How sustainable are offshore wind turbines to build, and how long do they last?

According to a 2023 report (1) from the National Renewable Energy Laboratory, depending on make and model, wind turbines are predominantly made of steel (66-79% of total turbine mass); fiberglass, resin or plastic (11-16%); iron or cast iron (5-17%); copper (1%); and aluminum (0-2%). Offshore wind turbines would need additional materials for their platforms, anchors, and other components related to their operation in an offshore environment.

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The expected life expectancy of an offshore wind turbine is approximately 20 to 30 years. In 2016, the British company Vattenfall successfully decommissioned (2) some of the first offshore wind turbines ever installed after two decades of operation. Once a turbine is decommissioned, the site can either be “repowered,” in which a new turbine is placed there, or infrastructure can be fully removed, or allowed to remain in place to act as artificial reefs, and the site abandoned. The U.S. Bureau of Ocean Energy Management (BOEM) and the U.S. Bureau of Safety and Environmental Enforcement (BSEE) both play important roles (3) in decommissioning. Before projects are built, the Bureaus require conceptual decommissioning plans and financial assurances in the Site Assessment Plan (SAP) and the Construction and Operations Plan (COP), both of which are published for public review and comment.

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Producing the materials required to build an offshore wind turbine does require resources and produce environmental impacts (4) — particularly from steel mining and smelting. However, offshore wind has considerably fewer environmental and climate impacts per watt of energy produced compared to other forms of energy production—fossil fuels in particular. According to the U.S. Department of Energy, the lifecycle greenhouse gas emissions (5) of offshore wind energy are one of the lowest of any source of electricity. The steel used in wind turbines is recyclable, as are many of the component parts. Researchers are also currently working on designing turbine blades that can be recycled (6), further reducing the environmental impact of offshore wind energy.