 and 8, currently down, usually supply a total of 5.56MW.
The technical problems for G7 is critical engine part failure, while G8 has an alternator burnt.
Shedding not daily
Finau said load shedding is sometimes needed to ensure diesel gensets currently online are not overloaded with the electricity consumer demand. But so far the renewable energy source has helped to offset this.
“Load shedding is required only when Battery Energy Storage System is incapable of releasing stored energy to the grid. When both are charged up, because it was charged up by available renewable generation, daily peak demand is met. And load shedding is not required.”
In addition, the load shedding plan is called upon only when required. Areas named in public announcements may or may not be turned off.
He said that the load shedding announcements were to alert the public and especially businesses operating during the hours announced, to be ready in case of a power outage, he said.
On Tongatapu the electricity demand is at its peak from 6:00pm to 10:00pm.
Renewable energy back up
Finau said, while G7 and G8 are out of service, their renewable energy sites in conjunction with the two energy storage projects, and Battery Energy Storage System are currently bridging the gap in generation capacity.
“Without the Battery Energy Storage System, demand cannot be met during peak demand hours of the evening. Because the sun doesn’t shine during evening peak time.
“Fortunately, with the two BESS systems online, renewable energy sites are keeping them charged up while sun is out and wind is available. The two energy storage projects and renewable sites are helping to keep power on to all Tongatapu electricity consumers during this critical time,” he said.
Load shedding operations began on 2 May.