Transmission integration project two-thirds complete

6th February 2009 By: Jacqueline Holman

Engineering and environmental consulting company PBA International has completed two-thirds of the Mmamabula-Medupi Transmission Integration project, which includes integrating the two power stations into the South African transmission network, comments director Stuart Dunsmore.

Medupi power station in Lephalale and the Mmamabula power station in Botswana are two key elements of State-owned power utility Eskom's strategy to manage the energy crisis in South Africa. Dunsmore says that as much as 90% of Mmamabula's power will be sold to South Africa and it must therefore be integrated into South Africa's network.

PBA International has carried out the environmental impact assessments (EIAs) and route planning for the power lines and associated transmission facilities for State-utility Eskom's transmission division. It is understood that additional power stations in the Waterberg coalfields area, Lephalale, are being considered for the future and a study was carried out to research whether the area can handle additional power stations.

The consultancy has been involved in the project for three years, analysing infrastructure, power lines and substations running between Lephalale, Botswana, Potchefstroom, Rustenburg and Brits. The entire project consists of six smaller projects and includes almost 3000 km of new power lines and two new 765-kV to 400-kV substations.

Dunsmore says that four projects have been completed with Records of Authorisation for each, though two are still under appeal. The remaining two projects are entering the second phase of their respective EIAs and include six 765-kV power lines that will run between the Delta substation, near Medupi, and the Epsilon substation in Potchefstroom, as well as the siting of the Epsilon substation in the Potchefstroom and Klerksdorp area.

765-kV alternating current (ac) power lines are the largest lines currently used in South Africa. Dunsmore says that Eskom is reviewing tower structures to reduce their effects on the environment while still ensuring network stability. The power utility is also considering using direct current (dc) lines, as these may be designed for greater capacities. He explains that this will, however, mean that different substations and network links will be needed to ensure stability.

The environmental effect that the power lines will have is a sensitive issue, says Dunsmore. In the Delta-Epsilon corridor the six 765-kV lines that will have to travel through the countryside. He says that in the study area, game farming and tourism focussing on the international hunting market has grown substantially in recent years. Power lines are not easily compatible with the wilderness environment and the visual effects of the lines is a particularly contentious issue.

"The great difficulty is balancing the need to confine lines into a smaller area, such as an utility corridor, or spread them out over a larger area. Finding the balance is part of the study, as the issue is also one of network stability," says Dunsmore.

He adds that if the lines are too close together, there is a greater chance that more than one might fail at once owing to an environmental event, such as a veld fire or tornado. Instability in this part of the network, which is linked directly to two power stations, could cause widespread and uncontrolled blackouts. He says the challenge will be to decide which option is the best.

Many communities would like to see the lines confined to a single corridor, though this is not the case in all areas. The environmental effects of such a large transmission project has not been done in South Africa before.

PBA International senior environmental practitioner Jean Beater adds that the large public consultation campaigns have also been a challenge. In accordance with the National Environmental Management Act, PBA International, and the public participation consultant Margen Industrial Services, have had to consult with all affected landowners along the length of the power lines and the EIA included a wide study area.

Beater says that, working with Margen, PBA International has adopted a multi-level approach to public consultation to the cover the more than 80 000 km2 study area. Keeping all interested and affected parties informed of the project progress and changes has been a big challenge, especially regarding the project's technical side. She says that conveying this information to the public, when there is a fair amount of opposition to it, is also a challenge.

PBA International environmental director Tsepo Lepono says that a challenge at the Epsilon substation in Potchefstroom was finding a suitable location, as the area's crop land farmers are unwilling to have a substation on their land. This is further complicated by the presence of large areas of dolomite in the area.

"It is an ongoing process and hopefully the need for power and to protect the environment will convince the farmers to become involved and to work together with PBA International to find the right balance," says Lepono.

Dunsmore says the project has taken longer than anticipated, but the remaining two projects should be completed during 2009.

He concludes that the company is a multidisciplinary practice and services projects in the mining, energy, transport and land development sectors. Its profile in Africa is growing steadily with projects in Botswana, Cote d'Ivoire and Morocco. It also works closely with the PBA International offices in Mauritius and India to assists clients in the developing world.