Analysis - The Institute for Southern Studies

One important reason for this change is that dry systems allow plants more flexibility in the type of coal they use as fuel. For example, as
plants switched from bituminous to sub-bituminous coal, they also converted to dry fly ash handling systems because the ash from some subbituminous
coals has cementitious properties that can cause plugging and high maintenance costs for some wet ash disposal systems, thus
necessitating dry ash systems. Also, some types of sub-bituminous coal fly ash are in economic demand by the cement industry because of
their low carbon content and need to be stored dry for transport. EIA’s historical data for coal-fired electric plant fly ash disposal confirms this
same trend away from wet disposal to dry disposal (and to beneficial reuse). In 1996, 26% of fly ash was disposed of in ponds (aka
“impoundments”). This fly ash disposal method dropped to 21% in 2005.
Possible Factors Behind this CCR Dry Disposal Conversion Trend
In the next few years, there will be a number of factors that may affect the way coal-fired plants in the electric utility industry operate
that may further encourage CCR dry disposal rather than wet disposal. Five example factors are:
1. Federal regulations: EPA plans to issue a number of regulations that will affect electric utility plants under the Clean Air Act
and the Clean Water Act. For example anticipated Clean Air Act regulations will likely lead to increased use of SO2
controls on existing electric utility plants that will increase the tonnage of flue gas desulfurization (FGD) solids that must be
processed (i.e., beneficially used or disposed) and is some cases add calcium derivatives to the existing fly ash (through use
of dry scrubbers). While the incremental costs of handling such additional materials are site specific, there are a number of
factors that are likely to drive electric utility companies to give more consideration to dry CCR disposal. While wet disposal
was common on earlier generations of wet scrubbers, in recent cases, some electric utility companies have focused much
more strongly on options to reduce costs by finding beneficial uses for CCR. Furthermore, given the magnitude of the
upcoming projects and growing public interest in how CCR are handled and disposed, expediting approval of the project
may also drive towards consideration of dry disposal methods.
2. State regulations: A number of state governments are considering programs that may affect their respective state-wide
economic demand for electricity.
3. Technology: New technologies for generation, transmission, and use of electricity are being introduced into the market.
4. Fuel cost: Spot markets for coal make it easy for plants to fuel switch or mix coal fuel types. This means, among other
things that wet CCR disposal systems, because they limit the types of coal that these plants can use, are likely to be further
reduced.
5. Plant property: As land availability constraints becomes more important to electric utility plants (e.g., some electric utility
plants are located in riparian settings), on-site wet disposal areas become less important in favor of smaller footprint on-site
dry disposal landfills and sending CCR off-site for disposal or beneficial use.
As electric utility companies face this myriad of changes, they are likely to be reconsidering at a very detailed level how they are
operating their plants. In fact, this is evident in the fact that some electric utility companies have already announced actual or planned
closures of a number of coal-fired electric generator units, while other companies have announced plans to switch some units or plants
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