15 ms·

Old salt mine is the first emission-free compressed air energy facility (2019)

80 points by luu 6y ago

rmason 6y ago
Left me wondering whether this would also work in Detroit? Detroit sits atop a huge abandoned salt mine. There's a mine across the border in Windsor (Canada) but that's still actively being mined.
- colomon 6y ago
  Goderich also has active salt mines... I'm presuming this project is using a played out branch of them.
52-6F-62 6y ago
Goderich is a beautiful town—I've been looking at getting out of the city for a while. Maybe we should look to head that way and I should start looking for a job with these guys. This, to my naive understand, seems like an enormously good idea and seems like they would have a lot of opportunity for relatively cheap resources and developing solutions for stabilizing fluctuating power generation resources like wind/solar. Please someone with more knowledge in this domain explain further what might be the benefits and shortfalls and pragmatism of this group.
- rich_sasha 6y ago
  I’m no expert for sure. I’m surprised they can be as much as 70% efficient, I would have thought the heat losses would be much greater. But clearly it doesn’t work like that.
  - msandford 6y ago
    Some of the diagrams I've seen in the past show that as the air comes out of the compressor its passed through a gravel bed before being allowed into the general mine. This picks up a lot of heat and then when the system is run in reverse the incoming air is pre-heated by the gravel bed prior to going into the turbine.
- propter_hoc 6y ago
  Been tracking them for a long time. They've been at "pilot" stage since at least 2011. Personally I don't think that any form of alternative energy storage has much chance against Li-ion, which has experienced unbelievable declines in cost (driven mostly by cell phones and electric cars). A bunch of extremely well funded compressed air storage companies have already run aground against this problem: Lightsail (Thiel & Gates backed), SustainX, etc. I'd be skeptical unless they can somehow actually prove economics against Li-ion, but these media pieces always seem to skirt that question.
  - KSteffensen 6y ago
    From the article: "compared to a similar capacity battery, it's not only half the cost, the facility has a service life of 50 years, five to 10 times longer than a battery." It doesn't explicit say what kind of battery, but a service life of 10 years suggests Li-ion.
- pletsch 6y ago
  From the area, there's a lot of people with your line of thinking from different fields. I think you'd like it, although there's quite a few small communities in SW Ontario I think are worth moving to.
yabones 6y ago
This type of storage, whether it be water reservoirs or compressed air, is especially important in Ontario. We have a very strong base supply from our three large nuclear facilities and hydroelectric dams, but the rest is largely made up of wind, solar, and gas. Because the peak supply from solar is midday and the peak load is often in the evening [1], you're left running the 'peakers' (gas plants) for most of the night to make up the difference. If we were able to store more energy short term, we could conceivably remove natural gas energy production and be 100% green/renewable. As of 2018 we were 96% renewable [2] so it's really not some pipe dream. [1] https://en.wikipedia.org/wiki/Duck_curve https://en.wikipedia.org/wiki/Duck_curve [2] https://www.cer-rec.gc.ca/nrg/ntgrtd/mrkt/nrgsstmprfls/on-eng.html https://www.cer-rec.gc.ca/nrg/ntgrtd/mrkt/nrgsstmprfls/on-en... And honestly, I'm okay with paying a little more on my energy bill for the next couple years knowing that my province has made the decision to be part of the solution.
- pwarner 6y ago
  It's important or will be everywhere. Source: California where the lights are literally about to go out...
- hervature 6y ago
  You are aware that nuclear power is not considered renewable by the majority of people correct? That puts Ontario at less than 50% renewable.
  - yabones 6y ago
    You're technically correct, and what I should have said was 'zero-carbon emitting sources' as was in the source. But for practical purposes there is so much Uranium on this planet that we'll most likely never even use 1% of it. Especially when you factor in newer or experimental reactor designs such as fast breeder reactors [1] that can generate even more power and use waste materials from current systems. So yes, it is technically not a renewable source of energy, but there is such abundance of fuel that it's not 'non-renewable' the way Coal or Gas is. [1] https://en.wikipedia.org/wiki/Breeder_reactor#Fast_breeder_reactor https://en.wikipedia.org/wiki/Breeder_reactor#Fast_breeder_r...
JoeAltmaier 6y ago
But is it scalable?
- bdamm 6y ago
  There only needs to be one no?
  - freeone3000 6y ago
    No. Much as one battery would not be sufficient, this storage station that can only power half of one small town for five hours is insufficient storage for the province, much less the country.
    - bdamm 6y ago
      It doesn't have to power the town, it only has to pull power when it's abundant and deliver power when it is not abundant. Using the resource more as a market balancer. There are many examples of this being profitable.
- hokkos 6y ago
  To get a salt cavity just pump in water in salt deposit and pump out brine. It can be used to store H2, CH4 or compressed air, from 70 to 200 bars. H2 is way more energy dense, but has a lower efficiency round trip. There is many salt deposit around the world.
  - Scoundreller 6y ago
    Disposing of the brine is a bit complicated when you have nothing but freshwater lakes around :) I'm guessing they're planning on using the existing caverns from mining. Unsure if they plan on expanding.
    - joncrane 6y ago
      Can't they just evaporate off the water and use the remaining salt to treat roads in the winter?
cjhveal 6y ago
In case anyone is curious, hydro is the general term for electrical power from a utility, at least in the part of Canada where I grew up.
- elric 6y ago
  That's ... weird. But thanks for clarifying that, that really confused me.
  - 52-6F-62 6y ago
    It's weird on the surface, but it's because our entire electrical utility has roots in hydroelectric power. Adam Beck was one of the people chiefly responsible for the creation of a public electrical utility in Ontario. I like one of his quotes "the gifts of nature are for the public" referring to his slogan "Power at cost". https://en.wikipedia.org/wiki/Adam_Beck https://en.wikipedia.org/wiki/Adam_Beck
    - cjhveal 6y ago
      Thank you for this context. I vaguely knew of the term's connection with the names of utilities, but this is some fascinating Canadian history.
mleonhard 6y ago
Has anyone analyzed the viability of a compressed-air energy distribution system? It could be simpler and safer than electricity distribution.
- ericbarrett 6y ago
  In the quantity and pressure required to match even a fraction of the existing energy grid, wouldn’t transportation be insanely dangerous? A cylinder of highly pressurized air is basically a bomb.
  - mleonhard 6y ago
    I was thinking more of a pipeline of compressed air.
    - ericbarrett 6y ago
      I think they would have a similar issue. Since the compression of the gas itself is the potential energy, rather chemical bonds (e.g. fossil fuels), the pressures would need to be extremely high. This means any compromise of the pipeline would be catastrophic. That said, natural gas already causes home and pipeline explosions, so I'd be interested in an engineering study.
    - dredmorbius 6y ago
      Live steam is another alternative, also used in industrial applications.
- repiret 6y ago
  In what ways are compressed air safer and simpler for transmission? Off the top of my head I can only think of advantages for electricity: * Electrical transmission lines are lighter and smaller per watt than compressed air transmission lines. * Electrical transmission has lower inductance than compressed air has equivalent momentum. * Compressed air vessels can fail explosively; electrical stuff just heats up. * One has to contend with adiabatic heating/cooling when exchanging air pressure for flow rate, while there's no analogous concerns when using transformers to exchange voltage for amps. * Electrical equipment tends to be much quieter than air equipment.
kevin_b_er 6y ago
Sometimes I hate the quality of science reporting due to obvious mistakes. > The Hydrostor facility can keep up to 10 megawatts of power, enough to keep the lights on in about 2,000 homes, or approximately half the town of Goderich for about five hours. Megawatts instantaneous power, but the sentence wording makes it sound like capacity. That's how much energy it can supply at any moment vs how big the battery is. And they talk about X number of homes for Y hours. Did they mean 10 megawatt-hours? Or did they mean 10 megawatts for 4 hours? That's 40 megawatt-hours or MWh. Judging from this other site, it is 1.75 MW max and a capacity of 10 MWh. Which means someone messed up units in the article. Possibly even they read "MWh" from a technical summary and just guessed it meant megawatts. Because they spelled it out in the article. http://www.energystoragejournal.com/hydrostor-and-nrstor-announce-worlds-first-commercial-advanced-caes-facility/ http://www.energystoragejournal.com/hydrostor-and-nrstor-ann...
- lultimouomo 6y ago
  I would have parsed the article as saying that the facility could provide 10MW power for about five hours, so with a total capacity of 50MWh... this is terrible reporting. Hydrostor own website confirms your figures: https://www.hydrostor.ca/goderich-a-caes-facility/ https://www.hydrostor.ca/goderich-a-caes-facility/
- knolax 6y ago
  It's such a common error, someone should travel the country giving lectures to every journalism school about the diffences between W and Wh.
  - ntsplnkv2 6y ago
    It's such a common error that perhaps the terms are too close and confusing and could've used a better nomenclature.
    - NavinF 6y ago
      Do you have a suggestion for better nomenclature? Watt hours are fairly straightforward IMO.
1over137 6y ago
I know people that live there. Many worry about the safety of using compressed air below the town and wonder if it would cause collapse of any tunnel in the current salt mine.
- Cthulhu_ 6y ago
  I'm definitely not a geologist but I can imagine the "breathing" motion of pressurizing and depressurizing the mines causes some movement and damage over time. What pressures are we talking about anyway?
ericvanular 6y ago
This is in my backyard (ish)! Strange given that I started https://collective.energy https://collective.energy to create more dialogue around innovative climate solutions but never even saw the old salt mine as an opportunity
walrus01 6y ago
At a certain point if photovoltaic panels become very, very cheap (far below the $0.20-$0.35/watt STC price to buy panels in huge quantities today), it will be economical to crack hydrogen from water and compress it into tanks, then use it to run massive fuel cells to feed power back into the grid. Because of the significant engineering challenges in storing, transporting and refueling hydrogen at very high pressures, I am much more optimistic about the use of hydrogen in medium to large sized fixed, professionally-run facilities than I am about people driving around with hydrogen fuel cell powered cars. Or home use of hydrogen fuel cells.
- andromeduck 6y ago
  that generally requires high cost or temperature catalysts and even then it's not that efficient for short-medium term
  - pfdietz 6y ago
    Alkaline electrolysers do not require high cost electrocatalysts, and are likely the low capital cost (and mediocre efficiency) ones to be used with intermittent renewables.
- tonyedgecombe 6y ago
  Or spread it around the world and run lots of interconnectors. It's always daytime somewhere in the world.
- Tade0 6y ago
  Ethanol may be better suited for this: https://www.anl.gov/article/turning-carbon-dioxide-into-liquid-fuel https://www.anl.gov/article/turning-carbon-dioxide-into-liqu...
- Mvandenbergh 6y ago
  Tank storage is challenging because at that scale you're competing with batteries which have much better round-trip efficiency. There was a DNV GL paper earlier this year which quoted a time of about 24 hrs as the cross-over point between H2 and battery tech. Underground cavern storage lets you do inter-seasonal storage at a very low cost per MWh. It's critical to understand that liquid and gas fuels have uncoupled per MW and per MWh costs in a way that batteries don't. You can adjust battery chemistry of course but fundamentally you're stuck with a narrow range of peak MW / MWh performance which means that if you want to build a massive battery for inter-seasonal storage (needs MWh >>> MW) you end up "buying" discharge capacity in MW that you don't need. Hydrogen decouples the size of the production (in MW), the storage (MWh), and the fuel cell (MW) which lets you size them independently of each other. I am also sceptical of the need for home use or vehicular hydrogen (certainly in passenger cars). You get a lot of efficiency improvement if you are able to use the waste heat from fuel cells. Yes that can be done domestically, but putting them in large urban centres and driving district heating schemes from them seems like a much more natural fit. Especially in places like Europe where total energy demand (heat and electricity both) peak at the same time in the winter as renewable generation decreases. N.b. there are already times in the UK grid when prices are negative wholesale. Even one of the retail energy suppliers here had a few half hourly periods of negative prices a few months ago. The subsidy for hydrogen electrolysers in The Netherlands was set assuming 2,000 hours a year of operation (using the cleanest and cheapest 2,000 hrs) since that maximises the environmental benefit with the current Dutch grid.
sunkenvicar 6y ago
66% efficiency sounds amazing for compressed air. I was expecting 10%.

80 points by luu 6y ago

Left me wondering whether this would also work in Detroit? Detroit sits atop a huge abandoned salt mine. There's a mine across the border in Windsor (Canada) but that's still actively being mined.

colomon 6y ago
Goderich also has active salt mines... I'm presuming this project is using a played out branch of them.

52-6F-62 6y ago

Goderich is a beautiful town—I've been looking at getting out of the city for a while. Maybe we should look to head that way and I should start looking for a job with these guys. This, to my naive understand, seems like an enormously good idea and seems like they would have a lot of opportunity for relatively cheap resources and developing solutions for stabilizing fluctuating power generation resources like wind/solar. Please someone with more knowledge in this domain explain further what might be the benefits and shortfalls and pragmatism of this group.

rich_sasha 6y ago
I’m no expert for sure. I’m surprised they can be as much as 70% efficient, I would have thought the heat losses would be much greater. But clearly it doesn’t work like that.
- msandford 6y ago
  Some of the diagrams I've seen in the past show that as the air comes out of the compressor its passed through a gravel bed before being allowed into the general mine. This picks up a lot of heat and then when the system is run in reverse the incoming air is pre-heated by the gravel bed prior to going into the turbine.
propter_hoc 6y ago
Been tracking them for a long time. They've been at "pilot" stage since at least 2011. Personally I don't think that any form of alternative energy storage has much chance against Li-ion, which has experienced unbelievable declines in cost (driven mostly by cell phones and electric cars). A bunch of extremely well funded compressed air storage companies have already run aground against this problem: Lightsail (Thiel & Gates backed), SustainX, etc. I'd be skeptical unless they can somehow actually prove economics against Li-ion, but these media pieces always seem to skirt that question.
- KSteffensen 6y ago
  From the article: "compared to a similar capacity battery, it's not only half the cost, the facility has a service life of 50 years, five to 10 times longer than a battery." It doesn't explicit say what kind of battery, but a service life of 10 years suggests Li-ion.
pletsch 6y ago
From the area, there's a lot of people with your line of thinking from different fields. I think you'd like it, although there's quite a few small communities in SW Ontario I think are worth moving to.

yabones 6y ago

This type of storage, whether it be water reservoirs or compressed air, is especially important in Ontario. We have a very strong base supply from our three large nuclear facilities and hydroelectric dams, but the rest is largely made up of wind, solar, and gas. Because the peak supply from solar is midday and the peak load is often in the evening [1], you're left running the 'peakers' (gas plants) for most of the night to make up the difference. If we were able to store more energy short term, we could conceivably remove natural gas energy production and be 100% green/renewable. As of 2018 we were 96% renewable [2] so it's really not some pipe dream. [1] https://en.wikipedia.org/wiki/Duck_curve https://en.wikipedia.org/wiki/Duck_curve [2] https://www.cer-rec.gc.ca/nrg/ntgrtd/mrkt/nrgsstmprfls/on-eng.html https://www.cer-rec.gc.ca/nrg/ntgrtd/mrkt/nrgsstmprfls/on-en... And honestly, I'm okay with paying a little more on my energy bill for the next couple years knowing that my province has made the decision to be part of the solution.

pwarner 6y ago
It's important or will be everywhere. Source: California where the lights are literally about to go out...
hervature 6y ago
You are aware that nuclear power is not considered renewable by the majority of people correct? That puts Ontario at less than 50% renewable.
- yabones 6y ago
  You're technically correct, and what I should have said was 'zero-carbon emitting sources' as was in the source. But for practical purposes there is so much Uranium on this planet that we'll most likely never even use 1% of it. Especially when you factor in newer or experimental reactor designs such as fast breeder reactors [1] that can generate even more power and use waste materials from current systems. So yes, it is technically not a renewable source of energy, but there is such abundance of fuel that it's not 'non-renewable' the way Coal or Gas is. [1] https://en.wikipedia.org/wiki/Breeder_reactor#Fast_breeder_reactor https://en.wikipedia.org/wiki/Breeder_reactor#Fast_breeder_r...

JoeAltmaier 6y ago

But is it scalable?

bdamm 6y ago
There only needs to be one no?
- freeone3000 6y ago
  No. Much as one battery would not be sufficient, this storage station that can only power half of one small town for five hours is insufficient storage for the province, much less the country.
  - bdamm 6y ago
    It doesn't have to power the town, it only has to pull power when it's abundant and deliver power when it is not abundant. Using the resource more as a market balancer. There are many examples of this being profitable.
hokkos 6y ago
To get a salt cavity just pump in water in salt deposit and pump out brine. It can be used to store H2, CH4 or compressed air, from 70 to 200 bars. H2 is way more energy dense, but has a lower efficiency round trip. There is many salt deposit around the world.
- Scoundreller 6y ago
  Disposing of the brine is a bit complicated when you have nothing but freshwater lakes around :) I'm guessing they're planning on using the existing caverns from mining. Unsure if they plan on expanding.
  - joncrane 6y ago
    Can't they just evaporate off the water and use the remaining salt to treat roads in the winter?

cjhveal 6y ago

In case anyone is curious, hydro is the general term for electrical power from a utility, at least in the part of Canada where I grew up.

elric 6y ago
That's ... weird. But thanks for clarifying that, that really confused me.
- 52-6F-62 6y ago
  It's weird on the surface, but it's because our entire electrical utility has roots in hydroelectric power. Adam Beck was one of the people chiefly responsible for the creation of a public electrical utility in Ontario. I like one of his quotes "the gifts of nature are for the public" referring to his slogan "Power at cost". https://en.wikipedia.org/wiki/Adam_Beck https://en.wikipedia.org/wiki/Adam_Beck
  - cjhveal 6y ago
    Thank you for this context. I vaguely knew of the term's connection with the names of utilities, but this is some fascinating Canadian history.

mleonhard 6y ago

Has anyone analyzed the viability of a compressed-air energy distribution system? It could be simpler and safer than electricity distribution.

ericbarrett 6y ago
In the quantity and pressure required to match even a fraction of the existing energy grid, wouldn’t transportation be insanely dangerous? A cylinder of highly pressurized air is basically a bomb.
- mleonhard 6y ago
  I was thinking more of a pipeline of compressed air.
  - ericbarrett 6y ago
    I think they would have a similar issue. Since the compression of the gas itself is the potential energy, rather chemical bonds (e.g. fossil fuels), the pressures would need to be extremely high. This means any compromise of the pipeline would be catastrophic. That said, natural gas already causes home and pipeline explosions, so I'd be interested in an engineering study.
  - dredmorbius 6y ago
    Live steam is another alternative, also used in industrial applications.
repiret 6y ago
In what ways are compressed air safer and simpler for transmission? Off the top of my head I can only think of advantages for electricity: * Electrical transmission lines are lighter and smaller per watt than compressed air transmission lines. * Electrical transmission has lower inductance than compressed air has equivalent momentum. * Compressed air vessels can fail explosively; electrical stuff just heats up. * One has to contend with adiabatic heating/cooling when exchanging air pressure for flow rate, while there's no analogous concerns when using transformers to exchange voltage for amps. * Electrical equipment tends to be much quieter than air equipment.

kevin_b_er 6y ago

Sometimes I hate the quality of science reporting due to obvious mistakes. > The Hydrostor facility can keep up to 10 megawatts of power, enough to keep the lights on in about 2,000 homes, or approximately half the town of Goderich for about five hours. Megawatts instantaneous power, but the sentence wording makes it sound like capacity. That's how much energy it can supply at any moment vs how big the battery is. And they talk about X number of homes for Y hours. Did they mean 10 megawatt-hours? Or did they mean 10 megawatts for 4 hours? That's 40 megawatt-hours or MWh. Judging from this other site, it is 1.75 MW max and a capacity of 10 MWh. Which means someone messed up units in the article. Possibly even they read "MWh" from a technical summary and just guessed it meant megawatts. Because they spelled it out in the article. http://www.energystoragejournal.com/hydrostor-and-nrstor-announce-worlds-first-commercial-advanced-caes-facility/ http://www.energystoragejournal.com/hydrostor-and-nrstor-ann...

lultimouomo 6y ago
I would have parsed the article as saying that the facility could provide 10MW power for about five hours, so with a total capacity of 50MWh... this is terrible reporting. Hydrostor own website confirms your figures: https://www.hydrostor.ca/goderich-a-caes-facility/ https://www.hydrostor.ca/goderich-a-caes-facility/
knolax 6y ago
It's such a common error, someone should travel the country giving lectures to every journalism school about the diffences between W and Wh.
- ntsplnkv2 6y ago
  It's such a common error that perhaps the terms are too close and confusing and could've used a better nomenclature.
  - NavinF 6y ago
    Do you have a suggestion for better nomenclature? Watt hours are fairly straightforward IMO.

1over137 6y ago

I know people that live there. Many worry about the safety of using compressed air below the town and wonder if it would cause collapse of any tunnel in the current salt mine.

Cthulhu_ 6y ago
I'm definitely not a geologist but I can imagine the "breathing" motion of pressurizing and depressurizing the mines causes some movement and damage over time. What pressures are we talking about anyway?

ericvanular 6y ago

This is in my backyard (ish)! Strange given that I started https://collective.energy https://collective.energy to create more dialogue around innovative climate solutions but never even saw the old salt mine as an opportunity

walrus01 6y ago

At a certain point if photovoltaic panels become very, very cheap (far below the $0.20-$0.35/watt STC price to buy panels in huge quantities today), it will be economical to crack hydrogen from water and compress it into tanks, then use it to run massive fuel cells to feed power back into the grid. Because of the significant engineering challenges in storing, transporting and refueling hydrogen at very high pressures, I am much more optimistic about the use of hydrogen in medium to large sized fixed, professionally-run facilities than I am about people driving around with hydrogen fuel cell powered cars. Or home use of hydrogen fuel cells.

andromeduck 6y ago
that generally requires high cost or temperature catalysts and even then it's not that efficient for short-medium term
- pfdietz 6y ago
  Alkaline electrolysers do not require high cost electrocatalysts, and are likely the low capital cost (and mediocre efficiency) ones to be used with intermittent renewables.
tonyedgecombe 6y ago
Or spread it around the world and run lots of interconnectors. It's always daytime somewhere in the world.
Tade0 6y ago
Ethanol may be better suited for this: https://www.anl.gov/article/turning-carbon-dioxide-into-liquid-fuel https://www.anl.gov/article/turning-carbon-dioxide-into-liqu...
Mvandenbergh 6y ago
Tank storage is challenging because at that scale you're competing with batteries which have much better round-trip efficiency. There was a DNV GL paper earlier this year which quoted a time of about 24 hrs as the cross-over point between H2 and battery tech. Underground cavern storage lets you do inter-seasonal storage at a very low cost per MWh. It's critical to understand that liquid and gas fuels have uncoupled per MW and per MWh costs in a way that batteries don't. You can adjust battery chemistry of course but fundamentally you're stuck with a narrow range of peak MW / MWh performance which means that if you want to build a massive battery for inter-seasonal storage (needs MWh >>> MW) you end up "buying" discharge capacity in MW that you don't need. Hydrogen decouples the size of the production (in MW), the storage (MWh), and the fuel cell (MW) which lets you size them independently of each other. I am also sceptical of the need for home use or vehicular hydrogen (certainly in passenger cars). You get a lot of efficiency improvement if you are able to use the waste heat from fuel cells. Yes that can be done domestically, but putting them in large urban centres and driving district heating schemes from them seems like a much more natural fit. Especially in places like Europe where total energy demand (heat and electricity both) peak at the same time in the winter as renewable generation decreases. N.b. there are already times in the UK grid when prices are negative wholesale. Even one of the retail energy suppliers here had a few half hourly periods of negative prices a few months ago. The subsidy for hydrogen electrolysers in The Netherlands was set assuming 2,000 hours a year of operation (using the cleanest and cheapest 2,000 hrs) since that maximises the environmental benefit with the current Dutch grid.

sunkenvicar 6y ago

66% efficiency sounds amazing for compressed air. I was expecting 10%.