Wind turbines, or at least their predecessors, the wind mills, have been around for millennia, always improving their power and efficiency.
Generally-speaking, however, the wind turbine efficiency improvements require replacement of some very expensive components. For example, old generators or transmissions can be replaced with more efficient versions. Recently, it has been calculated that larger wind turbines are more efficient, increasing power generation without increasing the footprint. That being said, the average diameter of commercial wind turbines has increased by some 1,000%, from an average of 50 ft, thirty years ago, to 500 ft, today.
The problem is, replacing short wind turbine blades with long turbine blades is expensive, not to mention wasteful. General Electric, a leader in electrical generation, including wind turbines, came up with a method to extend the blades to increase efficiency, reducing waste and costs associated with full replacement. Because the blades are the most critical part of wind turbine design, efficiency, power output, and resilience, a lot of time and money goes into engineering them. Because of this, you can’t simply add on to the ends of the blades to increase their length, so General Electric’s method adds material to the middle of the blade.
For one of its wind turbine blade designs, General Electric takes the original composite blade, at 120 ft long, and cuts it in half. Then, technicians put in a 23 ft section that has been blended into the original profile and curvature of the blade. The resulting 143 ft blade weighs little more than the original, and increases wind turbine diameter to a little over 286 ft, about 20% more than original. General Electric estimates that this increase in diameter increases power output of the original wind turbine by about 20%, without making any other changes to the generator, gearbox, or tower.
Photo credit: floato