Power generation company Hitachi Power Africa (HPA), a subsidiary of the Germany-based Hitachi Power Europe, which will be exhibiting at Power-Gen Africa 2014, announced in November that it had completed 98% of its scope of work on Unit 6 of the Medupi power station and was in a position to support State-owned utility Eskom’s revised commissioning programme.

Medupi is located on an 883 ha site in Lephalale, Limpopo. It will be a dry-cooled, coal-fired, baseload power-generating plant, comprising six 794 MW units, with a 4 764 MW installed capacity – the biggest of its kind using dry cooling in the world.

The planned operational life of the station is 50 years.

The power station will use high-tech supercritical boilers, which will operate at higher temperatures and pressures than the older boilers, thereby providing greater efficiency.

It is the first baseload coal-fired station to be built in South Africa in more than 20 years and its delivery on schedule is viewed as critical.

The project will form part of the utility’s integrated strategic electricity plan and is designed to be flue-gas-desulphurisation- ready, which means sulphur is removed from the plant’s emissions. The estimated cost of the project is R105-billion.

The next milestone in respect of the Unit six boiler is the execution of the hydro test in March, which HPA is on schedule to meet.

“HPA has full control of the areas for which it is responsible, and is supervising and managing all remaining work. Rectification of the weld defects noted earlier in the year is now nearly finished,” says HPA CEO Tom Brown.

HPA continues to manage its subcontractors, ensuring that all parties meet their obligations and do not compromise the given timeframe, says Brown, adding that HPA is clear that its scope is not affecting the timeline revised by the client and so not causing any delay to the project.

Using the given timeframe, HPA is in the process of improving the Unit 6 boiler in two ways: namely, the modification of reheater elements, which will be realigned at the request of the client, and the replacement of up to four separators.

Brown explains: “HPA identified some weaknesses in a very few welds during regular quality checks. Each boiler at Medupi contains four separators, and based on this number, the amount of work is of a manageable size. In terms of cost, HPA is in discussions with the local subcontractor. [Nevertheless], the replacement of the four separators will not increase the overall cost of the Medupi project.

This will be the first boiler of this type manufactured in South Africa in 25 years and these issues are all part of the learning curve involved in re-establishing the skills base in South Africa,” concludes Brown.