Our two-blade turbine offers simpler installation and lower maintenance requirements for a lower total cost of energy, as well as lower noise and reduced flicker. The Nordic design is optimized for wind energy capture and load resistance to meet or exceed the efficiency, reliability and overall cost effectiveness of competitive three-blade alternatives.

With more than 13 years of proven, reliable operation (>140,000 operating hours) with no significant maintenance issues or component failures, the N-1000 delivers clean energy at exceptionally low and predictable costs.

These advantages make the N1000 the perfect choice for community wind, on-site generation, and small wind farms.

These advantages include a more material-efficient foundation, fewer components to ship, reduced crane picks, and smaller crane requirements.

The two blades are attached on the ground before lifting the nacelle, greatly simplifying construction, requiring fewer crane lifts and requiring less mid-air assembly compared to three-blade turbines. With the rotor attached the nacelle can be lifted in higher winds, reducing weather delays. As a result, ground assembly is much safer, faster, and easier.

A wind turbine generator extracts energy from the wind by reducing wind speed. For a wind turbine of a certain power, diameter and rotational speed, a certain total area of aerodynamically active surface is needed to achieve a specific wind braking effect. Several advantages can be achieved by distributing the necessary area on just two blades, rather than three. The primary advantage is a lighter, less costly system, with a longer blade chord (“blade width”). Since a blade profile is characterized by its relative thickness (blade thickness to blade chord ratio, normally 15-20%), increased chord allows for a thicker and stronger beam and less structural material. The result is a lighter, less costly blade, with two rather than three. See Figure 1 to the right. While a two-blade turbine may be slightly less efficient (2-3% annually) than a three-blade model of the exact same size, a 1% increase in turbine diameter fully compensates for such efficiency difference.

Until recently, wind-energy companies did not master asymmetry because the necessary computer codes had not been developed. Nordic operates a highly sophisticated modeling program developed in the Swedish wind energy research program to build the most efficient / lowest total cost of energy turbines available. Due to complex calculation interrelations of two-blade wind turbines, the access to a comprehensive and easy to use computer simulation program is critical for exploiting the advantages of two-blade technology.

In early cases, the lack of appropriate computer modeling capability resulted in high fatigue loads, noise issues, and other technical problems. As a result, most commercial producers implemented the less demanding three blade technology.

Nordic’s two-blade configuration allows utilization of a unique load dissipating strategy; incorporating a patented teeter hub that allows the blades to teeter up to +/- 2 degrees. This allows the blade and hub system to adjust to differential loading across the rotor from wind turbulence, shear or tower shadow. As the blades rotate they will incur different loading patterns on their path; a teetering hub allows the blades to adjust to this condition rather than forcing the hub and gearbox bearings to absorb it. The teeter prevents these load impulses from being transferred into the gearbox and drive train as bending loads. Historically, bending loads have been found to be a primary culprit in gearbox premature wear and subsequent early failure.

Because of reduced fatigue loading, the design focuses on extreme conditions. When the extreme conditions fit into the design envelope, turbines run more reliably for the 20+ year design life. Nordic’s stall regulated blades limit power in high winds which reduces drivetrain loads. Stall regulation is well understood technically and much simpler mechanically than competing pitch regulated turbines.

Fundamentally, there are two ways to handle turbine structural loads; either design to rigidly endure loads or design to flexibly respond and dissipate loading. The advantage to the former is relative ease from a design standpoint – just make the components bigger. Nordic’s lighter, more flexible machine uses material more efficiently for the most reliable, cost effective 1 MW turbine available.

Nordic’s two-blade wind turbines are designed for the same tip speeds as their three-blade counterparts. Two-blade designs achieve this with less surface area, thus reducing noise by approximately 1dB or more.

A wind turbine’s shadow may result in periodic and occasionally distracting variations in lighting. A Swedish governmental investigation (Vindkraftsutredningen, SOU 1999:75, p. 101) cites 10 hours per year as an acceptable, cumulative shadow time for building inhabitants. Nordic’s two-blade turbine has a shadow frequency one-third less than that of corresponding three-blade models.