Wind and Other Renewable Energy Sources

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Wind and Other Renewable Energy Sources

• Physics 1303

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Renewable Energy comes in many forms

• Wind Energy
• Hydroelectric
• Geothermal
• Biomass
• Ocean Thermal

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Wind Energy

• Uses the kinetic energy of wind.
• Needs high wind speed.
• Maximum efficiency is 59.
• Practical efficiency is nearly 50.

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Wind Resource Map of the US
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Desert Sky

• Wind project
• Iraan, Texas
• Owner American Electric Power
• Customer CPS
• Manufacturer GE Wind Energy (formerly Enron)

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Desert Sky

• 1.5 MW/Turbine
• 107 Turbines
• Min. Wind 8 mph
• Max. Wind 56 mph

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Desert Sky

• Financing Depends on State Renewable Tax
  Incentive Program.
• AEI must guarantee to operate the system for 30
  years

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Desert Sky

• ERCOT (Energy Reliability Council of Texas)
  maintains the electric grid for most of the
  state.
• AEI is not allowed to generate more than 100 MW

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Desert Sky

• Wind has some impact on the site as shown in the
  photo.
• Source of income for ranchers.

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Wind Calculation

• Stop and do the wind problem.

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Wind Problem
The Desert Sky Project near Fort Stockton, Texas
has 107 wind turbines spread over 15 square miles
on Indian Mesa. Each Turbine has a maximum
capacity of 1.5 MW of power.
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1.    Calculate the total power capacity of this
wind farm.

• Capacity
• 107 turbines 1.5 MW / turbine
• 161 MW

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2. The capital cost of this project is about 175
million. Calculate the capital cost for each watt
of installed capacity..

• Cost per Watt
• 175 million / 161 MW
• 1 / watt

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3.  Assuming the project runs on average at 50
of capacity, calculate the total energy produced
in a year. Express your answer in kWh. .

• Annual Energy Production
• 0.50 161 MW 24 h/day 365 day/year
• 700 Million kWh / year

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4. Assuming the commercial value of this
electricity is 0.03/kWh, calculate the value of
the energy produced in a year.

• Value
• 700 million kWh 0.03 / kWh
• 21 million / year

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5. Neglecting the cost of running and maintaining
this system, estimate the payback period for this
investment.

• Payback Cost / Savings
• 175 million / 21 million /year
• 8 years

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Hydroelectric power

• Energy is stored as gravitational potential
  energy.
• Electrical generators convert mechanical energy
  to electrical energy.

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Hydroelectric power

• Largest source of renewable energy in US
• Fill with silt
• Loss of wild rivers
• Catastrophic flooding
• Salmon breeding blocked

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Geothermal Energy

• Localized surface level hot spots.
• Geothermal energy may be exploited for local
  uses.
• Not an important global resource.

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Geothermal Energy

• An important resource for Costa Rica and some
  other countries.
• Not really renewable.

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Biomass Energy

• Plant material is burned directly or converted
  into a fuel.
• An example Conversion of grain to ethanol and
  the production of gasohol (10 ethanol and 90
  gasoline)

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Biomass Energy

• Renewable
• Recycles CO2
• Could use agricultural waste
• Competes for agricultural land
• Low efficiency

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Ocean Thermal Energy Conversion

• OTEC uses the temperature differences between the
  ocean surface and ocean depths to run a heat
  engine.
• Highest potential in deep tropical waters like
  the Gulf of Mexico.

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OTEC

• Second Law of Thermodynamics
• Max eff. (Thigh - Tlow )/ Tlow
• So, efficiency is pretty low.

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Wind and Renewable Energy Technologies

• Do these technologies represent the dawning of a
  new age of sustainable development?