Questions hang over Kapichira power outage

Supposedly mistimed repairs of floodgates at Kapichira Power Station have brought Electricity Generation Company (Egenco) into question for the loss of one third of the country’s power supply.

Three spillway gates failed to open the way for the floods caused by Tropical Storm Ana.

Now energy engineers ask whether the power producer took the necessary precautions in time to save the 132 megawatt (MW) hydropower plant opened in 2000 and upgraded in 2014.

However, Egenco senior public relations officer Moses Gwaza said in a response vetted by chief executive officer William Liabunya that the sticky gates had “very little if anything” to do with the extensive damage of Kapichira Dam, now buried in mud and debris.

Power tripped in many parts of the country on January 23 when floods choked four power dynamos at Kapichira.

The turbines spin no more since sudden surges in the Shire River ripped a dyke that diverts the country’s largest river to the powerhouse and a fuse plug—a soft rock dam wall designed to crumble when such floods kick in.

Stuck at work

Last Saturday, the extensive devastation and siltation forced Escom director Overtone Mandalasi to ask Egenco staff if the gates that eject floodwater were functioning when the Shire swelled.

However, Egenco engineers told Escom board members that when tragedy struck, two gates were stuck under maintenance and another snapped.

One of them detailed the dramatic desperate efforts to open the spillway: “The first gate opened and the second too, but the third did not open because it was under repair. The fourth didn’t open too. Even the fifth, was stuck in mud that accumulated in the intake.”

This brings under scrutiny the power plant’s capacity to flash out the debris-infested floodwater that halted the turbines.

And Mandalasi—whose corporation owned Kapichira and other power generation sites before handing them over to its offshoot, Egenco—rebuked the power producers for repairing the gates just when flooding was bound to happen.

“Why didn’t you conduct the repairs during the dry season,” he asked. “It’s unheard of, so the free advice to you is never, never schedule such repairs in the rainy season. You should have repaired the spillway gates in the dry season so that the floods can find them in good shape.”

For the bad timing to repair the gates, Egenco will now require K18 billion to restore power generation and end blackouts—a task that will take at least six months.

The collapse of some 180-metre dam wall left the active reservoir that flows into the turbines filled with mud as the Shire River reverted to its natural course. This has left the intake to the powerhouse dry.

“Water rose until the dyke was submerged together with the fuse plug, which did its work. Then water levels suddenly dropped and started rising again. We suspect that’s when the fuse plug and the wall of the training dam was washed away,” said one engineer at the site.

Unstoppable damage

However, Gwaza said the damage was unstoppable even if all the gates and the falling dam were wide open.

He stated that the floodgate repairs announced to happen two weekends before Tropical Storm Ana arrived from Madagascar could not happen in the dry season because Egenco had not received modified spares from South Africa. 

He said the delayed imports included wire ropes redesigned by local engineers and sent to manufacturers. They only arrived “towards the end of the year”, according to Gwaza.

He said the floods “left devastating impacts not only for Egenco but also the whole nation”.

Gwaza said: “The repair works were aimed at improving performance and safety of Kapichira intake civil structures. They involved replacement of worn out wire ropes for operation of the spillway gates for the power reservoir.

“This is a clear sign that we took necessary steps to reduce the power shocks caused by the floods.”

The massive siltation of Kapichira Dam has disempowered the national grid that serves about 12 percent of the country’s population, according to the 2018 Population and Housing Census.

To blame or not?

An electrical engineer with experience in power generation said: “Preventive maintenance could have been done before the rainy season, but corrective repairs on emerging problems can be done anytime.

“However, if they delayed either corrective or preventive maintenance, then they could have contributed to the cause and severity of the damage.”

However, a strongly-worded internal memorandum signed by Liabunya has gagged Egenco insiders on the Kapichira tragedy.

It warns certain unpatriotic individuals against circulating confidential company information amid “the current disaster that has befallen the company”.

Although Liabunya’s letter refers to “the current disaster,” Gwaza said “it had nothing to do with Tropical Storm Ana” or “anything to hide”, but an internal matter of good governance and prevention of chaos.