New Pollution Limits Could Help Quench the Thirst of Coal-Fired Power Plants

The Environmental Protection Agency (EPA) recently published a proposed rule to amend its effluent limitations guidelines (ELGs) and standards for coal-fired power plants.  The proposed ELGs, once finalized, could for the first time set meaningful federal limits on levels of toxic metal discharges, including the pollutants contained in coal ash, from existing and new power plants.  But only if EPA chooses the right approach.  

The aim of the proposed ELGs is to reduce toxic metals and other pollutants discharged into surface waters by thermoelectric power plants. According to the EPA, 72 percent of all toxic water pollution in the country comes from coal-fired power plants, making coal plants the number one source of toxic water pollution in the U.S. 

In 2011, coal-fired power plants generated approximately 76 million tons of coal ash.  Coal ash is simply the solid residue that is left over from the burning of coal. There are two types of coal ash: fly ash and bottom ash.  Fly ash refers to the tiny particles that escape up the chimney or stack.  Ash which does not rise is termed bottom ash. 

Seventy-six million tons of coal ash is enough material to fill 17.2 stadiums the size of the Superdome – that 76,000-seat football stadium in New Orleans, LA.

Coal ash contains unsafe levels of mercury, arsenic, lead, chromium, and other toxic metals known to cause cancer, neurological and organ damage.  And to make matters worse, coal ash is often mixed with water and stored in unprotected and unlined sludge ponds, which causes potentially catastrophic spills/releases as was the case in a disastrous coal ash spill in Tennessee in 2008.

However, water quality is only part of the problem.  Coal-fired power plants also use an enormous amount of water.  In 2005, thermoelectric power plants used an estimated 201 billion gallons of water per day. That is almost half (49%) of the total water use across the country. It is also enough water for the entire state of New York… times 13.4. Although 90 percent of the water withdrawn by power plants is used for cooling purposes, these facilities use water in other ways as well.  For example, a tremendous amount of water is used in the handling and transport of coal ash to ash ponds.  Moreover, the large boilers at thermoelectric power plants produce significant amounts of sulfur dioxide emissions, which in turn require certain technologies to control.  These air pollution control technologies need a substantial amount of water to operate.  The water discharged from these systems is also regulated by the proposed ELGs.

Not only could the proposed ELGs reduce or eliminate discharges of pollutants contained in coal ash and other types of waste from thermoelectric power plants, but they could also dramatically decrease the amount of water that is used to handle the pollutant discharges.

EPA’s proposed rule sets out a total of eight regulatory measures, four of which are dubbed “preferred options” by the agency. The eight options increase in levels of control and pollutant reduction.  Higher levels of control mean lesser amounts of toxic metals and pollutants are allowed to be discharged.  In order to comply with the more protective effluent limitations standards, plants will have to adopt certain technologies that use very little water or no water at all for managing fly ash and bottom ash and for controlling their toxic emissions.  This is where and how the water savings come in.

Unfortunately, EPA’s four preferred options do not include the top two most protective measures (aka Options 4 and 5).  

NRDC signed onto a joint set of technical comments prepared by Earthjustice, Sierra Club, and Environmental Integrity Project, which urged EPA to select Option 5, or at a minimum, Option 4, as the final rule.  We commented that EPA failed to follow its own rules in choosing the preferred regulatory measures, which require the agency to select the best available technology (BAT) that is “economically achievable” – a term that has been interpreted by the courts to mean costs that can be reasonably borne by industry.  Instead, EPA allowed a flawed cost-benefit analysis to dictate its conclusion regarding the four preferred options, an approach that is actually forbidden by the Clean Water Act (CWA). Our comments went on to demonstrate that Options 4 and 5 clearly meet the BAT standard, and thus EPA is under an obligation to select Option 5, or at a minimum Option 4, as its final rule.

NRDC also contributed a separate memorandum addressing the water savings aspect of the proposed ELGs.  As discussed above, not only is the stringency level directly correlated with reductions in pollutants, it is also directly correlated with reductions in water use. In other words, the two most stringent options (Options 4 and 5) would not only remove the most pollutants from coal-fired power plant discharges, but they would also yield the greatest amount of water savings.

EPA calculated that power plants would reduce water use by 153 billion gallons per year, or about 419 million gallons per day, under Options 4 and 5, due to reductions in water use for handling ash transport water and for recycling of FGD wastewater.  What does this mean exactly? One hundred fifty-three billion gallons is nearly as much water as delivered by public water utilities to all the homes in North Carolina each year. 

The water savings resulting from the proposed ELGs will be especially helpful for those regions of the U.S. where power plant withdrawals are posing a serious threat to the well-being of surrounding communities. The southeast, in the past decade, has experienced particularly acute drought conditions and continues to suffer problems of decreasing water availability.  In the southwest, where surface water resources are stretched thin during extended drought and record-breaking heat, there is little available to meet growing demand, including new power sector needs.  Even without factoring in the exacerbating role of climate change, water supply conflicts involving several major Southwest cities – including Denver, Albuquerque, Las Vegas, and Salt Lake City – are considered highly likely by 2015. Thus, if EPA selected Options 4 or 5 as the final rule, the resulting water savings will be especially useful for those states facing deepening challenges posed by the water dependency of steam electric power plants.

As our precious water resources are becoming increasingly challenged to meet the demands of the electricity sector, any additional amount of reduction in a power plant’s water withdrawals is crucial.  Hence, from a water efficiency point of view, NRDC urges the EPA to select Option 5, or at a minimum Option 4, as the final rule. EPA has a responsibility to protect the supply and quality of our water resources.  If EPA selects anything less than Option 4 or 5 as its final rule, it will have failed its mandate under the CWA to choose the most environmentally protective option that is economically achievable. 

About the Authors

Becky Hayat

Staff Attorney, Water program

Join Us

When you sign up you'll become a member of NRDC's Activist Network. We will keep you informed with the latest alerts and progress reports.