Green Stack: Shallow offshore wind

To find the theoretical energy per day per person of shallow offshore wind in the Netherlands the following calculations were done:

Assume the shallow area of the coastline is 1800 km^2
Assume the average wind speed on the coast is 15 mph given that the average wind speed on land is 11 mph.  15 mph = 6.7 m/s
To compute the effective velocity you must add 1.5 so the effective velocity is 8.2 m/s
The density of air = 1.22 kg/m^3

Power per unit area
                    = π/400 ρv^3 = (π/400) * 1.22 kg/m^3* (8.2 m/s)^3 = 5.3 W/m^2

Assume that 25% of shallow water is used
                    = .25 * 5.3 W/m^2 * (1800 * 10^6 m^2) * 10^-9 = 2.385 * 10^6 kW

Possible shallow offshore wind power per person, per day
                    = (2.385 * 10^6 kW) * 24 hours / (16.5 * 10^6 people) = 3.5 kWh/d per person