R&D Forum

Hydro-Québec studying greenhouse gases at Eastmain 1

Canadian utility Hydro-Québec is in the midst of an eight-year study to quantify greenhouse gas (GHG) emissions from its 480-MW Eastmain 1 project on the Eastmain River.

Hydro-Québec’s goal is to evaluate net GHG emissions from a reservoir impounded for a hydro project, says Dr. Alain Tremblay, senior environment advisor – aquatic systems for Hydro-Québec Production. The utility began studying the site of the Eastmain 1 project in 2003, three years before impoundment of the reservoir began. Research will be completed in 2010, five years after impoundment of the reservoir.

To determine net GHG emissions, Hydro-Québec is studying:

    – Aquatic systems, to quantify carbon dioxide (CO 2) and methane (CH 4) fluctuations, as well as the amount of carbon in the reservoir compared with natural lakes or rivers in the area of the reservoir;
    – Terrestrial systems, to quantify CO 2 and CH 4 fluctuations, as well as the amount of carbon in a natural forest; and
    – Stable isotopes, to determine the source of organic matter.

The reservoir for the Eastmain 1 project covers 603 square kilometers. Tremblay says the area being studied includes forests and peat land in the basin, at a radius of about 20 kilometers, that were flooded by the reservoir. To determine the carbon stored in the peat, the utility performed core sample drilling. This provided information on the state of decomposition of the organic matter and the quantity of organic matter flooded. Having this data will allow Hydro-Québec to determine how much carbon is lost after flooding and whether the reservoir is a sink or a source of greenhouse gas over the long term.

To monitor CO2 fluctuations from the surface of the reservoir, the utility is using floating chambers – made using plastic containers covered with aluminium foil – connected to a model CIRAS-SC real-time analyzer manufactured by PP-Systems. The measurements are taken over a period of ten to 12 minutes, Tremblay says. This technique allows good coverage of the CO2 emissions over the reservoir surface.

To document temporal variations in CO2 fluctuations, Hydro-Québec is using four automated systems that measure CO2 and CH4 every three hours. Two of those systems are installed on rafts in the Eastmain 1 Reservoir, one is installed at the inflow of the reservoir, and one is installed in the Eastmain 1 powerhouse.

Hydro-Québec is using floating chambers, made using plastic containers covered with aluminium foil, to monitor CO2 fluctuations from the surface of the reservoir of its 480-MW Eastmain 1 project. Click here to enlarge image

Hydro-Québec also is gathering data using two Eddy covariance towers supplied by Campbell Scientific and Li-cor. These towers are being used to determine CO2 concentration, temperature, light, wind speed, and wind direction. One tower is on a small island to provide an image of the reservoir CO2 emissions, and the second is in unburnt forest to the west of the reservoir to establish a baseline for the natural systems. These towers measure carbon dioxide fluctuations at a high frequency (i.e., ten measurements per second). Using this technique allows measurements from a small surface area (about 0.5 square meters) to be extrapolated to cover a larger area of about 1 square kilometer.

Measurements carried out over the life of the project are being entered into an ecosystem model developed by Dr. Nigel Roulet’s research group from McGill University. This will allow comparison of predicted levels against actual measurements.

– For more information, visit the website: www.eastmain1.org.

Study finds similar survival in dammed and undammed rivers

A new study indicates that factors other than the presence of dams in a river are causing survival problems for salmon populations in the Pacific Northwest. The study, directed by Kintama Research Corporation, found that survival in the heavily dammed Snake and Columbia rivers in the U.S. was approximately equal to survival in the undammed Fraser River directly north of the Columbia River in Canada.

This research was partly funded by the Bonneville Power Administration, the Northwest Power Planning and Conservation Council, and the U.S. Army Corps of Engineers.

Researchers tracked fish using two methods. On the Columbia and Fraser rivers, they used the recently installed Pacific Ocean Shelf Tracking (POST) system, an acoustic telemetry system that consists of a series of 300 receiver arrays that run from San Francisco Bay up to southeast Alaska. They compared these results with data from passive integrated transponder (PIT) tags and detectors installed at dams on the Columbia River in the 1990s. Use of acoustic tags, with much greater range than PIT tags, allows tracking of smolts in large undammed rivers such as the Fraser.

From 2004 to 2006, researchers implanted hatchery-reared spring chinook and wild steelhead smolts in the Fraser River with acoustic tags and tracked them from tributaries to the mouth and then into the ocean. To provide comparable data for the Snake and Columbia rivers, researchers used existing PIT tag data, in combination with a single acoustic study covering this entire river system, in 2006, and several years of acoustic tagging that covered only the lower Columbia River.

For both rivers, results indicated that about 35 percent of the tagged fish survived to the river mouth, says David Welch, president of Kintama Research in British Columbia, Canada. However, the trip down the Columbia River is much longer – 900 kilometers versus 340 kilometers in the Fraser. Accounting for the distance traveled, results indicated hatchery spring chinook incurred higher mortality rates per kilometer in the Fraser River than those traveling down the Snake and Columbia rivers.

Although survival rates in the two rivers are similar, Welch says it is unclear whether these rates are a result of past efforts to improve hydropower operations and reduce predators in the Columbia or unidentified problems in the Fraser River. The bottom line is, if survival in a dammed river is the same as that in an undammed river, it is likely something other than the dams is causing survival problems, Welch says. He says poor survival to adulthood in both rivers could be due to the common effect of ocean conditions. Possible negative factors include ocean warming, increased predation by seals and sea lions, and parasite or disease infestations spread by coastal salmon farms.

Applying cone penetration testing in intermediate soils

Research being performed at the University of California Davis aims to develop a recommended test procedure and data interpretation methodology for using cone penetration testing in intermediate soils.

Intermediate soils are those between coarser-grained soils (sands) and finer-grained soils (clays and plastic silts). Cone penetration testing can be used in these soils to assess the stability of existing earth dams and levees. This testing is assumed to create drained conditions in sands and undrained conditions in clays at a standard penetration rate of 2 centimeters per second. However, because the permeability of intermediate soil falls between that of sand and clay, neither drained nor undrained conditions exist at the standard penetration rate. As a result, it is difficult to reliably estimate drained and undrained strengths for intermediate soils using conventional cone penetration test data.

Researchers at the university are examining the potential to control the drainage conditions in the soil around the test area by varying the rate at which the testing apparatus is penetrated into the ground. The theory is that increasing the rate of penetration during the test can create undrained conditions. Similarly, decreasing the rate of penetration during the test can create drained conditions.

Preliminary results indicate that varying the penetration rate can control drainage conditions during cone penetration testing and can be used to estimate the drained and undrained properties of intermediate soils, says Robert A. Jaeger, PhD student, a member of the research group.

The end product of this research will be a recommended test procedure and data interpretation methodology that practitioners can use to improve the characterization of intermediate soils in dams and levees, Jaeger says.

Study finds many states fail in communicating emergency plan

Nearly half of all U.S. states either do not have a state-level emergency plan or do not make this plan readily available to the public. This is according to a study called “Using Sense-Making and Co-orientation to Rank Strategic Public Communication in State Emergency Operations Plans,” performed by Carl Botan, communication professor at George Mason University.

The Stafford Disaster Relief and Emergency Assistance Act, passed in 1988, requires all states to have an emergency operations plan (EOP) in order to qualify for some federal funding. However, 22 states were unable to provide their EOP to Botan, withheld the plan on security grounds, or made it difficult for even trained researchers to gain access to the EOP.

Botan analyzed the 29 accessible state EOPs (28 states and the District of Columbia) for three criteria: a two-way communication component, addressing the communication needs of vulnerable populations, and treating public communication as important enough to specifically address it.

Of these 29 EOPs, only 16 make explicit or implicit provisions for two-way public communication (such as community forums or focus groups). Only 13 state EOPs discussed specific communication strategies for vulnerable populations (such as dispatching special teams targeting vulnerable populations like the disabled). With regard to specifically addressing public communication, 26 of the 29 states fulfilled this criterion.

Only two states – the District of Columbia and New Mexico – received perfect scores for communication of their EOPs.

EPRI seeks funding of generator repair research

EPRI is seeking $180,000 in funding from the hydroelectric industry to support research on how to restore safe operation of a generator after failure of one or more coils in the stator winding.

The institute seeks supporters who will provide $30,000 each. Companies that fund any EPRI program can take advantage of tailored collaboration funds for up to half of their contribution, says Jan Stein, senior project manager.

After failure of a stator winding, project personnel can isolate, or cut out, the failed coil from the rest of the winding and quickly return the units to service, Stein says. Use of temporary repair procedures such as this can keep a machine in service until it can be permanently repaired or replaced, providing substantial economic benefit, Stein says.

This research project updates work described in EPRI report EL-4983, Synchronous Machine Operation with Cutout Coils, published in 1987.

The objectives of this project are to:

    – Update and expand calculations about how many and which coils can be safely cut out;
    – Provide guidance for performing parallel circuit current measurements to validate stator winding operation within its thermal limits; and
    – Learn more about the effect of the winding with cut-out coils on vertical shaft run out.

– To fund this research, contact Jan Stein at (1) 650-855-2390; E-mail: jstein@epri.com.

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