Its regional rival Saudi Arabia, a country built on oil and sand, has always counted the USA as an ally. But as demand for oil declines and the USA becomes more energy-independent, its interest in the Middle East will slowly wane. Elsewhere it is not oil but water that is causing turmoil. As the ‘water tower of Africa’, Ethiopia holds a crucial advantage over its neighbours, particularly Egypt. This is one of the key sites for the potential ‘water wars’ this century, but also shows the power of technology as Ethiopia uses hydroelectricity to change its fortunes.