[pfdietz]

Right. Using biomass to generate that hydrogen would be bad. Biomass, among all the renewable energy sources, has very poor power/area. PV is an order of magnitude better.

It's not at all clear that PV is more expensive. In the best global locations it's already below $0.02/kWh -- and one would want to do this processing where the inputs are cheap.

Add to that: this is all forward looking, so we must also consider that PV will continue to get cheaper. Extending the historical experience curve to the point the world is solar powered will drop its cost by another factor of 4. This may or may not happen, but calls in the past that the experience curve had reached its limit were wrong.

[ya_throw]

Using the advertised final cost of electricity is, in my opinion, a useless way to work out the sustainability of any power source. It is skewed beyond usefulness by government incentives, tax breaks, etc etc.

If we're talking about renewable and sustainable power, the only way to look at it is the embodied energy of the device. As I alluded to, the only way solar panels are as cheap as they are is because they are all made using coal or other fossil power. Solar panels require an enormous amount of energy to manufacture - the energy payback period is over 20% of the panel's expected lifetime. This clearly indicates that the price per unit of energy in a system powered by solar would be much higher than it is now.

We also haven't even touched on the idea of where on earth (literally) all of the minerals required to make this gigantic number of solar panels, will come from. PS. Invest in mining, "renewables" are making it a very profitable business right now.