4 ms·
I wonder at what point the up-front costs of massive desalination would overcome the (often hidden and externalized) costs of projects like this.
by bombcar 8mo ago
I wonder at what point the up-front costs of massive desalination would overcome the (often hidden and externalized) costs of projects like this.
- JumpCrisscross 8mo ago> the up-front costs of massive desalination Desalination is dominated by operating costs.
- rtkwe 8mo agoCorrect it's massively energy intensive to filter the salt out the newest best ideas still use ~2 KWh/m3 of water and that's a lab system in perdue that batches the process instead of having it run continuously which is why current RO desalination systems require so much energy.
- smm11 8mo agoCalifornia pays other states to take its excess solar energy. Power for a project like this isn't the issue, actually building the system is the issue.
- JumpCrisscross 8mo ago> California pays other states to take its excess solar energy Intermittently. Essential services like water (with expensive fixed costs) aren’t a good fit for absorbing variable supply. > Power for a project like this isn't the issue California has the country’s most expensive power [1] in part due to policymakers constantly assuming it’s free. [1] https://www.electricchoice.com/electricity-prices-by-state/ https://www.electricchoice.com/electricity-prices-by-state/
- rtkwe 8mo agoThey wouldn't if you switched just Urban water use from natural sources to desalination. To do that you need to replace the ~5 million acre feet of water, ~6,167,400,000 m3, that goes into the Urban bucket which is all of the water used to keep people alive, clean, and all industrial uses of water. [0] That comes to ~ 12BkWh of energy needed to scale up batched reverse osmosis to take over just the life and job required water needs which is about 25% of the total solar power generated in all of 2025 via grid-scale solar farms. CA does export some during the day due to excess solar but is still a net importer of power. [0] p2 of https://cwc.ca.gov/-/media/CWC-Website/Files/Documents/2019/06_June/June2019_Item_12_Attach_2_PPICFactSheets.pdf https://cwc.ca.gov/-/media/CWC-Website/Files/Documents/2019/...
- bombcar 8mo agoThose are the numbers I was looking for - that means that (ignoring build-out costs) total desalination for CA would be on the order of 10% of the 3 gorges dam yearly output (max).
- rtkwe 8mo agoUsing a system that's currently in a lab scale only and ignoring other energy costs like moving the water to the plant, mixing the briny output back down to acceptable levels, and then pressurizing the system to replace the gravity fed design it currently uses. For a rough estimate for replacing agricultural uses too ~6x that urban figure at least then weep at the amount of pumps you'd need to bring that water up and inland to the farm lands from the coast. At least for replacing urban use most of the population lives on/near the coast where the water would be produced.
- bombcar 8mo agoFarm use is by far the biggest, but "taking" water from the inland empire and dragging it to LA is also a cost. But all of this is firmly in the "we could do it if we really wanted/needed to" not "needs more energy than the sun will produce in its lifetime".
- detourdog 8mo agoA scaled down perspective is…. The most efficient commercial desalinator for boats is 32 Watts a gallon.
- fhdkweig 8mo agoDo you mean 32 Watt-hours / gallon?
- masklinn 8mo agoFor a real world comparison, the Perth desalination plant claims ~4kWh/m3.
- zahlman 8mo ago> it's massively energy intensive to filter the salt out the newest best ideas still use ~2 KWh/m3 of water Am I alone in thinking that doesn't sound like a lot? That would be something on the order of 10% of what major cities charge for tap water?
- kjkjadksj 8mo agoI don’t think the brine pollutant issue has been meaningfully solved. You are also now pumping water inland uphill the whole way.
- SoftTalker 8mo agoFor usage where the water mostly returns as sewage, is treated and then returned to the ocean, you can just dilute the brine with the treated discharge and then it returns at basically the original salinity.
- kenhwang 8mo agoIt is common now for treated discharge to be sent to a discharge lake/leach wetlands so it can be used to replenish groundwater supplies.
- kibwen 8mo agoAs long as we don't try to hide and externalize the cost of all the hyper-saline brine management that comes with desalination.
- bombcar 8mo agoWe can store it in the remains of Owens Lake ;)