The National Transmission Company South Africa (NTCSA) has hosted its inaugural Transmission Development Plan (TDP) briefing since starting commercial operations in July this year, with the 2024 TDP reporting higher required transmission capacity installations compared with the prior TDP, in line with expected generation capacity increases.

NTCSA interim CEO Segomoco Scheppers says the prior TDP projected that 53 GW of new generation capacity would be online by 2032, with nearly 39 GW of the capacity coming from renewable energy. That would have required 14 200 km of high-voltage transmission lines and 170 transformers providing 105 000 MVA of capacity.

The 2024 TDP projects that 56 GW of new generation capacity will be integrated between 2025 and 2034, which will require 14 500 km of new transmission lines, along with 210 transformers providing 113 000 MVA of capacity.

The NTCSA has earmarked R112-billion in capital over the next five years to advance the TDP.

The key changes from the last TDP are associated with new generation capacity assumptions for the country, in line with the Integrated Resource Plan 2023, as well as Eskom’s generation decommissioning strategy, connection application processes through various Department of Energy and Electricity procurement programmes, application processes for private-sector procurement programmes and information obtained through consultations with renewable-energy associations.

Project Progress

Scheppers says Eskom and the NTCSA have made notable progress in advancing transmission infrastructure development, with 61 projects currently in the execution phase. These 61 projects will unlock about 30 GW of new generation connection capacity by 2030.

Of these projects, 31 are currently under construction and will deliver 1 445 km of transmission lines and 16 900 MVA of transformer capacity. This will allow the connection of nearly 16 GW of generation capacity by 2028.

The remaining 30 projects, which are also in the execution phase, will enable 40 GW of new generation capacity by 2030. The NTCSA has also identified 47 priority projects that are being accelerated to unlock the connection of 37 GW of new generation capacity by 2033.

Notably, the number of projects in the phase before execution has increased from five in the 2022 financial year to 22 in the 2023 financial year, which shows NTCSA and Eskom’s commitment to advancing these projects towards final investment decision and construction.

Scheppers emphasises that the NTCSA itself represents a major transformation of the South African electricity industry following a lengthy unbundling process. This entity is now focused on ensuring non-discriminatory access to the grid and rolling out critical transmission infrastructure for South Africa’s energy security and future demand.

Customers and grid connection senior manager Makoanyane Theku confirms that more than 8 GW of generation capacity from independent power producers has been connected to the grid in recent years, with an additional 5.2 GW of connections currently being executed.

Transmission network capacity in the Western, Eastern and Northern Cape provinces remains severely constrained and will require substantial strengthening at local and corridor level to provide additional network capacity to integrate new generation plants to the system, he adds.

“There has been a rapid increase in the volume of grid connection applications since 2022, as well as in the required connection capacity from applicants owing to larger plant sizes.

“These increasingly complex connection studies have led to longer processing times; however, the NTCSA continues to collaborate with all stakeholders and ensure that accurate information is provided for the management of grid connections.”

Strategic grid planning adviser Jana Breedt says the NTCSA is planning for total generation capacity of 106.5 GW by 2034, taking into account the Renewable Energy Independent Power Producer Procurement Programme, the Integrated Resource Plan and Eskom’s Generation Production Plan.

System operations chief engineer Paul Davel says the increasing penetration of behind-the-meter solar rooftop generation is changing the behaviour of load in many instances and their installations have rapidly outstripped the installations on the part of contractors.

In 2021, Eskom did not calculate behind-the-meter solar rooftop PV, as it only totalled 2 GW at the time; however, there is now an estimated 6.1 GW of this resource installed, mostly in Gauteng.

The NTCSA is keeping an eye on increasing interest in private connections and the additional 9 MW of solar rooftop PV capacity that is expected to be installed by 2034.