A very detailed and useful piece in Renewable Energy World by Elize de Vries yesterday. It highlights the supply chain pinches of the wind industry in the face of excess demand - which have led to rise in wind turbine prices these last few years.

Some of the chronic shortages or limited supplier choices are in;

• Turbine blades - LM Glasfiber of Denmark have a worldwide market share of over 27% on a MW basis, while it delivered rotor blades to nine out of the Top10 wind turbine suppliers. This market dominance allows them to call the shots on other blade suppliers and dictate a semi-standard in the blade root bolt circle
  
• Bearings - particularly the larger ones with outer ring diameters of 200-250 mm
• Gearboxes  - they are breaking down too frequently particularly in the larger turbines and many windfarms are operating well below par whilst they await replacement
  
• Generators, main shafts, control cabinets - enough said
  
• Complex steel castings such as hubs and mainframes which require up to 6 weeks to forge and cool to prevent cracks - hence a typical steel foundry can only produce 6-8 a year.  Added to rising steel prices, this is a bit of a nightmare.
  

So how long will this continue?

Apparently, "according to wind industry sources, the shortage situation is unlikely to be fully resolved within the next two or perhaps even three years".

A sobering prospect - I can't see this not having some effect on the sometimes overly rosy growth predictions of the wind industry. This is definitely something to keep track of over the next few years.