THE federal government plans to convert its oil/gas-based power stations to coal-fired plants since price of imported fuel oil is rapidly increasing, whereas supply of indigenous natural gas is falling.

The power sector is heavily dependent on residual fuel oils (RFO), and conversion to coal is seen as the only sustainable option.The conversion aims to diversify fuel mix, improve thermal efficiency and lower electricity tariff.

The government plans to transform its old and inefficient gas-based and/or dual-fuel fired (natural gas and furnace oil) power stations to coal-fired power plants, of cumulative de-rated capacity of 2,605MW at a total cost of $1.18 billion.

In the first phase, Jamshoro power station of 675MW de-rated capacity and Guddu of 580MW de-rated capacity will be converted, while Muzaffargarh (of total 1,130MW), Multan (units 1,2 & 3 of total 120MW) and Faisalabad (units 1 & 2 of total 100MW) will be taken up in the second phase. Recently, the Asian Development Bank has agreed to extend $433 million for conversion-to-coal of Jamshoro and Guddu power stations.

Jamshoro power station of 850MW installed capacity operates four units installed during early 1990s, one of 250MW and the other three of 200MW each. Unit-1, commissioned by the Japanese, is based on furnace oil, whereas the remaining three units supplied by the Chinese are dual fuel (natural gas or RFO) based units providing operational flexibility.

Due to restricted supply of natural gas, however, all three units are also being run only on RFO for quite some time.

Guddu power station has a total installed capacity of 640MW. Its units 1& 2, each of 110MW installed capacity based on natural gas, were commissioned in 1974 and now have available capacity of 50MW each due to obsolescence.

Units 3 & 4, each of 210MW installed capacity dual fuel fired, which were commissioned in 1980s, have at present available capacity of 110MW each. Thus, the de-rated 580MW plant has available capacity of only 320MW. These two power plants will be coal-converted with the objective of regaining their dependable capacity to the level of about 700MW. Advanced coal conversion technologies will be adopted.

Some of the existing in-plant equipment will be retrofitted, modifications made in auxiliary equipment/components and major overhauls undertaken. As boiler is the most important component of a coal-fired power plant, the existing oil-fired boilers at Jamshoro will be replaced with 1x400MW supercritical coal-fired steam generator at a cost of $740 million.

In case of Guddu power station, which is characterised with supply of natural gas from the nearby Mari and Kandhkot gas-fields, all existing equipment (turbine, boiler and generator) will be replaced. Existing boilers will be replaced with 1x300MW supercritical steam generator.

Currently, Environmental Impact Assessment (EIA) reports are being prepared to address contamination issues and impacts of related wastes, which would follow detailed technical and economic feasibility studies for conversion-to-coal project.

Apparently, conversion-to-coal is a positive measure, but it is not likely to achieve desired results for a number of reasons.First, the proposed conversion is based on imported coal, meaning we will continue to have dependence on imported fuel, and fuel security will not be attained. Second, estimated capital cost of conversion is too high, around $618 per-kilowatt which is half the cost for a new green-field coal-fired power project.

Major coal handling infrastructure is required, besides infrastructure for transportation, storage of coal and handling/disposal of ash, notwithstanding site restrictions. For the purpose of developing in-plant infrastructure, acquisition and use of additional 100 acres land is required at Jamshoro site, which involves displacement/resettlement of population. Also, O&M costs of a coal-fired power plant are comparatively much higher than oil/gas.

Third, international prices of thermal coal (12,000 BTU/lb) has remained erratic in recent years — $141.43 per metric ton FOB in February 2008 aginst $74.30 per ton in August 2007 and $124.18 per ton in January 2012. It is constantly and steadily increasing again due to recent high demand of coal in Asia for power generation. Therefore, the generation cost will be higher than anticipated, and the targeted 50 per cent reduction in electricity tariff is not foreseen.

As supercritical steam generator technology has not been introduced in Pakistan, its acquisition, assimilation and developing expertise by plant operators will entail significant time.

China and India first mastered clean coal combustion technology, developed the machinery locally and then constructed coal-fired power plants.

Environmental degradation will be another sensitive issue since most of these power stations are located in major cities. Project completion will take 36 to 48 months, if at all re-commissioned without delays, and there would be colossal loss during this period of about 960MW electricity a day that could be available from these plants at present.

Perhaps, the least-cost and most feasible solution is to undertake rehabilitation and refurbishment of existing oil/gas-based power plants for which plans were underway till recently with the help of the USAID, and, if government claims are to be believed, imported gas will also be available in near future.

Pakistan may however establish new mine-mouth coal-fired power plants using indigenous coal. If development of Thar coal takes time, coal from developed coalfields like Lakhra, Sonda-Jherruk (Sindh) and Chamlang (Balochistan) could be utilised for power generation.

(Engr Hussain Ahmad Siddiqui is former Chairman of State Engineering Corporation)