Thank you. Another insightful post. One question. Is all water consumption equal in impact? For example, does using water for cooling thermal electricity plants and hydropower - where the water is diverted and reused - have less impact than water used for biomass production or materials processing? Would allowing for any difference in impact affect the outcome of the analysis? Thanks.
The impact of water use varies enormously from one geographic location to another, and, as you say, according to exactly how the water is used. My take-away is that global averages aren't very meaningful here; water use is something to be studied and addressed region by region.
Since agriculture is by far the biggest source of water consumption, doesn't it make more sense to promote water efficiency there instead. Perhaps promoting drip irrigation and water pricing.
Like several other commenters, I'm uncomfortable with the idea of compressing the diverse variety of ways of using water down to a single number that we call water "use". One nuclear plant (say Diablo Canyon) uses ocean water for cooling in a pass-through system. Another (say Palo Verde, just one state away from Diablo Canyon) uses municipal waste water for evaporative cooling. A third uses pass-through cooling with fresh water from a river, while a fourth uses evaporative cooling with water pumped from an aquifer. Some are in dry environments where water is scarce, while others are in places with abundant rainfall. All have environmental impacts, but I'm not sure it's meaningful to put these disparate impacts on a single numerical scale.
My take-away is that when it comes to water use, global averages aren't very meaningful. Water use, like land use, is something we need to study and address region by region.
This is what I was going to comment, and I agree. ‘Water use’ needs definitions for both terms.
For cooling thermal power plants, water can be seawater (of which nobody has to worry about overuses), fresh groundwater, fresh surface water, reclaimed municipal water, and for lithium production, brine from either the sea, inland sites like Mono Lake or Great Salt Lake, underground brine like in Chile or recycled fracking brine. Brine is useless for agriculture or municipal uses.
Which brings us to “use”. How is water used in these processes? For cooling thermal plants it is evaporated, which isn’t using it up but just a matter state change. For reclaimed water, like from Phoenix the Palo Verde nuclear plant, it is also evaporated rather than injected into the aquifer. For lithium production the brine after being ‘used’ is basically the same, but with lower concentrations of lithium and isn’t used at all, unless some is “lost” to evaporation. In some thermal power plants that use surface water, the water which isn’t evaporated, is warmed up, which some environmentalists claim is using cold water that river life needs, is that also a use? If the warm river water is injected underground, the water is preserved, but the river now has less.
And for biomass such as the Drax plant in Yorkshire which burns North American wood pellets (which is a ridiculous low-carbon energy definition), I assume the water used is that absorbed by the trees during their lifespans. What’s worse the lost water or the lost trees?
Superb again... All these discussions of water use keep me wondering how we can start to make sense or the "quality" of water use - not all uses are equal, some are downright wholesome. Some users put it back as they found it, some evaporate it, some contaminate it... hard to find a way to quantify this, but I feel it would be important work...
Please explain how hydropower “uses” water. The power of hydropower is drawn from gravity driving a turbine. It doesn’t actually use up water, just converts gravity to electricity. No?
According to the cited paper by Jin et al., the water "use" of hydropower is basically the evaporation from reservoirs. There are complications because reservoirs usually serve other purposes in addition to hydropower, and because there would be evaporation from the same land area even without the reservoir. For run-of-the-river hydropower without a large reservoir, there's little or no water use.
I wonder how much the geopolitical calculus changes given the US might look into directly extracting lithium from fracking wastewater in Appalachia, and deploying geothermal in the Salton Sea
Brilliant post addressing yet more of the nuances around clean-tech. There are many false equivalences and historic data bias in the 'water intensity' narrative, just as there is in the 'mineral intensity' narrative. Circularity of minerals is a big factor in both cases longer term.. the potential to dramatically reduce clean-tech mineral demand 10-20 years out if we can figure out how to recycle it effectively.
End of the day, resource intensity of fossul fuel and thermal power systems are MUCH more resource intensive.
@hannahritchie quick contextual question apologies. Appreciate the analysis - very interesting. As context though while there are differences in water impact what is the bigger picture in terms of environmental harm petrol vs electric? How much impact does water impact have versus using an ice engine? Isn’t that the first point to focus on? Happy if I’ve missed something…
Thank you. Another insightful post. One question. Is all water consumption equal in impact? For example, does using water for cooling thermal electricity plants and hydropower - where the water is diverted and reused - have less impact than water used for biomass production or materials processing? Would allowing for any difference in impact affect the outcome of the analysis? Thanks.
The impact of water use varies enormously from one geographic location to another, and, as you say, according to exactly how the water is used. My take-away is that global averages aren't very meaningful here; water use is something to be studied and addressed region by region.
Since agriculture is by far the biggest source of water consumption, doesn't it make more sense to promote water efficiency there instead. Perhaps promoting drip irrigation and water pricing.
Like several other commenters, I'm uncomfortable with the idea of compressing the diverse variety of ways of using water down to a single number that we call water "use". One nuclear plant (say Diablo Canyon) uses ocean water for cooling in a pass-through system. Another (say Palo Verde, just one state away from Diablo Canyon) uses municipal waste water for evaporative cooling. A third uses pass-through cooling with fresh water from a river, while a fourth uses evaporative cooling with water pumped from an aquifer. Some are in dry environments where water is scarce, while others are in places with abundant rainfall. All have environmental impacts, but I'm not sure it's meaningful to put these disparate impacts on a single numerical scale.
My take-away is that when it comes to water use, global averages aren't very meaningful. Water use, like land use, is something we need to study and address region by region.
This is what I was going to comment, and I agree. ‘Water use’ needs definitions for both terms.
For cooling thermal power plants, water can be seawater (of which nobody has to worry about overuses), fresh groundwater, fresh surface water, reclaimed municipal water, and for lithium production, brine from either the sea, inland sites like Mono Lake or Great Salt Lake, underground brine like in Chile or recycled fracking brine. Brine is useless for agriculture or municipal uses.
Which brings us to “use”. How is water used in these processes? For cooling thermal plants it is evaporated, which isn’t using it up but just a matter state change. For reclaimed water, like from Phoenix the Palo Verde nuclear plant, it is also evaporated rather than injected into the aquifer. For lithium production the brine after being ‘used’ is basically the same, but with lower concentrations of lithium and isn’t used at all, unless some is “lost” to evaporation. In some thermal power plants that use surface water, the water which isn’t evaporated, is warmed up, which some environmentalists claim is using cold water that river life needs, is that also a use? If the warm river water is injected underground, the water is preserved, but the river now has less.
And for biomass such as the Drax plant in Yorkshire which burns North American wood pellets (which is a ridiculous low-carbon energy definition), I assume the water used is that absorbed by the trees during their lifespans. What’s worse the lost water or the lost trees?
Superb again... All these discussions of water use keep me wondering how we can start to make sense or the "quality" of water use - not all uses are equal, some are downright wholesome. Some users put it back as they found it, some evaporate it, some contaminate it... hard to find a way to quantify this, but I feel it would be important work...
Please explain how hydropower “uses” water. The power of hydropower is drawn from gravity driving a turbine. It doesn’t actually use up water, just converts gravity to electricity. No?
According to the cited paper by Jin et al., the water "use" of hydropower is basically the evaporation from reservoirs. There are complications because reservoirs usually serve other purposes in addition to hydropower, and because there would be evaporation from the same land area even without the reservoir. For run-of-the-river hydropower without a large reservoir, there's little or no water use.
We use to call it run-of-mill hydropower.
Evaporated water eventually comes back down just not when and where you want it.
I wonder how much the geopolitical calculus changes given the US might look into directly extracting lithium from fracking wastewater in Appalachia, and deploying geothermal in the Salton Sea
Great insights Hannah, thank you. Water is our most important resource.
Brilliant post addressing yet more of the nuances around clean-tech. There are many false equivalences and historic data bias in the 'water intensity' narrative, just as there is in the 'mineral intensity' narrative. Circularity of minerals is a big factor in both cases longer term.. the potential to dramatically reduce clean-tech mineral demand 10-20 years out if we can figure out how to recycle it effectively.
End of the day, resource intensity of fossul fuel and thermal power systems are MUCH more resource intensive.
https://open.substack.com/pub/craigbonthron/p/clean-tech-fallacies-part-i-mineral?r=t9w83&utm_campaign=post&utm_medium=web
@hannahritchie quick contextual question apologies. Appreciate the analysis - very interesting. As context though while there are differences in water impact what is the bigger picture in terms of environmental harm petrol vs electric? How much impact does water impact have versus using an ice engine? Isn’t that the first point to focus on? Happy if I’ve missed something…