Leanna Rathkelly/UNEP/Still Pictures

The mighty Congo river rushes through the Democratic Republic of the Congo, at one point dropping 96 metres in just 14 kilometres. A dam at its Inga Rapids already supplies electricity to Rwanda, South Africa, Zambia and Zimbabwe - but the South African energy provider Eskom thinks it could provide much, much more.

Eskom aspires to build the world's largest hydroelectricity plant to harness the potential of Inga rapids and channel it across the continent. The $50 billion Grand Inga project would generate roughly 40,000 megawatts, twice the power of China's Three Gorges dam. But rather than damming the river, Eskom would generate this huge capacity with a run-of-river plant, which would siphon off the water, channel it through turbines and then return it to the river - avoiding the environmental and social problems often caused by big dams.

The project's proposers hope to power the whole of Africa with the output and export excess energy across the Mediterranean to Italy, Jordan, Spain and beyond. Plans to link Africa's fragmented supply lines to create a cohesive transcontinental electricity grid are already under way.

Success is likely to depend on solving such problems as cross-border disputes, long-distance transmission losses, maintaining the very diverse and species-rich local environment and funding. And even if all goes well, construction work on Grand Inga is still at least a decade away.

But Eskom's leaders are optimistic. North and South are already cooperating on the project. A study by French utility company Electricité de France has indicated that the plan is viable, and financial backers, like the World Bank, and private investors are beginning to show interest. Thulani Gcabashe, Eskom's CEO, believes that 'some day soon, hundreds of millions of Africans will use electricity to light up their homes, cook their food, and literally have the power to develop their potential'.