If we stopped relying on gas and oil imports tomorrow, the number of vessels sailing our seas would also be slashed by half overnight.
Tankers make up half of the world fleet, and their only purpose is to move oil and gas around the world.
Doc Freemo 
@fabio Ok but how many of those would be replaced by vessles transporting the materials for solar panels, solar panels themselves, or related green tech. I have no doubt it is less, but any honest analysis or assertation on this topic would include that since it is not accurate or fair to say those ships would be eliminated when clearly they would be replaced, at least partially.
@freemo I don’t have an estimate within reach of the shipments carrying green techware, but my working assumption is that that number (in steady conditions) may be at least 1-2 orders of magnitude lower than oil/gas tankers.
After they’ve been built, you need to replace a solar panel or a wind turbine after about 2-3 decades of operation, while you need a continuous supply of oil or gas to burn in order to produce energy.
The only trade that is likely to increase is probably that of lithium and cobalt, as energy storage becomes a more widespread practice, but again the lifespan of a high density battery is much, much longer than that of a barrel of oil.
I know the current estimates for shipping of hydrogen alone is something like 15 million tons per year within the next 5 years. but yea, I would certainly expect it to be much less than oil.
> hydrogen in this context is irrelevant, it's a fuel not a construction material.
So, how is that an argument that it is irrelevant? If fossil fuels are replaced and green options used then hydrogen is one of those, and when it comes to transporting energy really the only viable way to do it if your dealing in electricity.
> Hydrogen is by and large also more of a delay tactic than it is a green alternative
Not entirely, while Hydrogen would never be the dominate form of energy it serves a purpose, largely for long distance transport of energy where wires arent a feasible way to move the power. While hydrogen alone wouldn't be a massive component as hydrogen would never be a main fuel source it is very much relevant all the same.
So some back of the napkin estimates. Assuming we just talk in terms of solar panels to make the math simple...
To power the world it would take 51 billion solar panels which have an average lifespan of 25 years (sources cited at the end).
A solar panel requires mostly aluminum and copper to construct it with 12% being copper, 87% aluminum, and 1% other stuff like silver and lead.
Solar panels require about 21 tons of aluminum and 2 tons of copper to produce 1 MW of power producing potential from solar panels. Thats 12.6 lbs of aluminum and 1.3 lbs of copper per panel.
So total to support a world running on solar panels would take 321 million tons of aluminum and 33 million tons of copper every 25 years.Or 64 million tons of aluminum and 6.4 million tons of copper every year.
Figuring out how much of that would effect shipping is the tricky part, and will take a little bit of hand waving. But in 2022 there were 69 million tons of new aluminum consumed per year. Similarly there was 25 million tons of copper consumed each year. That means the total need for aluminum would almost double and the global need for copper would increase by about 20%. Thats a total increased ore shipment across the two ores of 75% increase.
Your average freighter can carry 165K tons of freight. So to carry the new resources it would take 440 additional shipping freight cargo ships making a trip each year.
By estimates there are "hundreds of thousands of shipping vessel crossings every year" So assuming going away from fossil fuels cut shipping vessle crossings in half we are talking about saving somewhere on the order of 50K+ crossings every year but adding back only about 440 crossings each year.
https://www.axionpower.com/knowledge/power-world-with-solar/
https://www.statista.com/statistics/863681/global-aluminum-consumption/
https://www.statista.com/statistics/863681/global-aluminum-consumption/.
@freemo @fabio hydrogen in this context is irrelevant, it's a fuel not a construction material. Hydrogen is by and large also more of a delay tactic than it is a green alternative