Using Biotic Factors to Estimate Average Annual Wind Speed A Series of Lab Activities Which Enable High School Students to Estimate Wind Speed Using Biotic Factors in the Environment

By K.C. Jones

Written in cooperation with the Idaho National Laboratories Gary Seifert, Mentor Kurt Meyers, Scientific Advisor

Idaho Falls School District #91

Estimating Wind Speed Using the Griggs-Putnam Index of Deformity Background: Plants subjected to environmental factors such as wind are often deformed. By measuring the amount of deformation, the average annual wind that has affected that plant can be estimated. Objectives: • Students will be able to identify wind deformation of trees and, by using a chart, estimate the average annual wind speed for the area in which the tree was grown. Management: Divide the class into small groups and have them walk around the school grounds observing the trees growing there. Have them refer to the Griggs-Putnam Index of Deformity Chart and estimate the wind speed using at lest 5 trees. In the absence of schoolyard trees, photos of trees can be found in magazines, on the internet, or provided by the instructor. It should only take 23 minutes per tree. Prior to the walk the teacher should instruct the students how to use the chart and discuss the following vocabulary words: Brushing – small limbs of a tree are bent downwind giving the branches a “brush” appearance. Flagging – large limbs are bent downwind and upwind limbs are shorter than downwind limbs. Throwing – the trunk of the tree is curved downwind. Carpeting – the trunk of the tree is bent nearly to the ground. Materials Needed: • Griggs-Putnam Index of Deformity chart for each student • Photos of trees if trees aren’t accessible on the school yard (Internet photos are easily obtained) Procedure: 1. Divide the students in groups of 4-5 2. Have them walk around the school ground to estimate the average annual wind speed in your area using the Griggs-Putnam Index of Deformity Chart. In the absence of trees in the area, you may use photos of wind-deformed trees. (See Attached) 3. Assign several of the students to find the average wind speed as recorded at the nearest meteorological station. 4. Have the students compare their findings with those of the meteorological station. Assessment: 1. What is the average annual wind speed for the area where your school is located? 2. Were there areas around the school yard where the wind speed was greater or lesser than other areas? Describe those areas. 3. From your data, could a wind turbine be used at the school yard to generate electricity? (Note: small turbines need average winds of 10-14 miles per hour.)

Idaho Falls School District #91

The Griggs-Putnam Index of Deformity Description of Deformity

Wind Speed

O

No Deformity

No Significant Wind

I

Brushing and Slight Flagging

7-9 Miles per Hour 3-4 Meters per second

II

Slight Flagging

9-11 MPH 4-5 m/s

III

Moderate Flagging

11-13 MPH 5-6 m/s

IV

Complete Flagging

13-16 MPH 6-7 m/s

V

Partial Throwing

15-18 MPH 7-8 m/s

VI

Complete Throwing

16-21 MPH 8-9 m/s

Index

VII

Top View of Plant

Side View of Plant

Carpeting

Idaho Falls School District #91

22+ MPH 10+ m/s

Estimating Wind Speed Using the Ponce-Mattio Formula Background: Plants subjected to environmental factors such as wind are often deformed. By measuring the amount of deformation, the average annual wind that has affected that plant can be estimated. The Ponce-Mattio formula allows wind speed to be estimated from photographs of wind-deformed trees. The formula is explained on the attached page. Objectives of the activity: • The students will learn to recognize deformation to trees caused by wind. • The students will use math skills (measurement of length, measurement of angles, and the use of formulas) to estimate the effect of wind on trees. • The students will use data to determine if a wind turbine might be a suitable source of power in the area where they live. Management: Divide the class into groups with 2-3 members per group. Each group should have a calculator, ruler, and protractor. Provide each group with 7-10 photos of trees located on the school grounds. In the absence of trees, you may use the photos attached to the lab packet. Instruct the students in how to make accurate measurements, how to place numbers into a formula, and how to solve the problem. The Ponce-Mattio formula is actually two formulas. The first creates a number which represents the amount of deformation to a tree. The second formula used the deformation measurement to calculate wind speed at 30 meters above the ground. Materials needed: • One protractor, ruler, and calculator per group • Photographs of trees deformed by wind. • One copy for each group of sheet titled “How to Use the Ponce-Mattio Formula”. Procedure: 1. Pass out supplies. 2. Have the students take the necessary measurements needed for the calculations. 3. Have the students put the measurements into the proper place in the formulas and calculate the average wind speed for the area. Assessment: 1. What is the average annual wind speed for the area where your school is located? 2. Were there areas around the school yard where the wind speed was greater or lesser than other areas? Describe those areas. 3. From your data, could a wind turbine be used at the school yard to generate electricity? (Note: small turbines need average winds of 10-14 miles per hour.) Idaho Falls School District #91

How to Use the Ponce-Mattio Formula for Estimating Wind Speed The Ponce-Mattio formula is based on the assumption that average annual wind speed can be estimated accurately based on the amount of deformation to a tree caused by wind. The wind speed is calculated by first finding an index of deformity (D) and then using that number in an equation that will generate an estimated wind speed in meters per second at 30 meters above the ground. Begin by drawing two lines on the photo of the tree. The first line, Z, is drawn from the center of the trunk at the base, perpendicular to the horizon. The second line, W, is drawn from the point on the upwind side of the tree closest to line Z perpendicular to line Z through the crown of the tree. The third line,Y, is drawn from point X to the downwind end point of line W. First, D is calculated using the following equation from the measurements of a tree. D = A/B +C/45 Where, D = The Deformation Index C = The angle formed between a line drawn vertically (Z) from the base of the tree (X) and a line drawn to the point on the crown furthest from the tree on the downwind side (Y). B = Width of crown along line W from the nearest point on the downwind side of the tree to line Z. A = Width of crown along line W from line Z to the point on the crown furthest downwind. Secondly, the wind speed in meters per second, 30 meters above the ground is calculated by using the following formula:

Velocity of Wind = 3.62 + .46D Z

A

B W

Y

C

X Idaho Falls School District #91

4

1

3

Idaho Falls School District #91

Photographs for Use in Wind Speed Estimation Activities

Trees at Skyline High School Idaho Falls, Idaho

5

2

9

6

8

Idaho Falls School District #91

Photographs for Use in Wind Speed Estimation Activities

Trees at Skyline High School Idaho Falls, Idaho

10

7

13

11 12

Idaho Falls School District #91

Photographs for Use in Wind Speed Estimation Activities

Trees at Skyline High School Idaho Falls, Idaho

Estimating Wind Speed Using the Watts-Winston Wind Speed Constant Background: Plants subjected to environmental factors such as wind are often deformed. By measuring the amount of deformation, the average annual wind that has affected that plant can be estimated. Shrubs grow near the surface if the ground and show less deformation than trees. However, the crown (leafy part) of the shrub is often displaced downwind of the base of the shrub. Objectives of the Activity: • The students will learn to recognize shrub deformation by wind • The students should be able to locate the crown and base of the shrub • The students will be able to measure the displacement of the crown and use a constant to estimate average annual wind speed from the amount of displacement. Management: Divide the class into groups of 3-4 students each. Each group should have a student who can multiply and calculate an average. Have the students select 5 shrubs from the schoolyard which are in an area where wind can affect their growth. In the absence of shrubs, photos can be used, and the class can be conducted indoors. The students need to be familiar with the following terms: Crown – the leafy part of a tree or shrub. Base – the center of a shrub with a single main stem or the center of all the stems of a shrub with multiple stems. Displacement – the horizontal distance between the center of the crown and the center of the base. Materials Needed: • Two straight sticks which can be used to mark the center of the base and the crown • 1 – metric ruler or meter stick to measure the displacement of the crown in centimeters. Procedure: 1. Divide the students into groups of 3-4. 2. Have them locate 5 shrubs in an area of the school yard where wind can affect their growth. 3. Instruct the students to devise a method for measuring the amount of displacement of the crown from the base. 4. Make sure the students record their measurements in centimeters and calculate an average for the 5 shrubs. 5. Multiply the average displacement of the crowns by .84 (the Watts-Winston constant) to determine average annual wind speed at an elevation of 30 meters (100 feet). Assessment: 1. What is the average annual wind speed in the school yard? 2. From your data, could a wind turbine be used at the school yard to generate electricity? (Note: small turbines need average winds of 10-14 miles per hour.) 3. Can you tell from observing crown displacement, which direction the wind blows from? Idaho Falls School District #91

Sage Brush at Gibson Ridge’ Fort Hall, Idaho Photographs for Use in Wind Speed Estimation Activities Using Crown Displacement

Idaho Falls School District #91

Earth Science Semester Project During the Earth Science course, you will be expected to produce a project concerning wind power as a supplement or alternative to other forms of energy in Southeast Idaho. The project will be completed over the twelve weeks of the trimester. Much of the research work will be done in class, but the project construction will need to be completed at home. The following is an outline of the requirements for the project. (300 Points) I.

Site Selection/Wind Power Availability – Using wind speed and wind power maps select general sites in Southeast Idaho that might qualify for as good sites to install a wind power generating facility. Here is a possible Internet site where you might find relevant data. (20 points) http://www.windpowermaps.org/

II.

Site Selection/Topography – Using topographic maps of the area, determine sites suitable for wind tower construction. Consider elevation, access, and distance to existing power lines. (20 points) http://terraserver.microsoft.com/ ,

III.

Site Selection/Soil Verification - Use US Department of Agriculture Soil Survey maps to verify the soil stability of the selected site. This information will be needed as you develop an anchor system for your tower. (20 points) http://soils.ag.uidaho.edu/pedology/Survey/

IV.

Site Selection/Availability – Using land ownership maps and restrictive covenants, verify that the area can be used for wind tower construction. (20 Points)

V.

Site Selection/On Site Verification – Visit the site and verify using biological or geological evidence the presence of persistent high wind conditions. (40 Points)

VI.

Turbine and Tower Selection – Choose a turbine that will produce energy efficiently with the available wind in your area. Choose a tower that will support your turbine. List reasons for your choice.(60 points) http://www.awea.org/ , http://www.windenergy.com/ , http://www.windpower.org/core.htm , http://www.suzlon.com/ , http://www.vestas.com/ , http://www.valmont.com/poles/poles10.shtml , http://www.nrel.gov/wind/, http://www.bergey.com/ VII. Estimate Cost and Benefits – Estimate the cost of the turbine, tower, inverter, etc and compare that to an estimate of the benefits. (20 points) VIII. Environmental Considerations - Analyze possible environmental impacts. Include the impact on aesthetics, birds, and big game, as well as noise pollution.(20 points) http://www.currykerlinger.com/ windpower.htm , http://www.nrel.gov/wind/avian.html IX.

Modeling – Build a scale model of your site. Make the model as realistic as possible. (100 points)

Extra Credit – Using Stella or similar modeling program, create a computer model that shows some aspect of wind energy applications (10-60 points). Build a poster that relates Beaufort’s scale to wind speed and generating power (3-10 points). Build a poster that converts between units used to measure wind speed; m/s, mph, km/hr, etc (3-10 points). Build a model wind turbine that generates electricity (60 points if it works). Do a 1-page comparison paper that shows, using graphics, the costs of electrical energy from a variety of sources such as, nuclear, coal, hydro, solar, wind, etc. (25-45 points). Compare using charts and/or graphs the cost of electricity in communities with populations of 40,000-70,000 people. Include Idaho Falls as one of the cities (25-45 points). Build an attractive “Green Power” poster that promotes the use of environmentally friendly sources of power (5-15 points). Idaho Falls School District #91