World’s newest and most expensive coal plant explodes after hydrogen leak

The newly completed Medupi coal plant in South Africa – one of the biggest and likely the most expensive and controversial in the world – has been severely damaged after an explosion in one of its units caused by a hydrogen leak.

The 4.8GW Medupi coal generator – the biggest “dry-cooled” coal plant in the world – was fully commissioned at the end of July after a drawn out construction process over more than a decade that some reports suggest cost more than R235 billion ($A21 billion).

On Sunday evening, little more than a week after its formal completion, the Unit 4 exploded while a generator was being purged of hydrogen. Air was allowed in, but the hydrogen was not fully purged, and an explosion resulted.

Local energy expert Chris Yelland said in an interview with eNCA that the operator, Eskom, was “busy purging the generator of hydrogen which is used as a coolant in the generator and they were purging the hydrogen in preparation for doing work on the generator when this explosion occurred.”

Yelland said the combined losses to generation capacity as a result of the incident (it also took out another unit) are equivalent to 1,440 megawatts. “That’s a significant amount of power to be taken out of service,” he said. Several employees have reportedly been stood down.

Yelland later Tweeted that there appears to have been “a deviation” from the procedure for carrying out the hydrogen purge and Eskom had suspended employees responsible for the work pending an investigation.

“The preliminary investigation indicates that while performing this activity air was introduced into the generator at a point where hydrogen was still present in the generator at sufficient quantities to create an explosive mixture, which ignited and resulted in the explosion,” Yelland wrote.

As for the damage: “The ends of the generator have been blow off, the generator is destroyed, and it will have to be replaced. This is a massive setback.”

In another interview with local media, Yelland said: “This generator is irreparable. If you follow the right procedure the probability of an accident is very very low. It could be just poor training, inexperienced, incompetence.”

The explosion occurred amid continuing controversy over Eskom’s decision to go ahead with such a massive coal generator, the huge funding support ($US3.7 billion) it received from the World Bank, and blockages in South Africa to the deployment of renewables, where many projects have been delayed.

Eskom has admitted that the scandal ridden project, originally scheduled to cost R80 billion, had blown out in costs to R135 billion, but analysts such as Yelland and others say the true costs could be nearly double that.

It has been beset by cost overruns and significant design issues that led to major delays in the project. Breakdowns of units had often contributed to the recent spate of load shedding in the country. It is expected to cost billions and take many years to repair the damaged generator.

The Medupi explosion also comes just a few months after a massive explosion took out a unit at the Callide coal generator in Queensland, leading to cascading events that caused half a million customers to lose power for several hours, and for an extended period of high prices in Queensland and NSW.