Sir

Your Special Report “Tide of censure for African dams” (Nature 440, 393–394; 2006) considers the social consequences of the Merowe project in Sudan, which will displace up to 50,000 people. Can projects that involve such large population transfers possibly be justified?

The principal argument in favour of the Merowe project is a pressing need for electricity in Sudan. Merowe will provide electrical power corresponding to an average load of 625 MW (see en.wikipedia.org/wiki/ Merowe_Dam).

With 50,000 displaced people for 625 MW of electricity, what I call the ‘displacement index’ for Merowe is 80 people per MW. By comparison, the smaller dam at Tignes in the French Alps, whose construction in 1953 caused agitation and rebellion, displaced 384 people, for an average load of 103 MW. The corresponding ‘displacement index’ is 3.7 — one-twentieth that of Merowe.

This discrepancy is all the more sinister when one takes into account that more than 50 years have elapsed since Tignes. In the interval, the human suffering generated by resettlement schemes has, presumably, received increased recognition and respect.

In this time, friendlier power generating alternatives have also proven their merit. It is significant that a single present-day nuclear reactor (with an average load of 960 MW) would provide more power than the Merowe dam, with the displacement of very few people, if any. Would that not be the greener solution?