Simply ask to quantify the cost of shaping those materials into machinery, respective to other means of energy production. You will be met with hostility and scorn, accused of all sorts of improprieties, and ejected from the tribe, without ever receiving a data-supported answer.
Because it's such a weasel "just asking questions" thing to do.
If you had a concern about the material costs of renewables you should know what they are and if you wanted to have a good faith discussion, you'd also be able to compare against legacy energy material costs.
