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Not at all, and sorry I guess I misspoke. Whatever works: pumping water up hill, spinning flywheels etc. all sound fine to me. It's simply a question of whether

by spangry 10y ago

Not at all, and sorry I guess I misspoke. Whatever works: pumping water up hill, spinning flywheels etc. all sound fine to me. It's simply a question of whether it meets current energy demand, environmental impact, and cost. Come to think of it, I've only ever looked at the per KW hour cost of batteries (lead-acid seems to be the clear winner). You wouldn't happen to have references for other energy storage methods?

grzm 10y ago
Other than Wikipedia, no; I was hoping you would. That's why I asked. :) https://en.wikipedia.org/wiki/Grid_energy_storage https://en.wikipedia.org/wiki/Grid_energy_storage I think it's an interesting field though.
- spangry 10y ago
  Me too. I recently read about these hybrid battery-capacitor thingies that sounded pretty promising. I'll see if I can dig up the link. EDIT: here we go - http://www.nature.com/articles/srep04315 http://www.nature.com/articles/srep04315 . Lithium iron phosphate batteries (LiFePO). Although I'm assuming this particular combination doesn't provide favourable enough economics (or it would probably be a household name already), I can definitely see how this approach in general could. You could have the best of both worlds: cheap, but slow charge/discharge storage combined with the ability to very quickly scale up to meet peak daily demand for a limited (but sufficient) period of time.
- nkurz 10y ago
  David Mackay's "Sustainable Energy - Without the Hot Air" has good numbers comparing many different forms of energy storage: http://www.inference.eng.cam.ac.uk/withouthotair/ http://www.inference.eng.cam.ac.uk/withouthotair/. It's a "hard-headed" engineering look at our energy options written by a physicist. It might be a bit outdated (published in 2008), but when it came out it was the best compendium I'd seen.
  - robryk 10y ago
    Note that some of the statements there (e.g. estimates of areas needed to provide power from solar energy) are not technology-dependent (ie. are about physical limitations).
    - philipkglass 10y ago
      MacKay's estimate of areas needed to provide power from solar energy are technology-dependent. See for example: http://www.inference.phy.cam.ac.uk/withouthotair/c6/page_41.shtml http://www.inference.phy.cam.ac.uk/withouthotair/c6/page_41.... "If a breakthrough of solar technology occurs and the cost of photovoltaics came down enough that we could deploy panels all over the countryside, what is the maximum conceivable production? Well, if we covered 5% of the UK with 10%-efficient panels, we’d have 10% × 100 W/m^2 × 200 m^2 per person ≈ 50 kWh/day/person. I assumed only 10%-efficient panels, by the way, because I imagine that solar panels would be mass-produced on such a scale only if they were very cheap, and it’s the lower efficiency panels that will get cheap first." This assumption was invalidated by the actual trajectory of solar power since 2008. Nobody is building solar farms with 10% efficiency panels any more. Low efficiency is too expensive -- because it requires more glass and aluminum for the panels, more cabling, racking, and labor for installation. Low cost, low efficiency Chinese panels, like the GCL Poly ones used at India's giant new solar farm that HN just had an article about, are now in the mid-teens. (I looked up the data sheet after getting a glimpse of the GCL shipping crates on that Indian project site): http://www.solarpanelsplus.com/PV-Specials/GCL%20245.pdf http://www.solarpanelsplus.com/PV-Specials/GCL%20245.pdf If they used the middle-of-the-road GCL‐P6‐60‐240 that's a 14.7% module; 47% better than MacKay estimated as the best one could hope for from large scale solar projects. And the minimum competitive efficiency for even low-price panels is still creeping up. (Though large scale storage sufficiently affordable to get UK energy primarily from PV is still but a dream.) MacKay also made the challenge look even bigger than it is by estimating the energy consumption of a "typical moderately-afﬂuent person" and then multiplying that value by the whole population of the UK: http://www.inference.phy.cam.ac.uk/withouthotair/c2/page_22.shtml http://www.inference.phy.cam.ac.uk/withouthotair/c2/page_22.... This leads to large over-estimates relative to actual measured UK energy consumption, particularly from air travel and automobile travel.
jcrawfordor 10y ago
A company called ARES is working on a system that basically consists of automated electric trains carrying bricks uphill to store and then coasting back downhill with them to retrieve power. Basically pumped hydro but without a need for large quantities of water (and really ideal for installation in the desert, where there's a lot of open land with gentle slopes). They say efficiency near 80% with a first installation going in in Nevada in 2017. This is comparable efficiency to batteries but less expensive and with significant reuse of well-established technologies and industries (e.g. most of the construction work can be done by existing rail contractors). Although battery technology continues to advance, my suspicion is that large-scale electricity storage is going to tend to be mechanical for cost reasons.
- spangry 10y ago
  Huh. That's some pretty impressive efficiency. I don't know why, but the thought of a train carrying a brick uphill only to bring it back down again strikes me as a little bit comical :) Very interesting though. I wonder how far those trains travel, and if there's some way to use them simultaneously as energy storage and transmission infrastructure. I guess it depends on how the energy is recaptured. I'm just wondering because that could solve some of the cost issues associated with putting big solar arrays out in the middle of the desert... Something like a linear alternator maybe? https://en.wikipedia.org/wiki/Linear_alternator https://en.wikipedia.org/wiki/Linear_alternator
- emilong 10y ago
  Is this the ARES you mean? http://www.aresnorthamerica.com/ http://www.aresnorthamerica.com/ Love that they call it the ‘Sisyphus Railroad’.

by spangry 10y ago

grzm 10y ago

Other than Wikipedia, no; I was hoping you would. That's why I asked. :) https://en.wikipedia.org/wiki/Grid_energy_storage https://en.wikipedia.org/wiki/Grid_energy_storage I think it's an interesting field though.

spangry 10y ago
Me too. I recently read about these hybrid battery-capacitor thingies that sounded pretty promising. I'll see if I can dig up the link. EDIT: here we go - http://www.nature.com/articles/srep04315 http://www.nature.com/articles/srep04315 . Lithium iron phosphate batteries (LiFePO). Although I'm assuming this particular combination doesn't provide favourable enough economics (or it would probably be a household name already), I can definitely see how this approach in general could. You could have the best of both worlds: cheap, but slow charge/discharge storage combined with the ability to very quickly scale up to meet peak daily demand for a limited (but sufficient) period of time.
nkurz 10y ago
David Mackay's "Sustainable Energy - Without the Hot Air" has good numbers comparing many different forms of energy storage: http://www.inference.eng.cam.ac.uk/withouthotair/ http://www.inference.eng.cam.ac.uk/withouthotair/. It's a "hard-headed" engineering look at our energy options written by a physicist. It might be a bit outdated (published in 2008), but when it came out it was the best compendium I'd seen.
- robryk 10y ago
  Note that some of the statements there (e.g. estimates of areas needed to provide power from solar energy) are not technology-dependent (ie. are about physical limitations).
  - philipkglass 10y ago
    MacKay's estimate of areas needed to provide power from solar energy are technology-dependent. See for example: http://www.inference.phy.cam.ac.uk/withouthotair/c6/page_41.shtml http://www.inference.phy.cam.ac.uk/withouthotair/c6/page_41.... "If a breakthrough of solar technology occurs and the cost of photovoltaics came down enough that we could deploy panels all over the countryside, what is the maximum conceivable production? Well, if we covered 5% of the UK with 10%-efficient panels, we’d have 10% × 100 W/m^2 × 200 m^2 per person ≈ 50 kWh/day/person. I assumed only 10%-efficient panels, by the way, because I imagine that solar panels would be mass-produced on such a scale only if they were very cheap, and it’s the lower efficiency panels that will get cheap first." This assumption was invalidated by the actual trajectory of solar power since 2008. Nobody is building solar farms with 10% efficiency panels any more. Low efficiency is too expensive -- because it requires more glass and aluminum for the panels, more cabling, racking, and labor for installation. Low cost, low efficiency Chinese panels, like the GCL Poly ones used at India's giant new solar farm that HN just had an article about, are now in the mid-teens. (I looked up the data sheet after getting a glimpse of the GCL shipping crates on that Indian project site): http://www.solarpanelsplus.com/PV-Specials/GCL%20245.pdf http://www.solarpanelsplus.com/PV-Specials/GCL%20245.pdf If they used the middle-of-the-road GCL‐P6‐60‐240 that's a 14.7% module; 47% better than MacKay estimated as the best one could hope for from large scale solar projects. And the minimum competitive efficiency for even low-price panels is still creeping up. (Though large scale storage sufficiently affordable to get UK energy primarily from PV is still but a dream.) MacKay also made the challenge look even bigger than it is by estimating the energy consumption of a "typical moderately-afﬂuent person" and then multiplying that value by the whole population of the UK: http://www.inference.phy.cam.ac.uk/withouthotair/c2/page_22.shtml http://www.inference.phy.cam.ac.uk/withouthotair/c2/page_22.... This leads to large over-estimates relative to actual measured UK energy consumption, particularly from air travel and automobile travel.

jcrawfordor 10y ago

A company called ARES is working on a system that basically consists of automated electric trains carrying bricks uphill to store and then coasting back downhill with them to retrieve power. Basically pumped hydro but without a need for large quantities of water (and really ideal for installation in the desert, where there's a lot of open land with gentle slopes). They say efficiency near 80% with a first installation going in in Nevada in 2017. This is comparable efficiency to batteries but less expensive and with significant reuse of well-established technologies and industries (e.g. most of the construction work can be done by existing rail contractors). Although battery technology continues to advance, my suspicion is that large-scale electricity storage is going to tend to be mechanical for cost reasons.

spangry 10y ago
Huh. That's some pretty impressive efficiency. I don't know why, but the thought of a train carrying a brick uphill only to bring it back down again strikes me as a little bit comical :) Very interesting though. I wonder how far those trains travel, and if there's some way to use them simultaneously as energy storage and transmission infrastructure. I guess it depends on how the energy is recaptured. I'm just wondering because that could solve some of the cost issues associated with putting big solar arrays out in the middle of the desert... Something like a linear alternator maybe? https://en.wikipedia.org/wiki/Linear_alternator https://en.wikipedia.org/wiki/Linear_alternator
emilong 10y ago
Is this the ARES you mean? http://www.aresnorthamerica.com/ http://www.aresnorthamerica.com/ Love that they call it the ‘Sisyphus Railroad’.