Wind turbines taller than most skyscrapers, with blades that bend like palm trees, could generate 50 megawatts (MW) of power, according to an analysis of a scaled-down prototype. This would be enough to power about 15,000 US homes.
The largest existing wind turbines top out at around 300 metres tall, more than twice the height of the London Eye, and can generate 15MW of power. Larger turbines produce more power, bringing down the overall cost, but scaling up isn鈥檛 straight forward because longer blades can bend in high winds and risk striking the tower. 鈥淵ou do not want that,鈥� says at the University of Virginia. 鈥淚t鈥檚 like an airplane crash.鈥�
Such strikes are infrequent, but the risk increases with the size of the turbine. 鈥淭he reason it鈥檚 very rare is because people design the turbine blades to be strong enough [to avoid bending],鈥� says Loth. 鈥淏ut when you start to build 50MW, it鈥檚 very difficult to do that. I don鈥檛 think it鈥檚 possible, to be honest.鈥�
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To get around this, Loth and his colleagues are taking a different approach. Rather than having three rigid blades facing into the wind, their design has two 250-metre turbine blades mounted downwind, on the other side of a 300-metre tower. The combined height of 550 metres means the top of the blades would reach higher than the One World Trade Center skyscraper in New York.
Both blades are angled away from the tower and can fold in strong winds like the fronds of a palm tree in a hurricane. 鈥淭he idea is that instead of trying to fight the wind, we go with the flow,鈥� he says. 鈥淚n a hurricane, the fronds [of a palm tree] can all go with the flow, even the trunk can bend down and almost touch the ground.鈥�
A small-scale prototype of the 50MW design, with two 20-metre blades, was up and running at the US National Renewable Energy Laboratory in Colorado for two years until July 2022. Loth鈥檚 team is now busy analysing the data from this pilot. 鈥淭he technical viability looks good,鈥� he says, adding that it appears the design could be scaled up successfully.
But to do this, Loth needs to find a company with very deep pockets. 鈥淚n order for us to build one, I need like $1 billion [for a prototype],鈥� he says. He is confident that turbine manufacturers would be interested in taking the idea on, once all the findings have been validated.
Others aren鈥檛 so sure. at Delft University of Technology in the Netherlands says wind firms are conservative. 鈥淭he industry has been very skilled and experienced in building three-bladed upwind machines,鈥� he says. 鈥淎nd it鈥檚 a huge risk鈥� to suddenly just change the concept.鈥�
But a step-change in technology will be needed if 50MW turbines are to become reality, says at the University of Exeter, UK. 鈥淲e can possibly get to 20MW the way we are doing it now, but I think beyond that it鈥檚 going to need some rethinking.鈥�
The real challenge with Loth鈥檚 design, says Cochrane, is to build boats, cranes and ports large enough to construct such mammoth turbines. Currently, the largest turbine installation ships only reach up to 336 metres.
Loth says it is likely that his huge turbines won鈥檛 be built within 20 years. at the Global Wind Energy Council worries that trying to build extreme-scale turbines could distract the sector from the job at hand: rolling out wind turbines as fast as possible to decarbonise electricity production.
鈥淚f we continue with the race to the top in terms of turbine size, we might start to lose focus on what we have now,鈥� she says. 鈥淭here鈥檚 a lot to be said for pushing forward, deploying at scale, with the available technologies.鈥�
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