R&D Forum

EPRI studying how climate policy affects retrofit investments

EPRI is undertaking a project to provide information on how climate policy and natural gas prices can affect decisions to invest in unit retrofits. The goal of this project is to provide information that may help a utility conduct a market-based assessment of how much investment its retrofit units can support (measured in dollars per kilowatt) and how a unit’s investment worthiness may change with respect to climate policy and natural gas prices, says Victor Niemeyer, technical executive with EPRI.

In addition to performing engineering and technology assessments when considering the cost of a retrofit, project owners must assess the unit’s role in the power market and how that role changes with climate policy or swings in natural gas prices, Niemeyer says. In the event of a stringent national policy to limit carbon dioxide emissions, the cost to retrofit a unit could exceed the benefits of keeping the unit compliant, he says. However, Niemeyer says hydro units are uniquely situated in that a national limit would positively influence a unit retrofit.

The analysis will be performed based on EPRI’s Regional Power Market Analysis framework. This analysis entails a detailed bottom-up simulation of a regional power market. EPRI works with the participating utility to specify its generation mix, candidate units for retrofit investment, regional power market, and key planning and financial analysis assumptions. Relevant climate policy and fuel price scenarios also are identified.

Projects are expected to take four months to complete, Niemeyer says.

Two Canadian companies recognized for research

Triton Logging Inc. and AXYS Technologies Inc. have been recognized as Canadian Innovation Leaders for linking scientific research to commercialization, jobs, and economic growth.

A Canadian Innovation Leader is a small- or medium-sized enterprise that demonstrates specific advances in research and development within its industrial sector. The National Research Council of Canada created the Canadian Innovation Leader Certificate Program.

Triton Logging researches, develops, and commercializes technologies to recover millions of trees flooded by construction of dams and hydroelectric facilities around the world. The company designs and manufactures underwater logging equipment, manages large-scale reservoir harvest projects, and markets certified eco-wood products.

AXYS Technologies designs, manufactures, and maintains remote environmental monitoring systems that can measure weather, water quality, greenhouse gases, and other environmental data. The company currently is developing an offshore wind-resource assessment buoy capable of gathering data needed to determine the best locations for constructing wind farms.

Hydropower research center to be established in Alaska

The University of Alaska Anchorage and the community of Girdwood, Alaska, are working to establish the Girdwood Renewable Energy Research and Discovery Center.

The center will study small-scale hydropower and other renewable energy technologies, says Professor Orson Smith, chair of the university’s Civil Engineering Department. The center will include research and education facilities, as well as field sites for instream hydrokinetic, tidal, and micro-hydropower turbine testing.

In August 2008, the team developing the center initiated a feasibility study to investigate options for building and operating this center. In June 2009, the team completed a feasibility report that indicates the facility will take several years to develop and cost about $20 million for planning, construction, and instrumentation.

The full report is available on the Internet at www.engr.uaa.alaska.edu/research/Girdwood-Renewable-Energy-Project.cfm.

The university’s School of Engineering is seeking partnerships with private industry and public agencies to help bring the project to fruition.

Professor receives grant for water quality research

Dr. Jane Caffrey, associate professor at the University of West Florida, received a $25,000 “Minding the Planet” grant from the YSI Foundation. This grant is intended to help Caffrey synthesize water quality data and address issues of climate change.

Caffrey plans to use the grant to fund a graduate student project. The goal of this project is to analyze nutrient and continuous dissolved oxygen data from five Natural Estuarine Research Reserves in the Eastern Gulf of Mexico and the Florida Atlantic Coast. This analysis will be performed in estuaries with ten or more years of data to determine how these systems respond to climate variability and human-influenced stressors.

YSI designs sensor instrumentation and real-time monitoring systems to protect natural resources and aquatic life.

More Hydro Review Current Issue Articles
More Hydro Review Archives Issue Articles

R&D Forum

Numerical model study of Smithland sediment mitigation

A recently completed numerical model study of flow and sedimentation patterns downstream from the Smithland Locks and Dams indicates that downstream sediment accumulation should be manageable, says Phil Meier, assistant vice president of hydro development with American Municipal Power Inc. (AMP).

The study, completed by Alden Research Laboratory Inc. for AMP, quantified changes in flow and sedimentation patterns resulting from a change in discharge patterns after construction of a power plant. The company plans to add a 74-MW hydro facility to the structure on the Ohio River in Kentucky. The lock and dam facilities are operated by the U.S. Army Corps of Engineers.

Construction of the power plant will change the downstream discharge patterns at the dam, Meier says. Currently, for all flow less than 300,000 cubic feet per second (cfs), flow passes through 11 radial gates on the west side of the river. Once the hydro plant is built, AMP proposes that the first 50,000 cfs will pass through the turbines, with about 3,000 cfs being used to operate the locks and as leakage. The powerhouse will be located on the east side of the river.

Alden used the MIKE 21-C model developed by DHI to simulate a range of steady state flows from 18,000 to 929,000 cfs, Meier says. The two-dimensional curvilinear model was used to simulate existing and proposed conditions. The effects of the power plant were quantified using the change in bed elevation. In addition, two 100-plus-day flood hydrographs were modeled to evaluate how the tailrace accumulates and scours sediment over extended periods of time at high flow.

Results from this model show that changes in sedimentation patterns are local. The model does not show significant changes in erosion and sedimentation in the navigation channel. The model did indicate that the tailrace channel, which will be excavated through a downstream island, requires armoring to prevent it from migrating downstream. The model also indicated that, although the tailrace channel will accumulate sediment during high-flow periods when the plant is not operating, low-flow periods will scour the tailrace with minimal use of mechanical dredging.

High salmon returns predicted for Columbia River in 2010

NOAA Fisheries predicts large returns of chinook salmon to the Columbia River in 2010. The federal government agency says its prediction is based on highly favorable conditions for growth and survival of salmon that entered the ocean in the spring and summer of 2008. NOAA Fisheries has tracked 11 ocean ecosystem indicators since 1997 to determine how variability in ocean productivity affects adult salmon returns in the Pacific Northwest, says John W. Ferguson, director of the fish ecology division of NOAA Fisheries’ Northwest Fisheries Science Center.

Scientists know that survival of juvenile salmon immediately after entering the Pacific Ocean varies with the state of ocean productivity. Salmon and steelhead in the Columbia River do best when the Gulf of Alaska is warm and the Oregon and Washington coastal ocean is cool, Ferguson explains. Under these conditions (known as a negative Pacific Decadal Oscillation or PDO), the flow of water coming down the coast from the North Pacific Ocean, called the California Current, is strong. This cold water contains lipid-rich zooplankton favored by juvenile salmon, Ferguson says. In addition, winds along the Washington, Oregon, and California coastline are strong and northwesterly, causing a phenomenon known as upwelling that brings nutrients up to feed the organisms that fish eat near the surface of the ocean.

To determine the PDO cycle, scientists compared conditions in the ocean against records of salmon harvests dating to the early 1900s. For most of the 20th century, the PDO occurred in about 20-year cycles. However, more recently the changes have occurred as close as four years apart, Ferguson says. During the most recent warm-water period (2002 to 2005), salmon returns declined. In 2006 and 2007, coastal ocean conditions for juvenile salmon were in transition from a warm (unproductive) state to a cool (productive) state but were improving each year.

The results of seven of the indicators NOAA Fisheries tracks are:

— PDO: The second most negative value of the past 11 years occurred in the winter of 2007 to 2008, providing good conditions for both coho salmon and yearling chinook salmon survival;

— Multivariate El Niño-Southern Oscillation (ENSO) Index: This index was negative through 2008, indicating warm water was not being transported northward along and into the coastal waters off Oregon and Washington. Thus, the coastal waters stayed cold and the productive source water continued to be supplied from the eastern Pacific Ocean;

— Sea surface temperature: Winter temperatures were the coldest in 11 years, providing favorable conditions for fish survival;

— Deep water temperature and salinity: The coldest and saltiest water in 11 years was measured in 2008, indicating nutrient-rich water was present during the entire upwelling season;

— Coastal upwelling: Upwelling began in late March 2008 and winds were steady during much of the summer, leading to an average year for upwelling. In addition, the transition from warm-water zooplankton to cold-water zooplankton occurred in early March 2008, meaning the food chain was populated by lipid-rich northern species early in the year;

— Copepod species biodiversity: There was moderately low biodiversity of copepod species (marine crustaceans) in 2008, again indicating that the source of the water along the coast was from the eastern Pacific Ocean; and

— Catches of juvenile spring chinook in the ocean in June: In June 2008, trawl surveys showed the highest number of juvenile spring chinook salmon caught of the 11 years studied.

Taken together, these indicators suggest that conditions juvenile salmon from the Columbia River experienced when they entered the ocean were highly productive and favorable for successful recruitment to adulthood. This suggests that the return of chinook salmon to the Columbia River in 2010 will be large, Ferguson says.

CEATI completes study on optimum rewind timing

CEA Technologies Inc. (CEATI) announces completion of a study that details a process for determining the optimum time to replace a generator stator winding. The report on this study is titled Optimum Timing for Generator Stator Rewinds.

The stator winding of a generator is a major component in the reliability assessment of a hydroelectric plant, CEATI says. Although failures of the stator winding are infrequent, their economic effects due to repair/replacement cost and outage cost can be significant. For this reason, plant owners often decide to rewind stators after signs of moderate aging, before the winding reaches the wear-out region of the reliability curve. Thus, they are replacing a winding that is not at or near the end of its useful operating life.

The objective of the study was to develop a process that would provide a rational basis for determining the optimum time to replace a generator stator winding, CEATI says. This process includes:

— Analysis of the causes of the gradual aging of a winding;

— Assessment of the winding condition from inspection and tests; and

— Assessment of the future failure probability for a specific generator, based on its winding condition.

The report identifies and describes key winding degradation mechanisms that contribute to high winding failure probabilities. CEATI then developed projected failure probability estimates from these mechanisms, using databases and assessments by specialists. When more than one failure mode is identified during a winding condition assessment, a combined failure probability must be evaluated, CEATI says. The failure probabilities can be combined using a software tool and a procedure developed as part of the study, CEATI says.

— For more information, contact (1) 514-866-5370; E-mail: chris.hayes@ceati.com.

More Hydro Review Issue Articles