South African power utility Eskom has successfully linked the second unit of its Koeberg nuclear power plant to the national grid after a major refit, further boosting electricity supply after years of power cuts, the company said on Tuesday.

After a bleak decade of controlled power outages, Eskom has provided uninterrupted electricity supply for the past nine months, helping to improve business confidence in Africa's most industrialised economy.

Koeberg power station, north of Cape Town, is currently the only commercial nuclear power plant in Africa and its two units contribute around 1,860 megawatts or 5% of national power supply.

"Koeberg exemplifies how nuclear power can align economic and environmental priorities to create a sustainable energy future," Dan Marokane, Eskom's chief executive officer, said in a statement.

In July, the nuclear regulator extended the 40-year operating licence of the plant's Unit 1 by a further 20 years. The regulator is expected to make a decision to extend Unit 2's licence for a similar period before the end of 2025.

South Africa is planning an additional 2,500 MW of future nuclear power. It is also considering resurrecting development of its small Pebble Bed Modular Reactor design, discontinued more than a decade ago due to a lack of funding and partners.