With advances in the wind industry, the focus of manufacturers is now on reducing costs and increasing efficiency. They are achieving this objective in a number of ways, for example, developing new technologies to power and de-ice turbines, building larger turbines, which have lower operating and maintenance costs and produce more megawatts per hectare, and replacing older, lower-capacity, turbine models in a process known as repowering. While demand has increased for larger turbines, there is still a market for older models in developing countries due to their lower cost and less demanding transportation requirements.
New technologies
With the wind industry nearing maturity, most research developments are focused on reducing cost and increasing the efficiency and performance of existing models, or on developing models for the offshore market.
Direct drive turbines
Most wind turbines use a gearbox to convert a rotor’s speed into high speed for a generator, but gearless turbines are now being developed. These turbines couple a rotor with a low-speed multi-pole generator (PMG), reducing the number of parts, and consequently operation and maintenance costs. The pioneers of this technology are Enercon, Vensys and Lagerwey/Zephyros.
Enercon has developed a gearless 6 MW turbine with a synchronous turbine. However, it is extremely heavy. Other models use permanent magnets, which are more efficient and can operate with partial loads.
Siemens has developed an extremely light 3.6 MW gearless turbines, which has a higher number of operating days and is 10% lighter than the Enercon model. If large scale production of the turbine occurs, Siemens predicts that the 3.6 MW turbine model will be competitive with the company’s 2.3 MW models. Goldwind also produces a gearless turbine.