6 ms·
> The precise technical details of how SWRO works are not critical to this analysis, but a summary is presented here. Yeah. This blog post spends a lot of word
by thaumaturgy 4y ago
> The precise technical details of how SWRO works are not critical to this analysis, but a summary is presented here.
Yeah. This blog post spends a lot of words on the idea of large-scale desalination, but it's closer to a child's blueprint of a spaceship than even a rough proposal for a viable engineering project.
The Carlsbad Desalination Plant near San Diego was completed a few years ago and is now operational. It is the largest, most technologically-advanced and energy-efficient desalination plant in the United States. It is approximately the best we can do right now for large-scale desalination.
It cost about $1 billion to construct, about $50 million per year to operate, and produces about 150 acre-feet of fresh water per day.
"Stage 1" from this blog post proposes to produce multiple millions of acre-feet of freshwater.
All of the costs in the blog post are off by a couple orders of magnitude.
- chrisseaton 4y ago> acre-feet That’s an incredibly strange unit.
- rrss 4y agoIt is very common for water projects. I think it comes from reservoirs, since the area is measured in acres and the depth in feet.
- kragen 4y agothis particular medieval unit comes from irrigation maybe a rice crop requires three feet of water from planting to harvest, and you normally only get three inches of rain during that time, so you need 2.75 acre-feet of irrigation water per acre of rice
- LegitShady 4y agototally normal while discussing hydrology in the usa
- kragen 4y agoit's the volumetric cousin of furlongs per fortnight, a popular unit of velocity
- LegitShady 4y agohydrology is a lot of magic and statistics the units don't need to make sense
- njarboe 4y agoThe "miner's inch" is another cool unit. Used to describe a flow rate of water[1]. [1]https://en.wikipedia.org/wiki/Miner%27s_inch https://en.wikipedia.org/wiki/Miner%27s_inch
- cnlevy 4y ago> The Carlsbad Desalination Plant near San Diego was completed a few years ago and is now operational. It is the largest, most technologically-advanced and energy-efficient desalination plant in the United States. It is approximately the best we can do right now for large-scale desalination. Israel built a 624000 m^3/day desalination plant for about $400M in 2013. It costs about $150M to operate per year, most of it probably from electricity consumption So you already have an order of magnitude reduction in cost Build 10 of them should reduce building cost even more per plant https://en.wikipedia.org/wiki/Desalination_by_country#Israel https://en.wikipedia.org/wiki/Desalination_by_country#Israel
- Aloisius 4y agoMmm. That’s not an order of magnitude reduction in operating costs. 185,022 m^3/day (150 acre-feet) for $50 million/year is about $0.74/cubic meter. 624,000 m^3/day for $150 million/year is about $0.65/cubic meter.
- credit_guy 4y agoOn the other hand if you look at the amortized capital cost (and you use a 40 year lifetime), it comes to 37 cents/m3 for Carlsbad and 4.4 cents/m3 for the Israeli desal plant.
- Linell 4y agoI live in Carlsbad and had no clue that this existed!
- kylehotchkiss 4y ago8% of your water comes from it!
- danw1979 4y ago> All of the costs in the blog post are off by a couple orders of magnitude. Even if they weren’t way off, the proposed capital costs to replace Arizona’s extraction with from the Colorado river with SWRO is $24bn, which seems like a lot ? (~$3200 per capita). Would like to see sources for his capital cost estimates and the detailed calculations around operational costs, system lifespan and input energy (battery lifespan ? what capacity factor on the solar ? 6 hours in 24 is given in the article, which seems high). That said, I love this kind of big thinking. I’m completely sold on Casey’s solar-derived synfuels idea.