Wind turbines have long life cycles, lasting several decades. Some turbines from the first wind farms built in California nearly 35 years ago still operate today. However, today’s turbines are far superior, and modern equipment makes up the vast majority of the U.S. wind fleet– over three quarters of U.S. wind turbines are less than 10 years old.

What happens to a wind turbine at the end of its life?

There are two main options for wind farm owners when a project nears the end of its original lifespan: repowering and decommissioning. Both options require new permits and can bring additional jobs and investment to the local community.

Repowering

When turbines become outdated or reach the end of their useful lives, the story isn’t over for the wind farm. Most wind project owners keep the site in use but replace older equipment with newer, upgraded technology. It makes good business sense to replace or refurbish turbines. Existing sites have the best wind resource areas and already have transmission access. And with new technologies, upgraded wind farms produce more electricity at a lower cost.

In some cases, wind turbines and foundations are completely removed and updated through a process known as repowering. “Repowering tends to become financially attractive, relative to investing in a nearby greenfield site, after approximately 20 to 25 years of service,” according to researchers from the National Renewable Energy Laboratory.

Repowering usually leads to cheaper electricity, with savings passed on to consumers. For example, Leeward Renewable Energy has repowered projects in Illinois, and expects 30 to 50 percent cost reductions per megawatt hour to result from using new equipment. “The benefits of that will flow through to our customers, whether through merchant sales or a long-term off-take partner,” said CEO Greg Wolf.

Decommissioning

In some instances, project owners may decide to completely remove a wind plant. This is called "decommissioning." Only a small number of projects have been decommissioned. Projects totaling 43 megawatts (MW) of installed wind capacity were fully decommissioned in 2017. These instances reflect the end of operational life for many 1980s wind projects.

Legal requirements

When a wind farm is built, the project owner signs a legally-binding contract to lease land for the project from local farmers and ranchers. These contracts typically require removal of the decommissioned turbines. Companies are always responsible for turbine removal: Neither landowners nor the local governments face this expense. Because almost all wind farms are built on private land, this covers nearly every turbine in the U.S., and the decommissioning of turbines on federal lands are regulated by the Bureau of Land Management.  Additionally, many local and state governments require decommissioning plans as a permitting condition.

The goal is to restore the area a wind farm occupies to as close as possible to the condition that existed before construction. It is important to protect the landowner's interest in proper removal, and the interest in investing in the wind resource.

Maximizing value when decommissioning

It's in a company's best interest to not let valuable machines sit abandoned—they can maximize value by reusing materials. There are a number of ways to reuse the towers, foundations and electrical cables. The steel, copper and other metal components that make up the bulk of a turbine have salvage value and can be recycled.