Acheiving 100% ash utilisation at coal fired power plants in India

The status of ash management and its use at coal-fired power plants in India is reviewed. The Indian government has set a goal of 100% ash use throughout India by 2024. Some States are achieving this and more, through the additional recovery of older ash pond stockpiles, but others have regional issues to address. For many plants, the challenge is finding industrial partners to take and use the fly ash at, or above, the rate of production (the latter being required to remediate stockpiles). The ash use directives have evolved to require coal power plants to deliver ash free-of-charge to end-users within a radius of up to 300 km. But some regions do not have sufficient users and markets (mainly in construction) within 300 km or any economic delivery distance from the plants. There may be mutual benefits from coordinating longer-range transport of bulk ash via rail networks and also from establishing construction and building material franchises at or near power plants in these cases.

There is potential to sell ash for high-value end uses. For example, cenospheres (hollow, lightweight fly ash ‘bubbles’) can be valuable as fillers in paints and plastics. The extraction of rare earth elements (REE) from ash in India could have dual benefits, including the production of high value materials both for export and for use in the growing national technology manufacturing base. It will be necessary to evaluate market prospects in conjunction with feasibility studies on Indian ash.

Achieving the goal of 100% utilisation of power station by-products, will require India to increase the focus on the challenge of legacy ash piles, which can pose a significant risk to human health. Many of these ashes may be unsaleable. It will also be prudent for utilities to plan to establish markets for the gypsum that will arise from the flue gas desulphurisation processes required across much of the coal power fleet. There is potential for India to use all this additional material profitably if the market is prepared.