It's unavoidable that fossil fuels will be needed to spin-up the infrastructure of a total clean global economy. However, there's no better use that fossil fuel

It's unavoidable that fossil fuels will be needed to spin-up the infrastructure of a total clean global economy. However, there's no better use that fossil fuels can be put to than preparing the ground for totally clean and abundant energy. However, it's most certainly feasible to make steel without fossil fuels. In the US, many newer iron makers use Direct Reduction of Iron in furnaces fed with CO and H produced from natural gas (and then this DRI product is refined electrically in electric arc furnaces at so-called "Mini Mills" which are not so mini). There's no reason you couldn't just use hydrogen directly produced via electrolysis instead. ...and power-to-gas is also feasible (although approximately twice as expensive to produce per unit energy as electrolytic hydrogen is). And with that synthesized gas, you can also produce any kind of petroleum-derived product via Fischer-Tropsch, including graphite and coke and the resins needed for wind turbine blades. And all these products would be higher purity than those produced from fossil fuels (although the price WILL be higher). So let's not let perfect be the enemy of the good. Let's transition now as soon as possible whatever we can. And that means off-shore wind.