Coal energy density: 6.7 kWh/kg [2] Iron Ore energy density: 1.4 kWh/kg [1]
Total iron ore energy reserves: ~236.04 billion kWh [3] Total coal energy reserves: ~ 7,068 billion kWh [4]
So as far as energy goes we have 30x as much coal energy.
Now the rust can be renewed with energy ... but you need the energy to renew it in the first place.
[1] https://spectrum.ieee.org/energywise/energy/renewables/iron-... [2] https://en.wikipedia.org/wiki/Coal [3] https://www.nrcan.gc.ca/our-natural-resources/minerals-minin... [4] https://energyeducation.ca/encyclopedia/Coal_reserve
> but you need the energy to renew it in the first place.
So am I hearing you could create the iron-fuel someplace with excess energy and then ship this stored energy someplace that wants to burn it?
And while Iron loses out to energy density per kilogram, it wins on kilogram per cubic centimeter :D (your math is much appreciated btw)
Coal energy density: 6.7 kWh/kg [2] Iron Ore energy density: 1.4 kWh/kg [1]
Total iron ore energy reserves: ~236.04 billion kWh [3] Total coal energy reserves: ~ 7,068 billion kWh [4]
So as far as energy goes we have 30x as much coal energy.
Now the rust can be renewed with energy ... but you need the energy to renew it in the first place.
[1] https://spectrum.ieee.org/energywise/energy/renewables/iron-... [2] https://en.wikipedia.org/wiki/Coal [3] https://www.nrcan.gc.ca/our-natural-resources/minerals-minin... [4] https://energyeducation.ca/encyclopedia/Coal_reserve