As machines, wind turbines are pretty good already; the problem is the wind resource itself, and we cannot change that. It’s a fluctuating stream of low–density energy. Mankind stopped using it for mission-critical transport and mechanical power long ago, for sound reasons. It’s just not very good.
As for resource consumption and environmental impacts, the direct effects of wind turbines — killing birds and bats, sinking concrete foundations deep into wild lands — is bad enough. But out of sight and out of mind is the dirty pollution generated in Inner Mongolia by the mining of rare-earth metals for the magnets in the turbines. This generates toxic and radioactive waste on an epic scale, which is why the phrase ‘clean energy’ is such a sick joke and ministers should be ashamed every time it passes their lips.
It gets worse. Wind turbines, apart from the fibreglass blades, are made mostly of steel, with concrete bases. They need about 200 times as much material per unit of capacity as a modern combined cycle gas turbine. Steel is made with coal, not just to provide the heat for smelting ore, but to supply the carbon in the alloy. Cement is also often made using coal. The machinery of ‘clean’ renewables is the output of the fossil fuel economy, and largely the coal economy.
A two-megawatt wind turbine weighs about 250 tonnes, including the tower, nacelle, rotor and blades. Globally, it takes about half a tonne of coal to make a tonne of steel. Add another 25 tonnes of coal for making the cement and you’re talking 150 tonnes of coal per turbine. Now if we are to build 350,000 wind turbines a year (or a smaller number of bigger ones), just to keep up with increasing energy demand, that will require 50 million tonnes of coal a year. That’s about half the EU’s hard coal–mining output.