How big is South Africa's transmission network?

OverWatts maps 33,200 km of transmission line in South Africa, across 1,317 segments, plus 84 substations. This is mapped length from OpenStreetMap, not an operator-reported total — where OSM is incomplete the figure is a floor, never a ceiling.

What voltage is South Africa's grid?

Most of the mapped network is extra-high voltage (380–764 kV): 22,000 km of 33,200 km. The highest voltage tagged anywhere in the country is 765 kV.

How complete is the grid map for South Africa?

Moderate — 27.3 km of mapped line per 1,000 km² of land, ahead of 68% of the 153 countries with any mapped grid. Coverage grades how completely OpenStreetMap has drawn the network, not how much network exists; large, sparsely-populated countries score low for geographic reasons alone.

Who operates the grid in South Africa?

Eskom, Ethekwini Electricity, Eskom / Ethekwini Electricity and 2 others are tagged as operators on mapped segments. Operator tags are present on 45% of South Africa's segments, so this ranks who is *recorded*, not market share.

What interconnectors connect South Africa to its neighbours?

6,236 MW of cross-border transfer capacity to Mozambique, Swaziland, Botswana, Namibia, Lesotho, Zimbabwe, plus 300 MW planned. Capacities are from the Global Transmission Database (v1.0, 2023).

South Africa · electricity network

South Africa power grid

OverWatts maps 33,200 km of South Africa's electricity transmission network across 1,317 line segments and 84 substations, the 10th most-mapped grid of 153 countries. Its backbone is extra-high voltage (380–764 kV), carrying 22,000 km — 66% of the mapped length, with the highest tagged voltage at 765 kV. That works out to 27.3 km per 1,000 km² of land — moderate OpenStreetMap coverage, ahead of 68% of mapped countries. It is connected to 6 neighbouring grids by 6,236 MW of existing cross-border transfer capacity, with a further 300 MW planned.

Open the grid lens →South Africa profile →

33,200 km

Mapped transmission line

Substations

#10

of 153 mapped grids

6.2 GW

cross-border · 6 neighbours

765 kV

Highest voltage

OpenStreetMap coverage

Moderate27.3 km / 1,000 km²ahead of 68% of 153 mapped countries

This grades how completely OpenStreetMap has drawn South Africa's network — not how much network exists. Large, sparsely-populated countries score low for geographic reasons alone, and every kilometre here is mapped length, so the totals are a floor rather than an operator-reported figure. 8% of segments carry a real line name and 45% an operator tag.

Mapped line length by voltage

≥765 kV2,726 km 8%
380–764 kV22,000 km 66%
220–379 kV8,441 km 25%

1,317 segments · a segment is credited to the country containing its midpoint, so a border-crossing line counts once, on one side.

Cross-border links from South Africa

Mozambique3.9 GW
Swaziland1.2 GW
Botswana615 MW
Namibia350 MW
Lesotho230 MW
Zimbabwe15 MW
Zimbabwe300 MW · planned

6.2 GW existing · 300 MW planned · capacities from the Global Transmission Database v0.1 (CC BY 4.0), existing as of 2023

On the interactive map

Open the interactive map →

Load against the network

59.7 GW

Operating generation

Data centres mapped

395

km of line per substation

27.3

km per 1,000 km²

Where there is room to connect a new load depends on published hosting capacity, which most operators release only as their own map. OverWatts does not yet ingest those feeds, so these are the density measures the open data supports — generation and mapped demand against mapped network — not a headroom figure.

Operators tagged on South Africa's network

Eskom588 99%
Ethekwini Electricity3 1%
Eskom / Ethekwini Electricity1 0%
National Transmission Company South Africa1 0%
National Transmission Company South Africa SOC Ltd1 0%

Segment counts from OSM `operator` tags, merged across spellings. Present on 45% of segments — this ranks who is recorded, not market share.

How South Africa compares · mapped grid by country

1. People's Republic of China624,300 km
8. Iran37,700 km
9. France34,500 km
10. South Africa33,200 km
11. Kazakhstan31,900 km
12. Spain29,800 km

Frequently asked

How big is South Africa's transmission network?: OverWatts maps 33,200 km of transmission line in South Africa, across 1,317 segments, plus 84 substations. This is mapped length from OpenStreetMap, not an operator-reported total — where OSM is incomplete the figure is a floor, never a ceiling.
What voltage is South Africa's grid?: Most of the mapped network is extra-high voltage (380–764 kV): 22,000 km of 33,200 km. The highest voltage tagged anywhere in the country is 765 kV.
How complete is the grid map for South Africa?: Moderate — 27.3 km of mapped line per 1,000 km² of land, ahead of 68% of the 153 countries with any mapped grid. Coverage grades how completely OpenStreetMap has drawn the network, not how much network exists; large, sparsely-populated countries score low for geographic reasons alone.
Who operates the grid in South Africa?: Eskom, Ethekwini Electricity, Eskom / Ethekwini Electricity and 2 others are tagged as operators on mapped segments. Operator tags are present on 45% of South Africa's segments, so this ranks who is *recorded*, not market share.
What interconnectors connect South Africa to its neighbours?: 6,236 MW of cross-border transfer capacity to Mozambique, Swaziland, Botswana, Namibia, Lesotho, Zimbabwe, plus 300 MW planned. Capacities are from the Global Transmission Database (v1.0, 2023).

Elsewhere in South Africa

Transmission lines Substations Power plants Data centres

Network geometry: OpenStreetMap (ODbL) © OpenStreetMap contributors, ingested and measured by OverWatts · derived 2026-07-26. Counts every mapped line of 220 kV and above; the map layer draws the ≥380 kV backbone only, so it shows less than is measured here.