Delivering on the promise of savings, however, is harder than it sounds. Nordic’s design, Carbone says, “is pretty simple in function. It’s a just a hinge that’s perpendicular to the rotor. But perfecting that simplicity took a lot of time and effort.”
Larry Miles has spent the last decade trying to develop a flexible two-bladed wind turbine with individually hinged blades. Miles’s Wind Turbine Company, based in Bellevue, WA, was preparing to push a 500-kilowatt prototype of its hinged-blade turbine to 750 kilowatts when a control-system error allowed one blade to swing too far and strike the tower. The resulting damage ultimately caused the DOE to withdraw support for the firm’s research program.
Carbone says that such setbacks have not tarnished Nordic because its teetered design is already well proven. Since the mid-1970s, the Swedish government has poured close to $75 million into Nordic’s Swedish predecessor, producing a string of prototypes. Four of the five one-megawatt turbines Nordic has installed since 1995 are still running, demonstrating an average mechanical reliability of 98 percent. “We can catapult off that experience and use today’s control [systems] and materials to make an even better product,” says Carbone.
Nordic’s plan is to first validate its design by selling turbines to community-scale wind-energy developments with up to 20 turbines–projects that are too small to support a dedicated maintenance staff and therefore need reliability. Nordic says it already has orders for 19 turbines for small installations at a military base in Arizona, a housing development in Minneapolis, and a power project in Uruguay. The primary use of the DOE loan guarantee will be expansion of the company’s assembly plant in Pocatello, ID.
Carbone says Nordic will ramp up carefully to assure reliability and customer satisfaction before engineering its next step: a 2.5- to 3-megawatt turbine to compete for use by large, utility-scale wind farms. “In 2012 we will prototype a 2.5 to 3-megawatt machine, which will take us to a $1 billion company in roughly seven years from now,” promises Carbone.
Miles estimates that the savings from Nordic’s design might be closer to 10 percent. But Miles says that could still make an important difference: “If their machine works reliably, they’re going to have a definite cost advantage over a three-blade machine.”