Around the globe administrations and intergovernmental bodies have established ambitious climate change mitigation targets, many of which revolve around increasing the use of renewable wind energy. However, the high carbon production costs and waste generated by traditional steel turbines has given rise to ambitious wooden wind turbines, which look primed to revolutionise the energy industry and allow for climate-neutral wind farms.
The EU has already moved to back plans in support of a Swedish design and construction company named Modvion in implementing several new builds, including the opening of a factory in Gothenburg and the creation of a 30-metre high turbine.
In April 2020 the first wooden wind turbine was erected at Björkö outside Gothenburg. The 30-metre high development remains a breakthrough in the feasibility of making turbines from lumber commonplace.
In order to provide the structural integrity and lightweight design, Modvion decided to use Laminated Veneer Lumber (LVL) as the main component of the build.
LVL is an incredibly strong and lightweight material used widely in the construction sector due to its low cost and stability. LVL generally consists of between 3-4mm thick rotary-peeled softwood veneers glued into a single sheet, with its grain all running in the same direction giving it a signature aesthetic.
A Modvion spokesperson elaborated on the materials longevity and strength stating: “LVL is a load-bearing plywood structure created through laminating many very thin wood-veneer layers, making the Modvion towers 250% stronger than CLT-based equivalents.”
The main LVL structure of the prototype was manufactured with the help of Moelven, at a local gluewood factory in Töreboda. During the construction, Moelven found that production costs of wooden towers would be significantly lower in comparison to steel towers.
Moelven reported that using wood instead of steel reduced their cost by 40%, and allowed for local sourcing of material, generating jobs and other community benefits in Töreboda.
Following the project’s completion the CEO of Moelven Johan Åhlén reinforced the benefits of increasing the inclusion of wood in construction by stating:
“Wood has fantastic properties and we need to build much more in wood if we are to meet the climate goals. For us, it is hugely inspiring to participate in this pilot project where we have been able to use renewable wood in a design for the production of renewable energy”.
But what makes wooden wind turbines more environmentally beneficial in comparison to traditional steel units? The answer lies in the full life cycle of these timber towers which have the potential to create: “fully climate neutral wind power”, as stated by Otto Lundman, CEO of Modvion.
A key to the successful widespread adoption of wooden turbines will lie in the fabrication of LVL panels. Creating the main turbine structure from wood is far less energy-intensive in comparison to that of steel, saving approximately 400 tons of CO2 with each new unit.
The construction and erection process is similarly more efficient. Unlike traditional towers where large cylindrical sections of the tower must be moved, smaller component sections of LVL panelling can be quickly flat packed and transported in trucks direct to site.
This advantage cannot be overstated, with the movement of traditional wind towers increasingly becoming an obstacle for EU and USA administrations attempting to expand wind farm capacity. Base diameters for 100+ meter towers exceed 4.3 meters, consequently the movement of such massive components is oftentimes in breach of road transport regulations, generating significant logistical difficulties.
The longevity of the timber turbines is equally impressive as its fabrication and construction. The towers themselves can match traditional units for lifespan (lasting approximately 25 years) and operating efficiency.
In order to protect the wooden towers from the effects of water, they are coated in thick layers of watertight paint designed to control the volume of air inside the structure to ensure stable levels of humidity.
One of the most glaring arguments against the use of wood in tall construction projects is the risk of life-threatening fires. However, it is very difficult to get large sections of wood to ignite due to their density. If exposed to fire, these towers will char and, unlike steel which becomes soft, maintain their structural stability.
In the past four years, Europe has seen a 16% rise in the number of wind turbines older than 15 years, heralding in a new waste disposal race for the EU. The new influx of plastic waste generated by traditional steel turbines may be the accelerant Modvion has been looking for to launch wooden wind turbines commercially.
In addition to the vast amounts of CO2 generated during the manufacture of traditional units, the plastic composites used in the blades of these towers cannot be recycled and can only be down-cycled (shredded and reused in reinforcing concrete) or landfilled.
In contrast, the component parts of wooden turbines can be upcycled and used in various construction and utility projects, all the while sequestering carbon and reducing emissions.
A recently published article by The Economist highlighted the danger of a dramatic upsurge in demand for balsa wood used in wind turbine blades. Ecuadorian forests have been ravaged by locals, who found themselves surrounded by a newfound wealth, resulting in devastating amounts of deforestation and forest degradation.