Ask HN: Could ships that convert CO2 + water to natural gas save the planet?
# IDEA
Imagine a ship sitting in the middle of the ocean (where little life naturally occurs), with an eSolar [1] installation deployed.
A giant array of mirrors, individually small, but in total much larger than the hull of the ship, automatically adjusts to keep an intense beam of heat focused on a boiler, even as the ship rolls in the waves.
Convection carries water from the ocean to quickly cool the boiler and keep pistons that generate electricity firing.
Generated electricity is used, along with water and carbon dioxide, to create CH4 (natural gas) and oxygen, at 80% efficiency [2].
Once the ship is full of natural gas, it folds up its solar array and sails to the port where the bid for natural gas is highest.
I haven't done any math to figure out cost, but it seems interesting/compelling from a high level. What do you think?
Anybody who wants to take this idea and execute on it should feel free to do so without reserve. I claim no ownership to anything. Execution is everything.
[1]: http://www.idealab.com/our_companies/show/all/esolar
[2]: http://newenergyandfuel.com/http:/newenergyandfuel/com/2009/04/01/boosting-bugs-with-electricity-to-make-natural-gas-from-c02/
If you're going to use a ship for this, it would also have to be able to liquefy the natural gas (you have can store about 1000 times more energy with natural gas as a liquid than as a gas)
Basically, the capital costs and operating costs for this probably don't make any economic sense.
Generating natural gas with 80% efficiency would solve tonnes of problems (if the price was right). If you could do that, you could get rid of 50% [totally made-up statistic] our existing power infrastructure - a good deal of our existing stuff is only there to "smooth out" demand. It would also make wind power a lot more practical.
If a ship could simply power itself, that would be a massive boon. Shipping companies would pay a lot for a ship that doesn't need to use fuel. And shipping doesn't always need to be timely - so storage isn't an issue.
If any part of your idea was economic, it would already be widely deployed. The main issue will be cost.
Ships are expensive to operate, difficult to keep running, break a lot. Why not park this ashore and then pipe or ship the fuel where needed?
A giant array of mirrors, individually small, but in total much larger than the hull of the ship,
You're going to have problems with balance. Such a large array might unbalance your ship and capsize her. Sail area should not be discounted: the wind is going to push on the array and kick your ship around.
Once the ship is full of natural gas, it folds up its solar array
Where do they stow the array? If it's on deck the salt air is going to corrode everything, quick. If it's inside where do you store the fuel?
Maybe a desert near the ocean though, like in Somalia, but then you still need a ship to transport the liquified natural gas to market (or a pipeline). If the economics worked, I guess either would be fine.
The reality is that if the idea were viable with a ship, it'd almost certainly be (probably more) viable without one too. If land use were the issue, then you could also imagine a flotilla of permanent rafts instead of ship.
Though other commenters have noted that the ships could move to the Southern Hemisphere in the winter to get more solar exposure.
Will have to take a closer look.
The motivation for it was threefold: 1. Less environmental impact (no covering up a large swath of land). 2. No cost to buy the land. 3. Plenty of access to water.
I hadn't even considered the possibility of moving the ships depending on sunlight conditions. That's really brilliant.