[ exact phrase in "" • results by date ]

[ Google-powered • results by relevance ]


Add NWW headlines to your site (click here)

when your community is targeted

Get weekly updates

RSS feeds and more

Keep Wind Watch online and independent!

Donate via Stripe

Donate via Paypal

Selected Documents

All Documents

Research Links


Press Releases


Campaign Material

Photos & Graphics


Allied Groups

Wind Watch is a registered educational charity, founded in 2005.

News Watch Home

Turbine output drops steeply after ten years: US research 

Credit:  By Craig Richard | Windpower Monthly | 14 May 2020 | www.windpowermonthly.com ~~

The performance of newer US wind turbines degrades at a slower rate than that of older projects, with a relatively abrupt decline in output after ten years of operation coinciding with the withdrawal of federal support, according to a new study.

Output from a typical US wind farm shrinks by about 13% over 17 years, with most of this decline taking place after the project turns ten years old, the Lawrence Berkeley National Laboratory (LBNL) found.

On average, output decreased by only 0.17% per year in the first ten years of operation, the researchers found.

Increased downtime for maintenance, the erosion of blade edges, and increased friction within rotating components all contributed to declines in output, they explained.

Tax credits

The research suggested project operators are incentivised to maintain turbines during the first decade by the tax credit support system. The fall in performance is noticed more acutely after a project is no longer receiving the subsidy.

As the production tax credit (PTC) is paid in line with a turbine’s output, operators maximise the benefit of the support before it is phased out by keeping their turbines in better condition to maintain output levels, the researchers explained.

The acceleration of declining performance after ten years – observed in the data from 917 wind farms across the United States – was not found in prior studies focusing on European wind fleets, in which output declined consistently over time, they added.

This rate of decline is apparently unique to US sites further supporting the hypothesis.

Gentler decline

Elsewhere, the researchers found a variety of project specifics afford gentler rates of decline.

They suggested a flatter terrain around projects means turbines encounter less wind turbulence and so reducing stresses put on them.

However, data on turbulence is not systematically available, the researchers noted.

Meanwhile, turbines with lower specific power ratings – which have longer blades relative to their generator size and are increasingly common – also fared better.

The researchers said this might be because these turbines are capable of harvesting a greater portion of the available wind energy, which partially offsets the decreasing aerodynamic efficiency experienced by all turbines.

Direct-drive turbines were also found to perform better than geared turbines, as gearboxes may be more subject to mechanical failure, leading to higher levels of output degradation. Although the data set for this was small.

Source:  By Craig Richard | Windpower Monthly | 14 May 2020 | www.windpowermonthly.com

This article is the work of the source indicated. Any opinions expressed in it are not necessarily those of National Wind Watch.

The copyright of this article resides with the author or publisher indicated. As part of its noncommercial educational effort to present the environmental, social, scientific, and economic issues of large-scale wind power development to a global audience seeking such information, National Wind Watch endeavors to observe “fair use” as provided for in section 107 of U.S. Copyright Law and similar “fair dealing” provisions of the copyright laws of other nations. Send requests to excerpt, general inquiries, and comments via e-mail.

Wind Watch relies entirely
on User Contributions
   Donate via Stripe
(via Stripe)
Donate via Paypal
(via Paypal)


e-mail X FB LI M TG TS G Share

News Watch Home

Get the Facts
© National Wind Watch, Inc.
Use of copyrighted material adheres to Fair Use.
"Wind Watch" is a registered trademark.


Wind Watch on X Wind Watch on Facebook Wind Watch on Linked In

Wind Watch on Mastodon Wind Watch on Truth Social

Wind Watch on Gab Wind Watch on Bluesky