There are actually many advantages to this. Not only does it avoid the carbon footprint of making all that steel, but because it is transported in sections rather than as complete tubes, it is not limited in diameter for transport like steel tubes are.
Because wood is lighter than steel, they can lift bigger sections. "Conventional steel tower constructions get dramatically more expensive with height due to the increasing need for thicker walls."
In Wind Power Monthly, Chief Technical Officer Erik Dölerud explains how they used Laminated Veneer Lumber (LVL) to get the strength they needed. "LVL is a loadbearing plywood structure created through laminating many very thin wood-veneer layers, making the Modvion towers 250% stronger than CLT-based equivalents." (Learn more about the different types of mass timber here.)
CEO Otto Lundman explains how it differs from steel towers.
"Our calculations indicate that the 150-metre tower will reduce mass by about 30% and cut manufacturing costs by roughly 40% compared with an equivalent tubular steel tower with a 6-7-metre base diameter. And wood is a natural product that can often be sourced locally, creating local jobs and other added benefits."
The wooden towers also offer additional environmental benefits compared with steel towers thanks to the lower-carbon manufacturing process. Lundman estimates a saving of 2,000-tonnes of CO2-emission per tower up until deployment. Plus, carbon sequestration in the wood offers the potential to make a wind-power plant carbon neutral.
This is all still at the prototype state, and we probably won't see steel being replaced by wood soon. But it does put paid to the steel industry argument that you absolutely need steel if you are going to go renewable.