China’s Three Gorges Dam, costing $25 billion, is acknowledged as the world’s largest dam. Actually, it is the Itaipu Dam across the Parana River between Brazil and Paraguay. Constructed during the period 1975-1984, the dam is 196 meter high and 7.6 km long. In comparison, the Three Gorges Dam is 185 meter high and 2.3 km long.

Likewise, the world’s largest hydropower system is not the Three Gorges, as generally perceived. In terms of energy output, it is the Itaipu hydropower station, generating 103.5 billion kWh electricity annually, whereas the Three Gorges power station is expected to generate 84.7 billion kWh at full capacity, on its completion by end 2008/early 2009.

The Itaipu power station, having a unique feature of housing its all 20 turbo-generating sets of 14,000 MW cumulative capacity in a single building, has been declared as one of the Seven Wonders of the Modern World by the American Society of Civil Engineers.

It is worth mentioning that the Three Gorges power station would have, on completion, an installed capacity of 22,500 MW---much higher than the Itaipu---but will be capable of generating electricity less than the Itaipu power station due to comparatively lower annual load factor.

Interestingly, Hydro-Quebec of Canada is the world’s largest hydropower generating company, with total installed capacity of 31,512 MW that is almost 40 per cent of total power generation capacity of Canada.

Pakistan has the potential to generate additional about 40,000 MW hydroelectric power generation. Sadly, nothing much, in concrete terms, is being done to tap the potential optimally.

Hussain Siddiqui,

Islamabad