Power giant National Thermal Power Corporation (NTPC) Ltd’s move to transfer fly ash from its 3,000-megawatt Rihand Super Thermal Power Station in Uttar Pradesh’s Sonbhadra to cement plants is a step in the right direction, according to Centre for Science and Environment (CSE), a Delhi-based think tank.
The move may help address the issue of overabundance of fly ash piling up in Singrauli-Sonbhadra region, located at the boundary of Uttar Pradesh and Madhya Pradesh, according to CSE.
The NTPC on August 16, 2020, flagged off transfer of fly ash in railways wagons from NTPC Rihand to ACC Ltd cement plant in UP’s Amethi district. The newly developed infrastructure includes facilities for loading dry fly ash from Silo storage systems to railway wagons for transfer.
According to the company’s statement, it had approached East Central Railways, along with leading cement manufacturing plants, to commence the supply of fly-ash in railway wagons covered with tarpaulin to cement plants at a distance.
The Singrauli-Sonbhadra region has at least nine major thermal power stations including three NTPC-owned plants — Rihand (3,000 MW), Vindhyachal (4,760 MW) and Singrauli (2,000 MW).
More than half the capacity in Singrauli-Sonbhadra region is relatively new and was added in the last 10 years. More capacity addition has led to an increase in amount of coal consumption and subsequent fly ash generation in the region.
Uttar Pradesh and Madhya Pradesh together account for about 51 gigawatt of installed coal power capacity, half of which is located in the Singrauli-Sonbhadra region.
Both UP and MP are in the top four states in the country in terms of fly ash generation and in the bottom four states in terms of its percentage utilisation, according to the Central Electricity Authority’s latest ash generation and utilisation report for 2018-19.
The high fly ash generation and low utilisation figures indicate huge amounts of residual / unused ash that could be accumulating either in ash ponds in wet form or stored in dry form in the region.
Three major incidents of fly ash breach from power plants in the Singrauli-Sonbhadra region within a year have already raised concerns over coal power plants struggling to manage unused ash. At times, overabundance of dumped ash slurry creates a burden on existing ash dyke structures that do not have enough capacity for storage.
As a result, ash dyke walls often break or an overflow / leakage occurs, causing sudden release of ash slurry to nearby agricultural fields and surface water bodies. This leads to extensive damage of fields and contamination of freshwater sources with toxic ash slurry. Sudden ash flooding to nearby settlements has led to loss of lives at times.
Though percentage ash utilisation is steadily increasing at an all-India level, what remains a concern is the huge backlog of unused ash that has accumulated over the past many years in India.
Power plants currently generate about 200 million tonnes of ash. The CSE analysis — looking at nationwide figures for fly ash utilisation — found unused ash stock from thermal power plants in the last 10 years amounting to as high as 627 million tonnes — more than three times the current ash generation from power plants.
The Ministry of Environment, Forest and Climate Change (MoEFCC) had set the target for 100 per cent utilisation of fly ash by December 31, 2017, according to its notification dated January 25, 2016. The first notification on fly ash utilisation came in September 1999.
However, even after 21 years since the first notification, several power plants still struggle to achieve the target. Around 43 per cent plants have not achieved this target yet, according to 2018-19 data from the Central Electricity Authority.
Coal will remain a mainstay for energy generation in India even in future, which will further aggravate fly ash management issues. Proper fly ash disposal and utilisation is, therefore, necessary in view of the growing environmental concerns associated with its generation.
Significant measures need to be taken at plant level as well as at Centre- and state-level for its efficient management. Cement manufacturing, brick / tiles manufacturing, constructing roads and highways, filling of low lying areas, mine backfilling are among the areas where fly ash is currently utilised, with cement being the major consumer.