The power supply system in the country has become'fraglle’ as the power generation units and distribution network were constantly overloaded during the last six years.

As a result of constant system overload, longevity of the power plants and distribution network has also reduced alarmingly. Power units are 'tripping.more frequently' than ever before and will continue to do so until total power generation exceeds the demand for it. sources concerned said.

The average loadshedding is around 400 mw to 450 mw nowadays. However, following Thursday's gird failure and subsequent system restoration work, the loadshedding situation improved last night. At 7 pm yesterday, the PDB plants were generating 1868 mw of

power against the demand for 2162 mw.

As per a standard practice worldwide, it is mandatory for the PDB to generate power at least 10 per cent less than the installed capacity of the power plants. But due to shortage of power generation capacity against a rapidly rising demand. PDB has been generating power at the maximum level since 1992-93, leaving no 'safety reserve margin', the sources pointed out.

Now. as PDB's total generation capacity has not increased virtually in the. last six years, although some new plants were commissioned, the power system is running without safety limit. In other words, there has been an increasing level of loadshedding of up to 550 mw during this period.

In 1971. the PDB's installed power generation capacity was 550 mw against a peak demand of 183 mw. The installed capacity rose to 822 mw in 1980 against a demand of 462 mw. In 1985. the demand rose to 887 mw while PDB generated 1141 mw. In 1990. the capacity rose to 2352 mw (with some units obsolute) against a demand of 1506 and in 1997 it rose to 2418 mw (with units having 650 mw capacity needing repair) against a demand of 2100 mw (loadshedding level reached 300 mw to 350 mw).

Safety reserve marginwise. PDB maintained a 46 per cent reserve in 1975. This level went down to 18 per cent in 1991 and 15 per cent in 1992. In 1993. the ■ margin went down 5 per cent minus.

, It is now suspected that

Thursday s power grid breakdown was simply caused by system overload.

"Before the national grid failed at 10 am Thursday, the Ghorashal 4th 210 mw power unit tripped for a technical reason. Subsequently the 230 KV Ashuganj-Comilla Double Circuit power distribution line tripped." said an official.

"At that time, the total stand-by power generation capacity was 1709 mw while there was a load of 1700 mw. If it was possible to keep the 10 per cent power generation reserve. PDB would nave had generated between 1500 mw to 1550 mw and avert the national grid failure by sustaining the sudden vacuum of power supply created by breakdown of the Ghorashal 210 mw unit." he added. The Ghorashal unit was later tested and PDB found no fault in the plant yesterday. "It now seems that the problem must have had originated from the line fault (Ashugani-Comilla Double Circuit Tine). Line fault can occur from any mishap — from a tree falling on the line to a transformer explosion." the official pointed out.

"It is very risky for the whole power sector to continue to generate power to the maximum level steadily for years. This situation is prevailing since '91-92. said an expert.

There is a demand for 2250 mw of power now and PDB can hardly generate 1800 mw. Again, this demand would have been higher if PDB this year had not succeeded in convincing farmers across the country to operate electricity-based irrigation pumps during night time, thus improving distribution of power load in different hours of a day. he mentioned.

"If the farmers did not agree to operate pumps at night, the demand for power would have been more than 2400 mw at peak hours now. instead of 2250 mw. That would mean the loadshedding would have been worse," the expert noted.

After Prime Minister Sheikh Hasina took over charge of the Energy Ministry.

the power generation level improved in the last one week due to Increased gas supply to the power plants. Because of gas supply shortfall, PDB could not generate 320 mw of power till early last week. Now. by diverting gas supplies from fertiliser factories, power generation has been increased by 80 mw to 100 mw.

British company Cairn will start supplying 60 million cubic feet of gas per day from Sangu Field from April 22. This will help PDB to add 200 mw more to the national grid.

The two Raojan 210 mw units are now generating about 200 mw due to gas supply shortfall. Sangu's gas will help them to generate up to 300 mw, if not 420 mw (the full capacity). To utilise Raoian plants' full capability, the PDB needs to set up a high-power line between Hath azari and Comilla because the existing line between Chittagong and the national grid does not carry more than 300 mw.

PDB has taken up a project to build the Hathazari line from government resources. It is expected to be completed by July.

Besides, the government should speed up the old power plants rehabilitation scheme, now a year behind schedule, and pursue the private power plant schemes at Meghnaghat (450 mw). Haripur (360 mw). and Baghabari (100 mw) and Barge-mounted plants (300 mw to 400 mw), one source said. "Otherwise, the coming years would be worse than ever."