## Problems

1. What are the two most important factors in the cost of energy? (The factors that influence COE the most)

2. Calculate the simple payback for a Bergey 1 kW wind turbine. Go to www.bergey.com to get price and place it on a 20 m or 60 ft tower. It produces 2,000 kWh/year. Assume a value for O&M and FCR = 0.

3. Calculate the cost of energy (use Equation 12.3) for a 400 W (Air X) wind turbine (Southwest Windpower). Installed costs are \$1,500, which includes 10 m tower and battery. Annual energy production is 400 kWh/year. Assume FCR and AOM = 0.

4. Calculate the cost of energy (use Equation 12.3) for a Bergey 10 kW wind turbine on a 30 m tower for a good wind regime. You can use a simple method for estimating the annual kilowatt-hours.

5. Calculate the cost of energy (use Equation 12.4) for a 50 kW wind turbine, which produces 120,000 kWh/year. The installed cost is \$150,000, fixed charge rate of 10%, O&M is 1% of installed cost, and levelized replacement costs are \$4,000/year.

6. Estimate the years to payback using Equation 12.7. IC = \$150,000, r = 8%, AKWH = 120,000 at \$0.09/kWh. Assume a fuel escalation rate of 4%. This problem has to be done numerically, assume an L, calculate, and then modify L in terms of your answer and do calculation again.

7. Explain life cycle costs for a renewable energy system.

8. In 2008, the COE for wind was around \$60-80/MWh. What is the estimated COE for electricity generation (large plants) for photovoltaic, solar thermal, biomass, and geothermal?

The estimated cost of energy from a wind farm is around \$0.08/kWh. Make a comparison to proposed new nuclear power plants. What is their COE (retail rate) for latest nuclear power plants installed in the United States? (Do not calculate; find an estimate from any source.)

What are today's values for fuel inflation, discount rate, interest rate? What is your estimate for the year 2015?

A 100 MW wind farm (100 wind turbines, 1 MW) is installed in the class 4 wind regime. The production is around 3,000 MWH/turbine/year. The utility company is paying an estimated \$0.04/kWh for the electricity produced. Estimate the yearly income from the wind farm. If the landowners get 4% royalty, how much money do they receive per year?

For the previous problem, installed costs are \$1,600/kW, FCR = 9%, capacity factor = 35%, AOM = 0.008/kWh. Calculate the COE using Equation 12.4. You will need to estimate the levelized replacement costs or calculate LRC using Equations 12.5-12.7. Compare your answer to the \$0.05/kWh, which is the estimated price the wind farm is receiving. How can the wind farm make money?

A number of wind farms are again being installed in the United States. In Texas the wind farm boom has seen over 7,500 MW installed from 2000 to 2008. Why? Explain in terms of economics.

What is the price of oil, \$/bbl, today? Estimate the price for oil, \$/bbl, for the years 2010, 2020, and 2030. Compare to the U.S. Energy Information Administration projections for the same years. Place results in a table.

Estimate the price for oil, \$/bbl, if the costs for the U.S. military to keep the oil flowing from the Middle East are added.

Why were wind turbines installed primarily in California during 1981-1985? Discuss in terms of economics.

How much should the U.S. federal government fund for conservation and efficiency, renewable energy, and wind energy? Compare your answer to the FY 08 budget for the same activities. What was the FY 08 budget for fossil fuels and nuclear energy (nuclear fusion counts)? See "Links" section.

At what dollar level should your national government fund renewable energy? Wind? Fossil fuel? Nuclear? Compare your numbers to the national budget for this fiscal year, or the latest year for which information is available.

Estimate the cost of energy for a Bergey windpower, 10.1 kW, hybrid (PV/wind) system. You will have to estimate FCR and O&M.

Estimate the cost of energy for a Southwest Windpower, 1.3 kW, hybrid (PV/wind) system. You will have to estimate FCR and O&M.

Estimate the cost of energy just for the three, 100 kW, wind turbines at Toksook Bay, Alaska. You will have to estimate FCR, O&M, and LRC.

A village power system in China consists of 10 kW wind plus battery bank and inverter. IC = \$4,500/kW, energy production = 50 kWh/day, FCR = 0.03, AOM = \$0.01/kWh. Calculate the cost of energy.

A renewable village power system in China consists of 20 kW of wind and 10 kW of PV. Use an average cost of \$4,300/kW, annual energy production = 65,000 kWh, FCR = 0.03, AOM = \$0.01/kWh. Calculate the cost of energy. How does that compare to the present rate you are paying for electricity?

For the following problems use data reported to the U.S. Federal Energy Regulatory Commission, http://eqrdds.ferc.gov/eqr2/frame-summary-report.asp. Pick any wind farm; however, if uncertain, pick Llano Estacado Wind (White Deer, installed capacity = 80 MW).

What is the rate of the power purchase agreement?

25. Installed cost was \$1 million/MW, \$80 million. For 2007, what was the income generated? Assume that is an average year. What is the time of simple payback?

26. For problem 25, take into account the additional \$20/MWh return for the production tax credit. Now what is the payback time?

27. Calculate the capacity factor for the wind farm for 2007.

28. Find another wind farm that is selling electricity at the market rate. For the latest quarter, what are the high, low, and average rates (\$/MWh)?

## Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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