Ducted Wind Turbine Doubles Performance at Clarkson University 

Adding the duct effectively increases the size of the turbine. Its the same as a bigger turbine which cannot be compared with a smaller one, no wonder it is more efficient.

Wind power is really stupid. Electric power output goes with the third power of the wind speed. So a 1 MW windmill will perhaps produce 1 MW at 10m/s wind speed but only 1kW at 1m/s. So not even enough to run one toaster. (1 x 1 x 1 x 1kW to 10 x 10 x 10 x 1kW) Now the case we have in reality is that 10m/s wind speed is rare. In most places you will only get that a few days of the year. And more importantly the windmill has to be shut off if the wind speed goes slightly above that to prevent self destruction of the windmill because the forces and the energies just become too much for the windmill to handle. Remember, third power so 20m/s would be 8 times the power and a windmill built for 1MW cannot handle 8MW. Most likely it cannot even handle 2 or 3. What does that mean in reality, what does greenpeace not want you to know? Because the windmills production can go from 1MW to 0 if the wind speed increases, you have to run a nuclear or coal plant at full power in the background to kick in when wind power fluctuates, which it constantly does with the third power, so with extreme fluctuations. Not only will wind mills produce only tiny amounts most of the year, but when it kicks in you are still burning coal at the full rate in parallel and you need a backup power plant, so price is at least double, normal power plant plus windmill. Plus you are burning more coal than you would without wind power, because you are wasting a lot of coal in hot standby and by running coal power plants in less efficient partial load modes. See Germany, without wind it would be burning less coal, the numbers are out. Price for a kWh has risen 6 fold to 30¢/kW and more CO2 is produced. 500 billion have been wasted for nothing but green stupidity and failure to think clearly and do the math.