In Ireland, old wind-turbine blades are being used to build bridges

For all their virtues, wind turbines have one major flaw: they’re notoriously difficult to recycle.

Wind blades are designed to last about 20 or 25 years. After that, there are currently two viable ways to dispose of them: Burn them or bury them in landfills. Now, a new bridge in Ireland made with two repurposed wind blades, offers a third promising option.

The so-called Blade Bridge is part of a soon-to-be-completed greenway snaking through the Irish countryside. Stretching over a 16-foot-wide stream, the bridge consists of a steel deck, but instead of steel girders, the structure is supported by two wind blades decommissioned from a wind farm in Belfast.

According to the wind energy trade association WindEurope, 25,000 tons of wind blades are expected to be decommissioned across Europe by 2025. In the US, that number is expected to balloon to 2.2 million in another 25 years. The Blade Bridge is only the second bridge in the world to be built with recycled wind blades—the first one opened to the public last October in Poland—but it offers a sensible, sustainable alternative for the million more wind blades that are going to retire in the coming years.

Most wind blades are made of fiberglass, or carbon fiber-reinforced polyester bound with resin. This renders them lightweight and durable, but it also makes it difficult to separate the plastics from the glass fibers. Energy companies are now starting to address this challenge by redesigning blades so that they can be broken down into raw, recyclable materials—but that won’t help with the millions of wind blades already in operation.

The Blade Bridge is the brainchild of the Re-Wind Network, which includes civil and structural engineers, geographers, and other scientists from University College Cork, the Georgia Institute of Technology, Queen’s University Belfast, and City University of New York. The researchers first joined forces four years ago, when they came up with 50 ideas for repurposed wind blades. Floating pontoons for solar panels, sound barriers for highways, breakwaters along the coast, and culverts all made the list. “There was always a climate adaptation aspect,” says Angela Nagle, a civil engineering doctoral student at University College Cork who is focusing on the environmental assessment of Re-Wind’s projects.

Each idea was then paired with the part of the blade that would be most suitable for it, the goal being to repurpose as much of the blade as possible. For example, the cylindrical part at the root of a wind blade could be reborn as a culvert. In the case of the Blade Bridge, the team repurposed two Nordex N29 blades, opting for the midsection of each blade. Nagle explains this is where the structural integrity lies, so that is what the bridge’s steel deck is bolted to.

N29 blades are also shorter and easier to transport with a regular flatbed truck. When a blade is longer than 14 meters, or about 46 feet, she says the cost of transportation skyrockets, making it all the more challenging to find a cost-effective way to repurpose larger blades. (The bridge was funded by a 1 million-euro grant from Munster Technical University, with additional public funding used for the deck and surrounding groundworks.)

In the end, each girder is made up of about half of one wind blade, mostly because the span of the crossing only called for that much. By virtue of its length, however, the blades look virtually complete, which Nagle says was essential to the project’s success: “The Cork City Council want it to be a very obvious repurposing solution to spur people on.”