Why always clockwise? We all know what's clockwise. Which way the hands of clock swept over its face might not seem to matter. Because no matter it is clockwise or anti-clockwise the time will be told faithfully. In history it is quite an accident decision made arbitrarily. But without doubt it is convenient and efficient. Similarly, this happens to turbine blade manufacturing industry. It is conventional to make wind turbine turn around clock-wisely. But a recent Germany discovery showed that it may not be that simple. The researchers build a computer system to stimulate the air flow get through the wind turbine. They found that in north hemisphere, the turbine blade will generated same power during the day time but at night the power output can be up to 20% higher if the upwind turbine switched anti clockwise.