Re:As Cape Town water crisis deepens, scientists prepare for...
by markatkinson on Saturday January 27, 2018 @09:23AM
(#16246311)
I live in Cape Town and I can tell you now people are freaked out and panicking. Every supermarket is sold out of water by lunch time. Driving around Cape Town you are accompanied by fleets of vehicles delivering large water tanks, and some people are straight up selling their houses, pulling their kids out of school and moving.
One of the borehole companies actually now runs a weekly auction for their services and the highest bidder gets a borehole! Pretty crazy.
Re:As Cape Town water crisis deepens, scientists prepare for...
by craftyguy on Friday January 26, 2018 @08:03PM
(#16244210)
They only have two long-term options:
1) depopulate those regions by causing folks to leave (e.g. no longer providing water services)
or
2) deploy costly (and energy-intensive) mechanisms to continue to provide water (desalination, or piping in water from some other place that will likely dry up next)
Re:As Cape Town water crisis deepens, scientists prepare for...
by amluto on Friday January 26, 2018 @09:10PM
(#16244443)
Desalination has high capital costs, but the energy usage isn't really a problem at all.
A modern plant uses 2.5-3.5 kWh/m^3 [1]. My household uses something like 9 m^3 per month, so that would be about 27 kWh per month. At PG&E's rather high peak rates, that's $10/month, which is less than the marginal cost of that water. Of course, to the extent that energy costs matter, desalination plants will not use retail power at peak times.
Re:As Cape Town water crisis deepens, scientists prepare for...
by cr0sh on Saturday January 27, 2018 @12:50PM
(#16247112)
Arizona actually has a lot of brackish and brine well water that is non-potable.
A lot of it is actually in the Gila Bend area, where people have been trying for decades to figure out something to do with it - there used to be a company that grew "desert shrimp" in ponds using the water. Later, during the housing crisis (for some reason) they tried to make a go of growing algae (in cooperation with one of our universities - maybe ASU) in the ponds by piping CO from diesel aeration pumps into the ponds - then harvesting the algae (which were high in lipids) to make biofuel.
Ultimately, I don't think either of these panned out, but the water is there.
One of the borehole companies actually now runs a weekly auction for their services and the highest bidder gets a borehole! Pretty crazy.
1) depopulate those regions by causing folks to leave (e.g. no longer providing water services)
or
2) deploy costly (and energy-intensive) mechanisms to continue to provide water (desalination, or piping in water from some other place that will likely dry up next)
A modern plant uses 2.5-3.5 kWh/m^3 [1]. My household uses something like 9 m^3 per month, so that would be about 27 kWh per month. At PG&E's rather high peak rates, that's $10/month, which is less than the marginal cost of that water. Of course, to the extent that energy costs matter, desalination plants will not use retail power at peak times.
[1] https://www.amtaorg.com/wp-content/uploads/7_MembraneDesalin...
A lot of it is actually in the Gila Bend area, where people have been trying for decades to figure out something to do with it - there used to be a company that grew "desert shrimp" in ponds using the water. Later, during the housing crisis (for some reason) they tried to make a go of growing algae (in cooperation with one of our universities - maybe ASU) in the ponds by piping CO from diesel aeration pumps into the ponds - then harvesting the algae (which were high in lipids) to make biofuel.
Ultimately, I don't think either of these panned out, but the water is there.