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One note - they don’t pump water out and back into the locks from a neighboring storage. They flush the water. Each ship needs like 40 million gallons? Maybe t
by donor20 3y ago
One note - they don’t pump water out and back into the locks from a neighboring storage. They flush the water. Each ship needs like 40 million gallons?
Maybe title should be insane wastes of water forces authorities…. :)
- huytersd 3y agoThey really should use solar arrays to pump the water back. If there’s no sun, you can always just flush it like they’re doing now.
- dralley 3y agoThat would risk introducing salt into the resovoir and water table.
- deleted 3y ago[deleted]
- nostrademons 3y agoThey do pump water out and back into the locks from neighboring storage. There is a limit to the minimum amount of water that you can use, though, since the potential energy to raise the ship comes from the loss of water. https://www.youtube.com/watch?v=SBvclVcesEE&t=338s https://www.youtube.com/watch?v=SBvclVcesEE&t=338s
- pacificmint 3y agoIsn’t that how all locks work? Or at least most? I’ve always assumed the energy cost to pump the water would make it cost prohibitive, but I wonder how it compares to rerouting ships or moving containers over land.
- perihelions 3y agoSome canal locks pump water back, - "The hydraulic cylinders enable the water used by the locks to be pumped back. Up to 48,000 cubic metres of water are displaced in a single lockage operation. In periods of low discharge on the Meuse, the screws can pump back the water lost due to the passage of a ship through the lock to the upper canal reach." https://www.inlandnavigation.eu/power-of-water-and-wind/ https://www.inlandnavigation.eu/power-of-water-and-wind/
- jorisboris 3y agoIn Belgium on the Albert Canal (a big canal for Belgium but nothing compared to Panama Canal) they started installing pomps 15 years ago for the exact same reason.
- paranoidrobot 3y agoAlso relevant: Gatun Lake that these locks are fed from/part of is freshwater. This makes recovering water from the locks problematic, since you can't feed it seawater.
- jorisboris 3y agoThis looks to me as the correct problem indeed. Inevitably you'll start pumping up salt water eventually.
- bluejekyll 3y agoOk, I’m no civil engineer, but couldn’t you design a siphon system that would only require opening and closing valves to capture the water without any pumping?
- aidenn0 3y agoNo; at some point you're going to lift the water up. That requires pumping.
- elif 3y agoWhy is that? Britain is covered with a preindustrial canal network with thousands of locks which use nothing but channels doors and gravity. Literally made of wood and operated by hand. Raising water on the low side to the level on the high side simply requires joining the two sides together. If sea level is their high side, I don't understand why they can't use this supply forever.
- bombcar 3y agoThe sea level is the low side. The lake is the high side - which works great until the supply of lake water dries up. The obvious solution is a sea-level tunnel a hundred miles long. Probably cheap. ;)
- ianburrell 3y agoThere has been proposed canal in Nicaragua. It would be 170 miles long and have locks to reach Lake Nicaragua. Chinese company got concession to build decade ago, but didn't do anything and then went out of business.
- elif 3y agoi dunno about tunnel... i am not a digger but I don't think digging 26 meters (highest point of canal) would require tunneling... just dredging.
- donor20 3y agoYou can cross fill and use separate storage - their new locks already use this - but my understanding (possibly wrong) was old locks may not have been using all possible options - it’s a cost / benefit trade off
- dogsgobork 3y agoThe new locks do have water saving basins, which reduce the water waste by about 60%.
- stkdump 3y agoI had to check if that realistic. 40 million gallons at 85 feet is 11MWh of potential energy. At 70% efficiency it would take 16MWh to pump that. That has to be a small amount of energy compared to what ships take for traveling the detour.
- londons_explore 3y agoAnd remember each ship goes up as well as down - so you can theoretically recoup all the energy you used pumping.
- actionfromafar 3y agoI am sorry, how?!
- londons_explore 3y agoImagine one ship going upwards in a lock, while another goes down. Ships and locks are the same size. To start with, there is a difference in the water levels - and this can be put through a generator to generate electricity as the water flows from one lock to the other. When the water has moved half way, the levels are equal. You can now use electricity to pump the rest of the way - and theoretically, assuming lossless pumps and generators, you use the same amount you generated earlier. Unfortunately, low-head generators tend to be inefficient and expensive. Variable head generators are even harder to design to be efficient.
- Mutttttioi 3y agoYou pump the water out of it into a reservaour, than later on when you need to fill it, you let it run back and generate energy. Water power efficency is about 80-90%
- rtpg 3y agoGravity is a conservative force, so if you raise something up really high, dropping it will recover the energy used to pull it up. Of course in practice there's a lot of other things that cause energy loss, but there are lot of dams in the world that exist as "stored power", by pumping water uphill, then getting energy back as the water goes through the dam later. Big bucket high up is basically a battery. The question then becomes about the details of, like, using the power when the water gets pumped down (if you had two canals, you could probably time filling one with draining the other?). There's a lot of practical things to consider