Opportunities in the refurbishment of transmission infrastructure

In addition to using EPC companies to build new transmission infrastructure, Eskom is also planning a huge transmission refurbishment drive.

As Atha Scott, Eskom's senior manager of asset investment planning for transmission, put it, the utility needs to balance expansion and refurbishment to ensure the sustainability of the entire network.

"It is important to ensure that the current network can continue to supply and be reliable, and we have more than 33,247 circuit kilometres of high voltage lines and 171 substations in total," explained Scott at an Eskom EPC Forum meeting.

Refurbishment of transmission infrastructure removes risk from the network by replacing assets in poor condition and mitigating network constraints. Eskom is comprised of various business categories that are complete for capital allocation. While expanding the network to address the integration of variable renewable energy sources takes up the bulk of the capex, strengthening the grid comes in second.

Eskom has more than 400 transmission infrastructure projects currently in execution and more than 1,000 in development over the next ten to 15 years.

In terms of outright refurbishment, Eskom has more than 400 transmission infrastructure projects currently in execution and more than 1,000 in development over the next ten to 15 years. These are across the following categories, which are not exhaustive but cover the prominent areas:

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Scott pointed out that addressing national security projects is one of their biggest current challenges.

"We do have specific focus areas, like we need to replace our target transformers – where we have transformers where conditions have deteriorated, we need to replace those."

She reminded that replacing the Adlash fibre wrap with optical ground wire is outage dependent. "So, one of the bigger challenges is to arrange the outages to replace the equipment," she explained.

The refurbishment plan starts with ten high-cost items at the top of all categories, which would require replacing 13,000 assets alone.

The team is following a phased approach as the market needs to be given an opportunity to ramp up either production of or import of replacement items.

"There's quite a lot of work that needs to be done. Just looking at Gauteng and KwaZulu-Natal, there are 154 projects across different phases of delivery. Throughout the country, there are [refurbishment of] different substations on the go."

On the transformer side, Scott identified a plan to replace an estimated 82 transformers over the next ten years. They have identified a further eight high-risk transformer projects to develop over the next three years to execute the replacement within the next five years.

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Scott pointed to 124 refurbishment projects which EPC companies would be interested in, which include line projects dealing with foundation repair, insulation replacement and tower refurbishment. "It might be a more difficult environment to enter due to outage challenges, and the commissioning of assets on existing networks," she cautioned.

Once they have removed transformers, Eskom has a process to assess what the problems were and whether the transformers can be repurposed or need to be scrapped. "It's quite important and high-cost equipment, so we need to ensure we do the right assessment," explained Scott.

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While Eskom is on a huge drive to embrace locally manufactured equipment, the utility is also looking at international suppliers to make it easier to package the transmission refurbishment contracts by geographic location.

"Like, in a province, so when we replace circuit breakers, we would target a specific province. That's addressed as individual projects, but packages together as a bigger programme," explained Scott.

Eskom is currently working out how to optimise the larger contracts to make them attractive to EPC companies. They are also considering, when starting the protection replacement, the viability of building a new control room and doing the replacement of protection equipment separately and integrating the new systems when work is completed. "But that is just one option," said Scott. ESI

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