A TOWERING CHALLENGE

Home

Advanced Search

ABOUT EEI

|

INDUSTRY ISSUES

|

PRODUCTS AND SERVICES

|

MEETINGS

|

MAGAZINE

|

NEWSROOM

home > magazine > editorial content

•	calendar
•	editorial index
•	guidelines

A TOWERING CHALLENGE

Richard Bozek is manager of environmental programs at Edison Electric Institute in Washington, DC.

Since the 1970s, electric companies have worked with state regulators to protect water resources in the absence of federal rules governing cooling water use. Now that is changing, and new federal regulations could be costly—both to the environment and the industry.

Electric companies are the largest industrial users of water. Generators use between 190 billion to 277 billion gallons every day, most of it for cooling purposes.

In February, the Environmental Protection Agency (EPA) will publish a proposed rule governing cooling water intake structures for existing powerplants under section 316(b) of the Clean Water Act (CWA). Since passage of CWA in 1972 (and in the absence of a rule), electric companies have protected the water resources they use by tailoring solutions to minimize harm to fish and other aquatic organisms. This has been done on a site-by-site basis—a particular technology that may be the most cost-effective for one facility is simply not the appropriate approach in another setting. Nature is always less uniform and more unpredictable than our expectations of it.

EPA's proposal will be finalized in August 2003. But the challenge facing the agency now is to find the right balance between protecting the environment and the costs of doing so. Its recent rule regarding new facilities seems to set some worrisome precedents regarding that balance.

The industry has a tremendous stake in the 316(b) rule for existing facilities. Millions of dollars have been spent on research and development related to cooling water intake structure technologies and protecting the aquatic environment. EPA may favor "wet" recirculating cooling towers as the technology of choice for existing generation facilities. If the agency decides to mandate such a requirement, retrofitting costs for the existing powerplant fleet could be excessive. Forty percent of installed steam generation capacity (288,000 megawatts—MW) uses once-through cooling. The results of a 1992 industry-commissioned economic analysis conclude that the capital costs alone of requiring plants to retrofit their cooling towers could exceed $35 billion (in 2000 dollars). A similar study conducted by Argonne National Laboratory for the Department of Energy (DOE) estimates that capital retrofit costs would range from $27.7 billion to $29.8 billion. As such, a universal cooling requirement could restrict the development of new power sources at a time when the nation has a heightened concern over its power supply.

But dollars alone are not the only issue. Widespread retrofits of cooling towers on existing units would extract a large energy penalty from the grid. First, for engineering reasons, units that are back-fitted with cooling towers are less efficient than originally designed and would not be able to produce as much power per unit of fuel burned. Second, the cooling tower and its associated hardware require energy to operate. This parasitic load would reduce the available output for sale from each unit. DOE is conducting a study whose initial results show energy penalties of between 2.8 and 4.0 percent if retrofits were required. What's more, in some cases it may be physically or operationally impossible to perform such retrofits and still operate the facility within safe design specifications.

Then there are direct environmental concerns associated with cooling tower operation. Among other things, cooling towers produce drift (raw water and solids, like salts, suspended in the evaporation plume), result in increased air emissions and evaporative water loss, take land to build, increase solid waste disposal concerns, produce noise, and can cause icing and fogging on roads. Requirements imposed by 316(b) may create reliability or maintenance problems, affect plant availability, decrease power production, and generate other environmental management concerns in the process.

Cooling Tower Basics
All steam electric generating stations (except those with air-cooled condensers) require cooling water to operate. The process is simple: Fuel is burned in a boiler; the heat converts water to steam; and the steam turns the blades of a generating turbine. The cooling water condenses the steam, which is returned to the boiler. The colder the cooling water, the more effectively it condenses the steam and the more efficiently electricity is generated. A powerplant's cooling water system typically consists of an intake structure (with access to a body of water), piping, pumps, valves, and condensers. The system is integral to the plant and thus often is designed in concert with the plant's structure and hardware in order to optimize performance.

Many plants in the United States are designed to use relatively low-temperature, once-through "open-cycle" cooling water taken directly from surface water—cold water in, warmer water out. Other types of cooling systems include recirculating systems or "closed-cycle" cooling. This configuration operates on the same principle as an open-cycle one; however, instead of returning the water to the water body after it is used to condense the steam, the water is cooled, often in a cooling tower (either naturally or with the use of fans), and then reused. There are many consequences that stem from the use of different types of cooling, but one obvious difference is that with closed-cycle cooling, less water is taken from the water body.

Less frequently, dry cooling systems are used, in which heat is transferred to the atmosphere without the evaporative loss of water. Cars, for example, use a form of dry cooling to control engine temperatures. Water is circulated through the engine block to absorb heat, then through the radiator to dissipate heat, and then back to the engine block. In powerplants, steam exiting the turbine is piped to an air-cooled, finned-tube condenser—the dry cooling tower. Air is typically forced across the finned tubes by fans to improve the cooling process.

Out of these options, one fact stands out: The more efficient generation facility is the one that can condense steam the most rapidly. Generally speaking, once-through systems are the most efficient, wet recirculating systems are less so, and dry-cooled systems are the least efficient.

The Road to 316(b)
No federal section 316(b) rules existed prior to November 2001—utilities have used the general guidance of CWA as interpreted by the states. The process to establish concrete regulations for cooling water intake structures essentially began in 1993 when the Hudson Riverkeeper and other environmental organizations filed suit against EPA, claiming that the agency had an obligation to promulgate rules under section 316(b). To settle the suit, EPA ultimately signed a court-approved consent decree. The agency then decided to split the rulemaking into three phases: the first for new facilities, the second for existing ones, and the final phase for other manufacturers. EPA issued a final rule governing intake structures of new facilities last November.

Faced with what could prove to be an arduous rulemaking, the industry worked with EPA in the first phase of the process by providing expert information based on its water resources experience. But developing and freely providing information and generating workable regulatory alternatives carried the risk that the information could be used inappropriately and ideas could be misunderstood. Still, most in the industry felt that being proactive through cooperation and negotiation would ultimately be beneficial.

The agency was open to such a dialogue. It afforded EPA personnel direct access to some of the foremost experts on this issue in the country and to valid information that could be brought to bear on the rulemaking effort. But 25 years is a long time. When dialogue began, virtually all EPA staff and contractors with any institutional memory of 316(b) were no longer involved. In fact, the electric utility industry was the only stakeholder that had the historical knowledge of the environmental, engineering, economic, and legal issues that go into cooling water intake structure design and construction.

Considering All the Issues
The debate about the 316(b) rulemaking process centers on those issues. Section 316(b) of CWA states:

"Any standard established pursuant to...this Act and applicable to a point source shall require that the location, design, construction, and capacity of cooling water intake structures reflect the best technology available [BTA] for minimizing adverse environmental impact [AEI]."

AEI is never explicitly defined, but at issue is the likelihood and effect of impingement (the killing of organisms against screens and other exclusion devices) and entrainment (the killing of organisms by passing them through the cooling system) on aquatic life.

A variety of site-specific factors associated with water body characteristics, biology, and engineering are important to the impact an intake structure may have on aquatic organisms. (See the sidebar, "Fish Behavior and Mitigation of AEI.") But should those impacts be evaluated in terms of their adverse effects at the aquatic population and community levels, rather than the individual organism level? Powerplants typically entrain organisms in their early life stages, and many entrained eggs and larvae survive. Impingement survival varies depending on the species and life stage affected, and in both cases survival can be significant. Finally, many technologies have proven effective in reducing impingement and entrainment. No one technology is universally necessary or applicable.

FISH BEHAVIOR AND MITIGATION OF AEI
By E. P. Taft

From a biological perspective, many factors influence whether an organism will be subjected to entrainment or impingement and whether the experience will result in organism losses.

Obviously, an organism must be present in the vicinity of the intake structures and must move or be moved into the zone of water withdrawal if it is to be exposed. Many species have life-history, morphological, distributional, and behavioral characteristics that keep them out of the vicinity. For example, the eggs and larvae of fish that build nests and protect their young are unlikely to be entrained, even if the spawning and nursery area is near the intake structures.

Such factors interact with structural design and operational factors that can further reduce exposure. For example, surface-oriented fish are protected from entrainment into deeply submerged, offshore intakes. Similarly, plants that do not operate during times of day or year when organisms are in the vicinity of the intake structures reduce the potential for entrainment or impingement.

Next, it cannot be assumed that organisms that are entrained or impinged are necessarily lost. The potential for entrainment mortality varies by species and life stage and is influenced by factors such as temperature and system transit time. Impingement mortality also varies by species and life stage and is influenced by whether existing fish protection measures are used (e.g., fish-lifting buckets). In fact, a range of species and life stages have been shown to experience relatively high survival rates following entrainment or impingement.

Finally, for fish that are particularly susceptible to entrainment or impingement mortality, technologies are available that can be considered as best technology available for protecting them. For small, entrainable organisms such as fish eggs and larvae, fine mesh screens of various designs can be used for bypassing them or collecting and returning them to the water body. For larger, impingeable fish, a suite of physical barriers, diversion devices, and collection systems are available for consideration. The engineering practicability of applying these technologies is site-specific and depends on existing plant design features and operational practices, as well as environmental factors such as debris loading and biofouling.

E.P. Taft is president of Alden Research Laboratory in Holden, MA.

Still, many in the environmental community contend that AEI occurs by virtue of the simple fact that utilities use water containing aquatic organisms, and therefore there is no need for a definition. The utility industry, on the other hand, argues that a reasonable definition of AEI must be made if an efficient, fair, and effective rule is to be promulgated. This is critical since a definition of AEI is the trigger for what, if anything, must be done to minimize adverse impact. (See the sidebar, "A Legal Perspective.") Inextricably linked are the specific characteristics of the water body and the area within the water body where the intake is located; the biological characteristics of the species likely to interact with the intake; and the engineering and operating characteristics of the intake structure and facility. They must be assessed on a site-specific basis to determine if AEI is occurring.

A LEGAL PERSPECTIVE

By Kristy A. N. Bulleit

By its deceptively short and simple terms, section 316(b) of the Clean Water Act requires that "the location, design, construction, and capacity of cooling water intake structures reflect the best technology available [BTA] for minimizing adverse environmental impact." The Environmental Protection Agency's (EPA's) quest to develop rules that properly implement this provision raises a host of complex issues, none of which is more important than the meaning of the term "adverse environmental impact" (AEI). Despite the prominent position of the term in 316(b), EPA has shown some reluctance to take a firm stand on what it means. For instance, in the preamble to its proposed 316(b) rules for new facilities, EPA offered a number of possible interpretations, but suggested it might take no action at all on this key point and declined to include any definition in the proposed rules.

From a legal perspective, it is clear that EPA needs to make a definition. Why? Because any rules the agency adoptsÂ€€€€€€€whether it provides for a uniform application of technologies or, as the energy industry has advocated, a more site-specific approachÂ€€€€€€€will not be defensible unless the agency interprets this key phrase. The agency will have to explain why the requirements it imposes will "minimize adverse environmental impact." To do that, regulators will have to explain which environmental impacts it considers, what level of impact it considers adverse, how it balances the trade-offs among different environmental impacts in arriving at the BTA determination, and how its requirement will "minimize" AEI.

So, even if EPA claims to have forsaken any definition, its regulations implicitly will embody some definition of AEI. Equally important, if EPA reserves any authority to permit writers to deviate from standardized requirements, whether in establishing more stringent limits (as it proposed to do) or less stringent limits on a site-specific basis, EPA will have to interpret AEI in order to give permit writers consistent guidance on selecting among technological alternatives.

A review of past 316(b) decisions suggests that state and federal permit writers have not had much difficulty interpreting AEI to distinguish between levels of impact that are adverse versus those that are not. As a practical matter, permit writers, with guidance from case law and a large body of scientific studies, have assessed the risk of AEI by broadly interpreting environmental impacts. With respect to entrainment and impingement, permit writers have assessed effects at the population level or higher. For example, in a 1977 decision affecting Public Service of New Hampshire, an EPA administrator found that a predicted 4.6 percent decline in Mya clam larvae would not result in a 4.6 percent reduction in the adult clam population due to high natural larvae mortality, natural compensatory mechanisms, and the conservative assumptions underlying the estimated reduction. The administrator concluded that "the entrainment of Mya will have an insignificant effect on adult Mya populations."

Similarly, an early 316(b) decision of the First Circuit examined intake effects on juvenile smelt. The court found the sampling that identified "the absolute number" of smelt near the powerplant's water intake area was not meaningful because it did not "help one determine whether the intake will affect the ability of the smelt to propagate and survive." The court affirmed EPA's decision, based on expert testimony, that most smelt would not be found in the vicinity of the intake.

Early section 316(b) decisional law endorsed a population-based approach to assessing risk of harm from intakes. There is no principled reason for EPA to reject this longstanding approach, which has proved amply protective, for purposes of its new regulations.

K risty Bulleit is a partner with Hunton & Williams, a law firm based in Washington, DC.

National Economic Research Associates (NERA), in a critique of the economic consequences of a one-size-fits-all regulatory approach, concluded that national uniform requirements would be wasteful for two reasons. First, national standards would result in greater costs than necessary to meet a given level of environmental protection and second, such standards would produce fewer environmental gains than possible for a given level of spending. (See the sidebar, "Economics Issues in Section 316(b) Decisions.")

Â€€€€€€€

ECONOMICS ISSUES IN SECTION 316 (B) DECISIONS

By David Harrison

Section 316(b) of the Clean Water Act provides an economic framework for determining on a site-specific basis what the best technology available (BTA) is to minimize adverse environmental impact. In its forthcoming regulations for existing facilities, will the Environmental Protection Agency (EPA) resist pressures to substitute a uniform technology-based approach?

Environmental economists have developed well-established procedures over the last four decades for estimating the costs and benefits of complex public policy choices. Recent 316(b) cost-benefit studies illustrat how the approach can be applied and how sound estimates of the dollar costs and benefits of technology alternatives can be developed. The cost analyses in these sophisticated studies take into account all the major costs of installing and operating fish protection technologies, including complex issues such as the value of lost power or increased air emissions. The benefit assessments take into account detailed biological information on the numbers of different species protected by the technologies as well as estimates of the commercial and recreational values per pound for these different species.

This approach to setting BTA has advantages over others. Under a technology-based approach, for example, a given technology would be required for all facilities located in certain areas (e.g., estuaries). An affordability approach would compare costs to overall facility or company revenues, requiring the technology's use as long as the facility would not close or the company would not go out of business.

Taking the cost-benefit route provides several things.

It allows decisionmakers to clarify what is at stake—in terms of society's commitment of resources and social benefits—in 316(b) decisions. The other approaches tend to obscure the trade-offs involved in these choices.
It helps decisionmakers identify the alternative that produces the greatest net benefit (benefits minus costs) among fish protection choices. These analyses reflect the unique factors at the individual site.
The cumulative use of the cost-benefit approach produces greater environmental benefits for a given level of social cost.
The approach provides incentives to site new facilities where they produce fewer fish losses. In contrast, an affordability approach would emphasize the facility's revenues.

But would a site-specific cost-benefit approach be too expensive and time consuming? Put another way, would this approach lead to "paralysis by analysis?" Those are legitimate concerns. Better 316(b) decisions can save societal resources by avoiding large expenditures for little environmental benefits. Cost-benefit analysis is only "too expensive" if study costs exceed these savings. Moreover, study costs can be reduced by a tiered approach that tailors the complexity of the study to the complexity of the facility. The cost-benefit studies also do not have to be one-size-fits-all. Indeed, there are several precedents for tailoring the complexity of the analysis to the characteristics of the site.

Economic analysis can be combined with biological and engineering information to develop sound 316(b) decisions. These decisions will protect the nation's fish resources and also provide the resources to meet important social objectives.

David Harrison is senior vice president of National Economic Research Associates in Cambridge, MA.

The Industry Alternative
While working with EPA on the first phase of the rulemaking, the industry proposed a two-track approach to regulating cooling water intake structures that preserves site-specific decisionmaking, is scientifically and technologically appropriate while being environmentally protective, and establishes a more consistent process for decisionmaking. The agency considered this alternative approach when making its new source rule and used parts of it in its final rulemaking.

Under track one of the suggested approach, the developer of a new facility could choose to install highly protective technology meeting two basic criteria: very low flow, as would be consistent with use of a wet recirculating cooling system, and very low intake velocity. Experience and research indicate that such conditions when met are highly protective and avoid AEI in the vast majority of cases. In exchange for installing this technology, developers would be afforded streamlined permitting and not be subject to reassessment in subsequent permits, absent regulatory changes. Alternatively, a developer could choose to submit data showing that an alternative approach would provide a level of protection that is within the range expected from the low flow/velocity approach.

Under track two, the developer would perform a site-specific study. The permit writer would use this study to assess whether the proposed intake structure presents an appreciable risk of AEI and, if so, to determine what constitutes the best technology available to minimize it. That specific technology or suite of technologies that maximizes net benefits would then be required.

The two-track alternative makes sense because it allows the full range of issues—environmental, engineering, economic, and in some cases, legal—to be balanced by the permit writer.

Setting a Precedent
In the end, last November EPA recommended a fundamental change to the long-used site-specific approach for making section 316(b) determinations in its rule for new facilities. Rather than encourage a case-by-case methodology for applying BTA, the rule establishes national technology-based performance requirements for the location, design, construction, and capacity of cooling water intake structures at new facilities.

While the requirements of the final new facility rule reflect years of effort by EPA, other agencies, industry, and some states, many feel that it suffers from some key shortcomings.

EPA did promulgate a rule modeled on the two-track approach: However, the agency's track one, or "fast track" option, is over-prescriptive by requiring additional design and construction requirements in some circumstances and calling for ongoing monitoring that may hinder quick permit obtainment. The other main difference is that EPA's track two relies less on site-specific analysis and more on the performance of intake technologies. The result is a two-track approach with reduced flexibility and less streamlined decisionmaking.

Moreover, there is no efficient mechanism in the new facility rule to take into account many situations where use of the prescribed technologies has little real biological benefit. This is because EPA requires something close to an "affordability" test as the measuring stick for making the cost-benefit decision—in essence, if you can afford it, you have to buy and install it. At the very least, according to industry observers, this test is not in keeping with general executive administration policy for achieving cost-effective regulation. In any event, the ability to balance costs of technology and accrued environmental benefits on a site-specific basis is an important industry goal for the existing facility rule.

How the agency ultimately deals with these central issues in the implementation of the new facility rule is of utmost importance to the industry. Why? Because those decisions will guide the agency and possibly restrict its actions in February when it proposes rules for existing facilities.

Next Steps
EPA is currently preparing its proposal for that rule—the agency is under court order to publish it by February 28, 2002.

As with the new facility rule, utilities have continued to work openly with the agency to craft a workable regulatory construct. The industry's multi-step decisionmaking approach is built on a rigorous process that was recently submitted for independent scientific peer review and received widespread endorsement. The proposal combines the notions of applying site-specific decisionmaking to achieve the most environmentally- and cost-effective reductions in AEI with reliance on pre-existing section 316(b) decisions and information from state regulators. It recognizes that a variety of protective intake technologies are available and allows for a meaningful consideration of their costs and benefits.

In the absence of federal rules, the electric utility industry has spent nearly 30 years applying its scientific expertise with cooling water intake structure issues—in coordination with state regulators—to protect the environment. This should be the goal of all stakeholders, whether regulatory, environmental, or industrial. Optimistically, those committed to this goal are working together to hammer out the regulatory details.

| | | | |

© 2008 Edison Electric Institute