Cooling Water Intake Structures Research Articles

ASSESSMENT OF COASTAL DAMAGE FOR THE COOLING WATER INTAKE STRUCTURE OF A COAL-FIRED POWER PLANT

Last October 2020, a strong tropical cyclone with international name Molave (local name: Quinta) caused widespread damage to agricultural and infrastructure sectors in the Philippines. Among those affected is a coalfired power plant located within the vicinity of Tayabas Bay. The velocity cap at the head of the cooling water intake structure of the power plant was found washed ashore in the morning of October 26, 2020 (PH time) after the onslaught of Typhoon Molave. Underwater site investigations post-typhoon revealed that the walls and other components of the intake structure were damaged as well. The intake structure head was initially built at seabed depths of 9m below Mean Tide Level (MTL), while the velocity cap was topped at 6m below MTL. This paper presents the forensic analysis and coastal damage assessment methodology carried out to identify the nearshore hydrodynamic conditions during the passage of potentially critical typhoons throughout the useful life of the intake structure (2017 to 2020).

Digital holography for real-time non-invasive monitoring of larval fish at power plant intakes

Effective evaluation of technological and operational approaches to reduce entrainment of marine organisms at cooling water intake structures (CWIS) requires accurate organism-sensing systems. Current detection methods lead to large temporal data gaps, require tedious manual analysis, and are fatal to organisms. Here, we describe integrating deep learning with a non-lethal, non-intrusive imaging method—digital holography—to rapidly detect fish larvae. Laboratory experiments demonstrated that the instrument could successfully image fish larvae at flow rates exceeding ranges seen in CWIS. Holograms of two fish larvae species, in the presence of bubbles and detritus, were collected to build a large database for training a lightweight convolutional neural network. The model achieves 97% extraction accuracy in quantifying larvae, and distinguishing them from other particles, including detritus and bubbles, when applied to a dataset of manually classified images, exceeding previous metrics for non-lethal, accurate, and real-time detection. These results demonstrate the potential of in situ holographic imaging for monitoring endangered larval fish species at power plant intake structures, and for high-fidelity, real-time applications in monitoring aquatic ichthyoplankton.

Quantifying Restoration Offsets at a Nuclear Power Plant in Canada

In Canada, the Fisheries Act requires all water takers to avoid, mitigate and offset fish losses. To satisfy the act’s requirements, operators of power plants are required to undertake habitat restoration projects to compensate for fish impinged and entrained at cooling water intake structures. Scaling the quantity of restoration needed, and measuring whether adequate compensation has been achieved, requires a metric that expresses the losses and gains in comparable units. Development of such a metric is especially difficult in the case of power plants, because the losses often consist of a mix of species and life stages that are very different from those produced by technically feasible restoration projects. This paper documents the method that has been developed for quantifying offsets for impingement and entrainment at the Bruce Generating Stations on the eastern shore of Lake Huron, and demonstrates how the method is being used to estimate the offset to be provided by removal of a dam on the nearby Saugeen River.

Cooling Water Intake Regulated Through Clean Water Act Section 316(b): A Critical Issue

Section 316(b) protects the aquatic ecology of the nation's waters. In May 2014, the Environmental Protection Agency (EPA) issued the final rule under Section 316(b) of the Clean Water Act. It outlined the regulations and standards for the design and operation of cooling water intake structures.

Quantifying nonuse and indirect economic benefits of impingement & entrainment reductions at U.S. power plants

Monetizing ecological benefits of reducing impingement and entrainment (I&E) at cooling water intake structures presents both ecological and economic challenges. Ecological challenges arise because it is difficult to demonstrate and measure these impacts. Economic challenges arise because of these ecological uncertainties and because many of the potentially affected ecosystem services cannot be valued using traditional methods. Under a recently promulgated U.S. regulation certain power generation and industrial water permit applicants may be required to monetize these “nonuse” benefits. However, stated preference (SP) surveys, the only method available for valuing nonuse services have not seen acceptance by mainstream economists. This paper describes an approach to valuation that incorporates the ecological service function approach advocated by the USEPA Science Advisory Board to characterize impacts. Data and models are used to quantify, to the extent possible, direct and indirect impacts of I&E on ecosystem services. Nonuse values are then estimated by an SP survey that measures respondents’ willingness to pay for reducing I&E. Methods are proposed for calibrating and validating results including identifying the source of nonuse values from commonly ascribed motivations (i.e. existence, bequest, altruistic), considering the role of pre-survey awareness of impacts, and evaluating results in the context of respondent willingness to pay for other nonuse benefits.

Impacts of entrainment and impingement on fish populations: A review of the scientific evidence

In 1972, the United States Congress enacted §316(b) the Clean Water Act, which mandates minimization of the adverse impacts of entrainment and impingement of fish and other aquatic life at cooling water intake structures. Since the Act was passed, there has been continuous controversy over the magnitude of any such impacts and over the need for mitigating measures to reduce these impacts. The objective of this paper is to examine the published scientific information relevant to this issue The review includes (1) peer-reviewed literature reporting results of studies of impacts of entrainment and impingement at power plants on fish populations, (2) peer-reviewed literature and “blue-ribbon” commission reports on aquatic resource degradation that evaluate causes of observed degradation of aquatic ecosystems, and (3) EPA's own assessments of causes of degradation in coastal environments. The clear conclusion from the review is that any impacts caused by impingement and entrainment are small compared to other impacts on fish populations and communities, including overfishing, habitat destruction, pollution, and invasive species. The available scientific evidence does not support a conclusion that reducing entrainment and impingement mortality via regulation of cooling water intakes will result in measurable improvements in recreational or commercial fish populations.

Energy v. Water

The role of economics in environmental regulation lies at the heart of the Supreme Court’s 2009 decision in Entergy Corporation v. Riverkeeper. In Riverkeeper, the Supreme Court determined that the Environmental Protection Agency (EPA) has the authority to conduct cost-benefit analysis when promulgating technology standards for cooling water intake structures at existing power plants pursuant to the Clean Water Act. Like many environmental regulations, the Clean Water Act is silent on the use of such analysis. Writing for the majority, Justice Scalia interpreted the Act to permit the EPA’s reliance on cost-benefit analysis. As Justice Breyer posits in his concurrence, in times of limited resources and dire environmental problems it is wasteful to force an industry to spend billions to save one more fish while those resources may be more wisely spent resolving other environmental woes. This Note argues that such an approach can only work when the environmental woes are properly defined. In the case at hand, the EPA grossly oversimplified the environmental problem and financial burdens and thus miscalculated the environmental and financial benefits of the best technology available. By ignoring the environmental harm caused by power plant water use and consumption, the EPA did not factor in the potentially huge environmental benefits of restoring instream flows and the financial and social benefit of averting a crisis in the energy-water nexus.

Brief of Environmental Law Professors as Amici Curiae in Support of Respondents

This is an amicus brief written by Professors Jim May (Widener) and Jared Goldstein (Roger Williams) on behalf of law professors in support of Respondent Riverkeeper, in a case before the U.S. Supreme Court, Entergy v. EPA, PSEG Fossil v. Riverkeeper, and Utility Water Group v. Riverkeeper, _ U.S. _, Nos. 07-588, 07-589 and 07-597, respectively. While the certified question seems improbably simple, Whether section 316(b) of the Clean Water Act, 33 U.S.C. 1326(b), authorizes the Environmental Protection Agency (EPA) to compare costs with benefits in determining the best technology available for minimizing adverse environmental impact at existing cooling water intake structures, what is at stake is much more complex and sweeping. The outcome of this case could have profoundly negative effects not only on the environmental concerns 316(b) was designed to protect, but also on the technology-based undergirding of the CWA and the rest of Environmental Law. This amicus brief examines the relevant language, structure and history of the CWA, including the role of costs in setting technology-based standards. The history of water pollution regulation before 1972 demonstrates that Congress wisely chose to meet water quality standards by adopting performance-based standards based on technological capabilities rather than balancing costs and benefits based on water quality impacts. Experience under the Clean Water Act vindicates Congress's choice: the technology-based standards adopted under the Clean Water Act have produced significant environmental benefits without causing economic disruption or absurd results.

Regulations for Cooling Water Intake Structures

Regulations for Cooling Water Intake Structures

CWA §316(b): Cooling Water Intake Structures Subtitled: Why Industrial Facilities May Soon Be Investing in Fish Hatcheries, Estuaries and Wetlands

CWA §316(b): Cooling Water Intake Structures Subtitled: Why Industrial Facilities May Soon Be Investing in Fish Hatcheries, Estuaries and Wetlands

A blueprint for the problem formulation phase of EPA-type ecological risk assessments for 316(b) determinations.

The difference between management objectives focused on sustainability of fish populations and the indigenous aquatic community, and a management objective focused on minimizing entrainment and impingement losses accounts for much of the ongoing controversy surrounding §316(b). We describe the EPA’s ecological risk assessment framework and recommend that this framework be used to more effectively address differences in management objectives and structure §316(b) determinations. We provide a blueprint for the problem formulation phase of EPA-type ecological risk assessments for cooling-water intake structures (CWIS) at existing power plant facilities. Our management objectives, assessment endpoints, conceptual model, and generic analysis plan apply to all existing facilities. However, adapting the problem formulation process for a specific facility requires consideration of the permitting agency’s guidelines and level of regulatory concern, as well as site-specific ecological and technical differences. The facility-specific problem formulation phase is designed around the hierarchy of biolo gical levels of organization in the generic conceptual model and the sequence of cause-effect events and risk hypotheses represented by this model. Problem formulation is designed to be flexible in that it can be tailored for facilities where §316(b) regulatory concern is low or high. For some facilities, we anticipate that the assessment can be completed based on consideration of susceptibility alone. At the other extreme, a high level of regulatory concern combined with the availability of extensive information and consideration of costly CWIS mitigation options may result in the ecological risk assessment relying on analyses at all levels. Decisions on whether to extend the ecological risk assessment to additional levels should be based on whether regulatory or generator concerns merit additional analyses and whether available information is adequate to support such analyses. In making these decisions, the functional dependence between levels of analysis must be considered in making the transition to the analysis phase and risk estimation component of the ecological risk assessment. Regardless of how the generic analysis plan is modified to develop a facility-specific analysis plan, the resulting plan should be viewed as a tool for comparing representative species and alternative CWIS options by focusing on relative changes (i.e., proportional or percent changes) in various measures. The analysis plan is specifically designed to encourage consideration of multiple lines of evidence and to characterize uncertainties in each line of evidence. Multiple lines of evidence from different levels of analysis, obtained using both prospective and retrospective techniques, provide a broader perspective on the magnitude of potential effects and associated uncertainties and risks. The implications of the EPA’s recent (April 2002) proposed regulations for existing facilities on the applicability of this blueprint are briefly considered.

Using attainment of the designated aquatic life use to determine adverse environmental impact.

Section 316(b) of the Clean Water Act requires that cooling-water intake structures (CWIS) use Best Technology Available (BTA) to minimize adverse environmental impacts (AEI). The U.S. EPA has not defined AEI, and there is no clear consensus regarding its definition. Nonetheless, operational definitions are necessary to evaluate design alternatives and to measure the success of mitigative measures. Rather than having to develop measures of aquatic health that are highly site-specific, controversial, and often unlikely to elicit agreement from all sides of the environmental “fence”, it may be more productive to use existing ecological assessment tools. Aquatic Life Uses (ALU) already provide a regulatory framework to assess the quality (health) of the aquatic community in various habitats (e.g., warmwater habitat, exceptional warmwater habitat). Attainment of the ALU indicates that further point source controls are unnecessary, whereas nonattainment indicates that those pollutants or stressors causing the nonattainment must be reduced. A similar approach for existing water intakes is recommended. That is, attainment of the designated ALU will be taken as an indication that there is no AEI. Although attainment of the ALU may not be a foolproof indicator of a lack of AEI, this approach seems more reasonable that using scarce monetary resources to fix problems that likely do not exist, or having both regulators and the regulated community expend their resources debating whether various observed biological responses do or do not constitute AEI.

A holistic look at minimizing adverse environmental impact under Section 316(b) of the Clean Water Act.

Section 316(b) of the Clean Water Act (CWA) requires that “the location, design, construction, and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact.” As the U.S. Environmental Protection Agency (EPA) develops new regulations to implement Section 316(b), much of the debate has centered on adverse impingement and entrainment impacts of cooling-water intake structures. Depending on the specific location and intake layout, once-through cooling systems withdrawing many millions of gallons of water per day can, to a varying degree, harm fish and other aquatic organisms in the water bodies from which the cooling water is withdrawn. Therefore, opponents of once-through cooling systems have encouraged the EPA to require wet or dry cooling tower systems as the best technology available (BTA), without considering site-specific conditions.However, within the context of the broader scope of the CWA mandate, this focus seems too narrow. Therefore, this article examines the phrase “minimizing adverse environmental impact” in a holistic light. Emphasis is placed on the analysis of the terms “environmental” and “minimizing.” Congress chose “environmental” in lieu of other more narrowly focused terms like “impingement and entrainment,” “water quality,” or “aquatic life.” In this light, BTA for cooling-water intake structures must minimize the entire suite of environmental impacts, as opposed to just those associated with impingement and entrainment. Wet and dry cooling tower systems work well to minimize entrainment and impingement, but they introduce other equally important impacts because they impose an energy penalty on the power output of the generating unit. The energy penalty results from a reduction in plant operating efficiency and an increase in internal power consumption. As a consequence of the energy penalty, power companies must generate additional electricity to achieve the same net output. This added production leads to additional environmental impacts associated with extraction and processing of the fuel, air emissions from burning the fuel, and additional evaporation of freshwater supplies during the cooling process. Wet towers also require the use of toxic biocides that are subsequently discharged or disposed. The other term under consideration, “minimizing,” does not equal “eliminating.” Technologies may be available to minimize but not totally eliminate adverse environmental impacts.

Maryland power plant cooling-water intake regulations and their application in evaluation of adverse environmental impact.

Maryland’s cooling-water intake and discharge regulations, the Code of Maryland Regulations (COMAR) 26.08.03, stem from Sections 316(a) and (b) of the Clean Water Act (CWA). COMAR 26.08.03.05 and litigative and administrative rulings stipulate that the location, design, construction, and capability of cooling-water intake structures must reflect the best technology available (BTA) for minimizing adverse environmental impacts (AEIs), providing that the costs of implementing the BTA are not wholly disproportionate to the expected environmental benefits. Maryland law exempts facilities that withdraw less than 10 million gallons/day (MGD) and less than 20% of stream or net flow by the intake. If not exempt, BTA must be installed if the cost of doing so is less than five times the value of fish impinged annually. Through site-specific studies and the use of a Spawning and Nursery Area of Consequence (SNAC) model applied to Representative Important Species, several power plants were evaluated to determine if they have had an adverse effect on spawning and nursery areas of consequence. Examples of application of the Maryland law to a number of power plants in the state are presented, together with the outcome of their evaluation.

Adverse environmental impact: 30-year search for a definition.

Since passage of the Clean Water Act in 1972, there has been a long, unresolved struggle to define a key phrase in Section 316(b) of the act: “adverse environmental impact” (AEI). Section 316(b) requires that the best technology available be used in cooling-water intake structures to minimize AEI due to entrainment and impingement of aquatic organisms. Various attempts were made to evaluate and define AEI, including focused national conferences on impact assessment. Unresolved arguments regarding AEI were reinvigorated following the 1995 Consent Decree requiring EPA to propose new rules to implement Section 316(b). This article reviews and compares eight proposed definitions of AEI. Six of the definitions define AEI as impact expressed at the population or higher level of biological organization. The two remaining definitions are unrelated to populations: a 1% cropping of the near-field organisms and “one fish equals AEI”. The latter definition is based on the desire of some stakeholders to define AEI as the loss of any public trust resources. Equating loss of public trust resources with AEI hampers consensus on a definition because a societal-based policy concept (public trust resources) is commingled with science-based definitions based on population effects. We recommend that a population-based definition of AEI be incorporated into Section 316(b) guidance and observe that this will not preclude a state from exercising its law and policy to protect public trust resources.

Preface

Most of the papers were presented at the EPRI conference on power plant impacts on aquatic resources, Atlanta, GA, USA, 12-15 Apr 1999. A few were presented at an EPRI-EPA Clean Water Act section 316(b) technical issues workshop, Berkeley Springs, WV USA, Sep 1998. The papers covered the assessment and potential impacts of impingement and entrainment of fish and invertebrates in cooling water intake structures. Other subjects included the assessment of aquatic resource impacts associated with power plant thermal and chemical discharges. One paper has been abstracted separately.

A draft regulatory framework for analyzing potential adverse environmental impact from cooling water intake structures

A draft regulatory framework for analyzing potential adverse environmental impact from cooling water intake structures

Fish protection technologies: a status report

Section 316(b) of the Clean Water Act has required that “best technology available” (BTA) be used to minimize adverse environmental impacts resulting from operation of the cooling water intake structure (CWIS). The primary effects of CWIS operations are the entrainment of small aquatic organisms through the cooling water system and the impingement of larger life stages on traveling water screens. Extensive research has been conducted since the early 1970s in attempts to develop technologies that will minimize entrainment and impingement. As a result, a suite of technologies is available that can be considered for application as the BTA at the CWIS. Available technologies include fish collection systems, fish diversion systems, physical barriers and behavioral barriers. The ability of a given technology to meet BTA requirements is influenced by a wide variety of biological, environmental and engineering factors that must be evaluated on a site-specific basis. The status of systems and devices in each category of fish protection alternatives is presented.

What is ‘normative’ at cooling water intakes? Defining normalcy before judging adverse

Judgments of adverse environmental impact from cooling water intake structures need to be preceded by an appreciation of what is normal. In its report, Return to the River , the Independent Scientific Group (now called the Independent Scientific Advisory Board) — the scientific peer review arm of the Northwest Power Planning Council — advanced the notion of a ‘normative river ecosystem’ as a new conceptual foundation for salmonid recovery in the Columbia River basin. With this perspective, the sum of the best scientific understanding of how organisms and aquatic ecosystems function should be the norm or standard of measure for how we judge the effects of human activities on aquatic systems. For the best likelihood of recovery, key aspects of altered systems should be brought back toward normative (although not necessarily fully back to the historical or pristine state); new alterations should be judged for adversity by how much they move key attributes away from normative or what might be considered normal. In this paper, I ask what ‘normative’ is for the setting of cooling water intake structures and how this concept could help resolve long-standing disputes between groups interested in avoiding damage to all organisms that might be entrained or impinged and those who take a more population or community perspective for judging adverse environmental impact. In essence, I suggest that if a water intake does not move the aquatic ecosystem outside the ‘normative’ range, based on expressions of normalcy such as those discussed, then no adverse impact has occurred. Having an explicit baseline in normal or normative would place 316(b) analyses on the same conceptual foundation as 316(a) analyses, which strive to demonstrate the continuation of a balanced, indigenous community of aquatic organisms at the power station location.

A retrospective evaluation of 316(b) mitigation options using a decision analysis framework

Choosing the best 316(b) mitigation option is a daunting task. Decision analysis (DA) provides an objective framework that can be used to choose among several mitigation strategies where there are multiple objectives and numerous uncertainties. This paper has two objectives: (1) to illustrate the use of the DA framework for making a 316(b) decision (using the Chalk Point Power Station as a case study); and (2) to show that DA is also useful for quantifying the benefits of a previous decision. The Chalk Point case, resolved in 1990, centered around the mitigation of adverse environmental impacts of a cooling water intake structure (CWIS) as a result of fish and blue crab losses associated with impingement and entrainment. Barrier nets and fishery enhancement programs were used to mitigate the losses. We compare the costs and benefits of the mitigation options actually employed to those of other options. The costs and benefits were estimated numerically using standard DA methods. Valuations and probabilities were derived largely by professional judgment based upon the original Chalk Point 316(b) studies and ongoing monitoring. DA indicated that the optimal strategy and expected utility were functions of the weighting of environmental benefits relative to cost.