As implied by Quamera's post above, the only way I see hydrogen being applied is for using up excess renewable energy grid generation - i.e. when electricity prices otherwise would literally go negative due to too much renewable energy being generated, as is now sometimes the case.
If people can make a business case for generating hydrogen and selling it to some energy-poor nation, then that is much better than what AEMO suggests as a solution to too much rooftop solar generation - i.e. to simply shut off residential PV systems during excess generation periods.
Rather than incurring all the conversion losses with hydrogen fuel cells, it might make more financial sense to build cross continental super high voltage DC cables as well as large scale pumped hydro storage.
Perhaps one day we will see a
super grid emerge. Sorry to say that I will not be around to witness that.
