The construction of Medupi Power Station is racing ahead to meet the extremely tight deadline. This power station will add critical electricity to the grid, while at the same time injecting much needed skills into the local community.
Relief for a parched land
Eskom’s new Medupi Power Station (‘Medupi’ means ‘rain that soaks parched lands’) near Lephalale in Limpopo is situated next to Eskom’s older Matimba Power Station. The large coal reserves of this area, that is situated just to the north-west of the Waterberg, was the main motivation for the older facility and now for the establishment of the mammoth Medupi Power Plant – Eskom’s new dry-cooled and coal fired power station that will eventually play a vital role in alleviating South Africa’s energy shortage.
This is the first coal-fired power station to be built in this country in 25 years and will be the world’s third biggest. At full operation, it will require about 14 million tpa of coal which will be supplied from the nearby Exxaro Grootgeluk mine. The coal will feed the six units that will have a total capacity of 4 788 MW.
When completed, Medupi will be a super-critical plant which means that it will be able to operate at higher temperatures and pressures than previous generation boilers. This implies that it will operate with greater efficiency – it will, for instance, use less water and coal which will contribute to its improved environmental performance.
Eskom’s expansion budget is R385-billion up to 2013 and by 2026 it would have grown to a trillion rand. By that year Eskom hopes to have doubled its capacity to 80 000 MW.
At the CIOB’s recent Construction Summit, Andrew Etzinger, Eskom’s general manager: business strategy and integration said that Medupi, Ingula and Kusile would be the only and last power stations that Eskom would build alone. “In the long term, from a financial point of view, it is not sustainable for Eskom to go it alone. In the medium term we have a programme running that will allow private energy producers to enter the electricity market,” said Etzinger. In the longer term, nuclear energy and sustainable energy have to form a significant part of electricity production.
The clock is ticking
As Eskom wants the first of Medupi’s six units (phase one) fully functional by the middle of 2012, time is of great importance: Medupi (and Ingula and Kusile) is seen as the core to Eskom’s immediate plans to provide enough electricity to prevent the power interruptions that plagued South Africa in 2008 from happening again. The other five units will thereafter come onto the grid in intervals of nine months which is in line with international practice.
The tight timeline of 52 months belies the scale of the project though.
The project was responsible for the largest equipment order Eskom has ever placed in its 86 year existence. It has awarded the R20-billion contract to Hitachi Power Africa to supply the boilers and R13-billion to Alstom to provide the cooling section, generators and turbines.
The greenfield nature of the site meant that Eskom first had to build the infrastructure for the entire power station – this before work could start on the first phase, which is the commissioning of Unit 6 by mid-2012. Unit 6 (and this will be replicated for units five to one) required air-cooled steam condensers, a turbine hall, a boiler house, materials-handling system, water treatment units and transformers.
Building Medupi’s backbone
A project of this scale (R125-billion) required extensive pooled expertise including Concor, Grinaker-LTA and Murray & Roberts. They formed a joint venture (JV) known as the Medupi Power Station Joint Venture (MPSJV) with Murray & Roberts as the lead contractor. This JV is set up and is run as an autonomous entity. The value of the civil engineering construction package of the project was approximately R2,9-billion at time of tender (2008).
Grinaker-LTA and Murray and Roberts (of which Concor is a wholly owned subsidiary) are the two biggest construction groups in South Africa. “I am sure price played a role in the selection of the contractors, but more important was the ability to supply the resources to execute the project,” says Graham Browne, MD of Concor Civils.
“Concor and Grinaker-LTA both have sliding capacity, so their people have been assigned by the JV to execute, inter alia, those aspects of the works,” he adds.
As it is not a consortium arrangement, the partners, who are all one third partners in the integrated JV, are involved in all aspects of the project, supplying their share of people, plant and equipment.
One of the major challenges of the civil engineering construction package, says Browne, has been to recruit, train, house, feed and effectively use a workforce drawn from the local area. “The local people have largely been unemployed since the last major construction projects of Matimba and Grootegeluk. Most of the people have never worked before, but have now acquired skills and have to play their role in completing the job quickly.”
Coenie Vermaak, MPSJV’s project director, says despite this being a challenge, it has given the JV the opportunity to create its own culture and values, something they call ‘The Medupi Way’. The JV has established a training facility where about 1 300 locals have been trained in construction skills including brickwork, formwork, concreting, steel fixing and safe working practices. This training is based on the National Qualification framework and all trainees are given a qualification that they can use afterwards.
In addition to training, the JV’s dedicated training and labour facility places a non-negotiable emphasis on safety. “In fact,” says Vermaak, “the MPSJV is investing some R180-million in safety which includes a safety officer for every 50 employees. As communication is key in safety and labour effectiveness, as system called ‘Invocoms’ (basically daily meetings) has been introduced whereby safety, quality and general information is conveyed to all employees. “This system ensures that all the team members – from the foreman to the labourer – is informed of project progress, individual targets and responsibilities,” says Vermaak.
Work on the site started in 2007 when the Eskom subsidiary, Roshcon, started with the main earthworks. The contract for the civil engineering construction was awarded in May 2008 and work commenced two months later. It involves, amongst others, all the foundations and structural concrete that is associated with the construction of a power station.
Eskom requires an operational lifetime for this project of 50 years and this has been a major feature of the design. Geotechnical conditions have necessitated extensivemass concrete pours to achieve uniformity in the foundations. To complicate matters further the design has to compensate for the variable ground conditions and the seismic loading – to cater for the latter, the reinforcing steel in the concrete is denser than the norm.
As mass pours are necessary, a major challenge for the contractors has been the management of heat hydration. Although the specified concrete designs envisage a 70/30 cement fly ash blend, a mix of 60/40 cement fly ash has been approved. As day-time temperature lead to increased heat, most pours are undertaken at night.
The turbine blocks, for instance, which have pours of up to 1300 m3 deep, have to be poured continuously without construction joints as itremains critical to have a monolithic structure..
When a pour has to be done during the day, chillers are used to drop the mix-water temperature to ensure that excessive heat is not generated during uninterrupted pours.
As the site is extremely congested, concrete is mainly placed by pump – eight pumps are utilised while 39 truck mixers ensure a continuous supply from the five batch plants at Medupi.
In addition to the logistics required to ensure the continuous supply of concrete, the operations executive, Peet Reneyke, and his teams have to cope with the 25 mobile cranes and the 12 tower cranes on site.
Work on the contract started slowly as the design and drawings were prepared for issue to the contractor. Since May 2009 the contract has been working 24/7 under an order to accelerate certain sections of the works to provide access to follow-on mechanical and structural contractors in an attempt to have the first generated power added to the grid by July 2012.
The fact that the last power station was built more than two decades ago means that the JV has to cope with rebuilding experience from first principles – the builders of those power stations are no longer in the industry.
|Organisational performance executive:
||Suzette van der Merwe
|Construction executives :
||Peet Reyneke and Mario de Carvalho