| > It assumes that pre-industrial agricultural output is the maximum that our planet can sustain. Which is completely off for a multitude of reasons I agree it's off because we've done significant damage to the biosphere since industrialization. As I've pointed out we have disrupted the natural nitrogen cycle. If we where to immediately rewind our population back to 1850 and try to life that lifestyle we would have a much harder time since we have depleted natural resources. We cannot go back because we the earth would not support us the way it once did. > There is no reason to assume that we're anywhere close to peak sustainable agricultural output, neither in pre-industrial times NOR now. Our entire current agricultural system relies on fossil fuels, so I agree, where nowhere near close... we're way past. > Viable pathways are - batteries: not for commercial transport, the energy density is still way too low. Your battery becomes your cargo. Modern global trade is impossible in a battery based economy. Nobody that is serious on renewables will disagree with this, they will claim that new battery technology is going to solve this. - Biofuel: require more energy to make they they provide [0]. So again, not only do you need to double the grid to handle intermittent power, you now need to expand it by the total biofuel energy required times 1/efficiency, so we're looking at at least tripling our current power output and trying to do it with only renewables. Please tell me how much silicon and lithium it would take to build a grid that large in that sort of a time span and you'll find it dwarf's annual production. - Fuel cells: same problem again, currently fuel cells are made with coal or natural gas today 95% of fuel cells are made with natural gas [1]. If you want to switch to electrolysis you come up with the same problem of having to double our current grid power. - Hydrogen in combustion engines: I'm not sure how this is different from hydrogen fuel cells, but the hydrogen production problem is the same. Please if you want sources, provide some of your own. Come up with some back of the envelope estimates on the total grid capacity needed to cover 100% of our energy needs. Then do some research on the energy costs to produce solar cells at that scale (or wind farms, hydro is already near full capacity at least in the US). I know you yourself don't really believe what you are saying. It's based on no research, you have provided no meaningful sources, and even the most die-hard solar/renewable proponents realize that grid scale storage is still an unsolved problems. What you have given are "hand wavy" explanations without sources, exactly as I expected. 0. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7320919/ 1. https://www.energy.gov/eere/fuelcells/hydrogen-fuel-basics |