8 ms·
> According to the PCA, it takes around 50 million gallons of fresh water to move a vessel through one of the locks. That's ~2e5 tons of fresh* water per ship.
by Jabbles 3y ago
> According to the PCA, it takes around 50 million gallons of fresh water to move a vessel through one of the locks.
That's ~2e5 tons of fresh* water per ship.
To add some perspective, the largest nuclear desalination plant in the world produces ~1e6 tons of fresh* water per year - enough for 5 ships.
*The standards for "fresh" may be different in each case, but the magnitude of the problem is clear.
https://world-nuclear.org/information-library/non-power-nuclear-applications/industry/nuclear-desalination.aspx https://world-nuclear.org/information-library/non-power-nucl...
- defrost 3y agoI'm still a little astounded no one has yet built seawater pipelines from coast to coast (65 km) to recharge the canal buffer dams with seawater rather than fresh water. IIRC there was a major refurb to make the Panama system more water efficient with better recovery, some look ahead should have forseen fresh water supply becoming a a limiting factor.
- nehal3m 3y agoSea water is heavier than fresh water and more corrosive. I don’t think it’s as simple as building the pipes, I imagine the locks themselves would also need to be retrofitted to account for that.
- defrost 3y agoThe locks would need to be treated as seagoing vessels are treated, with anti corrosive paint and sacrifical anodes.
- Scoundreller 3y agoWhile I agree it’s a nonstarter, heavier water would let the ships carry even more.
- peterpost2 3y agoThat would be an absolute disaster for the environment if you would do that. Also pumping up that much water would require an absolutely enormous amount of energy, and dozens of pumping stations.
- closewith 3y agoAm I right in thinking 9.8 joules per kilo per metre * 20,000,000 kilos * 26 metres = 5,096,000,000 joules or ~1.4 MWh? That seems low, so I must be missing something?
- Jabbles 3y agox10 -> 200,000,000 kilos
- closewith 3y agoGood catch. Even so, 14 MWH is only about $3,000 at Panama prices. That's nothing compared to the cost of transit. Obviously there'd be extreme capital costs and engineering/environmental challenges, but far less than an equivalent train. After all, the canal moves more tonnage daily than the proposed train could in a year.
- AndrewDucker 3y agoPotential energy is actually pretty cheap. Which makes it unfortunately useless for energy storage (lifting 1 ton by 1m is about the same as an AAA battery)
- patmorgan23 3y agoThe Panama canal is not really one canal. It's one canal from the east into a river and lake system and one canal from the west into the same river and lake system. Using sea water is not an option.
- cm2187 3y agoBut when a ship goes down in a lock, can't you push the water back in the lake instead of releasing it downstream? (ie you would pump fresh water, not seawater)
- KineticLensman 3y agoYou’d need monster engines and power supplies, which would be paid for by… Panama? the shipping companies?
- HPsquared 3y agoMuch cheaper than desalinating all that water... It's basically recycling.
- KineticLensman 3y agoBut still a cost that doesn’t currently exist. If the cost of transit goes too high, many companies will take the long route
- zo1 3y agoMaybe it should be too-expensive to achieve. I'm sitting her absolutely baffled at the scale of these numbers I'm seeing on this thread. I'd rather tell the other side of the world (both really) to just suck it up and pay for sustainable ways to transport this stuff. The era of "cheap" transport needs to stop and we absolutely have to find alternatives.
- mytailorisrich 3y agoFor the locks to work they need water. It does not matter if fresh or salty. The canal takes advantage of the natural store of fresh water on higher grounds. If needed, it would obviously be easier to pump sea water than to desalinise sea water, then to pump it anyway.
- Veserv 3y agoThat is only around 80 K$ per crossing using modern desalination plants. The internet says there are ~40 crossings per day resulting in ~14K crossings per year deriving ~3 G$ in fees for the Panama Canal Authority. At ~80 K$ per crossing that is ~1 G$ in drinkable water which is expensive, but not too onerous to be obviously economically non-viable. Also, that is nowhere near the largest desalination plant. The really big ones like the Sorek plant [1] do ~6e5 per day which would support 3 ships per day. Still only 1/10 of what is needed to support the full container capacity, but quite doable if the economics work out to support fully scaling out. [1] https://ide-tech.com/en/project/sorek-desalination-plant/ https://ide-tech.com/en/project/sorek-desalination-plant/
- Jabbles 3y agoI misread my source, I am off by 2 orders of magnitude. Please disregard.