Decommissioned wind turbines, load cells and turbine blade bridges

Published On: April 29 2022

Wind powered electricity is finally coming into its own. According to the ONC, the UK electricity generation from wind power increased by 715% from 2009 to 2020. In 2020, that amounted to 24% of the total electricity generation including both renewables and non-renewables.

During Storm Malik in early 2022, when wind speeds reached up to 100 miles an hour, UK wind farms generated more than 19,500 mega watts – over half the UK’s electricity.

The end of the line

However, there’s a problem. Modern wind farms have a lifespan of about 25-30 years. This means that some of the UK’s earliest installations are being decommissioned.

Some aging wind turbines can be refurbished or replaced with newer technology. Key elements of the structure can be recycled if demolished, according to WindEurope:

“85-90% of a dismantled wind turbine are recycled today, including the towers, foundations, generators and gearboxes. Most of these materials are made up of concrete, steel and cast iron which are easy to recycle and for which there is an active circular economy market in Europe.”

Decommissioned wind turbine blades are another story, as a report into blade recycling explains:

“Where fibre reinforced composites are recycled, the compromised quality of the recyclates means they are often only used for lower value applications – such as short fibre reinforcement or filler in new composite materials – limiting the economic case for using them.”

This leaves a lot of old turbines blades with nowhere to go except into landfill.

Blades as bridges

One organisation that’s doing something about this is the Re-Wind Network, a collaboration between faculty, staff and students at Georgia Institute of Technology, University College Cork, Queen’s University Belfast, City University of New York and Munster Technological University.

Rather than breaking up blades, the network are looking at ways of repurposing wind blades during wind farm decommissioning. They are looking at innovative ways to use wind turbine blades that embrace the strength, durability and sheer size of these strong, well-engineered – and large – components.

The result? Designer footbridges!

“BladeBridges are pedestrian, cycle and vehicle bridges that use wind turbine blades as their primary load-carrying structural members… The wind turbine blades are typically placed on the sides or underneath the bridge deck. … The bridge deck may be timber plank, cast-in-place concrete, precast concrete panel, steel grid, steel panel, FRP panel, or any proprietary decking system.”

BladeBridges can be for pedestrian or vehicle access, either as a single span or a series of spans. Not only are these bridges strong and highly economical, they look great too. As the company’s brochure says:

“BladeBridges are durable, sustainable, and have a unique aesthetic.”

Load cells and bridge testing

We just love the idea that load cells play an important role in the manufacture and precision balancing of wind turbines blades and now play a role in the testing of the new bridges.

A report for the company gives details of how load cells are used to determine the load-deflection of a blade when bending edgewise:

“Load was applied to the test specimen by a spreader beam system under each hydraulic jack with slots cut in the skin of the blade such that the spreader beam system applied load directly to the upper (TE) web of the test specimen. … Strain gauges (SG1 and SG2) oriented in the longitudinal direction were bonded to the skin of the specimen at midspan. Load cells were provided under each hydraulic jack and all instrumentation was logged with a multi-channel data acquisition monitoring system operating at a sampling frequency of 10 Hz across all instruments.”

And there’s more

The company also aims to repurpose decommissioned wind turbine blades into a whole range of items including:

  • powerline poles
  • cell phone towers
  • lighting and luminaire poles
  • sign supports
  • noise barriers
  • bus shelters
  • glamping pods
  • partitions for farm buildings

Recycling blades as raw materials

In the US, some blades are being recycled for raw materials, as a report from the Kleinman Center for Energy Policy explains:

“General Electric Renewable Energy signed an agreement with Veolia to recycle blades removed from its onshore turbines in the U.S. … Veolia will shred the blades and use the resulting material in the coproduction of Portland cement. 65% of the blades will be used as raw material (replacing sand and clay), and 28% will be used as energy for the kiln, resulting in almost 95% of the blade being reused.”

Recycling, load cells and more

We provide load cells for a range of green energy projects, from wind kites to wave power. Our load cells also help test the energy efficiency of vehicles, and are used in processes to recycle precious resources including car tyres.

If you’ve got a new project and are not sure which load cells to use, call us. We’ve designed systems for clients that are effective, efficient and reliable. We can supply most types of load cells from stock, or can manufacture to your specific requirements here in the UK.

Just let us now how we can help!