Fifty-two percent of the coal ash produced during 2019 was recycled – marking the fifth consecutive year that more than half of the coal ash produced in the United States was beneficially used rather than disposed. The volume of fly ash used in concrete increased 1 percent over the previous year, but most other uses saw significant declines, leading to an overall decrease in recycling activity of 31 percent.
“As coal ash production declines, beneficial use markets are adopting new logistics and technology strategies to ensure these valuable resources remain available for safe and productive use in the highest value applications,” said Thomas H. Adams, executive director of the American Coal Ash Association (“ACAA”) – an organization that advances the environmentally responsible and technically sound use of coal ash as an alternative to disposal. “However, declining use in applications with lower economic value represents a lost opportunity to create significant environmental benefits. We must continue to support these practices that safely conserve natural resources while dramatically reducing the need for landfills.”
According to ACAA’s just-released “Production and Use Survey,” 41 million tons of coal combustion products were beneficially used in 2019 out of 78.6 million tons that were produced. The rate of ash utilization decreased from 58.1 percent to 52.1 percent and the total volume of material utilized decreased by 18.4 million tons compared to the previous year. Coal ash production volume decreased 23 percent (or 23.6 million tons) from 2018 levels.
“Coal ash” is a generic term that encompasses several Coal Combustion Products (CCP) that can be beneficially used in a wide variety of applications. Highlights of CCP production and use in 2019 include:
- Use of coal fly ash in concrete increased 1 percent to 12.6 million tons. Concrete producers and consumers indicated a desire to use more fly ash, but several regional markets were affected by shifting supply dynamics associated with closures of coal-fueled power plants. Fly ash improves concrete durability and significantly reduces greenhouse gas emissions associated with concrete production.
- Use of all coal combustion products in cement production declined 22 percent to 5 million tons.
- Utilization of a key “non-ash” coal combustion product also declined. Synthetic gypsum is a byproduct of flue gas desulphurization units, also known as “scrubbers,” located at coal-fueled power plants. Use of synthetic gypsum inpanel products (i.e. wallboard) declined 21 percent to 9.7 million tons.
- Synthetic gypsum use in agricultural applications – in which the gypsum improves soil conditions and prevents harmful runoff of fertilizers – declined 38 percent to 572,399 tons.
- Use of CCP in pond closure activities declined 26 percent to 2.4 million tons, but remained well above 2016’s total of only 435,000 tons. This activity is driven by utility compliance with coal ash regulations enacted in 2015 that effectively require an end to the practice of wet disposal. Fly ash, bottom ash, boiler slag, and synthetic gypsum were all used in construction of new permanent disposal facilities.
- Following a one-year volume increase in 2018, use of CCP in structural fills resumed a multi-year decline in 2019, dropping 62 percent to 1.7 million tons.
- Production of boiler slag declined 37 percent as the number of cyclone boilers producing this material also continued to decline. Approximately 246,000 tons of boiler slag was utilized in the production of blasting grit and roofing granules. Approximately 362,000 tons of bottom ash was used in this application, a huge increase over 2018’s utilization of only 27,000 tons and an indication that consumers have begun to shift away from the declining boiler slag resource.
- Approximately 944,000 pounds of cenospheres were sold in 2019, down 21 percent from the prior year but still well above 2017’s volume of 148,000 tons. Increased cenosphere recovery was likely linked to increased pond closure activities.
- Resources related to the 2019 survey are available on ACAA’s website, including a news release, the summary survey report, helpful charts exhibiting production and use trends, and the updated “American Recycling Success Story” brochure providing background on coal ash types and beneficial uses.