The Economist's Technology Quarterly has picked up on recent developments in Vertical Access Wind Turbine (VAWT) designs, offering a glimpse at the latest peddler of these wares, one TMA Global Wind Energy Systems of Cheyenne, Wyoming. The story to look for in here is: why has VAWT technology struggled to make it to the mass, industrial scale market? It's been affirmed time and again as a more reliable and cost-effective design than the current upright tri-bladers (Horizontal Axis Wind Turbine -HAWT), from Darrieus to Savonius.
From what I can tell, there are two broad technical and commercial reasons why VAWT has struggled. On the technical side, VAWTs are low to the ground and don't capture the high winds like the 60-80m hub heights of HAWTs. The Darrieus version needs a generator to start up, and cables to keep it fixed. The Savonius model, more compact, spins even more slowly and is less productive for electricity though it's a decent grain-grinder. There is another version of the Darrieus principle proposed for 9MW offshore machines, though at first glance it appears prone to some of the same component stress as HAWTs. On the commercial side, it's the same old story of technical innovators whose marketing story hasn't been well-banked, well-communicated, nor well-timed.
Will the folks in Cheyenne overcome these challenges? On the technical side - it's still the same low-to-the-ground design capturing less resource, however it claims to get more production through the interaction between a set of moveable internal and fixed external blades. Its compact cylindrical frame definitely looks sturdier than a HAWT, and it is relatively cheap to build. This makes it an interesting offshore play: these machines may capture higher resources offshore where costs and mechanical stress are major issues. On the commercial side - here come the challenges. AMT isn't being incubated by a GE or Siemens and the marketing story will have to improve. The timing is not bad - offshore wind is adding less than 100 MW/year while costs are spiraling,HAWT components are hard to find. Getting more VAWT designs into the development pipeline is a good thing, particularly as the industry looks to scale on the water.
Image source: TMA Global Wind Energy Systems.
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