Engineering group Hitachi Power plant (HPA) reports that 98% of its scope of work on boiler Unit 6 at the Medupi power station, being built in Limpopo, has been completed. It has also confirmed that it is in a
position to meet Eskom’s revised commissioning programme, despite having to replace up to four separators.
Earlier this year, State-owned utility Eskom announced a further delay to the commissioning of the first Medupi unit to the second half of 2014, having already moved the schedule to the end of 2013 from an initial plan to synchronise the plant to the grid in 2011.
The budget for the 4 764 MW coal-fired power station was also revised upwards from R91.2-billion to R105-billion, excluding interest during construction.
The delay announcement followed an independent assessment of boiler-weld problems, as well as software failures relating to the control and instrumentation contract.
HPA COO Tom Brown reports that the programme to rectify weld defects is “nearly finished” and that the next milestone for Unit 6 will be the execution of the hydro test, which is scheduled for March 2014.
The company used a team of about 50 workers and supervisors for a period of six months to check and rectify the welds in line with Weld Procedure Qualification Record protocols.
Brown says there is sufficient time in the revised schedule to allow it to modify the reheater elements, which will be realigned at the request of the client.
In addition, it is in discussions with a subcontractor to replace up to four separators – a work package that is described as “manageable” and which Brown insists will not increase the overall cost of the project.Media liaison Yash Bridgmohan explains that the separators separate the water from the steam.
"The steam moves into the superheater and the collected water is returned to the boiler feed line. We double-checked some welds and although there is no immediate problem, the design lifespan may not be fully reached. While there is extra time available, the separators will be replaced with another set," she says, adding that the subcontractor, whose identify was not disclosed, will carry the financial burden.
“Hitachi is clear that its scope is not affecting the timeline revised by the client and so not causing any delay to the project,” Brown adds.
HPA is also increasingly confident that it should be able to commission boiler Unit 5 at Medupi straight after Unit 6 and that the first boiler at Kusile, which is being built in Mpumalanga, should be next.
Eskom told Engineering News Online that it was not prepared to comment on any of the other elements of the project that could threaten the revised schedule.
"We will give an update on the progress of the build programme at our next interim results announcement scheduled for December," the company said.
In an oral reply to a Parliamentary question posed on October 24, Public Enterprises Minister Malusi Gigaba said the Medupi management team had adopted a 24-hour, seven-day presence to oversee the performance of contractors.
“Contractors are working extended hours on a multiple-shift basis. Daily meetings are held between the Medupi site management and contractors’ site managers to resolve concerns, interface issues, integrate work areas and so on. Weekly meetings are held with the contractors’ managing directors to give immediate authorisation for construction decisions,” he said.
Gigaba added that no conditional relaxations are being offered to contractors and that all contractual remedies were being explored to ensure timeous delivery.