LAHORE, Aug 21: The power generation capacity of Tarbela Dam can be doubled by replacing old generators, which in financial terms means a relief of Rs20 billion, chief engineer Mohammad Ramzan said on Wednesday.

He said though there has been no formal proposal in this regard, President Pervez Musharraf hinted at such an improvement plan during his inaugural speech of the Ghazi Barotha Hydel Project on Tuesday.

He said that the first and second tunnels have 10 generators of 175-megawatt capacity each. But the third tunnel, which became operational in the early-90s, has four generators of 432-MW each. Ten years down the line, technology might allow the planners to install generators with even higher capacity. But, even if no new technology advancement has been affected since then, it is, apparently, possible to replace 10 generators of first two tunnels with a combined capacity of 1,750MW with 10 new ones with 4,320MW —- an increase of 2,570MW.

Calculated in financial terms, this could bring in a relief of Rs20 billion if Ghazi Barotha Hydel Project was a yardstick. If the GHBP, with an installed capacity of 1,450-MW, could benefit the nation with Rs13 billion, the Tarbela improvement plan, with additional 2,570-MW should certainly provide a relief of Rs20 billion.

This was the only possible improvement plan, he said, that could be effected so far Tarbela was concerned. There was no big margin of dam raising as had been done with Mangla because dam design did not contain any raising possibility. But replacement of the old generators could bring in much relief.

Talking about the silting problem, he said that delta movement had been successfully checked during the past four years; it had not moved even by an inch during this time. By raising the minimum level to 1,369 feet, the delta movement, which registered an advance of 2.5 kilometre in one year, has now been completely halted. The dam managers, he said, now hoped to extend the life span of the dam by 15 years — to 100 years, up from originally planned 85 years.

He also ruled out the possibility of de-silting the lake for being too expensive to be commercially viable. The calculations in this regard have proved that a new dam could be built with the amount of money that could cost de-silting. Secondly, there were mountains on the both sides of the lake which made it impossible to dump silt in the area. For these reasons, only option left with the planners was to go for new generators.