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.
Switzerland-based Calventis has also developed a gearless drive system, the Hydro-Electronic Power (HEP) DRIVE, which uses a hydraulic motor. The company reports that it improves electricity production by 30% and reduces operation and maintenance costs by 20%.
It is grid independent and can be used in remote areas such as parts of Africa, India and China. The company is currently building 30 kW and 150 kW prototypes.
Another company, EarthTronics, has developed a small scale gearless turbine for small scale use.
Blade de-icing
So far, there has been limited wind development in very cold countries because of safety concerns over ice falling from turbines and ice disrupting turbine efficiency. Several companies such as Vestas, Bonus, NEG Micro, Enercon and Lagerwey are investing in research into developing or improving blade-heating equipment.
Hydraulic Several companies are developing hydraulic transmissions for wind turbines, for example ChapDrive.
Technologies for operation and maintenance
Vestas has developed a severe fault detection scheme for wind turbines to reduce operation and maintenance costs.