Science/Ecology

A Cost Effective and Environmentally Sustainable Approach To Retrofitting Existing Dams for Hydroelectric Power Generation

Source: 
Waterpower XVI
Year: 
2009
Abstract: 

Hydraulic potential stored in water reservoirs can be converted to useful power through the work of turbomachinery. However, nations around the world have large numbers of existing dams with hydropower potential left unused. These dams were mostly built during the latter half of the 20th century. At that time, thermal electric energy supply, generated with abundant cheap fossil fuels made small scale hydropower generation less attractive. Another reason for such low utilization of these clean renewable energy resources is the significant capital cost of equipment and hydropower plant construction. This made small hydropower development economically noncompetitive. With the rapid depletion of fossil fuel and the increased environmental and global warming concerns, it becomes highly desirable to harness clean renewable energy sources.To retrofit a conventional hydroturbine onto an existing dam brings out several major issues. They include structural integrity and safety of the dam, and the cost of construction and complex engineering tasks involved in properly integrating a powerhouse into the existing structure. These issues have seriously impeded the progress in developing these hydroelectric potentials. In addition, available data indicates that existing hydroturbine technology has some undesirable ecological impacts by causing injury and mortality to passing fish and deterioration of downstream environmental condition resulting from undesirable levels of dissolved gas.In this paper the authors will first briefly summarize current hydropower development needs and challenges, and then describe a new approach to effectively meeting these challenges by using an innovative hydroturbine system. The new hydroturbine system consists of four key design innovations: 1) an updraft flow arrangement, 2) a vertical pressure-balanced turbine flow control valve in place of the conventional wicket gates, 3) a divergent runner flow chamber serving the function of the draft tube, and 4) exit flow at the free surface in the tailwater terrace.

Author(s): 

David T. Kao, Ting Zhong, James R. Mahar

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Fish Passage for Resident Fish?

Source: 
Waterpower XVI
Year: 
2009
Abstract: 

Public Service Company of New Hampshire (PSNH) is a vertically integrated public utility that owns and operates nine hydroelectric projects in New Hampshire totaling approximately 70 MW. PSNH’s 1.1 MW Canaan Project is located on the upper Connecticut River in the states of New Hampshire and Vermont. The relicensing of this project was one of seven “pioneer” projects electing to utilize the Federal Energy Regulatory Commission’s (FERC or Commission) new Integrated Licensing Process (ILP) during the initial transition period.During the ILP scoping process, resource agencies and intervenors requested that PSNH study the feasibility of upstream fish passage at the Canaan Project. There are no Atlantic salmon or other migratory fish in the project area: upstream fish passage was proposed for indigenous brook, and non-native brown and rainbow trout and other non-migratory resident fish. A standard Denil fishway and an Alaska Steeppass were determined to be technically feasible options and were evaluated for economic feasibility by PSNH’s consultant, Kleinschmidt Associates

Author(s): 

Catherine Shively, James Kearns

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Hoover Dam Modernization Project First of Its Kind

Source: 
Waterpower XVI
Year: 
2009
Abstract: 

The U.S. Department of the Interior’s Bureau of Reclamation (Reclamation), established in 1902, is best known for the dams, power plants, and canals it constructed in the 17 western states that led to homesteading and promoted the economic development of the West. Reclamation has constructed more than 600 dams and reservoirs including Hoover Dam on the Colorado River. Reclamation is the second largest producer of hydroelectric power in the United States. Its 58 power plants annually provide more than 40 billion kilowatt hours annually, generating nearly a billion dollars in power revenues, and producing enough electricity to serve six million homes.In October 2006, Reclamation awarded a contract for the modernization of the 26 hydroelectric generating units at Hoover, Davis, and Parker Dams on the lower Colorado River. Hoover Dam power generation is used to meet load regulation requirements and fast, predictable, repeatable unit control provides significant benefits. The project upgrades all unit control and protection equipment, replacing some equipment dating back to the 1940s that was not easily maintainable.Unique about this project was that Reclamation elected to obtain a commercial solution based on demonstrated success by the vendor in recent similar projects rather than issuing the traditional custom design specification. The vendor was to use commercially available components and previously proven designs. Reclamation identified work boundaries, conceptual requirements and objectives stating that cutting-edge technologies and custom solutions would not be considered.L&S Electric, Inc. (Rothschild, Wis.), was awarded a $5.7 million contract for the modernization project to upgrade the existing mechanical governors to digital, install new digital generator and transformer protective relays, install new programmable-logic-controller-based unit controls, and replace static pilot exciters with new digital equipment. L&S Electric was responsible for system integration, engineering and equipment modernization, and was required to standardize the hardware design for all 26 units. Twenty months after the contract was awarded, the first six upgraded units were operational. This is no small feat considering that similar automation projects based on traditional government specifications have taken five to 10 years from award to operation.The benefits received from just eight of 26 upgrades have already improved power system control. Power system oscillations caused by rapid changes in demand during heavy summer power requirements were reduced during the summer of 2008 using the improved unit control responses. Significant improvements are expected in operating efficiency (power produced from water delivered) as the remaining upgrades are completed.

Author(s): 

Chau Nguyen, Terry Bauman

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Rapid Hydropower Assessment Model Identify Hydroelectric Sites Using GIS

Source: 
Waterpower XVI
Year: 
2009
Abstract: 

The ability to identify renewable energy resources is of paramount importance in reducing fossil fuel dependency and addressing climate change. The Rapid Hydropower Assessment Model (RHAM) uses a Geographic Information System (GIS) to identify hydroelectric power opportunities. Using a Digital Elevation Model (DEM) and regional hydrologic data, RHAM calculates the amount of hydroelectric power available on all streams in a study area, screening out sites within parks and environmentally sensitive areas, and estimates project costs. RHAM can also assess the suitability of hydroelectric development in a given area, taking into account economic, environmental and social factors, and can assess storage hydro and clustered developments.n 2007, RHAM was used to assess run-of-river hydroelectric potential for the Province of British Columbia, Canada, an area of approximately 95 million hectares. Over 8,000 potential hydroelectric opportunities were identified. The Consulting Engineers of British Columbia recognized RHAM with an Award of Merit in 2008. RHAM is being applied in other parts of the world to unlock hydroelectric potential, reduce carbon fuel dependence, and help ensure a sustainable energy future for the world.

Author(s): 

Ron Monk,Stefan Joyce, Mike Homenuke, Kerr Wood

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