Extracting Energy from Wind Matt Aldeman Senior Energy Analyst Center for Renewable Energy Illinois State University
Overview Where does wind come from? Where is it windy? Wind Assessment Power in the wind
Where does wind come from? On a macro/global scale, wind is a result of: Uneven heating of earth’s surfaces - Jet streams and circulatory cells - Equator – 30 degrees: Hadley cell - 30 – 60 degrees: Ferrell cell degrees: Polar cell
Where does wind come from? On a macro/global scale, the direction of the wind is a result of: Coriolis Effect: in the Northern Hemisphere, moving bodies veer right
Where does wind come from?
Wind Rose
ISU Farm 2009 met tower energy rose
Where does wind come from? On a micro/regional scale, wind magnitude and direction are a result of 1) Storm systems and fronts Air is pushed from areas of high pressure to areas of low pressure
Where does wind come from?
On a micro/regional scale, wind magnitude and direction are a result of 2) Uneven specific heat capacity of various surfaces, especially water v. land -Water has a higher specific heat capacity than land. Warm air over land rises during the day. Warm air over water rises at night.
Where is it windy? Windy areas can be: Wide open spaces (pasture, fields) Plateaus (moraines) Elevated areas (ridgelines) Mountain passes (funneling effect) Offshore
Where is it windy?
Wind Assessment Tools used for wind assessment Visual observation Wind modeling & Wind maps Airport data & AWOS stations SODAR & LIDAR Meteorological towers
Visual observation
Wind Modeling & Wind Maps
Airport & AWOS Stations Important to visit the anemometer!
SODAR Emits sound “chirps” at defined intervals (~1-2 seconds) “…both the intensity and the Doppler (frequency) shift of the return signal are analyzed to determine the wind speed, wind direction and turbulent character of the atmosphere. A profile of the atmosphere as a function of height can be obtained by analyzing the return signal at a series of times following the transmission of each pulse. The return signal recorded at any particular delay time provides atmospheric data for a height that can be calculated based on the speed of sound.”
SODAR
LIDAR Same principle as SODAR (Doppler shift of echo return), but with laser light
Met Towers
Anemometers From NRG product literature: A four-pole magnet induces a sine wave voltage into a coil producing an output signal with frequency proportional to wind speed. The #40C is constructed of rugged Lexan cups molded in one piece for repeatable performance. A rubber terminal boot is included.
Met Towers
How to get (free) wind data Airports: Illinois met tower loan program: Meteorological tower search: ISU met tower: Matt
What can students do with wind data? Opportunity for learning Excel! Opportunity for learning Windographer
What can students do with wind data?
Calculate energy output of a wind turbine…
Compare with something familiar and useful…