Original equipment manufacturers are the brand-name turbine producers. They do most of the turbine research although often with the assistance of government labs such as Risø in Denmark and the NREL in the U.S. These companies are responsible for most of what goes into the nacelle. Although they may not manufacturer it, they specify most every performance characteristic, down to the high-flex bend life of cable for cold weather operations and torque in foundation bolts.
Items such as gearboxes and generator, and large bearings often come from other companies, so the OEMs work with those firms when they specify such complex components.
Component manufacturers also provide considerable research, in particular for bearings, gearboxes, and blades. These items soak up lots of R&D dollars because of their complexity but the payoff has been increased reliability and greater power outputs. Once all components are specified, the OEM orders them, assembles them, and writes their maintenance requirements.
The trend in turbine design is toward larger units, mostly because of the economy of scale. For instance, a 3-MW turbine costs less to install and operate than two 1.5 MW units. Other design trends include direct drives – turbines without gearboxes – and taller towers so larger units can work in stronger and steadier wind.
The world economy is also influencing the way OEMs operate. In the economic downturn, most countries are demanding their populations are put to work in exchange for the privilege of bidding on wind farm developments. Hence, many OEMs have set up shop in countries with promising wind programs. In the U.S., for example, the Midwest is dotted with production facilities and tower fabrication plants to serve particular OEMs.
OEMs range from manufact-urers of house-mounted units that turn out 200 W to 6.5 MW monsters. Worldwide, there are manufacturers for just about any power output, starting at 600 kW and up, and in reasonable increments. More OEMs means more design variations, a necessary factor considering the wide range of weather condition available around the globe. Many OEMs also mean more competition, a factor that works to keep costs relatively low. If the wind industry is to survive it must produce power at or below what it costs for natural gas generated electricity, the lowest cost power. OEM turbines are expected to last at least 20 years by today’s standards, and 25 years will probably be the goal of most purchasers by the end of the decade.