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Sustainable Energy Technologies

Homework #3Wind Energy1. Go to the Energy Information Agency web page, http://www.eia.doe.gov/cneaf/electricity/st_profiles/colorado.pdf to view electric generating data in Colorado. Scroll to Table 4 and find the Total Electric Industry generating capability for 2002. Assuming a 1.5% annual growth rate from 2002 until 2010, how much generating capacity in MW will Colorado need in 2010?

Answer: 9,435 MW x 1.0158 = 10,628 MW

2. Scroll to Table 5 and find the Total Electric Industry generation of electricity for 2002. Assuming a 3.2% annual growth rate from 2002 until 2010, how much generation in MWh will Colorado need in 2010?

Answer: 45,600,388 MWh x 1.0328 = 58,668,653 MWh

3. Based on your answer in Question Three, if Colorado decided to switch completely to wind, how many wind turbines would be necessary to meet Colorados electricity demand in 2010? Assume:

a. 1.5 MW Turbines

b. 33% Capacity Factor

Answer: 58,668,653 MWh/(1.5 x 365 x 24 x 0.33 MWh/turbine) = 13,530 turbines

4. What is the capital cost per capita in Colorado to build the number of turbines you calculated in Question 3? Assume capital cost of $1M per MW of wind turbine generating capacity and Colorados current population of 4,300,000.

Answer (13,530 turbines x 1.5 MW/turbine x $1M/MW)/4,300,000 = $4,720 per capita

5. Assume that Colorado decides to replace all its electricity generating capacity with the number of wind turbines you found in Question 3. To solve the intermittency problem, you suggest that we use hydrogen to store the wind energy. The round trip efficiency of wind (electricity hydrogen electricity) is 25%. That means youll need four times the number of turbines you found in Question 3. What will be the total cost of energy per kWh in 2010 if Colorado decides to do this? Ignore any PTC and accelerated depreciation benefits. Assume:

a. 1.5 MW Turbines

b. 33% Capacity Factor

c. 25% round trip efficiency

d. $1M capital cost per MW of wind turbine generating capacity

e. $500M capital cost for the hydrogen conversion and fuel cell equipment

f. 20 year life span

g. 6% interest rate

h. 2/kWh operating costs

Answer: Turbine capital cost = 13,530 turbines x 4 x 1.5 MW/turbine x $1M/MW = $81,180,000,000

Hydrogen conversion and fuel cell equipment capital cost = $500,000,000

Debt service = $7,131,234,614/year

2010 generation = 58,668,653 MWh/year x 1,000 kWh/MWH = 58,668,653,000 kWh/year

Capital cost of energy = ($7,131,234,614/year) / (58,668,653,000 kWh/year) = $0.121/kWh

Total cost of energy = $0.121 + 0.02 = $0.141

6. How does this cost compare with the current cost of new coal figured generation at 3.5/kWh? Write a brief (400 words or less) argument on why Colorado should or should not shut down its coal power plants and replace them with wind farms?