It's never quite as easy as it sounds

 From an AP story on "green steel":

Offshore wind is key to many plans to address climate change, because it partially replaces fossil fuel-burning electricity. It will require massive amounts of steel as turbines are built miles offshore from U.S. coastlines. Nearly 90% of an offshore turbine’s weight is steel, and each one, including the foundation, requires roughly 180 tons of steel per megawatt, according to the industry group American Clean Power.

Meanwhile (from the same story):

Steel is one of the world’s dirtiest heavy industries. Three-quarters of world production uses a traditional method that burns through train loads of coal to heat the furnaces and drive the reaction that releases pure iron from ore.

So there's that.