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Research under way to optimize hydro plant scheduling

Argonne National Laboratory, under sponsorship from the U.S. Department of Energy, is working to develop the Conventional Hydropower Energy and Environmental Systems (CHEERS) model.

This tool is designed to optimize hydro plant day-ahead scheduling and real-time operations. Its goal is to aid operators with such decisions as unit commitments and turbine level operating points by using a system-wide approach to increasing hydropower efficiency and enhancing the value of power generation and ancillary services.

The model will be capable of determining schedules and operations that are constrained by physical limitations, characteristics of power plant components, operational preferences, reliability and security regulations, and environmental considerations, says Thomas D. Veselka with Argonne National Laboratory. Hydropower system aspects the tool will incorporate into the optimization include head and tailwater calculations, cascade interactions, turbine efficiency curves and rough zones, switch and transformer limitations, and operator preferences.

The model will be applied at demonstration sites in several diverse hydrological regions, Veselka says. For example, CHEERS will be applied at the Salt Lake City Area Integrated Projects, which is composed of several hydro plants, including 1,320-MW Glen Canyon, 144-MW Flaming Gorge and the 283.4-MW Aspinall Cascade.

The target date for completion of model development and site demonstration is September 2012.

EPRI, DOE working on grid value study

The Electric Power Research Institute and the U.S. Department of Energy are working together on a research project, Quantifying the Value of Hydropower to the Grid.

With policies, regulations and market changes encouraging new renewables (such as wind and solar) and traditional renewables (primarily hydropower), expected future limits on CO2 emissions and the addition of variable renewables can shift economic break-points in favor of hydro, including pumped storage. The goal of this project is to enhance and expand analysis tools for applying and valuing hydropower assets in the changing electric grid.

Quantifying the value of the benefits from hydro facilities provided by ancillary services and renewable integration is crucial for formulating sound policies and regulations, for developing fair markets and for investing wisely in energy and transmission infrastructure to ensure energy security and to address climate change concerns, EPRI and DOE say.

The project is broken into nine tasks:

Each task will produce one or more public reports. Two workshops will be held to better define the modeling advances necessary to capture the value of hydropower, one focused on WECC and one targeted toward general hydropower modeling needs.

All work is expected to be complete in the second quarter of fiscal year 2012, culminating in publication of a final project report.

Study reveals benefits of gatewell inclusion screens

Results of a recent study performed at the 1,038-MW Wanapum and 855-MW Priest Rapids project indicate that exclusion screens on gatewells may be an effective method of keeping fish from becoming entrained into gatewell slots.

The Wanapum and Priest rapids powerhouses, owned by Public Utility District No. 2 of Grant County, Wash., each contain 10 turbine-generator units. These powerhouses, on the Columbia River, feature turbine intake structures that include bulkhead and wheel gate slots, commonly referred to as gatewell slots. These slots are vertical, rectangular-shaped columns that span the space between the turbine intake ceilings and dam deck. There are three bulkhead and three wheel gate slots at each turbine. The gatewell slots were designed as a safety mechanism by which steel bulkheads could be lowered into an intake to prevent water from entering the unit in the unlikely event of a turbine malfunction.

These gatewell slots have become a still water column where migrating juvenile salmonids can be diverted for a period of time before dam passage. The PUD attributes the tendency of fish to enter the gatewells to their vertical surface orientation near the intake ceilings. Currently, Grant County PUD uses dip-netting of the gatewell slots to remove, transport and release entrained smolts downstream from each project. At both dams, wheel gate slots are dipped seven days a week during the spring migration and five days a week during the summer migration.

Fish entrained in gatewells can experience decreased health due to several factors, which include stressors associated with crowding, increased exposure to forebay total dissolved gas saturation and the impacts of net-dipping. As a natural resource management tool, the PUD seeks to determine if gatewell exclusion screens can be an effective tool to stop entrainment. Scientists with Blue Leaf Environmental performed the study.

At each project, a single screen was installed in a bulkhead slot of a turbine intake. A dual-frequency identification sonar (DIDSON) camera was installed on the end of the screen, with 69 percent of the screen surface imaged. Jacobs Engineering designed the screens and camera mounts. For 18 days during the spring and summer salmonid migration periods, fish were counted as they passed near or had contact with the screen.

The fish observed had a low level of interaction with the screens and a low level of multiple or extended contact. At Wanapum, 10,632 fish were observed with 784 (7.4 percent) coming in contact with the screen. At Priest Rapids, the percentage was much lower, with 29,340 fish observed but only 360 (1.2 percent) contacting the screen. The lower number of fish observed at Wanapum is attributed to a combination of the unique characteristics of this dam and the diversion of about 70 percent of the out-migrating smolts into the newly constructed surface bypass.

As a result of this study, Grant County PUD determined salmonid interaction was minimal at the exclusion screens with respect to the number and severity of contact events. In addition, there were no violent impacts or screen impingement events observed.

EPRI elects six to board of directors

EPRI elected six people to its board of directors: James Kerr II, John Bohn, Benjamin Fowke III, Jong-shin Kim, W. Terry Boston and James Lash.

Kerr is a partner with McGuire Woods LLP and former commissioner on the North Carolina Utilities Commission. Bohn is a former commissioner on the California Public Utilities Commission. Fowke is president and chief executive officer of Xcel Energy. Kim is CEO of Korea Hydro and Nuclear Power. Boston is president and CEO of PJM. Lash is president and chief nuclear officer of First Energy Generation.

EPRI conducts research and development work relating to the generation, delivery and use of electricity.

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