If, like me, you've furnished about 80% of your home with items from a well-known Swedish
furniture retailer then I imagine the experience of trying to follow their assembly instructions
will be seared into your psyche forever. A long time ago in a previous job
I had the opportunity to visit their hallowed head office in Almhult in Sweden where I saw
the lengths they go to to make those instructions as simple and globally comprehensible as possible,
even paying unemployed people a day's wages to come in and build a selection of new products
specifically to assess how easy the instructions are to use.
Even so, it's still surprisingly easy to assemble a panel back to front or upside down, which is
fairly irritating if you're at home and you have to start building your billy bookcase again,
but it pales into insignificance compared to what these guys have to do. Their assembly instructions
are for a 120 meter tall flat-packed wooden wind turbine tower. So what's going on here? Is this
some kind of gimmicky art installation or a genuine solution for the wind power industry?
Hello and welcome to just have a think. As you may know, there's a bit of a global movement
in the architectural world right now towards creating large structures using timber instead
of the steel and concrete that we've become accustomed to. The production of steel and
cement accounts for about 16% of all global greenhouse gas emissions. In stark contrast,
using timber for construction locks up the carbon that the tree sucked out of the atmosphere while
it was growing. So as long as the source of the timber is a genuinely sustainable and carefully
managed forest or plantation then reverting back to a timber construction offers a promising
potential contribution to a more climate friendly future. That philosophy is part of the motivation
for a Swedish engineering and industrial design company called Modvion
who are planning to reintroduce wood as a structural material for turbine towers.
It's not as crazy as you might think either. In fact the more you dig into the details
the more you realize it's actually a very smart structural solution as well as being far more
climate friendly. During a recent interview with Zach and Jesse from the Now You Know channel,
Modvion's CEO Otto Lundmann and Development Engineer Geir Serderon explained that wind
turbines provide better power returns as they get taller because increasing the height gets you to
stronger and more consistent winds. The power of the wind is the cube of its speed so if you double
the wind speed you multiply the power by eight times. Going higher also means much larger blades
with a much larger sweep area. That means you can have a larger generator on each turbine and
that reduces the cost per kilowatt hour, making the whole thing more economically attractive.
But the taller the tower the larger its diameter needs to be to support the structure.
The current industry's standard material for towers as I'm sure you know, is tubular steel,
and the really tall steel towers are now becoming very difficult to physically get to site because
the size limit for road transport is a diameter of 4.5 meters. Go beyond that and you won't get under
some bridges or over them for that matter and you can forget about going through any road tunnels.
So advantage number one of the Modvian system is that flat pack feature that I mentioned earlier.
Not only are the towers constructed in stackable cone sections but each cone section itself is
constructed in separate segments. That means you can lay the segments flat and stack them
up on the back of a truck making them much easier to move around. The guys from Modvion
refer to timber as nature's carbon fibre, which is a nice way of thinking about it. And if it's
layered up as a stack of very thin veneers then you can produce an extremely strong but very light
material compared to steel, which is advantage number two. The locally sourced spruce timber
that Modvion use is only 1/16th of the weight of steel by volume and that means they can achieve
the same strength as steel for 30 percent less weight. So in fact the taller the towers become
the more advantageous it is to use timber construction, not just for transport but
for weight and strength too. There is some steel in the construction - it's used for
the adapters at the base and top of the tower to provide an interface with the other steel
components in the turbine construction - but the main structure is 100% timber.
You might be thinking that a wooden structure would start to rot away over time resulting in
collapsing turbines all over the place, but these things are rated to last just as long
as steel towers. If a longer life is specified by the client then the wall thickness can easily be
increased at the Modvion factory by adding more layers of veneer. The final protective coating
is a specialized polymer providing a similar level of protection for the timber as the steel towers
get from their rust inhibitor paints. What about fire? I hear you cry. And it's a fair question.
According to Modvion though, it's very difficult to cause a structure like this to ignite
because it's so dense. In these massive wooden constructions if there was a fire then the side
exposed to it would only start to char and at a very predictable and controllable rate.
High temperature steel gets soft and starts to buckle, so in these sorts of huge constructions
wood can actually hold its structural integrity longer than steel. And then there's advantage
number three which is the carbon sequestration I mentioned at the start of the video. The life
cycle emissions from a 110 meter tall wind turbine tower made of steel are about 1250 tons of carbon
dioxide. The same tower made of wood produces life cycle emissions of around 125 tons of CO2 - a
90% reduction. And because the timber also stores carbon the tower's actual climate impact is lower
still. A wooden construction stores approximately 1.8 tonnes of carbon dioxide per tonne
so a 110 meter tall tower would have a carbon dioxide storage capacity of as much as 540 tons
which means a net climate impact of about -400 tons of CO2. And of course at the end of the
tower's operational life span you're left with a whole bunch of extremely recyclable material. So
as long as it's used for something structural and useful then that carbon will be locked away more
or less indefinitely. Modvion built their first 30 meter tall test tower just outside Gothenburg in
April 2020, and in June 2021 the giant Danish wind turbine manufacturer Vestas announced
that it would be investing in Modvion to help accelerate progress towards full-scale production,
with a view to eventually integrating wooden towers into their own turbine installations,
the first of which will be a 150 meter tall tower supporting a turbine in the 4 to 4.5
megawatt class scheduled for completion in 2022. Now you might be watching this
thinking it's all very well to replace the towers with a more sustainable alternative
but it's actually the blades that are the least environmentally friendly and most difficult to
recycle element of a wind turbine, and of course you would be quite right. They're typically made
of a complicated combination of fiberglass carbon fiber and resin. At the moment the best they can
hope for in their second life is to be ground up and used as aggregates in road building,
but in reality most turbine blades end up in landfill or worse still just get burnt. The
industry is painfully aware of this environmental Achilles heel though, and they're racing to find
more climate-friendly alternatives like this one being developed by Siemens Gamesa in Spain.
Their latest innovation which they've cunningly called 'The Recyclable Blade' is made with a new
type of resin that can be efficiently separated from the other materials so that they can be
reused in future production. Vestas also claim to have new technology to recycle their blades
and they have a stated goal to make all their turbines zero waste by 2040. And for existing
blades that will be coming to the end of their operational lives over the coming years there
are now designers and architects looking for ways to repurpose them instead of destroying them and
adding to our global environmental catastrophe. Start-ups like Global Fibreglass Solutions have a
technology that can press decommissioned blades into fibre boards for flooring and walls. And
how about this cycle shelter made from an entire section of a decommissioned wind turbine blade.
The United Nations projects that nearly 70 percent of the human population will be living in cities
by 2050, so these kinds of smart solutions will become an important part of those urban
environments. It's just a great example of the sort of lateral thinking that we humans are
absolutely brilliant at if we just have a think about how to turn challenges into opportunities.
If you've got other examples of wind turbine repurposing solutions then it'd be great to
hear from you in the comments section below. That's it for this week though. As always,
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