There have been many voices lately saying that renewables could produce 80% or more of the world’s energy by 2050 in order to limit global warming to 2.5°C, as long as we develop sufficient energy storage and bring up efficiency and conservation. But the real issue is raw materials. It takes about 500 tons of steel and 1000 tons of concrete per MW of wind power. Even more to connect them to the grid.
The United States has used 40 million tons of steel to build 48,800 wind turbines totaling 74,512 MW and costing about 150 billion dollars. Wind energy produces about 200 billion kWhs each year or about 4% of our total electricity. Coal produces 41% of the world’s electricity and 30% of its primary energy with oil and gas bringing the fossil fuel total to 66% of primary energy. This amounts to about 25 trillion kWhs equivalent including petroleum for transportation fuels. Non-hydro renewables so far produce only 3% of primary energy despite aggressive policies to install them in the developed world. Total primary energy is projected to increase to 40 trillion kWh equivalent by 2050.
Wind output in the United States alone is projected to be 404 GW by 2050 representing an increase of 338 GW over 2015’s 66 GW of installed capacity. As wind penetration increases due to reduced capital costs along with lower prices for renewable energy, raw materials, especially steel, will naturally be greater in demand. The Department of Energy’s Wind Vision Study forecasts wind energy could supply 35% of US power by 2050. Since wind turbines only last about 25 years, this volume would have to be replaced every 25 years. Although global steel production is presently at an historic high, totaling 1.6 billion tons a year, the real question will be if the steel industry can keep pace with future demand for wind.