Coal Ash Recycling

Did you know?

There are many good reasons to view coal ash as a resource.

Recycling coal ash conserves natural resources and saves energy.  In many cases, products made with coal ash perform better than products made without it.  For instance, coal ash makes concrete stronger, less permeable and more durable.  It also reduces the need to manufacture cement, as it acts as an excellent partial replacement in concrete production, up to 50%! This results in significant reductions to CO2 greenhouse gas emissions.  Other beneficial recycling uses include:  mixing coal ash with native soils for road stabilization and other in-ground structural fill uses such as a reclamation product in oil fields and numerous other applications where it has an economic value.

Almost half of America’s electricity is generated by burning coal. That figure is not likely to change much in the future. Because Americans continue to consume more electricity every year, renewable energy sources will do well just to keep up with increases in demand. The U.S. Department of Energy predicts that in 2030, we will actually generate 19 percent more electricity from coal than we did in 2007.

Generating that much electricity produces large volumes of coal ash — solid materials left over from the combustion process. According to the American Coal Ash Association, about 136 million tons of this material was produced in 2008. The good news is that over 44 percent of it was recycled rather than disposed.


Coal ash comes a few forms, the main two being fly ash and bottom ash.  Fly ash (about 75% of coal by-products) is an extremely fine powder that can be recycled for numerous beneficial uses or disposed of in either dry storage such as landfills or wet storage such as ponds or impoundments.   Bottom ash (about 25% of coal by-products) is the heavier ash particles that exit the bottom of the boiler after the coal is burned.