Power generators face a sweeping fish protection rule
By David Wagman, Managing Editor
Consider the gizzard shad, a.k.a. mud shad or-in more formal circles-Dorosoma cepedianum. Toothless, stumpy, bony and squished from side to side, this member of the herring family can grow to eight inches in length and spend its life oozing slime.
Gizzard shad live in tidal waters as well as large rivers, small streams, ponds and lakes around the country. Females produce as many as 380,000 eggs making it prolific enough for one Kansas lake to stock Northern Pike just to keep the gizzard shad under control. The fish is commonly used as bait or spread as fertilizer on fields. According to the Maryland Department of Natural Resources Web site, a 1 million-pound commercial catch may have a dockside value of $80,000.
Gizzard shad are also the bane of many power plant environmental control officers. “If you look at a gizzard shad it rolls over and dies,” said one senior power plant engineer.
An exaggeration, but the gizzard shad’s delicate constitution is one reason why it takes center stage in many discussions about a U.S. Environmental Protection Agency waterlife protection rule, which could be one of the most expensive provisions of the Clean Water Act for power plants. The so-called section 316(b) provisions require existing power plants to reduce the number of aquatic creatures that either are impinged or entrained in a power plant’s water intake system. The rule was drafted assuming that significant numbers of aquatic animals, including gizzard shad, are being trapped, maimed or killed by water intake systems.
EPA estimates that section 316(b) compliance could cost power generators $585 million and affect more than 560 power plants across the country. Compliance cost estimates vary widely and sources said they could climb higher. For example, a relatively simple fish net barrier (a technology that may be most applicable in placid lakes) could cost $100,000 to $500,000, said Dave Stanislawczyk, principal hydrogeologist with WorleyParsons in Reading, PA. Replacing existing traveling screens with more fish-friendly models could cost $5 million to $10 million per power plant. More costly still, Stanislawczyk cited a power plant that is spending $90 million to build a “helper” cooling tower to comply with an earlier environmental settlement related to fish kills in a water discharge channel. The helper tower could also bring the plant into 316(b) compliance.
Farther up the extreme end of the cost scale, compliance could run into hundreds of millions of dollars at some nuclear power plants, said Rolf Wahanik, a hydraulic engineering consultant also with WorleyParsons. That’s because changing a screen on a water intake structure may set in motion a string of hydraulic pressure changes throughout the plant, requiring replacement of the facility’s water circulation system.
“You have to reconstruct the plant,” Wahanik said. “It’s astronomic, the cost to go into a nuclear power plant.” Like other plants, however, nuclear stations may receive a waiver if they can demonstrate that compliance costs significantly exceed anticipated benefits.
Then there is the handful of instances to date in which power plant owners have concluded that shutting marginal non-nuclear power plants makes more sense than investing in 316(b) compliance technology.
The baseline target set under 316(b) is for power plants to achieve an 80 percent to 95 percent reduction in impingement and a 60 percent to 90 percent reduction in entrainment. Although the rule was drafted at the federal level, enforcement is up to the states. Compliance is tied to National Pollutant Discharge Elimination System (NPDES) permit renewals. Plans detailing how individual power plants intend to comply with 316(b) are due in a little more than a year. Despite the approaching deadline, issues-including a federal lawsuit-remained unresolved as of mid-December.
Perhaps most fundamental is whether or not a fish kill problem exists.
Doubt stems from reports that little hard data exists either on total fish populations or on the numbers of fish and other aquatic animals that wind up impinged or entrained at a power plant. Studies are currently underway at a number of power plants to gather some hard data. This data will help power plants determine whether or not they have an impingement problem, an entrainment problem, both problems or none at all.
In studies involving rivers and lakes in Wisconsin, Iowa along the Upper Mississippi River valley and the Missouri River, Gregory Howick, senior aquatic ecologist at Burns and McDonnell, said he found fish impingement more often during winter months when fish naturally grow sluggish. In the case of the gizzard shad, it apparently stops eating when temperatures fall. Unfortunately, it continues to swim rather than drop to the bottom as other species as it gets cold. This leaves gizzard shad more prone to harmful or even fatal run-ins with power plant water intake systems.
Executives of Johnson Screens next to one of 24 screens built for a WE Energy power plant on Lake Michigan to meet 316(b) requirements. Total screened flow is 1,580,000 gpm. Photo courtesy Johnson Screens.
A second issue is whether or not the expense of installing screens and other equipment on water intake systems is appropriate. Here, power plant operators can turn to what are referred to as “cost-cost” and “cost-benefit” tests. These tools could be a good first line of analysis before plant operators buy and install equipment, sources suggested. Here’s how the analytical tools work.
When the EPA crafted 316(b) it surveyed power plants to gather information on items such as cooling water pump capacity and through-screen velocity. The agency also conducted an aerial review of power plants and their water intake systems. The agency then assigned compliance cost estimates to every power plant potentially affected by the 316(b) rule.
Using a cost-cost analysis test, a power plant operator compares the EPA’s estimate with its own compliance cost calculations. If the difference turns out to be “significant” (importantly, the term “significant” is left undefined) then the plant could be exempt from 316(b) compliance.
According to Terry Larson, civil department manager for Burns & McDonnell’s Energy Global Practice, most EPA estimates appear low or inconsistent, at least so far. For example, two plants in similar locations with similar flow rates can have widely different compliance cost estimates. “Most have been really low,” he said.
A power plant operator could claim to have no impingement or entrainment compliance liability at all. In that case, any cost above zero could be seen as significant. New York State environmental regulators, for one, reportedly have said they will not consider cost-cost analysis as an argument for exemption from 316(b).
An alternative is to pursue a cost-benefit analysis. A power plant may be granted exemption from 316(b) if its cost of compliance is “significantly” (again, left undefined) greater than the dollar value of the impinged or entrained aquatic life, a potentially touchy subject. It’s also where the fortunes of the fragile and sometimes-maligned gizzard shad may be most passionately debated.
“The gizzard shad will be a challenge for our program,” said Ron Stohlmann, senior production operations engineer for the Omaha Public Power District (OPPD). “We’re hoping for leniency on that fish.”
OPPD is looking at a $13 to $17 million 316 (b) compliance cost for seven power units. “It has quite an economic impact on us,” he said.
The utility is moving ahead with equipment modifications in part to correct problems with its existing traveling screens. Its power plants line the sandy and silty Missouri River, which has led to clogging and excessive wear. At its North Omaha station the utility has begun a year-long test of a Beaudrey-supplied screen, which uses a pump to ease fish from the screen while keeping them in the water.
One alternative being challenged in a federal court case is whether or not power plants may comply with 316(b) by restocking fish. In other words, operators would essentially replace fish that are killed or injured with other fish. Environmental groups argue that had EPA meant to allow restocking, it would have written 316(b) to include this option. Within the same court challenge is an argument from lawyers representing Entergy Corp. that 316(b) cannot be made applicable to existing facilities. They take the argument one step further to say that compliance is more difficult for nuclear power plants than for other affected power plants.
That’s because installing fine mesh screens could lead to more clogs and fouling on water intake devices that are critical in cooling nuclear power plants. In its “friend-of-the-court” brief, Entergy’s attorneys argued “if the passive screen becomes plugged to the point where backwash fails to maintain the necessary water level in the pump well, the pump flow rate must be reduced. This reduction may result in a derating or shut down of the associated generating unit.”
EPA Approved Equipment
EPA-approved technology for 316(b) compliance falls into two broad categories: equipment that discourages fish from getting too close or equipment that captures fish and safely returns them to the water.
The first set of solutions includes fish nets and sonic and light systems. Fish nets are most practical in calm water where the chance of damage from passing trash, tree limbs or ice is small. Despite their relative low cost (on the order of $100,000 to $500,000), fish nets require frequent inspections for holes and tears. A typical recommendation is for a power plant to have two or three replacement barriers on hand, said WorleyParsons’ Dave Stanislawczyk.
Sonic and strobe light systems are another option. These can cost up to $1 million and are not always effective with every type of aquatic creature.
Among fish capture and return equipment, the main technologies include modified traveling water screens (also called a Ristroph screen) and cylindrical wedge wire screens, said Ned Taft, president of Alden laboratory, based on Holden, Mass. Taft said that data developed through field tests suggests that traveling screens work well with young fish that are up to six inches long. He said wedgewire screens have resulted in “extremely high survival” rates.
Alden plans to study screens from four manufacturers between March and July 2007 to arrive at a base rate of survival for each product. The four products being tested are a Geiger screen (to be tested at the Potomac plant near Washington, D.C.), the Beaudrey fish protection system (currently seeing use in France), the Hydrolox band screen (operating at one location in the United States) and Eimco Water Technology’s Brackett/Green screen (installed at several locations).
With the deadline for having compliance plans in place just over a year away, uncertainty about next steps appears widespread. Some power plant operators may not be able to complete a comprehensive aquatic life study in time for the February 2008 deadline, said Terry Larson of Burns and McDonnell. “The schedule has to be a concern. And the lawsuit is an issue. There are a lot of people behind big time,” he said.
Larson’s colleague at Burns and McDonnell, senior aquatic ecologist Gregory Howick, recommends that power plant operators at a minimum should prepare their compliance paperwork and submit it to the EPA on time. he said some states have already agreed to work out details later, after the paperwork is filed.
With the first deadline for compliance a little more than a year away, the question of what effect power plant water intake systems are having on aquatic life remains unsettled.
“I look at rivers and lakes and I can’t say that the power plant is doing a number on fish populations,” Howick said. “It’s hard to make a case these power plants are having a significant impact on fish species.”