There is an apparent similarity between wind turbines and hydroelectric turbines: in both cases, the passage of an incompressible fluid drives a shaft which is connected to an electric generator. The maximum efficiency of wind turbines is given by the Betz' limit. By contrast, hydroelectric turbines are not subject to the Betz' limit and can have efficiencies ~ 90 %.

Explain this difference using simple physics. Hint: refer to Jaffe Box 13.1, book p. 238 = pdf p. 258.

2. Land intensity: Jaffee, problem 31.2

3. Pumped hydro: Jaffee, problem 37.2

4. Net present value of PV vs. location: