Re: ICD-10-CM G31.9
"...'green hydrogen' will become economically viable, once 'renewable' energy starts becoming cheaper...."
To be blunt: the only way green hydrogen will become "cheaper" is by widespread rollouts of molten salt nuclear energy plants - and it will STILL be three times the price per joule of the source electrons
This is where the fundamental conceit of piped hydrogen proponents falls down - natural gas is popular because it's 1/3-1/5 the price of electricity. Nobody is going to pay for it if it costs more than just running wires
Historically, electricity production accounts for only about 1/3 of our ENTIRE carbon emissions. Renewables can't bridge the gap between "replacing existing electricity production" and "making enough extra electricity to cover the other carbon sources", so their existence can only ever be regarded as a stepping stone along the way - they are NOT an "ends", merely one of the "means"
WRT "tidal" energy, the ecological impacts of large scale deployments are something that most people fail to take into account. Canada abandoned the Bay of Fundy proposals because it was realised that deploying it would result in extra tidal swings right down the east coast of North America - to the tune of 60-foot tides at Maine, 20-foot tides at New York and an extra 3-5 feet of tidal swing at Florida.
Yes, the Fundy proposal could have supplied 1/3 of Canada's needs, but at cost of unleashing ecological devastation upon its neighbour