Wind turbines whose axes point upwards co-operate, boosting the output of those near them, a new study has found. The research makes a case for building wind farms this way, rather than using conventional designs, but history is against the idea. Many designs have been tried in the effort to turn the wind's energy into electricity. One, however, has dominated. Known as the horizontal Axis Wind Turbine (HAWT) it's the one we are familiar with; a tall pole supporting a large turbine and long blades sweeping like the hands of a wall clock. HAWTs make 5 percent of the world's electricity and that is rising fast as ever-larger turbines capture higher altitude wins, many now out to sea where the winds are stronger.