PESHAWAR, March 26: Water shortage has seriously affected power generation at the Tarbela Dam Project (TDP), which is producing half of its total capacity, according to official sources.

Interviews conducted by Dawn at Tarbela, some 100km from here, on Tuesday showed that the TDP was producing 1,800mw a day on the average against its total installed capacity of 3,478mw.

TDP’s inability to produce electricity to the maximum of its capacity at this time of the year when the country is experiencing the shortage of water and inflows in the Indus have not picked up, the Water and Power Development Authority (Wapda) is forced to heavily rely on the expensive thermal power.

On Monday, the sources said, the TDP had contributed less than nine per cent of the total 126 million units of electricity Wapda consumers utilized throughout the country.

This appears to be a major setback to Wapda in view of the TDP’s ability to contribute 40 to 45 per cent of the electricity Wapda consumers use during the months of July, August, September every year when there is available enough water at the reservoir to operate the project’s power generation system round the clock.

“The TDP authorities’ compulsion to maintain the water reservoir level at the minimum 1,369-foot level — the dead level — for the last several days has seriously affected power generation at the TDP,” a senior TDP officer confirmed to Dawn.

In line with Irsa’s instructions, the TDP authorities are maintaining the water reservoir at 1,369 feet, discharging only that amount of water, which the Indus River brings in from its catchment area every day.

According to the sources, the move to maintain the water-level at 1,369 feet — the dead level - is in accordance with the TDP’s instructions to avoid complications.

Any further reduction in the water-level could move the huge delta made of sediment in the reservoir towards the dam leaving it and the whole of the TDP under threat.

“Due to low water availability from the TDP reservoir, majority of the 14 power generation units installed at the TDP power houses remains inoperative for most part of the day,” said the sources.

All the power generation units involving 10 small units with 175mw capacity each and four units with 432mw capacity each are operated simultaneously only for two hours every day round about from 6:30pm to 8:30pm.

“Except for these two peak hours of electricity consumption when there is greater demand for electricity throughout the country, majority of the generation units remain off rest of the day due to reduced water releases,” said the sources.

At 2pm on Tuesday, only four of the power generation units were operating with remaining lying useless.

The sources hoped that the situation would improve somewhere in the last fortnight of May when water inflows from the TDP reservoir’s catchment area would increase.

However, senior officials of the TDP’s power wing said power generation at the TDP recorded a fractional improvement during the last two days after water inflows from the catchment area recorded improvement due to rains.

The reservoir received 28,000 cusecs on Tuesday, recording marginal improvement in comparison with the inflows situation two three days back.

Before the recent rains received in various parts of upstream Tarbela, daily inflows in the Indus was around 15,000 cusecs.