Suriname Will Tow a Giant Bag of Water to Fight the Caribbean's Drought | Hacker News Reader

Suriname Will Tow a Giant Bag of Water to Fight the Caribbean's Drought

bloomberg.com

39 pointsprotomyth22 comments

I always wonder about ideas like this. Desalination is a known solution and big boats full of fuel that can power desalination plants are a solved problem. In terms of under utilized infrastructure you could put tanks in shipping containers and use unused container craft to move the water from port to port. Hanjin has a bunch available for cheap at the moment.

You need the destination to have a suitable container port, and a way of emptying a large number of containers into the water system quickly. If you want to use normal shipping it would probably be eaiser to just import and distribute bottled water.

A big bag would just need a pipeline to come ashore and could be more easily pumped than hundreds of shpping containers. Although the details of their plan seem sparse. Does the bag offload into a water mains system, and will it need treatment before use?

With climate change Caribbean islands would eventually have to invest more into desalination plants. Some already have these plants but they are small scale and used to augment main sources of fresh water.

All drinking water from the tap in Curacao has been from a huge desalination plant for many years, see also [1]. There's a shortage of water alright, but not drinking water.

I don't know anything about this story, but when I just asked a friend who lives down there it was not known to him. When I showed him the article he said that it reads more like a first of April joke as anything serious.

For the record, it does not happen much, but it has been raining down there now for 2 whole days.

[1] https://www.theguardian.com/sustainable-business/2015/feb/18...

This sound like an absurd way to get fresh water to an island.

Dunno. Maybe a few hours of a tug boat is less energy than desalinization of a similar amount of salt water? Not to mention desalinization plants likely cost more than a tug boat.

Doubly so if you need to ship fuel to the desalinization plant via boat.

> The trip to Barbados was expected to take five or six days.

One would think a pipeline would be cheaper. I guess they have done the maths on a $2 million investment though. But it's not intuitive.

Thats a long pipeline. Apparently, the Keystone pipeline cost 7 billion $. https://en.m.wikipedia.org/wiki/Keystone_Pipeline

I'm guessing a water pipeline would be cheaper, and it would need less capacity. But it would have to be constructed for underwater conditions, and any maintenance would be cumbersome.

The Langeled underwater pipeline, carrying natural gas from Norway to the UK, is a bit longer than the Barbados-Surinam distance (at 1200 km), and cost approx. 2 billion USD adjusted for inflation. That's a really big-ass pipeline though, at 44" diameter. I guesstimate they could probably get this water pipeline done at about a hundred million USD.

Edit: Digging a bit further, subsea pipeline lay cost can be roughly approximated at 0.04 million USD per inch-kilometer (that is, multiplied by pipeline length and by diameter in inches) for 8"-24" pipe. Furthermore we can estimate that Barbados would need a flowrate of 5 000 L/s to supplement their water supply, giving an optimal pipeline diameter of 8". That means it would cost 942km * 8in * 0.04 million USD/(km*in) = 300 million USD.

What do you base that estimate on, given that planning, permits, work etc don't scale with the diameter of the pipe?

Actually, work does scale with the diameter. For lower diameter pipe, you can use a smaller, less specialized lay barge with less crew, the welding goes quicker meaning progress is faster, and you can fit more km of pipe on each supply ship.

Also, the cost of permits (called Right-Of-Way, ROW) is a very small fraction of the total cost, as is the planning cost. Materials cost for the pipe, OTOH, can be as much as 60% of total.

I guess the boat system can be moved around the world to meet demand. Unlike a pipeline that might not get used again for another 10 years.

Still I think the numbers seem off for a boat dragging water in bags for 6 days to be cost effective.

If you've never purchased pressure-rated pipe, you'd be shocked at the cost of even a 6m piece of 1" PN20 pipe.

Pipelines for water are only energy efficient if you have gravity working for you. I'm willing to wager that there isn't a 10x difference in the cost of towing that water to the Barbados versus pumping it in a pipeline. And, of course, you don't need a pipeline when you tow it. (though you do need big bags)

They used to tow ice bergs back before refrigeration was common. This seems normal by comparison.

If people are willing to pay as much for water as they do for oil or gas, can we use oil infrastructure (tankers, pipelines, trains, etc) to transport water?

Can we assume they'd be willing? Here in Canada I use orders of magnitude more water than oil products, and would be willing to pay commensurately less.

http://researcher.watson.ibm.com/researcher/view_group.php?i...

Looks like water costs $2 / cubic meter, and oil costs 100x more than that, so we have a long way to go before this makes any sense.

Nothing to see here folks. Move along. Business as normal. Clever engineering is all it is.

Pretty soon we'll be towing icebergs & what an amazing day that will be.

Thus solving the problem once and for all! https://youtu.be/0SYpUSjSgFg

Historically, ice was actually towed (stowed and sailed) from the Northeastern US to e.g. India, and other hot climates.

It was a huge industry in the northeast in the 17th(? I think) century. Got this info from an awesome documentary called the Science of Cold.

Jesus, does this ever sound like a terrible idea to operate at scale.

I hope this is something that's only reserved for emergencies, and is otherwise unprofitable.

I get the feeling that this could become horribly destructive behavior, if it catches on as a global trend.

Meanwhile, quotes such as these are disturbing to read:

  We have a nearly unlimited 
  source of fresh water in 
  Suriname.

Actually, in terms of things human activity can place stress upon, and ultimately ruin, few things are "nearly unlimited."

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