Surrounded by the white-clad students of her all-girls academy, Oprah Winfrey is glowing with pride.

Stretching some 7,000 kilometers along the West African coastline, a submarine fiber-optic cable emerges off the coast of Nigeria to help bridge the digital divide in the continent.

It might be one of the world's worst polluting energy sources, but coal has allowed South Africa to become the continent's largest economy, according to the chief executive of the country's power utility company Eskom.