Indian coal has a high ash content of 30-45 per cent, resulting in huge quantities of ash generation from coal-based power plants. The unscientific handling and storage of fly ash by thermal power plants (TPPs) have detrimental health effects on local inhabitants, besides polluting the air and water. Fly ash, therefore, needs to be disposed of or repurposed in a scientifically managed manner. Last year, the National Green Tribunal outlined the Fly Ash Management and Utilisation Mission, which stipulated not only the monitoring of the disposal of annual stock of unutilised fly ash but also the overseeing of the utilisation of legacy (accumulated) fly ash. Therefore, TPPs need to actively carry out fly ash management.
There are various methods that can be deployed for effective utilisation of ash. These include utilisation in the building sector for making bricks, blocks, tiles, cement, concrete and plaster; utilisation as a base for land reclamation, filling low-lying areas, raising ground levels and mine filling; utilisation as construction material for roads, embankments, ash dykes and road blocks; and utilisation in agricultural and wasteland area development, among others.
Government initiatives
Over the years, the government has issued various guidelines and recommendations to enhance fly ash utilisation in the country. In January 2018, the expert committee for effective fly ash utilisation made several recommendations pertaining to effective fly ash disposal and management. The measures suggested that tender/auction of fly ash should only be issued for end-user/industries and not for traders. It also recommended TPPs and end-users to consider entering into long-term agreements for fly ash supply.
In November 2021, the Ministry of Power (MoP) issued a notification stating that all coal- and lignite-based TPPs are required to provide fly ash to end-users (such as cement plants, brick kilns, road and construction agencies, etc.) through a transparent bidding process only. In the notification, the MoP has also stated that TPPs may continue to provide fly ash for national capital projects under their existing commitments based on transportation rates arrived at on the basis of transparent competitive bidding or state schedule of rates (whichever is lower).
In a key development, in January 2022, the Ministry of Environment, Forest and Climate Change introduced a revised notification that prohibited dumping and disposal of fly ash discharged by coal- or lignite-based TPPs. In addition, it has introduced the “polluter pays” principle, requiring the polluting TPP to pay a penalty for non-compliance. These two norms are designed with the aim of ensuring 100 per cent fly ash utilisation in all TPPs. Non-compliant entities will be forced to pay Rs 1,000 per tonne of unutilised ash to the Central Pollution Control Board.
The government has also mandated all government, semi-government and private entities engaged in construction activities such as construction of roads and flyovers in a radius of 300 km of a TPP, to utilise fly ash in their construction. TPPs have to bear the cost of the delivery and transportation of fly ash to project sites.
Fly ash generation and utilisation trends
In 2021-22, India utilised around 259.86 million tonnes (mt) out of the 270.82 mt of fly ash generated. In other words, 95.95 per cent of the fly ash was utilised in 2021-22. Furthermore, 92 out of 200 power utilities managed to utilise over 100 per cent fly ash by reusing fly ash from the previous year. In addition, out of 200 power plants that provided data, around 19 have managed a fly ash utilisation rate of 90-100 per cent.
State-wise, 10 states, namely, Andhra Pradesh, Bihar, Chhattisgarh, Madhya Pradesh, Maharashtra, Odisha, Tamil Nadu, Telangana, Uttar Pradesh and West Bengal, generated more than 10 mt of fly ash each. Further, Gujarat, Haryana, Maharashtra, Punjab, Rajasthan Tamil Nadu and Telangana have achieved a fly ash utilisation level of more than 100 per cent. Andhra Pradesh, Bihar and Jharkhand have achieved a fly ash utilisation level of more than 90 per cent, but less than 100 per cent.
Conclusion
Fly ash needs to be systematically managed, which needs multiple chains of logistics to be in place. Internet of things can be a major tool in the management of fly ash. A data management system designed specifically to study ash generation and utilisation can be coupled with software that can process information to study the ash quality, quantity, suitability and availability. Another way to improve the utilisation of fly ash could be by creating a marketplace for various agencies and organisations to co-ordinate collection, distribution and management of fly ash. Besides this, ash utilisation can be handled by a separate ash utilisation division so that utilisation of ash can be prioritised.
Net, net, IoT-based ash management systems, coupled with government initiatives such as the Ash Track portal, are expected to result in improved ash utilisation at TPPs in the coming years.
