The biggest turbines in the region now top out around 100 to 110 meters in rotor diameter and 2.5 megawatts in generating capacity.
Longer blades give turbines a greater “swept area,” increasing energy capture for each watt of installed capacity. That translates to power production at closer to full capacity on a more consistent basis. The longer blades are becoming more commonly used in the industry, especially at sites with low-to-medium wind speeds.
At Montague, use of higher-capacity turbines would also mean fewer turbines will be needed to reach the 202-megawatt capacity of Apple's portion of a planned 404-megawatt project.
Under Avangrid Renewables’ site certificate, construction of the Gilliam County wind farm must begin by Sept. 14.
The Portland-based company had to seek a certificate amendment because the longer-bladed turbines will have ground clearance of just 14 meters, or 46 feet, less than the originally permitted 20 meters.
Oregon's Energy Facility Siting Council found no reason to object to the change, although it did note that Avangrid said in its application that “a larger rotor-swept area may increase the risk to birds and migratory bats from collision with turbine blades and that a lower minimum blade tip clearance could make low flying avian species, such as gamebirds or songbirds, more susceptible to collision.”
As a result, the council amended a few of the certificate conditions to ensure consultation with the Oregon Department of Fish and Wildlife on site monitoring and mitigation plans.
While Avangrid hasn’t commented on the energy buyer behind the project, Apple outed itself in April in its annual sustainability report, calling Montague its “largest (renewable energy) project to date.”
Apple (Nasdaq: AAPL) expects 560,000 megawatt-hours of electricity annually from its portion of the wind farm. That’s equal to the electricity usage of about 52,000 Oregon households. The company expects the project to be completed before the end of next year.
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