That answer sounds pretty April-firstey hokey. A swirl of the water going into a water turbine? My immediate offhanded reaction would be that any swirl in the incoming stream would have to be produced by some non-zero reduction in the stream flow, thus reducing the energy available to turn the turbine.
I haven't thought that out rigorously, but for now I'll stick with my "immediate reaction." You can't create energy; all you can do is transform it,.
Interestingly, I just commented to my son as how it was hard to get real information off the net.
Anyhow:
You be the judge, you do the counting.
Now, for "doors..."
Terry, 230RN
Poll