Flashcards in 8.5 Wind Power Deck (5):
Where is wind power useful?
For isolated area and for agricultural use.
How much energy can a modern large wind turbine produce?
A few megawatts of power.
How can the scale of energy transfer in a wind power be estimated?
Consider a mass of air moving at wind velocity v that in time delta t passes through the cross sectional area A spanned by the blades of a wind turbine. This is equal of a tubular volume of length vdelta. If p is the density of air this mass is pAvdeltat. The kinetic energy of this mass of air is 0.5(pAvdeltat)v^2 = 0.5pAdeltatv^3
The rate at which this energy passes through the blades is P = 0.5pAv^3
What are the advantages of wind power?
Essentially unlimited energy supply
No extraction costs
Practical for remote locations away from other energy sources