BASIC ASSESSMENT REPORT FOR THE PROPOSED NTCSA SOUTHERN GRID STRENGTHENING 2X GAMMA-GRASSRIDGE 765KV POWERLINES IN THE EASTERN, NORTHERN, AND WESTERN CAPE PROVINCES

There is an upward trend in the generation requirements in the Eastern Cape province, predominantly renewable energy generation, i.e., wind. There is also interest in gas-to-power generation in the Eastern Cape, Coega Industrial Development Zone (IDZ). Subsequently, this increased demand has resulted in an equally high demand for connection requirements for wind generation from Jeffrey’s Bay, extending towards the Port Elizabeth (Qgebera) power pool, between Grassridge, south of Poseidon and north of Poseidon towards Hydra substation near Middleburg. Therefore, the National Transmission Company South Africa Limited SOC Ltd (hereafter referred to as NTCSA) proposes developing ±360km of 2x-765 kV powerlines from the Gamma Substation in the Northern Cape to the Grassridge Substation in the Eastern Cape. The proposed development also entails extending the substation yard at the Grassridge substation to accommodate the 2 x 765 kV feeder bays and 2 x 765/400 kV transformer bays. The proposed project was approved under EA Ref 12/12/20/873 on 19 November 2007.
The project entails the following:

Gamma Substation

Extend the 765 kV busbars at Gamma substation to accommodate two additional 765 kV feeder bays;
Equip a 2 x 765 kV feeder bay at Gamma substation for the line to Grassridge substation;
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Install 2 x 400 MVar line reactor at Gamma substation for the new 2 x 765kV lines to Grassridge substation; and
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Install and commission all associated secondary and primary plants.
Grassridge Substation
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Extend the substation yard at Grassridge substation. Establish and equip 2x 765 kV feeder bays at Grassridge substation for the 2 x 765kV lines to Gamma substation;
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Establish and equip 2 x 765 kV transformer bays at Grassridge substation;
Establish and equip 2 x 400 kV transformer bays at Grassridge substation;
Install 2 x 2000 MVA 765/400 kV transformers at Grassridge;
Install 3x400MVAr Busbar Reactors and 2x 400MVAr Line reactor; and
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Install and commission all associated secondary and primary plants.
Gamma-Grassridge 765 kV Line
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Construction of 2 x ±360KM 765kV Transmission lines from Gamma to Grassridge substation; and
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Ensure alignment with future network developments comprising the EC-KZN 765kV link.
Draft BAR: Gamma-Grassridge 2X-765kV Powerline and associated infrastructure
NTCSA SOC Ltd March 2025 iv
The Distribution Scope entails the following:
Dismantle the existing +/- 2000m Grassridge – Nooitgedacht 132kV line built on wooden poles with a Wolf conductor and steel earth wire. The breakdown shall start from structure GR-NT-11 up to the Grassridge substation, including the closing span.
Dismantle the existing +/- 2000m Grassridge – Olifantskop 132kV line built on steel lattice towers with Kingbird conductor and OPGW. The breakdown shall start from structure GR - OLI - 009 to the Grassridge substation, including the closing span.
Build a new +/- 3000m Grassridge – Olifantskop 132kV line on steel lattice towers with Kingbird conductor and OPGW.
Build a new +/- 3000m of Grassridge – Nooitgedacht 132kV line on steel technology with Kingbird conductor and OPGW.
Associated Infrastructure:
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The existing access road to the towers will be widened by approximately 6m, and additional access roads will be required
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Build a new Telecoms site with two Prefabricated 6x3 m equipment containers to house the regeneration station with a security fence (specification 240-89498731 Container specification).
Trench an underground Fibre Optic Pipe to structure 1 Gam/Grass 568.
Four 7-meter concrete plinths.
Build an 11 KV line from the closest rural supply point.
The proposed Strategic Infrastructure Project (SIP) aims to strengthen the electricity transmission network across the Eastern, Northern, and Western Cape Provinces. This powerline is designed to facilitate efficient and reliable transfer of electricity between substations, thereby supporting economic growth, enhancing energy security, and meeting the rising renewable generation in these regions. The project is important in providing a reliable transmission network to meet customer needs, support government initiatives, and uplift communities.
Under the National Environmental Management Act, 1998 (Act 107 of 1998) (as amended) (NEMA) and the December 2014 EIA Regulations GN.982 and GN.983 as amended, the proposed 2x 765kV powerline triggers activities that require NTCSA to obtain an Environmental Authorisation (EA) through a Basic Assessment (BA) process from the National Department of Environment Forestry and Fisheries (DFFE) before the proposed development commences. This is an application for Environmental Authorisation for listed activities as contained in Government Notice Regulations (GN R), GN 983, GN 984 and GNR 985.
Province(s): Eastern Cape, Northern Cape, Western Cape