Siemens Gamesa produced 6 recyclable wind turbine blades in Aalborg in 2021. 5 years later, the technology helped advance circular design for offshore wind power worldwide

In 2021, Siemens Gamesa produced six 81-meter wind turbine blades at its factory in Aalborg, Denmark. They were built to do the same basic job as other offshore blades. They had to capture wind and withstand years of repeated loads. Their unusual feature was something that would not be visible once the blades were installed.

The resin used inside them was designed so it could later be separated from the other materials.

For years, the industry had to treat a retired blade as a single piece of waste. Old blades were routinely sawed into segments for landfill burial or incinerated. Occasionally, they found second lives repurposed as playground equipment or bridge supports. None of those local solutions addressed the core material waste generated by thousands of aging turbines worldwide. The resin was doing its job too well.

Six 81-meter blades changed a difficult problem in offshore wind

A turbine tower is mostly steel. Much of the machinery inside the nacelle can also enter established recycling streams.

A blade is different. Its strength comes from combining materials such as fiberglass with resin. The bond has to remain intact through years of operation. Breaking that structure apart later is difficult.

Old blades can be reused in other ways. They can be cut up and incorporated into new products or structures. That keeps material in use, but it does not necessarily return the original components to a form that can be used again.

Siemens Gamesa changed the whole point. Instead of building a conventional composite blade and dealing with its disposal later, the company developed a resin system intended to make separation possible at the end of the blade’s life.

Kaskasi was where the recyclable blade had to prove itself

The six blades in Aalborg could show that the technology could be manufactured. They could not show whether it would work as part of a commercial offshore turbine.

That test came at RWE’s Kaskasi wind farm in Germany. The first RecyclableBlades were installed there in 2022. The project sits about 35 kilometers north of Heligoland and became the first offshore wind project to use the technology in commercial operation.

A recyclable material still has to perform under the same conditions as a conventional blade.

Kaskasi moved the technology from controlled production into an operating offshore wind farm. The blades had to remain useful as turbine components while carrying the additional promise of easier material recovery later.

Chemistry inside the blade

The resin is the crucial part of the system. Siemens Gamesa says a mild acidic solution can be used at the end of the blade’s life to separate the resin from other components. Materials including fiberglass and wood can then be recovered while retaining their properties for further use.

This may sound technical, but it changes the entire approach to waste. A conventional composite is designed mainly around strength during operation. A recyclable composite considers what happens after that period as well.

The technology did not remain at the original 81-meter scale. Siemens Gamesa later extended RecyclableBlade technology to larger offshore blades measuring 108 and 115 meters. The change followed the industry's wider move toward larger turbines.

Larger blades can help turbines capture more wind, yet they also contain more composite material.

The turbines being installed today will operate for many years. Their eventual retirement may be decades away. The material decisions made during manufacturing will still shape what can be done with those blades then.

The idea became more significant when developers began ordering larger batches

In 2023, Siemens Gamesa announced an agreement to supply 132 of its 108-meter RecyclableBlades for RWE’s Sofia offshore wind project in the United Kingdom.

That order marked a change from the original six-blade production run. Aalborg demonstrated the concept. Kaskasi put it into commercial offshore use. Sofia brought it into a much larger procurement decision.

Siemens Gamesa also worked with EDF Renewables and wpd on potential future deployments.