R&D Forum

EPRI releases report on best practices at Alaska plants

EPRI announces availability of a report on the results of Ketchikan Public Utilities’ assessment of performance best practices and implementation of performance improvement projects at its four hydro plants in Alaska. The report says that through this work, the utility increased generation and profitability at these plants: 5-MW Beaver Falls, 4.2-MW Ketchikan, 2.1-MW Silvis, and 22.6-MW Swan Lake.

This Hydropower Technology Roundup Report, the twelfth published by EPRI, discusses Ketchikan Public Utilities’ experience with improving the overall performance of its hydroelectric plants, says Patrick A. March, principal consultant with Hydro Performance Processes Inc. and author of the report. The report uses a best practice approach based on the Protocol for Appraisal of Hydro Performance Processes, March says. This protocol addresses four aspects of operational performance, including unit performance data, organizational use of performance results, optimization, and integration with business processes and systems.

In 2004, the utility used an informal initial appraisal to identify gaps in its performance best practices at these four plants. Ketchikan Public Utilities then initiated numerous performance improvement projects. In November 2008, a follow-up appraisal documented improvements that resulted from these performance improvement projects.

Projects implemented include: improving flow measurements, determining detailed unit performance characteristics, improving operations using these performance characteristics, analyzing and reviewing performance data to achieve further improvements, and implementing operational rules based on the performance analyses.

The report provides results from the initial and follow-up performance appraisals, performance characteristics for each plant, and results from the detailed performance data analyses.

– To purchase a copy of this report, contact EPRI Customer Assistance Center at (1) 800-313-3774; E-mail: askepri@epri.com.

Studying effects of pulsed flows in California

The Center for Aquatic Biology and Aquaculture of the University of California, Davis, is operating a pulsed flow research program to determine the effects of pulsed flows from hydro projects on aquatic habitat and biotic communities in California streams and rivers.

A pulsed flow involves a sharp, sudden increase in the amount of flows for a relatively short period of time, and then a decrease back to the original flow level. According to the center, more than 380 hydro projects in California release pulsed flows as a byproduct of electricity production, for recreational purposes, or for sediment management.

Because the effects of these pulsed releases are poorly understood, in 2002 the Public Interest Energy Research (PIER) program of the California Energy Commission and the Division of Water Rights of the State Water Resources Control Board established and provides funds for the pulsed flow program. Since 2003, nine research projects have been awarded funding, and seven are now complete.

Two ongoing projects are studies of:


    – Gaps in scientific understanding of instream flows and research needs related to developing economically efficient and ecologically effective management tools for use in the Federal Energy Regulatory Commission hydropower relicensing process; and
    – Effects of aseasonal pulsed flows on the Foothill yellow-legged frog. This frog has disappeared from as much as 45 percent of its range in California, possibly due to water released from reservoirs washing away eggs and forcing adult frogs to leave streams.

 

Findings from some of the seven completed projects include:


    – Preventing sharp fluctuations in water levels from April through June (breeding season for the Foothill yellow-legged frog on the North Fork Feather River) can enhance breeding success of this species;
    – Under slow flow conditions, increasing water velocities associated with pulsed flows may decrease the severity of infection with the parasite Ceratomyxa shasta in fish (such as salmon) in the Klamath River;
    – Seasonal pulsed flows for channel maintenance/recreation in the Pit River should be scheduled during or after September to minimize interference with reproduction of freshwater mussels;
    – Pulsed flows from hydro projects have no significant effect on the distances certain fish species (rainbow trout, brown trout, hardhead, and Sacramento suckers) move before, during, or after the release of the flow or on the number of fish in a particular river reach; and
    – Operators of hydro projects in the snow/rainfall transition zone of large Sierra Nevada river watersheds should develop a specific regimen to release pulsed flows that will help recover and sustain the river ecosystems (which are significantly affected by the annual snow melt and winter floods).



– For more information, visit the website: http://animalscience.ucdavis.edu/pulsedflow/index.htm.

 

R&D Forum

PGE to perform telemetry study at Willamette Falls

In the spring and summer of 2009, Portland General Electric (PGE) plans to implement a telemetry study at its 16.8-MW Willamette Falls project in Oregon. The goal of this study is to evaluate lamprey passage at the project as a result of several recent modifications to the fish passage structures, says Tim Shibahara, fish biologist with Portland General Electric.

The 2009 telemetry study will characterize lamprey passage at the project, including recent modifications to the flow control structure and the north fish bypass, Shibahara says. The study also will focus on the performance of the several recently installed lamprey passage structures and aid in continuing to investigate opportunities for improvements. Shibahara says results of the study will provide passage efficiency and timing data.

During the 2008 lamprey passage season, PGE initiated construction of several significant structures on the concrete cap that sits on top of Willamette Falls, on the Willamette River, to improve passage of Pacific lamprey, Shibahara says. This work included:

– Construction of three lamprey ramps. Personnel verified successful upstream passage of Pacific lamprey using these ramps;

– Modification of a once defunct fishway to provide lamprey passage. Again, successful upstream passage was verified; and

– Minor modifications to improve lamprey passage within the fish ladder. These changes primarily addressed migration barriers posed by bulkhead slots.

The need for the above changes was identified from research performed to satisfy the conditions of the project’s Federal Energy Regulatory Commission new license (relicense), issued in 2005. The research showed that only 35 percent of the Pacific lamprey studied passed the Willamette Falls project in 2005, Shibahara says. In contrast, more than 90 percent of radio-tagged fish returned to the project each year. These numbers led PGE to the conclusion that passage of upstream migrating Pacific lampreys at the project was relatively low.

EPRI continues development of fish-friendly turbine runner

EPRI is continuing development of its Alden/Concepts NREC turbine. The next phase of research on this technology will entail producing an engineering design, fabricating a physical turbine model, and testing the model, EPRI says.

Funding for this research comes from an award from the U.S. Department of Energy (DOE) for research and development of advanced water power projects. The DOE award requires a minimum 50 percent industry funding match.

EPRI began development work on this new turbine in 1996. The goal was to develop a turbine that is more than 90 percent efficient and allows fish to pass with a mortality rate of 5 percent or less. The Alden/Concepts NREC turbine features a helix-shaped runner with only three blades. Pilot-scale tests have demonstrated mortality levels below the 5 percent goal for many fish species.

Voith Hydro will produce a preliminary engineering design for the turbine. This includes design of the spiral case, stay vanes, head cover, gate system, bearings, and seals. All major components will undergo stress/strain checks to validate the design. Then Voith Hydro will design and fabricate a physical model for performance testing. Testing will measure turbine efficiency, cavitation inception, power, pressure pulsation, gate torques, axial thrust, and runaway speed. Results of these analyses will support refinement of the design and assessment of its performance relative to traditional hydro turbine designs. All of these tasks are scheduled to be complete in 2009.

Brookfield Renewable Power is interested in testing the new turbine at its 49.8-MW School Street project on the Mohawk River in New York. In February 2007, the Federal Energy Regulatory Commission granted Brookfield a license to test the advanced turbine-generator at the project.