Wind Today - Q2 2008 - (Page 64)

Glossary Wind Resource Assessment T erms: A Critical Start for Wind Energy Development Northwest SEED (Sustainable Energy for Economic Development/206-328-2441), Seattle, WA, helps communities pursue development of sustainable energy projects. This article is based on the Resource Assessment and Siting page of the agency’s web site, www.nwcommunityenergy.com. Wind resource is the first consideration in choosing a wind development site. Without a good wind resource, no wind project will be viable. In considering a site’s wind resource, assessors use a “wind vocabulary” with terms that explain how the wind behaves. Wind energy developers, equity investors, and wind farm owners and operators need an understanding of these terms in order to create an estimate of the energy that may be produced by a prospective wind farm. Wind Power Density (Wind Class): The power density of the wind determines how much energy can be extracted by a wind turbine and is influenced by two factors—wind speed and air density. The power density is proportional to the cube of the wind speed—every time the wind speed doubles, the power density increases by a factor of eight. As air density decreases at higher altitudes and temperatures, the power density decreases proportionally. For simplicity in comparison of wind resource at different sites, wind power density has been standardized in Wind Power Classes. These classes are based on wind speeds taken at specific heights, generally using sea level air densities. Shear: Friction created by a site’s vegetation and terrain slows the wind close to the ground. The shear of a site determines how quickly the wind speed increases with increasing height above the ground. Turbulence: Wind obstacles such as trees, buildings, and large land features affect the smoothness of the wind. When the wind is turbulent, forces on the turbine blades can vary, affecting the turbine’s production. Frequency Distribution: The basic tool for estimating energy production. A frequency distribution shows the percentage of time the wind is blowing at certain speeds over the course of a study period. Wind Rose: A wind rose is a tool for delineating the directions from which the wind blows. It displays not only wind direction, but also the percentage of the power in the wind that comes from that direction. 64 Response No. 641 WIND TODA Y Second Quarter 2008 http://www.nwcommunityenergy.com

Table of Contents Feed for the Digital Edition of Wind Today - Q2 2008

Wind Today - Q2 2008 Contents WINDPOWER 2008 - Host City - Houston WINDPOWER 2008 Special Events CanWEA 2008: Fast Forward to Wind Global Wind Plant Ownership Top 15 States with Wind Energy Installed Ranking the Percentage of State Electricity from Wind Largest Wind Farms in the United States Owners with the Most Wind Power Assets in the United States Rick Perry Bluegrass Ridge, Cow Branch, and Conception Wind Farms Loess Hills Wind Farm Bob Emick enXco V and enXco V Repower Climb Assist Devices GWEC Market Forecast Ports of Entry Satisfy Customers WINDPOWER 2008 Schedule Calendar Seven Principal Financing Structures Used in Utility-Scale Wind Projects Raising Project Funds Through Private Placements The Minnesota Flip Business Model Wind Resource Glossary WT Transmission Corn Plus Coop Adds Wind Energy Wind Resource Maps Ryan Orban, Iberdrola Renewables Liz Cussans, TransAlta Wind Bolton & Menk Trachte Port of Corpus Christi NPPD Interstate Truck Rental & Sales Dr. Shrink Aldridge Electric HYTORC Product Surveys Ad Index

Wind Today - Q2 2008

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