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TLDNR Excess renewable energy is fed to electric rail cars which move boxes of rocks up a slope. When renewables are not producing power the rail cars roll down

by jefurii 11y ago

TLDNR Excess renewable energy is fed to electric rail cars which move boxes of rocks up a slope. When renewables are not producing power the rail cars roll down the slope and regenerative braking produces power. A very creative combination of existing technologies. Zero emissions, nearly zero waste, and can probably switch back and forth between consumption to production on a minute-by-minute basis. Also, looks like a crazy Factorio project.

Retric 11y ago
Vastly more costly than pumped water, high upkeep costs. Does have relatively high efficiency though. PS: "Cost comparisons with pumped hydro are difficult, he said, because there are so few projects and not many data points." Is pure BS, here is someones coursework on the subject: http://large.stanford.edu/courses/2014/ph240/galvan-lopez2/ http://large.stanford.edu/courses/2014/ph240/galvan-lopez2/
- joezydeco 11y ago
  If your state is running out of water, the switch to rocks might be something you can't avoid.
  - Retric 11y ago
    Or stop farming Almonds which use 1/2 as much water as all non farm use combined. Agriculture alone is 80% of all water use in the state. So, running out is less of an issue than trying to farm land that's just shy of a desert.
    - jefurii 11y ago
      The real problem is all the alfalfa and the cows. Per pound of protein/carbs/whatever, cows consume way more water than pretty much any plant. And much of our alfalfa is just being shipped to China.
      - Retric 11y ago
        Cutting Alfalfa production is fairly cheap in the long term which fits well with California's regular droughts. However, using prehistoric water to farm Alfalfa is crazy IMO. The problem with Almonds is they are trees, so letting them die is far more costly.
        vanattab 11y ago
        What is prehistoric water?
        Retric 11y ago
        Underground water gained by lowering the water table. There seems to be several terms in common usage. https://en.wikipedia.org/wiki/Aquifer https://en.wikipedia.org/wiki/Aquifer Basically, if the water table is dropping then people are pumping out water faster than its being replaced. If you look into when that water was put there you quickly get into geologic timeframes. Aquifer's often do flow meaning that specific drop may only be decades old, but replenishment rates in many places are vastly smaller than extraction rates. EX: Some places in China have seen 10+ feet drops in the water table per year. PS: “Fossil water” or paleowater is a related idea. Basically water that's been undisturbed for long periods. https://en.wikipedia.org/wiki/Fossil_water https://en.wikipedia.org/wiki/Fossil_water
        ScottBurson 11y ago
        But almonds are a high-value crop. If the price of water went up substantially, the almonds would get a little more expensive, but demand wouldn't collapse. I don't think it's right to say we shouldn't grow almonds in California, though they should pay for their water. > using prehistoric water to farm Alfalfa is crazy IMO Agreed -- completely insane. And we wouldn't, if water cost what it should cost.
  - dragontamer 11y ago
    Did Nevada have much water to begin with? I think they have lots of hills and lots of land. Probably not much water in that desert.
- LeifCarrotson 11y ago
  High upkeep costs? The article says: > Rail storage also does not have life cycle limits that batteries do. “There is zero degradation,” he said. They must be using rails, wheels, and bearings made of unobtainum. I know little about conventional rail maintenance, but a quick search suggested annual grinding of rails and 10-year replacement intervals.
- jefurii 11y ago
  > Vastly more costly than pumped water, high upkeep costs. I dunno, large areas of land, large earthmoving equipment, and the labor to turn it into a pumped-water storage system are all pretty expensive too.
  - Retric 11y ago
    California already uses a lot of pumped storage built into their long water distribution network. As to land use these tracks take up space at both end plus the space for the tracks between them unlike a pipe which can cheaply be placed under ground. So, per kWh stored these are likely far worse in terms of land used.

by jefurii 11y ago

Retric 11y ago

Vastly more costly than pumped water, high upkeep costs. Does have relatively high efficiency though. PS: "Cost comparisons with pumped hydro are difficult, he said, because there are so few projects and not many data points." Is pure BS, here is someones coursework on the subject: http://large.stanford.edu/courses/2014/ph240/galvan-lopez2/ http://large.stanford.edu/courses/2014/ph240/galvan-lopez2/

joezydeco 11y ago
If your state is running out of water, the switch to rocks might be something you can't avoid.
- Retric 11y ago
  Or stop farming Almonds which use 1/2 as much water as all non farm use combined. Agriculture alone is 80% of all water use in the state. So, running out is less of an issue than trying to farm land that's just shy of a desert.
  - jefurii 11y ago
    The real problem is all the alfalfa and the cows. Per pound of protein/carbs/whatever, cows consume way more water than pretty much any plant. And much of our alfalfa is just being shipped to China.
    - Retric 11y ago
      Cutting Alfalfa production is fairly cheap in the long term which fits well with California's regular droughts. However, using prehistoric water to farm Alfalfa is crazy IMO. The problem with Almonds is they are trees, so letting them die is far more costly.
      - vanattab 11y ago
        What is prehistoric water?
        Retric 11y ago
        Underground water gained by lowering the water table. There seems to be several terms in common usage. https://en.wikipedia.org/wiki/Aquifer https://en.wikipedia.org/wiki/Aquifer Basically, if the water table is dropping then people are pumping out water faster than its being replaced. If you look into when that water was put there you quickly get into geologic timeframes. Aquifer's often do flow meaning that specific drop may only be decades old, but replenishment rates in many places are vastly smaller than extraction rates. EX: Some places in China have seen 10+ feet drops in the water table per year. PS: “Fossil water” or paleowater is a related idea. Basically water that's been undisturbed for long periods. https://en.wikipedia.org/wiki/Fossil_water https://en.wikipedia.org/wiki/Fossil_water
      - ScottBurson 11y ago
        But almonds are a high-value crop. If the price of water went up substantially, the almonds would get a little more expensive, but demand wouldn't collapse. I don't think it's right to say we shouldn't grow almonds in California, though they should pay for their water. > using prehistoric water to farm Alfalfa is crazy IMO Agreed -- completely insane. And we wouldn't, if water cost what it should cost.
- dragontamer 11y ago
  Did Nevada have much water to begin with? I think they have lots of hills and lots of land. Probably not much water in that desert.
LeifCarrotson 11y ago
High upkeep costs? The article says: > Rail storage also does not have life cycle limits that batteries do. “There is zero degradation,” he said. They must be using rails, wheels, and bearings made of unobtainum. I know little about conventional rail maintenance, but a quick search suggested annual grinding of rails and 10-year replacement intervals.
jefurii 11y ago
> Vastly more costly than pumped water, high upkeep costs. I dunno, large areas of land, large earthmoving equipment, and the labor to turn it into a pumped-water storage system are all pretty expensive too.
- Retric 11y ago
  California already uses a lot of pumped storage built into their long water distribution network. As to land use these tracks take up space at both end plus the space for the tracks between them unlike a pipe which can cheaply be placed under ground. So, per kWh stored these are likely far worse in terms of land used.