National Wind Watch: Wind Energy News » Giant Oregon wind farm seeks bigger turbines

Oregon’s biggest wind farm, which officially began full operations only seven years ago, is apparently ready for an upgrade.

Caithness Energy, owner of the Shepherds Flat wind farm in north-central Oregon, is asking regulators for permission to use longer blades on its 338 turbines, growing the tip-to-tip diameter from 100 meters to 127 meters.

In filings, the company said the move will “extend the useful life of the facility; take advantage of the latest turbine technology; and produce more electricity, especially at lower wind speeds.”

What’s also true is that turbines qualify for the lucrative federal Production Tax Credit for only their first 10 years of operation. In most circumstances, repowering earns the wind farm owner another decade of the PTC.

Caithness Energy said the executive with knowledge about the repowering project was traveling and unavailable for comment.

Repowering has become common with wind farms built in the 2000s – Portland-based PacifiCorp is repowering around 1,000 megawatts of wind projects in the West as part of its $3 billion Energy Vision 2020 plan.

Shepherds Flat is technically three licensed facilities, South, North and Central Shepherds Flat, in Gilliam and Morrow just south of the Columbia River and east of Arlington.

It went into operation in stages early this decade, and was fully completed in September 2012. At a total of 845 megawatts, at the time it was called “one of the world’s largest wind farms,” and it retains that stature, representing about a quarter of Oregon’s total wind power capacity.

Energy from Shepherds Flat is sold to Southern California Edison, and annually matches the consumption of around 240,000 residential customers.