Modular wood-based wind turbine towers are cost efficient and CO2 neutral When it comes to wind turbine towers, the bigger, the better. But that proves problematic for their transportation. The Modvion project has tapped the power of wood for a pioneering modular solution. Energy © Modvion AB According to the International Energy Agency, wind power is expected to become the EU’s largest power source by 2027. A significant part of achieving this will be building taller wind power plants. The taller the power plant, the more renewable power can be produced, at less cost. Modvion has developed a modular, laminated wood, transportable tower to be cost-efficiently assembled on site. The company has already built a 30-metre prototype for a research turbine commissioned by the Swedish Wind Power Technology Centre, soon to be installed on Björkö, an island near Gothenburg. EU support through the Modvion project has enabled the Swedish company of the same name to create a business plan. This was based on analysis of the conceptual design, technical and commercial feasibility, and risk assessment of developing a 110-metre tall tower for a 150-metre tall power plant. The Swedish utility company Varberg Energi has expressed their intent to buy just such a commercial-scale tower with a view to a 2022 installation. The wind project developer Rabbalshede Kraft has expressed an interest in buying 10 towers, over 150 metres’ tall, for their Fägremo project. Nature’s carbon fibre The most common turbine towers are made of tubular steel which, due to their large base diameter, are difficult to transport, with road restrictions generally limited to around 4.5 metres in height/width. Other solutions, such as hybrid steel-concrete, modular steel or lattice towers, are all more expensive and cause large amounts of CO2 emissions during production (15 % of global CO2-emissions; 8 % for concrete and 7-9 % for steel). Modvion’s engineered wood solution bends and glues plywood-like modules to shape, which are designed for ease of transportation. The modules are assembled together in situ into circular sections which are then piled on top of each other and joined to form the full tower. “While laminated wood requires greater volumes than steel, resulting in thicker walls, this is not a problem. Wood is 70 % cheaper than steel for the same strength and has already absorbed CO2 from the atmosphere, which will then be stored in the construction. By replacing one single 150-metre steel tower with a wooden tower, we’ve calculated you avoid 2 000 tons of CO2 emissions in its construction,” says Karin Björe, project manager. Tests and simulations of the prototype have included the finite element method (FEM) and structural analysis of the tower construction, laboratory tests of fatigue and static structural strength, as well as tests for manufacturability. After testing, the team achieved deviation of the straightness of the wood over the full length of the 30-metre tower, of barely 2-3 mm, well inside tolerance limits. Branching out Modvion is contributing to the EU’s target of increasing renewable energy production. Its innovative approach can replace fossil-based CO2-emitting energy with less environmentally hazardous and more cost-efficient wind power. At the same time, it replaces CO2-intensive materials, like steel and concrete, with renewable laminated wood. “We have demonstrated that it is possible to build the most demanding constructions in laminated wood, further reducing the barriers to using wood in other applications, such as skyscrapers or bridges,” says Björe. After the 110-metre tall commercial tower has been installed for Varberg Energi, the team intend to expand their manufacturing capacity and market their offer to early adaptors in Sweden and beyond. Keywords Modvion, wood, laminate, turbine towers, wind power, energy, fossil, renewable, steel, concrete, emissions
