EPRI discusses possible implications of 316(b)

By BrianW

The U.S. Environmental Protection Agency (EPA) is reviewing public comments filed in regards to the proposed 316(b) rule of the Clean Water Act for cooling water structures. The 316(b) rule requires that the location, design, construction and capacity of cooling water intake structures reflect the best technology available for minimizing adverse environmental impact. EPA says more than 1,500 facilities nationwide use large volumes of cooling water from lakes, rivers, estuaries and oceans to cool their facilities, including power plants.

During an August 30 media call hosted by the Electric Power Research Institute (EPRI), Doug Dixon, an EPRI technical executive who focuses on fish protection, said EPRI submitted over 150 pages of technical comments in regards to EPA’s proposed 316(b) rule. Those comments were supported by additional technical reports, he said.

Currently, the draft rule in place is for existing power plants and EPA has proposed two standards: impingement mortality and entrainment mortality. The impingement standards relates to organisms large enough to become trapped on intake system screens and that must be removed with a fish return system. Plants using more than two million gallons of water a day have two options, said Kent Zammit, EPRI senior program manager for Water and Ecosystems. One is to prove that impingement mortality is reduced by both 69 percent monthly and 88 percent annually. The second is to reduce the maximum design through screen velocity to less than 0.5 feet per second during minimum source water levels, such as low tide.

Plants using more than two million gallons a day are also subject to an entrainment mortality standard. This standard relates to organisms small enough to go through water intake screens and travel through the plant. Facilities that are using more than 125 million gallons a day of actual flow must also submit a comprehensive entrainment characterization study. This study must evaluate entrainment reduction technologies, including environmental impacts. Compliance would be determined on a case-by-case basis. The agency would also determine whether or not cooling water intake structures would be the best technology available or if the facility would be required to install cooling towers.

“If there were a national requirement for closed-cycle cooling, the cost to the nation, to the power industry, would be approximately $100 billion to build the towers,” said Dixon.

Dixon said that as much as 42,000 MW of generation could be lost because plants may not be able to afford cooling towers or lack sufficient space on the plant’s property to build towers.

“The loss of generation would cause some system violations and would be an impact on our distribution of power,” he said.

One compliance option is a traveling screen. EPRI said that if traveling screens are used to meet the velocity reduction requirement, they must be modified for entrapment with fish protection measures and a fish return system.

“If you were required to evaluate entrainment reduction it is one technology you would likely investigate,” said Zammit.” And it could be chosen on a cost benefit analysis."

Dixon said that EPRI’s comments to EPA included detailed information for traveling water screens. He said a “host of problems” exist with biological monitoring of traveling screens that EPA would have to overcome.

“The rule does not encourage innovation of additional R&D. It is prescriptive to certain types of technologies and excludes a number of technologies that are on a site-specific basis that have been found to be effective,” he said.

As part of related litigation, EPA must issue a final rule on July 27, 2012. Following that, the next phase of implementation would begin, or another round of litigation if one or more parties sue after rule is issued.

For impingement mortality, EPRI said power plants withdrawing more than 50 million gallons a day must submit a range of information that includes source waterbody physical data, cooling water intake structure data, source water baseline biological characterization data, cooling water system data, Impingement Mortality Reduction Plan, performance data and operational status information. That information must be submitted within six months of the rule’s effective date. Results of the Impingement Mortality Reduction Plan would have to be submitted within three and a half years. Facilities withdrawing between two million and 50 million gallons a day have up to three years to submit that information. All existing facilities must be in compliance with eight years from the rule’s effective date.

For entrainment mortality, facilities withdrawing more than 125 million gallons a day actual flow must submit an Entrainment Mortality Data Collection Plan within six months, complete peer review of the plan within one year and submit study results within four years of the rule’s effective final date. The facility must be in compliance with any requirements no later than eight years from the effective rule date.

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