Shifting South Africa's coal-heavy economy to a greener structure will require at least $250bn over the next 30 years, according to a report published by the World Economic Forum.
It said about half of the total investment ($125 billion) would be needed to increase wind and solar projects as the country mothballed coal-fired plants that currently supply most of its energy needs.
South Africa is the world's 12th largest emitter of warming gases and the largest in Africa. In November, the United States, Britain, France, Germany and the European Union agreed to provide an $8.5 billion package to help South Africa speed up its transition from coal, but details and timetables are still under discussion.
"Under ambitious decarbonisation scenarios (coal burning by 2040), South Africa's transition to a low-carbon, more equitable energy system would require spending at least $250bn over the next 30 years," the authors say.