Hamish Pritchard at BBC News explains that although the vertical-axis turbines are "less efficient individually than the propeller-style turbines, they are able to use turbulent winds from many directions." The technology is currently being tested in the California desert by engineers from CalTech.
The "school of fish" influence is reflected in the momentum gained, rather than lost, by clumping the turbines close together. Current blades are less efficient when close together because of turbulence, but the new turbines benefit from the funneled wind because they can gather gusts from all directions. The next step for CalTech's team is to see if the effect will work on a larger scale.