With known technolgy could a large ship store enough electrical energy to power itself to another part of the globe and be hooked up the the grid to help supply a city and then power itself back to a sunny location for a recharge. The chargers would not be on the ship, only the storage batteries. Maybe the deck could be a charging system to help power it.
Doesn’t a nuclear submarine do that now without the need for the re-charge part? I don’t know about the part where it has to offload power to help a distant location with their own power needs, but I suspect it can be or has already been done. The Ohio class boomer subs are the largest ones the U.S. has, so I presume they can produce the most power.
You certainly could, in principle, pack a crapload of lithium-ion batteries on a ship and use it to power a city, though I have a hard time seeing how it would be worth it.
Why not just generate electricity onboard, though? The concept has been done several times. For instance, Tacoma, Washington was supplied with emergency power by an aircraft carrier all the way back in 1929.
Slightly more recently, a ship-based nuclear reactor supplied Panama with 10 MW of power in 1968-1975. I’m sure there are many other examples.
I was thinking more in terms of pure solar power storage. For instance we had a huge solar farm somewhere in Africa that was used to charge up a fleet of ships that could go anywhere in the world. I am wondering if this is something we can envision as being not only possible but feasable.
The largest ships in the world have a deck area of perhaps 350x50 meters. Reasonably priced panels deliver about 150 W/m[sup]2[/sup], so all told we’re looking at about 2.6 MW. That’s only enough to power a pretty small town (and that’s peak, not average, power).
The biggest cargo ship has a capacity of 194,000 tons. Filled with lithium-ion batteries, that’s enough to provide about 50 MW of power for a month. That’s a fair amount of juice, but still only enough for a small city. Maybe more if you’re talking about a developing country with lower requirements.
By contrast, the upcoming USS Gerald R. Ford will have >100 MW of generation capacity, and virtually indefinite lifetime.
Maybe some kind of deployable solar panel system could work. You can fit a heck of a lot of panels on a container ship, but they would need to somehow unfold and float on the water surface to give you enough surface area. That’s a highly non-trivial engineering challenge…
It isn’t really feasible right now. If we had better battery or storage technology, I imagine it would still be better to load up cargo ships with batteries or new-fangled power storage units and unload at the terminal anyway.
Kind of reminds me of transmitting large volumes of data over a network. For truly huge volumes of data, we get better bandwidth (though incredibly high latency) by giving a bunch of hard drives to FedEx to deliver rather than trying to use the internet.
Why do this as opposed to a fission plant like present day naval vessels.
an aircraft carried flight deck covered with solar cells would generate about 1.8 MW
For comparison a Nimitz class aircraft carrier burns about 2.1MW on air conditioning alone.
I assume your thought is that you use this method to transport energy from locations with a lot of sun, to locations with less. Power generation and distribution is however, as I understand it, all about efficiency.
Setting up solar panels where they only get a few hours of weak sunlight a day is inefficient. But setting up solar panels somewhere sunny, then converting the electricity created into chemical energy (batteries) then carrying the batteries a long way, then powering something with the batteries, is going to be very inefficient. You are going to lose energy every step of the way. I doubt you would end up with a more efficient solution than just setting up the solar panels where they are required in the first place.
The most efficient way to achieve your goal would probably be to use your ship to tow a lot of timbers from a tropical to an arctic zone, and then burn it as fuel.
You did not specify what type of ship, so spaceship I assumed allowed
I’ve heard that a Space Shuttle’s booster tank’s capacity worth of He3 mined from the moon and returned to earth could supply the entire USA power at its peak usage rate for a year (through a yet unknown controlled clean fusion reaction), and He3 is a byproduct of solar radiation.
Also the concept of a solar satellite, a solar collector in Geo-sync orbit beaming a highly directed microwave ‘power beam’ to a receiving station, though a satellite is getting away from the concept of a ‘ship’
But more to your point, what would be the point? That city importing oil or CNG or cyro LNG or other alternatives would be much easier and most likely ‘cleaner’ as in ‘more green’ then recharging batteries that have to be inefficiently recharged by oil or Nat Gas and also shipped across the sea.
I think better than that would be to supply fresh water. Which I guess an aircraft carrier did after the southeast tsunami.
Wouldn’t it be better to lay transmission cables? Or would the heat losses be too high?
Even with current technologies (so, no room temperature superconductors), you can transmit power an arbitrarily-long distance at an arbitrarily-high efficiency through wires. Just make it DC, and crank up the voltage high enough (not necessarily in that order).
Since the idea is to use the ship to capture energy it would be wasted if it used the electricity to move itself when that could be done with sails.
The problem with solar energy isn’t so much a shortage of sun that you need to find it half a world away, it’s making the whole thing cheap enough to compete with other sources. Big boats and batteries and putting them out to sea where many are bound to be lost just makes it more expensive.
But it does sound like an artistic way to get your power.
Ok, the showstopper is this: I’m using this battery as an example because it is using an ultra-long life technology and it’s at a reasonable retail price. This particular battery stores 200 amp-hours at ~3 volts. That’s 600 watt-hours, or 0.6 kilowatts. That means it stores 6 cents worth of electricity assuming the electricity is worth $0.10 per kilowatt hour.
It’s rated between 3000 and 7000 charge/discharge cycles, depending on conditions. Taking 5000 cycles as the median, over the battery’s lifespan it can store and supply $300 worth of electricity later.
The battery itself costs $270. Not very cost effective.
That was interesting, suppose you took a very primitive approach and simply used the excess electricity to pump water up to an eleveated lake say 500 feet higher. How much would loose pumping it and then generating it back into electricity when you needed it?
A well engineered pumped hydro plant can recover around 75% of the energy it consumes to pump the water uphill.
Edit - and I wouldn’t exactly label that as a primitive method. It has it’s drawbacks as in being location specific and posing some engineering challenges. But there are pumped hydro plants in service today.