State-owned electricity utility Eskom says all connection costs relating to 27 outstanding renewable-energy projects have been included in its latest Transmission Development Plan (TDP), which covers the ten-year period from 2018 to 2027.

The renewable-energy projects were legally procured in late 2015, but have stalled, owing to Eskom’s refusal to sign new power purchase agreements.

Steps are currently being taken to end the impasse, but government has set a price cap of 77c/kWh for all outstanding renewable-energy projects, regardless of tariffs bid, or the technology involved. Therefore, while the TDP 2018-2027 caters for the projects, it remains to be seen whether independent power producers (IPPs) will accept the proposed retrospective change to the contract terms, or mount legal challenges.

Over the next ten years, Eskom expects to invest a total of R18-billion to facilitate the integration of additional renewables and conventional IPPs, as well as a further R119-billion for network expansions and for improving grid reliability. A significant portion of this investment will be directed towards the integration of the Medupi and Kusile coal-fired power stations, which are currently under construction in Limpopo and Mpumalanga respectively. However, there are also significant grid-strengthening projects planned or in execution in most other parts of the country.

Together with refurbishment expenditure, the acquisition of land servitudes and spares, as well as the upgrade of the telecommunications systems associated with the country’s power lines the full capital expenditure (capex) associated with the latest TDP is estimated at R174.5-billion.

Speaking at the release of the plan in Johannesburg on Thursday, group executive for transmission and acting group executive for risk and sustainability Thava Govender said the plan included the addition of 6 700 km of high-voltage lines and 41 000 MVA of transformation capacity over the coming ten years.

He also reported that 61 renewable-energy IPP projects had been connected to the grid, with nine more projects in execution. The connected IPP projects had a combined capacity of 3 520 MW, while Eskom had invested R2.4-billion to connect the projects.

Infrastructure planning support manager Makoanyane Theku indicated that the TDP included provision for all 8 269 MW of potential capacity associated with Ministerial determinations published to facilitate the procurement of IPP capacity since 2010, including the renewable energy projects, the diesel peakers, as well as coal and gas projects.

However, he said that most of the available grid capacity would be exhausted once the renewable-energy projects procured during the fourth bid window of the Renewable Energy Independent Power Producer Programme (REIPPPP) had been integrated. It would be important, therefore, to direct future IPP projects towards areas where network capacity is available.

Govender indicated that the 765 kV line that had been strengthened in the Western Cape would be able to facilitate the evacuation of any potential additional nuclear capacity that might be added alongside the Koeberg nuclear power station, with the Department of Environmental Affairs (DEA) having granted permission to proceed with the nuclear installation at Duynefontein.

Transmission grid planning manager Leslie Naidoo stressed that the TDP was based on demand and generation assumptions that might not materialise in reality. Neverthless, it offered visibility of some of the major transmission projects that were either in execution, or under consideration.

Naidoo said the main risks to the TDP arose from Eskom’s current liquidity problems and the ongoing difficulties associated with servitude acquisition. However, there was also a concern that future IPP projects could result in higher-than-expected expenditure, owing to the fact that there would be grid capacity constraints once the projects associated with the fourth bid window of the REIPPPP had been connected.

He added that, while the capex and project profile for the first three years of the TDP period was relatively certain, the level of uncertainty grew for the outer years.

More certain, however, was the way South Africa’s transmission system was set to evolve over the coming decades.

In fact, strategic grid planning senior manager Ronald Marais said that regardless of whether renewable-energy or nuclear capacity was added, the traditional directional flow from north to south would, in time, be reversed.

He said Eskom had prepared for this change in the spatial characteristic of the country’s generation footprint by identifying the future transmission corridors required to ensure that the electricity could be transported from the generation sources in the south to load centres across the country.

It has also made progress, in partnership with the DEA, in preparing strategic environmental impact assessments for the corridors to enable faster grid development in future.