September 17, 2005

Pakistan is blessed with huge reserves of coal, estimated at 184 billion tonnes. When in the early nineties, huge coal reserves were found in Tharparkar, Sindh, the country joined the 20 countries with the best resource potential in the world.

Pakistan’s lignitic and sub-bituminous coals, if exploited properly, could usher in an era of prosperity. However, the use of these coals as fuel is extremely difficult due the presence of high sulphur, ash and moisture contents in them.

These coals emit harmful emissions upon combustion. And possible environmental pollution has been a major impediment in their utilization. The problem may be resolved if heavy investments are made on advanced and clean coal technologies.

Even if Islamabad does decide to invest heavily in this area, we don’t have enough trained manpower to handle the problems associated with using low-grade coals. In the absence of such expertise, the import of state-of-the-art technologies becomes a non-starter.

In the past several decades, proper utilization of indigenous coals has been a very important component of the government’s energy policies. The 6th, 7th, 8th and 9th five-year plans all stressed upon the need to produce at least a fraction of the total electricity produced in the country from indigenous coals.

However, despite the authorities’ best efforts, only a negligible portion of the total energy supply comes from these coals. Actually, the production of coal remains stagnant, as no significant market demand has been created for its consumption.

Presently more than 90 per cent of the coal produced in the country is utilized for making bricks and the rest for generating power. The question that needs to be asked here is: Why have we been unable, for the past several decades, to make any headway when it comes to utilizing indigenous coals.

Harmful emissions

Coals — especially the lignitic coals of Pakistan that contain high sulphur, ash and moisture contents — are difficult to use. These coals are difficult even to store because, due to self-oxidation, they may catch fire by themselves.

What’s more, high ash content may cause blockage in the combustion equipment. The most troublesome areas, however, are health and environment, as the coals produce hazardous pollutants.

While using these coals as fuel, emissions from three recognized pollutants need to be suppressed:

— The oxides of sulphur;

— The oxides of nitrogen, and;

— Extremely fine particulate matter.

Each of the pollutants poses unique threats to the ecology and human health.

Sulphur oxides, predominantly sulphur dioxide, are formed due to the combustion of sulphur contained in the coal, whether in the form of iron pyrite or as elemental sulphur. The presence of sulphur dioxide in the environment causes chronic and acute respiratory diseases.

The emissions may travel to the upper atmosphere, depending on climatic conditions, and get oxidized to sulphur trioxides, which may fall as acid rain. All of this could generate adverse effects for humans and could even cause widespread death among aquatic creatures.

Nitrogen oxides are formed during the combustion of coal, the amount depending on the conditions, particularly the temperature. Nitrogen-containing compounds are found in indigenous coals that, upon liberation, are chemically active.

They may combine with amines, to form carcinogenic compounds called nitroamines and nitriles. Nitrogen oxides are a mixture of several discrete nitrogen/oxygen compounds. In the upper atmosphere, they enter into complex chemical reactions with ozone, catalysed by ultraviolet radiation, to form a series of compounds that make themselves felt as “smog” and atmospheric haze.

Ash or particulate matter — the third pollutant — is specific to coal. It is composed of minerals and some unburned combustible matter and trace elements.

In addition to the obnox-

ious effects of the smoke formed during the combustion of aromatic hydrocarbons, the trace elements in ash are fine enough to be inhaled, producing acute pulmonary irritation and chronic obstructive and restrictive lung diseases.

Technology to the rescue?

The technologies so far developed for the control of emissions may be classified as:

Control technologies — These are in use for quiet some time now and are widely used in large coal-fired power plants. The technologies involve the removal of nitrogen oxides and the collection of ash and sulphur dioxide emissions through sophisticated techniques, converting them into useful products.

Advance clean coal technologies — Being recently developed, these technologies control the environmental discharge during combustion without the use of outside scrubbers, achieving good economics in the process.

Recently a substantial reduction in emissions was reported through the development of clean coal technologies that followed certain minimum environmental standards. In 1985, the US department of energy launched a $2.5 billion programme for utilizing American coal resources within environmental safe limits based on clean coal technologies.

Various other countries like Germany, Greece and Turkey also use low-grade coals for energy production using clean coal technologies. It remains to be seen if Pakistan will also do so.

Past experiences

For utilizing coal found in Lakhra, various feasibility studies were carried out by the Geological Survey of Pakistan and the United States Geological Survey in the early sixties. The favoured technology was of the control type.

It was as early as 1970 that Wapda formulated a plan for an indigenous coal-based power plant in Lakhra. Detailed feasibility studies were formulated by John T. Boyd and Company of the US in 1985, on behalf of the USAID and Wapda, for utilizing Lakhra coal for power generation. Capital costs for mining and installation of power plants were then worked out.

Lakhra coal was tested for boiler design and an assessment of the environmental impact was made by some American consultants, following certain World Bank guidelines. The assessment suggested that three 50-megawatt plants, using flue gas desulphurization technique, should be set up in Lakhra.

For the three plants, the total amount of coal required was 750,000 tonnes per annum. The government in 1988 approved the installation of coal-fired power plants in Lakhra using indigenous coal.

On Oct 4, 1987, Wapda signed an agreement with China for the design, manufacture, supply, and commissioning of the three units based on modern clean coal technologies and using coal from Lakhra.

The National Electric Power Regularity Authority was created through an act of parliament in December of 1997 to set out a new regulatory regime for the power sector in the country. The authority has expended considerable time and efforts with a view to ensuring that new power projects are based on indigenous coals.

Conclusion

Exploration and exploitation of indigenous coal resources is a very attractive option for power generation, which requires long-term planning. So far, however, the efforts made by the government in this area have not been successful.

The impediments in this regard need to be carefully identified and analysed. Efforts should be made to develop indigenous manpower to handle the immense problems associated with the combustion of low-grade coals. There is a need also for a long-term national initiative to create, expand and strengthen energy research and development programmes based on clean coal technologies.

Instead of large power plants, small experimental units for coal-based power generation should be set up and studied. Based on the results from these units, we may decide on our future course of action.

Meanwhile, coal is a big organic complex and it contains a wealth of chemicals that can be produced in sizeable amounts without producing harmful environmental effects. These chemicals are used all over the world for agricultural, industrial and pharmaceutical purposes.

If it turns out that the high sulphur, ash and moisture contents of our low-grade coals make them absolutely unsuitable for power generation, then alternate avenues be explored for their effective utilization in agriculture as well as industry.

The writer, a freelance contributor, used to work for the PCSIR Laboratories, Karachi