Says this article at Nature Geoscience. Their numbers:
If the contribution from wind turbines and solar energy to global energy production is to rise from the current 400 TWh to 12,000 TWh in 2035 and 25,000 TWh in 2050, as projected by the World Wide Fund for Nature, about 3,200 million tonnes of steel, 310 million tonnes of aluminium and 40 million tonnes of copper will be required to build the latest generations of wind and solar facilities. This corresponds to a 5 to 18% annual increase in the global production of these metals for the next 40 years.
Of course, Oyu Tolgoi is one of the World’s largest copper deposits. If demand is going up because of the transition to renewable energy, shares of Oyu Tolgoi will be worth more in ten years as they are now.
And if a large scale renewable energy project in the Gobi desert actually gets to speed, it will of course help to have the necessary copper resources right at the doorstep of the project, which would be another strategic advantage the Gobi has over the Sahara for the concept of energy from the desert (besides the convenient location right next to the gigantic Chinese energy demand).
Full disclosure: I do not hold Turquoise Hills Resources stock right now, but intend to invest there in the next couple of months.