Written by Andy Corbley

Reproduced with kind permission of Wood for Good – www.woodforgood.com

New methods for joining together lumber are opening the door to a variety of construction projects long since closed off to wood—most recently wind turbines.

A 330-foot (100-meter) prototype wooden wind turbine is being made in the land of wooden innovation, Sweden, to reduce the substantial carbon footprint of manufacturing a wind turbine from steel.

But how can a structure so battered with wind and gravity be made of a material that can be broken by a human with a machete? The answer is laminated veneer lumber (LVL), a wood construction product that is made by bonding three millimetre sheets of peeled spruce under intense heat and pressure to create flexible timber material stronger than steel, but lighter and less carbon-intensive.

Prototype of 30-meter wooden turbine tower – Modvion . Image credit: Modvion/Wood For Good

Prototype of 30-meter wooden turbine tower – Modvion . Image credit: Modvion/Wood For Good

Made by Stora Enso, one of the world’s oldest timber companies, LVL was used in 2020 to build a 130-foot (30-meter) prototype wind turbine tower. Hefty curved slabs of LVL are made and shipped to the build site where they are then glued together to form the tall cylinder onto which the spinning blades will be mounted.

Wood can reduce the CO2 emissions in creating a tower by 90% while also storing carbon dioxide that has been taken up by trees during their growth. Wood selected for transformation into LVL is taken from mature trees that have already absorbed the largest reasonably achievable amount of CO2 they’re able to.

The wood used for advanced constructions such as wind turbine towers can be reused in new wood-based products which provides further long-term climate benefits by continuing to store the carbon within their fibres.

Modvion is a Swedish firm that builds towers, and they see three major benefits compared with steel for building turbines.

Modvion

“Wood has a higher specific strength which enables a lighter construction. High steel towers need extra enforcement to carry their own weight—which wooden towers don’t need. And finally, modular steel towers demand a vast number of bolts that need regular inspections while our modular wooden towers are joined together with glue,” Modvion writes.

The towers would look about the same as a steel turbine, and not like a giant tree trunk due to an applied waterproof paint layer. At the moment, capturing carbon, done when the trees are turned into LVL, is more important than reducing emissions, since any reduction in emissions today won’t be felt in the global carbon cycle for far longer than any current predictions on warming or temperature changes. It’s only through actively taking emissions out of the cycle that are already there that humanity can change Earth’s climate.

Still, if humanity is building wind turbines to reduce emissions from energy use, we might as well reduce them from manufacturing too.