A draft scoping report reveals that planning for the 80km Middelburg to Marble Hall power line began in 2007, despite Eskom denying involvement.
A lengthy draft scoping report outlining the impact of the project was sent to the Observer by a contact in Australia.

Project history

Nemai Consulting was appointed by Eskom in 2009 to undertake an environmental impact study.
“The document serves as the Draft Scoping Report for the proposed Emkhiweni Substation and 400kV Line from Emkhiweni Substation to Silimela,” the report states. “The proposed activity entails the construction of a 400kV power line from the Middelburg area in the south to the Marble Hall/Wolwekraal area in the north. The construction includes the Rockdale B Substation (now referred to as the Emkhiweni Substation), with two 500MVA 400/132kV transformers; and the construction of the Rockdale B to Wolwekraal 400kV line (now referred to as the Emkhiweni Substation to Silimela 400kV line).”
The projects were authorised in May 2011 (Emkhiweni Substation) and July 2011 (Emkhiweni-Silimela 400kV line).

According to the report, Eskom decided to proceed with the construction of the approximately 80km Emkhiweni-Silimela 400kV line, but the previous record of decision has lapsed.
“Therefore, Nemai Consulting is undertaking a new application for environmental authorisation as part of the 2014 EIA Regulations, as amended on April 7, 2017,” the report adds.

Network capacity issues

Nemai Consulting is an independent environmental, social development and occupational health and safety consultancy founded in December 1999.
The company is directed by a team of experienced environmental engineers, scientists, ecologists, sociologists, economists and analysts.

According to the report, lines in the study area are heavily loaded.

“If maintenance is required or there is a fault on the line, the remaining lines may exceed their thermal limits; as a result, load-shedding would become necessary,” the report notes. “The transfer capacity is insufficient, and an existing substation called Rockdale reached its firm capacity in 2007. The distribution network supplied by the Vulcan substations is passing through a burning ground, and the network is failing; therefore, these lines need to be diverted to other supply sources.”

The report states that the distribution network in the Marble Hall area is experiencing low-voltage problems, and the proposed Steelpoort (Tubatse) Pumped Storage Scheme requires transmission network strengthening.

To combat these issues, several phased projects have been authorised, including:

• Mokopane to Wolwekraal 400kV power line and associated secondary infrastructure
• Steelpoort to Wolwekraal 400kV power line and associated secondary infrastructure
• Wolwekraal substation and associated secondary infrastructure

Once implemented, these projects aim to improve network security, create capacity for future load increases and increase revenue.

Substation overload

Rockdale is an existing substation located to the southwest of Middelburg near the N11. The transmission lines that feed into it are the two Arnot-Rockdale 275kV lines.

“The firm capacity at the Rockdale substation is 500MVA and was exceeded in 2007. The new loads at the substation cannot be accommodated without violating the loading conditions of the transformers, which are 45 years old,” the report states. “The existing Rockdale substation also does not have the correct busbar arrangement. If a single transformer is lost, load-shedding would be necessary. If a transformer needs to be maintained, then this would also result in load-shedding. Additional power demands are expected for the Rockdale substation; however, due to the abovementioned problems, these cannot be accommodated.”

The proposed solution is the construction of a new substation near the existing Rockdale substation, to be known as Emkhiweni, designed to:

• De-load the Rockdale and Vulcan substations
• Create capacity at existing substations
• Cater for new loads
• Improve reliability in the Middelburg area

Environmental impact

Hundreds of pylons will be erected from Middelburg to Marble Hall to support the power line.

Piles of steel stretch along roads for kilometres to the north.

The width of the power line servitude upon completion will be 55m. In addition to specialist studies, a walk-down survey of the previously authorised route was conducted to ensure final pylon placement has a minimal impact.

According to the scoping report, Eskom proposed to undertake the Highveld North West Lowveld Strengthening Scheme project to alleviate problems and strengthen the network.

“The proposed Emkhiweni Substation to Silimela 400kV powerline forms part of the Highveld North West Lowveld Strengthening Scheme, and therefore forms a critical part in the strengthening of the network,” the report states. “Without the Emkhiweni Substation to Silimela powerline, the network cannot be strengthened, and electricity supply problems in the affected areas will remain and will potentially worsen over time as electricity demands increase.”

The main road in the study area is the N11, which runs in a north-south direction to the west of the proposed line.
The distance between pylons depends on terrain, with a standard servitude width of 55m (27.5m on either side of the power line).

“The impact the power line would have on the proposed route varies along its length. In places like Middelburg and Marble Hall, at the line’s start and end points, the lines would have an impact on the people within the town, as they would be exposed to the line daily,” the report says. “Along the routes, fewer people would be exposed to the line; however, the area is scenic in places, and the lines would therefore have an impact on the scenic quality of the area.”

The report notes that pre-construction and construction activities will negatively impact aesthetics due to soil exposure during site clearing and materials laydown areas.

Eskom denied involvement in the power line project on August 27, after replying to an enquiry from the Middelburg Observer.

“Our sincere apologies for the delay in sending you a response. Eskom can confirm that it does not have a project at Duvha Power Station or in the surrounding areas that corresponds with the activities described in your enquiry,” Eskom stated.

Erecting a heavy-duty national grid pylon costs between R3m and R4m.

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