A “substantial” portion of South Africa’s existing electricity transmission system is not currently compliant with the regulatory requirement that the system remain operable even when key equipment on the network fails, Eskom Transmission has acknowledged.
But infrastructure investment planning manager Leslie Naidoo reports that its current investment programme, as outlined in the recently published Transmission Development Plan (TDP) 2013-2022, is designed to ensure that 80% of the expanding network meets that stipulation by 2017.
Speaking at a recent South African National Energy Association lecture, he said the requirement, also known as ‘N minus one’ (N-1) is a National Energy Regulator of South Africa Grid Code stipulation to which Eskom was committed to comply.
The focus over the next five to six years was, therefore, not only to position the network for growth, but also to catch up “yesterday’s problems”.
Dealing with the prevailing N-1 deficit would require substantial investments, informed by sound planning and an improved visibility of the new capacity nodes and load centres.
The division was planning to invest about R149-billion over the coming ten years on various projects designed to bolster network reliability and integrate new generation capacity into the power grid – an investment forecast outlined in the TDP 2013–2022, released in October.
About R121-billion would be required for projects designed to improve the reliability of the network, another R25-billion for programmes aimed at integrating new power generation projects, such as the Medupi, Kusile and private renewable-energy projects, and about R3-billion for customer-related projects.
Under the current TDP, which was the fourth to be published by Eskom Transmission, the division anticipated adding about 12 700 km of new transmission lines to the existing 28 500 km network by 2022.
More than 8 600 km of that would be in the form of new 400 kV capacity. The balance comprised 3 700 km of 765 kV lines and 402 km of 275 kV lines.
Also planned was the introduction of an additional 83 500 MVA of transformer capacity, 2 600 megavolt-ampere reactive (MVAr) of capacitive support and 9 200 MVAr of reactors.
Besides the R149-billion expected to be required for upgrades and expansions, Eskom also expected to spend R12.2-billion on refurbishment projects and another R2.3-billion on capital spares. It was budgeting a further R4.7-billion for the acquisition of servitudes and the completion of environmental-impact assessments.
Naidoo said that, while South Africa had sufficient capacity to build the transmission infrastructure, Eskom was finding it difficult to transition from planning to implementation, owing partly to the time it was taking to secure servitudes.
“For instance, the Cape Corridor was already supposed to be completed and it is now only scheduled for completion in 2014 due to the fact that the servitudes have taken so long to secure.”
He said its Grid Connection Capacity Assessment showed that Eskom had capacity to connect 4.6 GW of renewable-energy capacity to the network. But these facilities would need to be positioned within close proximity to the existing transmission network.
The assessment would be updated in 2013 to take account of the capacity that would absorbed by projects that advanced through the first two bid windows of the Department of Energy’s renewables procurement programme.