Instructions:

Download this document and save to your hard drive. Type the answers to the questions directly into this document. Use a different color than black for your answers, so that I can easily differentiate your answers from the questions.

Some questions require math and written calculations: do these calculations on paper and clearly show your work. Upload all of your handwritten work as one single, multi-page pdf to Canvas.

You will upload two items to Canvas: a word document and a pdf. The word document contains all of your typed answers to the questions. The pdf contains all of your handwritten calculations to support your answers.
Energy Flow diagram

Visit Lawrence Livermore National Laboratories websites, https://flowcharts.llnl.gov/ and https://flowcharts.llnl.gov/commodities/energy
Review class notes on how to read and interpret such a diagram.

1. Describe what is meant by a "Quad".

2. What is the definition of a BTU?

3. Energy use in the United States in 2015 is estimated to be 97.5 Quads for the year (Lawrence Livermore). How many kWh per year is that? Refer to page 331 of your text. Write out your calculation.

4. Using the web resource above, describe how the United States "estimated energy use" has changed from year-to-year, for each and every year since 2011. What trend do you see?

5. In the United States in 2011, what sector imposed the greatest demandfor energy?

6. In the United States in 2011, what supply source satisfied the greatest demand for energy?

7. In the U.S. in 2011, how many Quads of energy were supplied by Wind (Lawrence Livermore)?

8. In the U.S. in 2012, how many Quads of energy were supplied by Wind (Lawrence Livermore)?

9. In the U.S. in 2013, how many Quads of energy were supplied by Wind (Lawrence Livermore)?

10. In the U.S. in 2014, how many Quads of energy were supplied by Wind (Lawrence Livermore)?

11. In the U.S. in 2015, how many Quads of energy were supplied by Wind (Lawrence Livermore)?

12. In the U.S. in 2015, what percentage of the overall energy use was supplied by Wind (Lawrence Livermore)?

Wind
13. Describe the Betz limit.

14. What part of the wind turbine energy conversion process does the Betz limit apply to?

15. What is the Betz limit value?

Calculate the power output of a wind turbine. Do the calculation by hand, and upload your work as a pdf. Study "Power from a wind turbine" in Files on Canvas.

16. Calculate the actual power output of a wind turbine given:
This is a horizontal axis, three-blade commercial unit
Blade length is 40 meter
Wind speed is 10 m/s
Density of air is 1.225 kg/m3

ηoverall = .35 (ηoverall = ηturbine *ηmechanical *ηelectrical)

Calculate the efficiency of a wind turbine: given the available power in the wind at the front of the blades, and the amount of electrical power coming out of the base of the tower. See "Power from a wind turbine" in Files on Canvas.

17. Calculate the efficiency of a wind turbine given:
Pin = 3.3 MW (power available in the wind)
Pout = 1.8 MW (power available to the grid after all energy conversions)