The German steel federation sees the current wind energy boom as "a big technical challenge." A single 5 MW offshore turbine requires 3000 tonnes of steel, it points out, so the expected installation of 4000 turbines offshore by 2010 will require 12 million tonnes of steel. "An interesting market," says Dieter Ameling, president of the German steel federation Wirtschaftsvereinigung Stahl. German wind has sent ripples through the steel market beyond its own borders. Czech steel company Skoda expects to step up supplies to Germany by 31% this year to 3663 tonnes in the form of finely-machined wind shafts. "The total supply to Germany may be even higher as more than half our wind shafts are delivered roughly machined to another European manufacturer, who does the final machining and who may also have sales to Germany," says the company's Martin Koca.