GOLD Gamesa G114-2.0MW
The long blades gives this relatively new model for low-wind speed sites an exemplary low specific power rating, which measures rated capacity against rotor-swept area, pushing up the potential capacity factor. Two prototypes are running, and the first commercial project to use the model is now under construction in Sweden. Already gaining a bronze in last year's small turbine category, the order book has grown to 800MW, according to Gamesa.
Technically, the G114 builds on the G97-2.0MW platform, and includes a non-integrated drivetrain with a main shaft supported by two bearing and a DFIG. The 196W/m2 specific power rating should drive down the cost of energy substantially to bring wind power within reach of markets without adequate financial support systems.
The turbine's key innovation is its 56-metre single-piece rotor blade that provides its class-leading rotor diameter of 114 metres. The blade development was based on the design and operational experience of the blade launched in 2010 on the G97 model. This included new-generation airfoils optimised for ease of manufacture and aerodynamic performance. Aiming to further reduce manufacturing costs and substantially boosting aerodynamic performance, the G114's blade also features modular design, and uses a new vacuum-infusion manufacturing process for the glass-fibre reinforced expoxy composite material, and contains no carbon content.
SILVER GE 1.7-100
GE's 1.7MW turbine, for the second year running making second place in the smallest turbine category, is an optimisation of the 2010 GE 1.6-100 model, a trendsetting low-wind product that is still available, and that boasts a record-low 204W/m2 specific power rating.
The 1.7-100, however, is credited here despite its less extreme 217W/m2 specific power rating, because it has the additional benefits over the 1.6-100 technology by incorporating electrical system upgrades and industrial internet capabilities. These help manage wind's variability by providing short-term predictable power back-up during short grid disturbances while communicating seamlessly with neighbouring turbines, service technicians and operators.
GE claims the 1.7MW yields 6% more energy annually than the 1.6MW, although its capacity factor is slightly reduced from 54% to 53%. But the company deserves credit for showing that optimising the highest annual energy production and the lowest possible cost of energy is what really counts.
BRONZE Enercon E-92
Enercon's 2.3MW E-92 turbine is focused on export markets and IEC class IIA locations. It shares many main components with the German manufacturer's E-82 model, including the cast main carrier, generator, power electronics and controls.
The re-used water-cooled generator of the 3MW E-82 model now operates air-cooled without signficant additional measures despite the E-92's reduced rotor speed.
The new 43.8-metre blade is slender in shape to minimise stress, optimise load distribution and reduce mass. Noticeable is the slightly reduced spoiler width that now stretches over a substantially increased length of the airfoil.