Oil is also fungible, see e.g. biofuels made from sunlight using algae, or whale oil harvested from sperm whales. We just don't bother with alternate sources b

Oil is also fungible, see e.g. biofuels made from sunlight using algae, or whale oil harvested from sperm whales. We just don't bother with alternate sources because it's cheaper to pump it out of the ground, we wouldn't bother with alternate electricity generation either if we could just dig fully charged batteries out of the ground.