RE:Solar to hydrogenYou just can't change the laws of physics.
Even with the most current advancements, the mass based energy density of batteries is in the range of 0.1 to 0.27 kWh/kg.
Gasoline, is 13 kWh/kg energy density.
Hydrogen gas at 700 bar pressure is 39.6 kWh/kg, which is 3 times better than gasoline. Now this is why you don't have gasoline powered spaceships, where weight is critical.
We must look at it in terms of overall cost efficiencies for widespread use as a 'container' of energy.
The cheapest cost and way of producing hydrogen is from natural gas, which is about 16$/kg, and equates to around a $6 per US gallon gasoline eqivalent. This is blue hydrogen, made from methane, steam and a catalyst.
In order to succeed in this green energy transition using green hydrogen which is so widely promoted, it must be made from renewables like solar or wind as you pointed out. So green hydrogen ends up being at best about 5 times as costly as the hydrogen from natural gas, about $30 a gallon gasoline equivalent. the costs and infrastructure needed for such installations are extreme.
So yes, it is at best a costly experimental way of moving emissions from a tailpipe to a remote smokestack, and the laws of physics is the reason pigs still don't fly.