Innovative Environmental Technologies Brighten Hydro's Future
Statement of Richard K. Fisher, Jr., Vice President, Technology, Voith Hydro, Inc.
Patrick A. March, Senior Manager, Norris Engineering Laboratory, TVA Resource Management
Dilip Mathur, Ph.D., Vice President, Normandeau Associates
Fotis Sotiropoulos, Ph.D., Assistant Professor, Georgia Institute of Technology
Gary F. Franke, Senior Engineer, Voith Hydro, Inc.


Environmental concerns broadly affecting the electric power generation industry include the potential for global climatic changes as a result of greenhouse gases produced by combustion, the depletion and disruption of fossil fuel supplies, air and water quality, aquatic life impacts, and uncertainties about long-term nuclear waste management. As a result of these concerns (in many instances stimulated by environmental groups and regulatory agencies), the U.S. electric power industry is focusing attention on technologies for renewable, non-polluting energy generation. Among these, hydroelectric power generation can play a significant role.

By impounding water in reservoirs and harnessing nature's energy through hydroelectric generating plants as a part of the solar water cycle, hydropower provides a renewable, nonpolluting source of energy. Hydropower is by far the largest developed renewable energy resource in the world, supplying about ten percent of the electricity output in the U.S. and approximately twenty percent of all electricity generated worldwide [1]. In the near term, further development of hydroelectric energy generation potential, through upgrade of existing plants and installation of new facilities, could increase clean energy production and make a near term contribution to the reduction of greenhouse gas emissions [2].

Impoundments and releases from hydropower facilities can, under certain conditions, adversely impact the water quality of impounded and discharged flows as well as the aquatic life upstream, downstream, and migrating through the sites. These impacts have been severe enough to cause political and environmental activists to demand improvements. Today, in the U.S., environmental demands include the release of higher spills from impoundments to increase fish passage survival and even demands for the removal of large dams in some areas of the country, in both cases reducing hydra energy generation.

To address these adverse effects of hydropower facilities, new technologies are emerging which, when applied, can remove many of the negative environmental effects of hydroelectric power generation and enhance the recognition of hydra power as a source of renewable energy. Some of these new developments address the improvement of fish passage survival and the reduction of hydro's impact on both water quality and aquatic habitat. This presentation will discuss work currently underway in the U.S. related to these issues.

Hydroelectric Power Generation

Developing Better Environmental Alternatives

Beginning in the mid-1950s, some operating utilities in the U.S. began to respond to environmental concerns and initiated steps to improve the environmental compatibility of their hydro plants. Two areas of the country were particularly active. In the Pacific Northwest, biologists, governmental agencies, and utilities on the Columbia River were experimenting with ways to increase survival of fish as they passed downstream through hydro plants (Fish passage is now also emerging as an important issue in the eastern U.S.). In the Southeast, the Tennessee Valley Authority (TVA) was a pioneer in utilizing an integrated system approach, finding improved ways to balance the multiple uses of water resource projects among hydro power generation, flood control, municipal and industrial water supply, water quality, and recreation. TVA, adopting a proactive approach to environmental stewardship, has invested significantly in R&D and hardware to develop and implement improvements to system operation that optimize benefits among all stakeholders in their water resource projects [3].

As part of its strategy to be responsive to the needs of its customers, Voith has had a long-term commitment to developing hydro equipment designs with technologies for environmental enhancement. In the 1950s, Voith played a leadership role in Europe with R&D to develop turbine designs capable of boosting dissolved oxygen (DO) levels in water passing through low head turbines [4]. In the 1970s, their engineers began investigations into the use of greaseless components in turbine power control elements. In the 1980s, Voith continued the development of oil-free Kaplan turbine hub designs with the installation of several "Oil Free" Kaplan turbines and began R&D to improve the understanding of issues leading to the mortality of fish passing through hydro turbines [5, 6]. In this same time frame, Voith Hydro, Inc., invested significant funds with TVA into a joint R&D partnership to develop improved hydro turbine designs to enhance DO concentrations in releases from Francis-type turbines.

In the 1990s, these efforts were further intensified [7]. In 1995, under the stimulus of a cost~ shared Department of Energy contract, Voith Hydro, Inc., began an in-depth effort to develop an "Advanced Environmentally Friendly" family of turbine designs, in collaboration with Georgia Institute of Technology, Harza Engineering Co., Normandeau Associates, and the Tennessee Valley Authority. The environmental improvements for the advanced designs addressed the goals of: 1) improving fish passage survival; 2) increasing the levels of dissolved oxygen in hydro plant discharges; 3) developing special turbine designs for efficiently providing minimum stream flows to protect downstream aquatic habitats; and, 4) developing designs to provide reduced oil and grease pollution. These concepts primarily addressed the enhancement of hydropower's environmental compatibility through upgrades of turbines in existing hydro power stations. However, the environmentally improved design concepts also provide added benefits, including improved plant energy generation and reduced operating and maintenance costs, and the concepts are applicable to new turbine installations as well. An independent investigation by the joint venture of Alden Research Laboratory, Inc., and Northern Research and Engineering Corporation, under a second DOE contract, also supported the achievability of "fish friendly" turbines with a unique design that is primarily applicable to fish bypass flow schemes and new turbine installations.

Today, progressive U.S. operating utilities are upgrading turbines to environmentally friendly designs as a part of their programs for relicensing and energy generation improvement. Utilities and water resource agencies are also developing strategies and implementing control systems that improve how they operate their turbines to enhance water quality and fish survival when fish and/or low levels of DO are present. The direct fish mortality of turbine bypass systems, including spillways (which may also add detrimental dissolved nitrogen) and fish collecting structures, are under investigation to provide an understanding of how all of the components of a hydro project can be used to improve its environmental compatibility. In many cases, passing fish through environmentally enhanced turbine designs can result in higher overall survival than bypassing fish through the dam's spillways [8, 9].

This presentation focuses primarily on environmentally advanced turbine and control system designs and technologies that are being developed to increase fish passage survival and improve levels of DO in turbine discharges.

Increasing Fish Passage Survival

By 1990, over forty years of investigating fish survival by catching fish downstream of turbines had not provided in-depth insights into actual mechanisms affecting fish survival. The turbine had been treated as a "black box" by many researchers, and only vague rules of thumb had been developed to biologically characterize turbines. Statements such as "Turbines are like blenders - - they chop and kill a significant portion of passing fish," "Kaplan turbines are more fish friendly than Francis turbines," and "Operation at best efficiency is best for survival" were used regularly to characterize hydra turbines. Beginning in 1990, a more precise method for measuring fish passage survival was introduced. This technique uses carefully designed and controlled testing with fish which can be recovered with "balloon tags" [10]. Based on the results of those experiments, statistical characterizations demonstrating much higher fish survival began to emerge [11]. Survival rates, measured for fish passing directly through large turbines, ranged from 88 to 94%.

In the past 5 years, important research aimed at further understanding the mechanisms leading to fish mortality has been completed. Numerous workshops bringing biologists, operators, regulators, and designers together to exchange views have improved insight into factors which may influence survival. The US Department of Energy's (DOE) Advanced Hydro Turbine (AHT) program further stimulated an in-depth investigation into mechanisms for fish passage mortality through the use of detailed numerical simulation of fluid flows in turbines with 3-D viscous computational fluid dynamics (CFD) methods and careful balloon tag testing. As a result of the studies, turbine design improvements which can be implemented in new machines or through rehabilitation of existing machines have been developed [12]. Limited field testing to date has verified many of the conclusions reached [13, 14]. An especially enlightening test of the existing turbines at Wanapum Dam using balloon tagged fish verified many of the fish mortality mechanism models [15, 16] and showed that best efficiency operation of Kaplan turbines is not necessarily the most favorable operating condition for fish survival as was previously believed. Instead, operation at higher flows was found to be safer for passing fish (Figure 2). The research developed insights into mortality mechanisms for Kaplan turbines, with mortality being related to: turbulent flows resulting from low efficiency designs or plant operating strategies; turbulent flows and the trapping and cutting of fish in the zone of flow passing near the turbine hub when large gaps between blade and hub exist (characterizing the lower output operation of Kaplan turbines); strike of fish by turbine blades or impact of fish on other turbine structures; cavitation in turbine water passages; abrasion of fish driven into rough turbine surfaces by flow turbulence; and even turbulence~ induced or impact-induced dizziness enhancing the chance for predation losses as disoriented migrating fish are eaten by birds or other fish when they emerge from the draft tube. The number of turbine runner blades and stay vanes, the length of the fish compared to the size of the turbine, and the quality of the flow at the point of operation are key elements that characterize survival [12,16]. Also, the location of the fish in the water column and the zones of flow through which the fish pass are observed to be important.

As a result of insights gained, a comprehensive environmentally enhanced Kaplan turbine concept was developed. The required features depend on site specific goals and include designs having: 1) high efficiency over a wide operating range with reduced cavitation potential (results from today's advanced technology design verification tools); 2) a gapless design for hub, discharge ring, and blades (Figure 3) that enhances fish passage survival; 3) a non~ overhanging design for wicket gates; environmentally compatible hydraulic fluid and lubricants; 4) greaseless wicket gate bushings; 5) smooth surface finishes in conjunction with upgrades for stay vanes, wicket gates, and draft tube cone.

To address the changes in mortality associated with how the turbines are operated, new technology in measurement transducers and in control systems have been used to develop control system designs to: 1 ) sense fish presence at each turbine and limit turbine operation to "fish friendly" modes when fish are present; 2) automatically update Kaplan turbine "digital cam surfaces" to most efficient operation at each head and flow to ensure proper optimization of operations and minimization of fish injuring flow turbulence; 3) sense active cavitation and limit turbine operation to non~ cavitating conditions; and 4) optimize plant output when fish are present to achieve targeted fish passage survival based on fish presence, location, turbine passage mortality, spillway fish mortality, fish bypass characteristics, and total dissolved gas generated during spilling (Figure 4). Furthermore, new technology for generator designs can be implemented for plants with large changes in head. Particularly important for Francis units, turbine operations can be adjusted for optimum fish survival conditions independent of operating head by using adjustable speed generators and advanced control systems.

Elements of the e-"fish"-ent_ Kaplan have been implemented in the rehabilitated designs installed at the Rocky Reach power plant of Chelan County P.U.D. in Washington state in the U.S. [17] and at the Bonneville project of the U.S. Corps of Engineers [18]. An even more advanced design has been developed and model tested for the Grant County P.U.D.'s Wanapum Dam [19]. These turbines feature partially or fully gapless designs as well as a mix of the other features discussed above. Fish survival testing using balloon tags at Rocky Reach showed that elimination of the gaps downstream of the blade center of rotation resulted in a 4% improvement in fish passage survival at lower operating powers where gap size was large [20]. Testing of the fish passage survival of the new minimum gap design at Bonneville is planned for the spring of 1999.

An environmentally enhanced Francis turbine concept was also developed. Features include: a low turbulence, high efficiency design with reduced cavitation having a reduced number of blades compared to traditional designs; a non-overhanging design for wicket gates; use of environmentally compatible hydraulic fluids for governors; greaseless wicket gate bushings; upgraded surface finishes for stay vanes, wicket gates, and draft tube cone; adjustable speed generator for wide head range plants; an advanced control system for speed adjustment and/or for optimized energy generation while operating units and the plant at flows maximizing fish passage survival when fish are present in the flow. Table 1 illustrates the impact of turbine size and number of blades on fish survival.

Further research is underway. Advanced zonal matrix models to estimate fish passage survival as a consequence of turbine geometry and operational characteristics are being developed and evaluated. Figure 5 shows the results of such a model where lines of constant fish passage survival are shown superimposed on the turbine efficiency performance characteristics. Field tests of eel survival for a propeller turbine design correlated well with predicted survival [14] using the zonal matrix model.

In another application of new technology, an advanced computational method for estimating trajectories of fish- like bodies passing through hydropower installations is currently under development. The method is based on the assumption that a fish swimming through the complex, three-dimensional flow field of a hydro turbine (obtained via a separate 3-D viscous calculation) can be approximated as a body of simplified, yet fish-like geometry moving through the precomputed flow field. The motion of such a "virtual fish" is governed by a set of differential equations that account for the fish mass and various flow- induced forces. This model can not only be used to estimate the trajectory of a virtual fish from the forebay to the tailrace (Figure 6), but can also provide very specific information about a variety of flow-induced loads to fish passing through various zones of turbine flow (Figure 7) [21]

Use of these advanced tools in conjunction with wellplanned and well-executed physical tests to validate the injury mechanisms will help turbine designers and biologists improve fish passage survival and enhance the image of hydra power as "green power" and a renewable resource.

Increasing Dissolved Oxygen in Turbine Discharges

Development of methods for increasing dissolved oxygen in turbine discharges has been underway for nearly 50 years. In the last 10 years, significant progress has been made. TVA has been a consistent driver of these developments. Through its Norris Engineering Laboratory, TVA has developed reliable line diffuser technologies for low cost aeration of reservoirs upstream of hydro plants [22] and effective labyrinth weirs (see Figure 8) and infuser weirs for aerating flows downstream from hydra plants [23]. The most cost-effective technology for Francis turbines, where site conditions support it, has been found to be the use of the low pressures induced by the water flowing through the turbine to aerate the flow.

For upgrades and new construction an ongoing joint development effort by TVA and Voith Hydro, Inc., has made substantial improvements in the design of the "auto-venting" turbine (AVT) [23,24,25]. Extensive development with scale models and field tests was used to validate aerating concepts and determine key parameters affecting aeration performance. Specially shaped turbine component geometries were developed for enhancing low pressures at locations for aeration outlets in the turbine water passage, for drawing air into an efficiently absorbed bubble cloud as a natural consequence of the design, and for minimizing power lost as a consequence of aeration. New methods were also developed to manufacture turbine components for effective aeration.

TVA's Norris Dam was selected as the first site to demonstrate this technology. The two Norris AVT units contain options to aerate the flow through central, distributed, and peripheral outlets at the exit of the turbines.

In testing the new auto-venting turbines, measurements are required to maximize the environmental and hydraulic performance of the aeration options. The environmental performance is evaluated primarily by the amount of DO uptake, while the hydraulic performance is based on the amount of aeration-induced efficiency loss. At Norris (Figure 9), each aeration option has been tested [27, 28] in single and combined operation over a wide range of turbine flow conditions. For environmental performance, results show that up to 5.5 mg/L of additional DO uptake can be obtained for single unit operation with all aeration options operating. In this case, the amount of air aspirated by the turbine is more than twice that obtained in the original turbines with hub baffles. To meet the 6.0 mg/L target that has been established for the project, an additional 0.5 mg/L of DO improvement is obtained by the flow over a re-regulation weir downstream from the powerhouse. For hydraulic performance, efficiency losses ranging from 0 to 4 percent are obtained, depending on the operating condition and the aeration options. Compared to the original turbines at the plant, these specially designed replacement units provide overall efficiency and capacity improvements of 3.5 and 10percent, respectively [28]. The new runners also have shown significant reductions in both cavitation and vibration.

In general, the environmental and hydraulic performance of a given option varies with the site head and site power output. Under these conditions, the options used to meet a target DO can be strategically chosen to minimize the aeration~ induced efficiency loss. As an example, consider the 1996 DO data for the new units at Norris, shown in Figure 10. Turbine aeration was initiated in July, when the scroll case DO began to drop. Throughout the low DO season, based on the head, power, and required DO uptake, a mix of aeration options was used. Aeration ended in November after reservoir turnover. On the average, the DO downstream of the project was maintained near the 6.0 mg/L target (except for a period when aeration was disrupted for an extreme series of performance tests of the new units). During the same period, the average aeration-induced turbine efficiency loss was about 1.9 percent.

As is the case with improvements to fish passage survival, additional research is underway to further improve designs for aerating turbines. In one project, computer flow simulations using advanced numerical methods have been developed to model the processes involved in increasing the effectiveness of aeration. "Virtual bubbles" injected into turbine flows are being used to calculate bubble size and oxygen transfer efficiency (Fig. 11, 12). Through the use of the advanced numerical simulation, oxygen uptake efficiency as a function of changing design and operating parameters can be further refined. Improved software to calculate the influence of aspirated air on turbine performance and on the pressure at the air admission point is being studied, and design of improved mechanical systems for transporting air to critical locations is underway. Field tests to verify design assumptions continue to play an important role in improving the methodology.


This paper has reviewed some of the activities and innovative technologies which are currently being used to improve the environmental compatibility of hydropower and to increase its energy generation potential. Rehabilitation of existing hydroplants incorporating new fish-friendly runner designs, aerating turbines, and advanced control systems for environmental optimization is providing improved environmental compatibility as well as increasing generated revenue and reducing maintenance costs. Testing of prototype solutions has indicated that effective improvements are being achieved, improving water quality at hydra sites and reducing hydro's impact on aquatic life. Progressive utilities are working hard to implement these new developments and to operate their hydro systems to balance environmental responsibility and economical power generation.

Significant progress is being made in removing the "tarnish" from hydro's image and supporting hydro's legitimate role as a clean, environmentally sound, renewable, and affordable resource. These advanced technologies and the insights from ongoing R&D are playing a key role in making hydra "shine." The results of the recent improvements in turbine design have been verified at the first test installations. Additional research is needed to refine fish damage models and additional testing must be conducted to enhance the understanding developed to date and to verify the applicability of the new designs to a wider range of projects.


1. SERI (Solar Energy Research Institute), "The Potential of Renewable Energy: An Interlaboratory White Paper," Report No. SERI/TP-260-3674, Golden, Colorado, 1990.

2. Sale, M. J., and D. Neuman, "Hydro's Role in Curbing Greenhouse Gas Emissions," Hydro Review, February 1998.

3. TVA (Tennessee Valley Authority), "Tennessee River and Reservoir System Operation and Planning Review- Final Environmental Impact Statement," Knoxville, TN: Tennessee Valley Authority Resource Development Group, December 1990.

4. Wagner, H., "Experiments with Artificial River Water Aeration," Voith Forschung und Konstrucktion, Heft 4, November 1958.

5. Breymaier, D., "Small Standardized Pit Turbines (ANT) with Oil-Free Runner Hub, Double Regulated," Hydro Vision '94, Phoenix, 1994.

6. Eicher Associates, Inc., "Turbine Related Fish Mortality: Review and Evaluation of Studies," Final Report, EPRI AP-5480, Research Project 2694-4, November 1987.

7. Fisher, R. K., and A. D. Roth, "Design Considerations for Enhancing Environmental Compatibility of Hydraulic Turbines," Proceedings of Waterpower '95, San Francisco, CA, July 1995.

8. Ledgerwood, R., D. Dawley, E. M. Gilbreath, L. G. Bentley, P. J. Sanford, and M. H. Schiewe, "Relative survival of sub-yearling chinook salmon which have passed Bonneville Dam via the spillway or the second powerhouse turbines or bypass system in 1989, with comparisons to 1987 and 1988", U. S. Army Corps of Engineers, Contract E85890024/E86890097, 1990.

9. Normandeau Associates, Inc., and J. R. Skalski, "Chinook salmon smolt passage survival through modHied and unmodified spillbays at Rock Island Dam, Columbia River, Washington," Report prepared for Public Utility District No. 1 of Chelan County, Wenatchee, WA, 1997.

10. Heisey, P. G., D. Mathur, and T. Rineer, "A reliable tag-recapture technique for estimating turbine passage survival: Application to young-of-the-year American shad (Alosa sapidissima)," Can. Jour. Fish. Aquat. Sci., 49:1826-1834, 1992.

11. Mathur, D., and P. G. Heisey, "Debunking the Myths about Fish Mortality at Hydro Plants," Hydro Review, April 1992.

12. Franke, G. F., D. R Webb, R. K. Fisher, D Mathur, P Hopping, P. March, M. Headrick, l. Laczo, Y. Ventikos, and F. Sotiropoulos, "Development of Environmentally Advanced Hydropower Turbine System Design Concepts," York, PA: VoHh Hydro, Inc., Report No. 2677-0141, U.S. Department of Energy Contract DE-AC07-961D13382, July 1997.

13. Normandeau Associates, Inc., and J. R. Skalski, "Relative survival of juvenile chinook salmon (Oncorhynchus tshawytscha) in passage through a modified Kaplan turbine at Rocky Reach Dam, Columbia River, Washington," Prepared for Public Utility District No. 1 of Chelan County, Wenatchee, WA,1996.

14. Normandeau Associates, Inc., and J. R. Skalski, "Estimation of survival of American eel after passage through a turbine at the St. Lawrence FDR Project, New York," Prepared for New York Power Authority, White Plains, NY, 1998.

15. Normandeau Associates, Inc., J. R. Skalski, and Mid-Columbia Consulting, Inc., " Fish survival investigation relative to turbine rehabilitation at Wanapum Dam, Columbia River, Washington," prepared for Grant County Public Utility District No. 2, Ephrata, WA, 1996.

16. Fisher, R. K., S. Brown, and D. Mathur, "The Importance of the Point of Operation of a Kaplan Turbine on Fish Survivability," Proceedings of Waterpower '97, Atlanta, GA, August 1997.

17. McKee, C, and G. Rossi, "Rocky Reach Kaplan Turbines: Development of Fish-Friendly Runners," Hydropower into the Next Century, Barcelona, Spain, 1995.

18. Moentenich, B. "Model Testing Replacement Turbines for the Bonneville First Powerhouse, Proceedings of Waterpower '97, Atlanta, GA, August 1997.

19. Hron, J. J., J. B. Strickler, J. M. Cybularz, "Wanapum Kaplan Turbine Replacement," Proceedings of Waterpower '97, Atlanta, GA, August 1997.

20. Franke, G. F., D. R. Webb, R. K. Fisher, D. Mathur, P. Hopping, P. March, M. Headrick, l. Laczo, Y. Ventikos, F. Sotiropoulos, "Development of Environmentally Advanced Hydropower Turbine System Design Concepts," York, PA: Voith Hydro, Inc., Report No. 2677-0141, U.S. Department of Energy Contract DE-AC07-961D13382, July 1997, Section 4.4.5, page 11 0.

21. Sotiropoulos, F. Y. Ventikos, R. K. Fisher, "A Computational Method for Predicting Fish Passage through Hydropower Installations," Proceedings of Waterpower '97, Atlanta, GA, August 1997.

22. Mobley, M. H., and W. G. Brock, "Aeration of Reservoirs and Releases Using TVA Porous Hose Line Diffuser," ASCE North American Congress on Water and Environment, Anaheim, CA, June 1996.

23. Hauser, G. E., and W. G. Brock, "Aerating Weirs for Environmental Enhancement of Hydropower Tailwaters," Norris, TN: Tennessee Valley Authority Engineering Laboratory, 1 994.

24. USDOE, "Environmental Mitigation at Hydroelectric Projects, Volume 1, Current Practices for Instream Flow Needs, Dissolved Oxygen, and Fish Passage," U.S. Department of Energy Report DOE/ID-10360, 1991.

25. March, P. A., T. A. Brice, M. H. Mobley, and J. M. Cybularz, "Turbines for Solving the DO Dilemma," Hydro Review, Vol. 11, No. 1,1992.

26. Ruane, J. R., and G. E. Hauser, "Factors Affecting Dissolved Oxygen in Hydropower Reservoirs," Proceedings of Waterpower'93, Nashville, TN, 1993.

27. Hopping, P. N., P. A. March, T. A. Brice, and J. M. Cybularz, "Update on Development of Auto-Venting Turbine Technology," Proceedings of Waterpower '97, Atlanta, GA, August 1 997.

28. Hopping, P. N., P. A. March, and R. K. Fisher, "Status and Vision of Turbine Aeration," Proceedings of 27th IAHR Congress, San Francisco, CA, August 1997.

Copyright 1998, Voith Hydro, Inc. All rights reserved.


An Environmentally Friendly Turbine

Program Update

What: The Advanced Hydropower Turbine Systems (AHTS) program seeks to develop turbine and control systems that will allow fish to pass more safely through a hydropower facility. A major technical goal is the reduction of turbine-induced fish mortality to 2% or less compared to current levels ranging up to 30% or greater. The program also addresses other fish habitat issues such as raising dissolved oxygen levels in the water, eliminating pollutants associated with turbine mechanics and improving turbine management to produce minimum stream flows to support aquatic life.

Who: A partnership between the Department of Energy, the Hydropower Research Foundation, Inc. ( a consortium of companies organized by the National Hydropower Association), and two Teams comprising engineers, manufacturers, universities, fish biologists, and plant operators.

Phases: The program is set to begin Phase II and lil when new resources will be used to test the concepts developed in Phase I. Phase I resulted in four turbine design concepts to improve fish passage; Team 1 developed three design concepts that are modifications of existing turbine designs, known as Kaplan and Francis turbines, and Team 2 developed a completely new turbine wheel, or "runner". Once testing of the Team 2 design has been completed using pilot scale turbines and live fish, Phase lil can begin with full-scale prototypes to be built and tested at operating hydropower plants. Team 1 designs are ready for Phase lil full-scale prototype testing, and being integrated into ongoing rehabilitation projects.

Funding: Since 1994, the program has received approximately $4 million with industry spending an additional $10 million in design development. The AHTS program is scheduled for additional funding consideration. Congress appropriated $2 million for FY '99, a significant increase from the $750,000 in federal funding the program received last year. $35 million for continued Phase II and lil testing are being requested for FY 2000~ 01.

The Turbine Concepts:

Modified Kaplan: Eliminating runner gaps, improved blade shapes and an advanced control system to sense the presence of fish are some modifications to a Kaplan turbine designed by the Voith Hydro, Inc. led team of engineers, biologists and university researchers that may increase survival rates to 98% according to one preliminary study. These modifications, usable today at existing hydro plants, also result in more efficient energy production, increasing the value of the turbine to the owner. Bonneville Dam on the Columbia River is installing an advanced "minimum gap" turbine now which is scheduled to go into operation in early 1999. A replacement turbine with even more advanced "fish friendly" features has been developed and scale model tested for the Wanapum Dam on the mid-Columbia River. The manufacture and conversion of the existing turbines at Wanapum Dam into this more advanced design is waiting for regulatory agreements to allow its productive use. A control system to sense the presence of fish and operate turbines at their points of maximum fish passage survival when fish are present has also been developed to work with existing or the advanced design Kaplan and is ready for Phase lil evaluation now.

Modified Francis: Fewer blades, improved blade shapes and larger spaces between blades make this turbine act more like a revolving door for fish passage. Several of these "lower blade number" designs have been installed and are operating. Another revolution in design is the use of hollow blades and aerating holes that increase the amount of dissolved oxygen in water passing through the turbine. This helps fish thrive in waters below dams in the Southeastern part of the U.S.. An aerating turbine, jointly developed by Voith Hydro, Inc. and TVA has been installed at TVA's Norris Dam. Another aerating turbine is currently being manufactured for Duke Power's Wateree project. Further refinements could be incorporated into U. S. Army Corps of Engineers projects currently funded for conventional turbine rehabilitation.

Spiral blade design: Only two or three blades and an elongated helical shape define the new runner developed jointly by Alden Research Laboratory, Inc. (ARL) and Northern Research and Engineering Corporation (NREC). This turbine has the potential to approach 100% fish survival. Because of its reduced power generation characteristics, and its size, it is mostly suited for new hydra projects, or for installation in fish bypass flows.

The Big Picture: The successful completion of the Advanced Hydropower Turbine Systems program could greatly enhance the nation's ability to produce a domestic source of clean and renewable electricity while lessening, or even eliminating, impacts to fish and fish habitats. Additional benefits include further reductions in greenhouse gas emissions and establishing a competitive edge for U.S. exports of turbine technology.

For further information, please call: Richard K. Fisher, Jr, Vice President, Voith Hydro, Inc. (717) 792-7848 James McKinney, National Hydropower Association (202) 383-2535 RKF, NHA, 10/98