A wagon loaded with coal moves to Kamarajar Port in Ennore, near Chennai. File | Image Credit: The Hindu
The story so far: A new report from the Organized Crime and Corruption Reporting Project, an effort backed by billionaire hedge fund manager and philanthropist George Soros, has provided new documents to reveal that in 2014, the Adani Group claimed ‘low-grade’ coal, imported from Indonesia, to turn into coal ‘high quality’ coal, increased its value and sold it to the Tamil Nadu power generation company, TANGEDCO (Tamil Nadu Generation and Distribution Company).
What is ‘high grade’ and ‘low grade’ coal?
High and low quality are relative terms and are only useful in the context of where the coal is used and how it is processed. Gross Calorific Value (GCV), or the amount of heat or energy that can be produced from burning coal, determines the grade of coal. Coal as a fossil fuel is a mixture of carbon, ash, moisture and many other impurities. The higher the carbon available in the coal unit, the higher the quality or ‘grade.’ There are 17 coal grains according to this metric of class 1, or the highest quality coal, with one kilo yielding more than 7,000 kcal, and the lowest yielding between 2,200-2,500 kcal, according to the classification by the Ministry of Coal. However, caloric value is not a useful metric by itself. The most important use of coal is to run thermal power plants or to power blast furnaces to produce steel and both require different types of coal. ‘Coking’ coal is the type required to produce coke – an essential component of steel making – and thus requires a minimum ash content. Non-coking coal, despite its ash content, can be used to generate enough useful heat to run boilers and turbines.
What are the characteristics of Indian coal?
Indian coal has historically been evaluated as high in ash content and low in calorific value compared to imported coal. The average GCV of domestic thermal coal ranges between 3,500-4,000 kcal/kg compared to imported thermal coal +6,000 kcal/kg GCV. Also the average ash content of Indian coal is more than 40% compared to imported coal which has less than 10% ash. The consequence of this is that high-ash coal when burned produces higher particulate matter, nitrogen and sulfur dioxide. Because of this, the government, since 1954, has controlled the price of coal in such a way that power companies are not disincentivized to use high coking coal for power generation.
Thus, to balance India’s need for coal production, power generation and pollution, the government recommends using imported coal with lower ash and moisture content. The Central Electricity Authority (CEA) in 2012 recommended, and still does, that about 10-15% of imported coal blends can usually be safely used in Indian electric boilers, which are designed for low-quality Indian coal.
Is it clean coal?
In general, we get clean coal when the carbon content has been increased by reducing the ash content. Coal plants have ‘washing plants’ on site that can process the coal in a way that reduces ash and moisture content. They use large blowers or ‘baths’ to remove fine and coarse ash. However, deploying such equipment is expensive and increases power costs. Another way to clean coal – again requiring significant investment – is coal gasification. Here, the need to burn coal is bypassed by converting it to gas. By relying on an integrated gasification combined cycle (IGCC) system, hot pressurized steam and air or oxygen combine with coal in a reaction that forces carbon molecules into two. The resulting syngas, a mixture of carbon monoxide, hydrogen, CO2 and water vapor, is then cleaned and burned in a gas turbine to make electricity. Since IGCC power plants create two forms of energy (steam from the gasification process apart from syngas as fuel), they increase the efficiency of the coal used.
What is the future of coal in India?
Official data says India will produce 997 million tonnes of coal in 2023-24, a growth of 11% over the previous year. Most of these are produced by Coal India Ltd and its subsidiaries.
In March 2024, India produced 261 tons of coal, of which 58 million tons was coking coal. Despite the commitment to transition India’s electricity sector away from fossil fuels, coal is the mainstay of India’s energy economy. However, change is in the air as for the first time this year, renewable energy accounted for 71.5% of the record 13.6 GW of power generation capacity added by India in the first quarter of this year, while the share of coal (including lignite) of the total . power capacity dropped below 50% for the first time since the 1960s.
