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The big issue here in CA is that farmers are growing water-intensive crops that offer a better return (like almonds), but they're growing them in the desert kno

by tdeck 5y ago

The big issue here in CA is that farmers are growing water-intensive crops that offer a better return (like almonds), but they're growing them in the desert known as the central valley. That leads to water shortages. As someone living in California I certainly appreciate the huge variety of great produce that's available because of CA agriculture, but even the almond farmers know this isn't going to last forever. They're all in a race to drill deeper wells than their neighbor and make a quick buck before the aquifer runs out. At that point we'll have no reserve at all and the party will grind to a halt. The better idea would be to grow different crops here, not to stop agriculture altogether. That requires some kind of rationing.

sologoub 5y ago
We really need to re-think our water sources in CA. We have nearly unlimited solar potential that can be used to power desalination and pumping of the water were we need it. Best part - we don’t need to worry about power storage (just transmission, which is not trivial, but can be done), it’s not an issue if we cannot desalinate at night.
- tdeck 5y ago
  I was curious about the energy requirements, so I did some envelope math. The average US household consumes 11,000 KW-hours of energy per year. Let's say an average person uses 80-100 gallons of water a day, so a low end of about 30,000 gallons of water per year. One article [1] suggests desalination takes about 15kJ/kg water at the most efficient plants. That translates to 473 kilowatt hours of energy required per household each year: 30000 gallons * 3.79 kg/gallon * 15 kilojoules So that's about a 4% increase in household energy usage just for domestic water for one person (domestic is less than 10% of our water use in CA). I'm not sure what conclusion to draw from this, but I suspect that it isn't practical to use desalination as a primary source of water. I also expect that much salt would become an environmental problem to dispose of. Once we drain our aquifer, the water shortage will be really severe and we'll need to cut back on agriculture regardless of desalination, but it could help a lot in urban areas. [1]: http://www.desware.net/Energy-Requirements-Desalination-Processes.aspx#:~:text=Theoretically%2C%20about%200.86%20kWh%20of,the%20type%20of%20process%20used http://www.desware.net/Energy-Requirements-Desalination-Proc....
  - sologoub 5y ago
    Seems to work just fine for Israeli farming: https://www.scientificamerican.com/article/israel-proves-the-desalination-era-is-here/ https://www.scientificamerican.com/article/israel-proves-the... Percentage of household use is a strange measure to use here - Ivanpah plant produces nearly 400 MW and it’s relatively small plant. We have a lot of desert to go around. Producing more solar for the regular grid is not very practical because we can’t use all that up during daylight. If you have dedicated use for desalination that is concurrent with peak production of power, you can bring online a lot more production without risking destabilizing your grid. In effect, desalination can be used to balance the excess supply of solar - the more sunlight we get the more water we can produce. Water is relatively easy to store, modulating the demand to match the available excess supply.
sparrc 5y ago
If you care about limiting agricultural water usage, the first target to go after is dairy and animal ag, not almonds. Almonds are on the high side compared to other plants but their water usage per calorie is much less than animal ag. Also consider that almonds flourish in the mediterranean type of climate that California has, whereas dairy and beef (and their feed crops) can be raised almost anywhere.
- dragonwriter 5y ago
  > Almonds are on the high side compared to other plants but their water usage per calorie is much less than animal ag. The world produces far more calories of food than is needed, so water impact per calorie is a dumb metric since calories aren't the critical figure of merit. What matters is water impact per $ of dependent economic activity.
  - sparrc 5y ago
    In a strictly capitalist sense yes, but then by that argument we should just completely cut off all California farmers since they seem to make less money per water used when compared to California cities (I'm just stating your argument, which I would argue is "dumb" and overly simplistic way of looking at the world). You're missing the point that we are talking about regulating water usage external to the industry (in which people should and do care about water usage as it relates to sustainability of California as a whole), and water usage internal to the industry (in which an individual farmer cares about yields, efficiency, and economic value of crops). Internal to farming the entire reason we have so many almonds in CA is exactly because it's a high-efficiency and high-value crop. https://slate.com/business/2015/04/almonds-in-california-they-use-up-a-lot-of-water-but-they-deserve-a-place-in-californias-future.html https://slate.com/business/2015/04/almonds-in-california-the... "In a real sense, the almond industry is the future of California agriculture—high value, high efficiency, but still high consuming. That’s not necessarily a bad thing, as it makes most sense to use a scarce resource for the highest value application possible."
    - dragonwriter 5y ago

by tdeck 5y ago

sologoub 5y ago

We really need to re-think our water sources in CA. We have nearly unlimited solar potential that can be used to power desalination and pumping of the water were we need it. Best part - we don’t need to worry about power storage (just transmission, which is not trivial, but can be done), it’s not an issue if we cannot desalinate at night.

tdeck 5y ago
I was curious about the energy requirements, so I did some envelope math. The average US household consumes 11,000 KW-hours of energy per year. Let's say an average person uses 80-100 gallons of water a day, so a low end of about 30,000 gallons of water per year. One article [1] suggests desalination takes about 15kJ/kg water at the most efficient plants. That translates to 473 kilowatt hours of energy required per household each year: 30000 gallons * 3.79 kg/gallon * 15 kilojoules So that's about a 4% increase in household energy usage just for domestic water for one person (domestic is less than 10% of our water use in CA). I'm not sure what conclusion to draw from this, but I suspect that it isn't practical to use desalination as a primary source of water. I also expect that much salt would become an environmental problem to dispose of. Once we drain our aquifer, the water shortage will be really severe and we'll need to cut back on agriculture regardless of desalination, but it could help a lot in urban areas. [1]: http://www.desware.net/Energy-Requirements-Desalination-Processes.aspx#:~:text=Theoretically%2C%20about%200.86%20kWh%20of,the%20type%20of%20process%20used http://www.desware.net/Energy-Requirements-Desalination-Proc....
- sologoub 5y ago
  Seems to work just fine for Israeli farming: https://www.scientificamerican.com/article/israel-proves-the-desalination-era-is-here/ https://www.scientificamerican.com/article/israel-proves-the... Percentage of household use is a strange measure to use here - Ivanpah plant produces nearly 400 MW and it’s relatively small plant. We have a lot of desert to go around. Producing more solar for the regular grid is not very practical because we can’t use all that up during daylight. If you have dedicated use for desalination that is concurrent with peak production of power, you can bring online a lot more production without risking destabilizing your grid. In effect, desalination can be used to balance the excess supply of solar - the more sunlight we get the more water we can produce. Water is relatively easy to store, modulating the demand to match the available excess supply.

sparrc 5y ago

If you care about limiting agricultural water usage, the first target to go after is dairy and animal ag, not almonds. Almonds are on the high side compared to other plants but their water usage per calorie is much less than animal ag. Also consider that almonds flourish in the mediterranean type of climate that California has, whereas dairy and beef (and their feed crops) can be raised almost anywhere.

dragonwriter 5y ago
> Almonds are on the high side compared to other plants but their water usage per calorie is much less than animal ag. The world produces far more calories of food than is needed, so water impact per calorie is a dumb metric since calories aren't the critical figure of merit. What matters is water impact per $ of dependent economic activity.
- sparrc 5y ago
  In a strictly capitalist sense yes, but then by that argument we should just completely cut off all California farmers since they seem to make less money per water used when compared to California cities (I'm just stating your argument, which I would argue is "dumb" and overly simplistic way of looking at the world). You're missing the point that we are talking about regulating water usage external to the industry (in which people should and do care about water usage as it relates to sustainability of California as a whole), and water usage internal to the industry (in which an individual farmer cares about yields, efficiency, and economic value of crops). Internal to farming the entire reason we have so many almonds in CA is exactly because it's a high-efficiency and high-value crop. https://slate.com/business/2015/04/almonds-in-california-they-use-up-a-lot-of-water-but-they-deserve-a-place-in-californias-future.html https://slate.com/business/2015/04/almonds-in-california-the... "In a real sense, the almond industry is the future of California agriculture—high value, high efficiency, but still high consuming. That’s not necessarily a bad thing, as it makes most sense to use a scarce resource for the highest value application possible."
  - dragonwriter 5y ago