In a major development, the government plans to use indigenous Thar coal, instead of imported coal, for generation of 3,960MW.
The three power plants that would be shifted to indigenous coal are Sahiwal Coal Power (Sahiwal), China Hub Coal Power (Hub) and Port Qasim Coal (Port Qasim, Karachi), each of 1,320MW installed capacity. It is indeed a landmark and timely decision since when implemented it would reduce reliance on costly imported coal, and bring down electricity rates, resulting in energy security and overall economic development.
Various measures have already been taken by the government in this direction. Consultants have been appointed to work out feasibility of substitution of existing import-based fuel mix to Thar coal. These power plants would require conversion of existing plant machinery partially, involving lead-time and additional capital cost for the conversion, since coal-based power plants are custom-designed and technology selected depends on coal analysis and characteristics. Also, the government will develop Thar Rail Project, a 105km long rail link for bulk transportation of coal from Thar coalfields to various power-plant destinations through main railway line at the New Chhor station. The project (track and rolling stock) will be established on BOT basis.
Thar lignite (brown coal) is suitable for thermal power generation, and a series of integrated mine-mouth power projects are being established. Two power plants of cumulative capacity of 990MW are operational. The pioneering project Engro Powergen Thar Coal of 660MW (2x330MW) installed capacity, is successfully generating billions of units (kWh) of low-cost electricity on an annual basis since July 2019, whereas Thar Energy Ltd (Hubco) of 330MW has been commissioned this month and will achieve commercial operations soon. Both power plants, which are connected to the national grid, are part of the China-Pakistan Economic Corridor (CPEC) energy programme.
Today, Pakistan stands 7th in the list of top coal-rich countries of the world, with total estimated coal reserves of 185 billion tonnes. But its global ranking is 19th with 3.38 billion tonnes proven coal reserves and 22nd in coal extraction. Thar coalfield, spread over an area of 9,100 sq km located in Tharparker District having 175.5 billion tonnes of assessed coal reserves, is known as the 16th largest coal reserve globally. When developed fully and effectively, Thar lignite coal could generate 30,000MW for next hundred years or so. A total of 13 specific blocks having an area of 1,192 sq km have been allocated for development of mine-mouth power projects. Total estimated coal reserves of these blocks are 40 billion tonnes, out of which 11.23 billion tonnes have been measured and proven, whereas the remaining deposits are indicated or inferred.
Sindh Engro Coal Mining Co (SECMC) is engaged in coal mining from Block-II, one of the 13 blocks of Thar coalfields. Currently, SECMC extracts 3.8 million tonnes of lignite annually, which will increase to 7.6 million tonnes of coal by end of this year, and further to 12.8 million tonnes in near future. Under the coal off-take agreements, SECMC supplies lignite coal to Engro Powergen Thar Coal and Thar Energy power plants, and has committed to making regular supplies of coal to these power plants for a period of 30 years of plant life.
Total yearly requirement of these two mine-mouth power plants is about 6 million tonnes, which works out to be 180 million tonnes for 30 years. Total estimated coal reserves at Block-II are about a billion tonne, but so far, the measured and mineable reserves are 640 million tonnes. For generating 3,960MW as per installed capacity of the three imported-coal-based power plants, additional coal of 24 million tonnes will be required to be extracted from Thar Block-II to meet their annual demand. This will be beyond the envisaged yearly mining capacity of SECMC, which has also to supply coal to the 330MW project of Thal Nova Power Thar Ltd currently under construction at Block-II, scheduled to generate electricity in 2024. SECMC has also signed an agreement with Lucky Electric Power for delivery of 3.6 million tonnes of Thar coal annually for its 660MW power plant at Bin Qasim (Karachi).
Another three blocks, namely Block-I, Block-V and Block-VI, have been allocated to other international and local investors for coal exploitation and development, but unfortunately work on these projects is progressing very slowly. Mine-mouth 1,320MW power project at Block-I of SSRL Thar Coal is now in advanced stage of construction, but there is no progress on 1,320MW Thar Mine Mouth Oracle Power Plant and Surface Mine project at Block-VI. Remaining nine Thar coal blocks are currently available for investment.
At present, understanding about the nature of Thar coal is limited insofar as its physical properties, chemical analysis, and behaviour are considered. Thar coal, which is classified as lignite-B and subbituminous-A (ASTM classification) having heating value in the range of 6,244-11,054 BTU/lb, is suitable for power generation. Lignite of similar character and quality is being used for power generation on commercial scale in India, Germany, Hungary and Serbia. Its chemical composition and heating values vary from block to block, which have not been largely tested in use. Coal at Block-II has moisture 48.80 percent, ash 5.21 percent, sulphur 1.05 percent, fixed carbon 19.37 percent, and volatile matter 25.57 percent, having heating value 5,780 BTU/lb. High moisture is a major contributor restricting its transportation to long distances due to a variety of problems and risks.
According to experts, the best option for Thar coal is at the mine-mouth for power generation. Coal, especially newly mined coal, emits methane, an inflammable gas when mixed with air and liable to gas explosion in certain conditions. Thar coal having high moisture and moderate sulphur content will be liable to create chemical action, particularly in summer, causing spontaneous combustion, in spite of ventilation and thus is not suitable for long-distance movement. However, transportation of Thar coal by trucks to Karachi (Port Qasim) is said to be feasible. Handling and transportation to long distances of Thar coal, besides presenting adverse environmental effects, can result in corrosion to railway wagons and other coal carriers of steel.
A viable and sustainable option would be using major coal reserves at Lakhra and adjoining areas in southern Sindh, such as Sonda-Jherruk, Metting-Jhimpir and Badin, which all are suitable for power generation, instead of Thar coal.
The developed Lakhra coalmines have total estimated coal resources of 1.33 billion tonnes of lignite and sub-bituminous coal of which 244 million tonnes are measured and mineable. Current extraction of Lakhra coal is about 3 million tonnes per year which can be enhanced progressively. For over 20 years a 150MW power plant operated by Lakhra Power Generation Co in public sector had been generating electricity using Lakhra coal, which was shutdown indefinitely in 2018 in the wake of its privatisation. Lakhra coal, which has low moisture content--about 30 percent-- can be transported to the existing imported coal-based power plant sites without risks and additional expenditure on creating infrastructure. Also, the washed coal of Lakhra is more feasible to save the environments as it produces less emissions.
It is imperative therefore that a detailed techno-economic feasibility study of the proposed use of indigenous coal at upcountry power plants using imported coal be carried out ensuring regular and reliable supply of coal to identified power plants. It is considered a pre-requisite for implementation of indigenous coal replacing imported coal on long-term basis. The nation can no longer afford expensive experiences with Thar coal. Our memory is still haunted by the controversial Underground Coal Gasification (UCG) project to generate100MW (2x50MW) by December 2010, which proved to be unsuccessful even after spending more than a decade and making huge investments, and thus plan for generating 1,000MW electricity at Thar Bloc-V using the UCG technology remains a pipedream.
– The writer is retired Chairman of State Engineering Corporation