Wind Power

Wind map

• Real time wind map

Energy Conversion

• Solar radiation heats land and air
• Expanding air creates kinetic energy in wind
• Wind kinetic energy transfers to turbine kinetic energy
• Converts kinetic energy to electrical energy using a generator

History

• We have been harnessing wind since ancient times
• Sailboats
• Windmills
• American West
• Modern wind turbines

Vestas Website

Vestas, Turbine Manufacturer

Similarities and differences

• What similarities does wind share with other generation?
• Spinning electromagnetic generators
• No heat engine or fluid

Environmental impacts

• What are the impacts?
• Carbon emissions only during manufacture and installation
• No significant water impact
• Visual impacts?

Wildlife impacts

• Birds and bats can strike the blades and be killed

• How can we reduce deaths?

• Schuster, Bulling, Koppel, Consolidating the State of Knowledge: A Synoptical Review of Wind Energy’s Wildlife Effects

• Sovacool, The Avian and Wildlife Costs of Fossil Fuels and Nuclear Power

• Ecological Society Report

Kinetic Energy

A mass m traveling at a speed v has a kinetic energy

\frac{1}{2} m v^2

Note the units \frac {kg \cdot meter^2}{sec^2} = 1\ Joule

Fan Law

Power = \frac{1}{2} \rho A v^3

• \rho density of air (kg per cubic meter)
• A swept area of wind turbine (square meters)
• v velocity of the air (meters per second)
• Power is in watts

Air density

• How much does the air weigh?
• About 1.2 kg per cubic meter
• Varies with altitude
• Varies with temperature