The bigger the blades on a wind turbine, the more megawatts the machine can produce. So it’s no wonder the typical rotor diameter grew nearly 115 feet from 1995 to 2012, increasing average capacity from 0.75 megawatts to 2.5 megawatts. But at some point, rotors get so big they cost more to build than the value of the energy they can produce. Pretty soon, “we’re going to run into a wall,” says Eric Loth, an engineer at the University of Virginia. Inspired by a palm tree’s ability to bend in strong winds, Loth designed the Morphing Downwind-Aligned Rotor (MoDaR). Its hinged blades rotate downwind to capture energy efficiently. The blades are also lightweight, so they could be as long as 780 feet, which could increase output to 50 megawatts. Something this large likely won’t hit the commercial market before 2025, but that’s not a problem for Loth: “This concept isn’t necessary for today’s smaller turbines,” he says. “We’re working on the future.”
How It Works
The MoDaR attaches to the downwind side of the tower. Blades can bend on hinges to adjust for wind conditions without striking the tower.
A downwind rotor has one big disadvantage: Wind forced around the tower causes turbulence, stressing the system and fatiguing parts. MoDaR’s fix is an aerodynamic fairing for the tower.
During storms, the blades can be stowed in a horizontal position to avoid damage.