12 ms·

As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much cap

by rakoo 6y ago

As usual everyone is fixated on price when the real hurdle will be scale. If we're going to replace our existing fossil fuel plants we need at least as much capacity. A quick grep in the article tells me these guys have a plan for a 4MW plant that involves a 1km shaft. That's the same order of magnitude as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land use. For reference (https://en.m.wikipedia.org/wiki/Coal-fired_power_station https://en.m.wikipedia.org/wiki/Coal-fired_power_station): > As of 2018 coal power under construction was 236 GW, planned 339 GW, and 50 GW was commissioned and 31 GW retired If we want to replace those new plants we'll need 100.000 of those shafts. And that's not counting the existing plants, and the other fossil-fuel based plants. Think of the quantity of concrete that involves. That's just insane. If we want to actively tackle electricity generation we need to use the most efficient low-carbon tech that we already know. Also, we already have gravity-based systems, only nature does all the work of raising the payload for us in gaseous form, and we let it fall in liquid forms. But it takes so much dam place.

pedrocr 6y ago
That's the wrong comparison. We don't need to replace generation capacity with the same capacity of batteries. Batteries don't generate any electricity after all. We need batteries to smooth out differences between demand and generation. The total amount we'll need is very much still up in the air. Better interconnects, good use of existing hydro, overbuilding renewables, shaping demand, are all other ways to balance loads and guarantee enough power at all times, all of which reduce the need for batteries.
- ben_w 6y ago
  I think[0] we should probably be aiming for a few hours of storage, even with every affordable grid interconnect (which would help a lot with short winter days). We use less power at night — and some of what we do use is incentivised by lower nighttime electricity costs from power plants that don’t scale down well — but I expect we will continue to use some at night forever. For the sake of Fermi estimation, I assume average electricity use in a developed nation is 1kW/person, and that average all-forms power use in the same is 5kW/person. Transportation is almost certainly going to be batteries or synthesised fuels like hydrogen, and can only be backed by gravity storage if you have the kind of beamed power that would be banned by international treaty on the grounds of being too easily weaponizable[1]. If you’ll permit me to assume grid interconnects and lower nighttime demand than at present due to different pricing incentives, we might be able to need a mere 3kW-hours/person of electricity storage per night. Using the lifetime cost estimates in the article, 3kWh/person/night is about $0.51/person/night for gravity storage and $1.10/person/night for LiIon. Neither is bank-breaking, but cheaper is better. However, the volume required is a different question: 3kWh of batteries has a volume of 4.3 to 12 litres, while 3kWh of gravity storage is 1.1 metric ton kilometres[2]. You can make the distance required smaller by using more mass, but if I assume the average home mass is about 200 tons, you’d still have to raise the entire building 5.5 meters every day to store the same energy as a backpack of batteries. I do not expect construction on this scale to be the optimal solution in general, despite it being a very good idea in some specific cases such as hydro dams and preexisting deep shafts. [0] Armchair opinion — I’m a software engineer not a civil engineer. [1] Assuming they’ve read or watched any Larry Niven, the Bobbiverse, The Expanse, Babylon 5, or the news at any point in the decade following the second week of September 2001 — 'A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive.' [2] http://www.wolframalpha.com/input/?i=3kWh%2F%289.8m%2Fs%2Fs%29%20in%20%28metric%20ton%20km%29 http://www.wolframalpha.com/input/?i=3kWh%2F%289.8m%2Fs%2Fs%...
  - Retric 6y ago
    Large scale hydro electric dams are already large scale batteries across months. The specific day of the week energy is released is not particularly relevant let alone time of day. 6.6% of US electricity is from hydro, assuming 2/3 flexable your looking at 4.4% of daily power demand or ~1 hour of full grid storage every day is already built. Excess capacity is required for storage to work and reduces the need for energy storage. But, once you start talking excess capacity, transmission dramatically reduces the need for storage. Assuming storage costs say 2x as much as wind generation then building excess wind capacity is worth it until ~1/2 of a wind turbines output is wasted. Thus if we are looking at 3kWh of storage that can be banked at any time of the day we are looking at a lot of excess capacity, yet somehow still supposed to have a 3kWh per night deficit.
FooHentai 6y ago
I did a bit of scratch math with the notion this might be more suited for individual, home power storage rather than grid supply - You need something in the order of a 5m tall tower bearing 73 tonnes to store 1 kilowatt hour (even then, ignoring conversion losses). So that's the weight of ~ten class-4 fully laden heavy trucks. Once you can get it up in the air then the higher you can go you're doubling your storage in a linear fashion. Hoist one of those trucks to 50 meters (perhaps you have a handy cliff in your backyard) and you've stored as much as the ten trucks did at 5 meters. So yeah scale seems hard, but the low technology/materials requirements and potential for gradual scale-up make this worthy of deep investigation. I think there's a lot of wandering off into dead-ends as far as limitations go though - Solutions that depend on a lot of concrete pouring, for example, are a no-go if the end goal is reducing atmospheric carbon.
- chris_engel 6y ago
  Hm, you also need to consider that 5 trucks can have a much higher combined output than the 1 truck 5 times as high. The storage might scale this way but not the output when demand is high.
  - rsa25519 6y ago
    > Hm, you also need to consider that 5 trucks can have a much higher combined output than the 1 truck 5 times as high. How so?
  - SagelyGuru 6y ago
    You can make that one truck descend five times faster, giving the same output.
    - randallsquared 6y ago
      "...for a given drop rate" seems implied. There will be a maximum drop rate that is supported by the machinery being built, and it seems reasonable, though not mandatory, that a 5x weight system will be designed to handle more generation than whatever it's 5x of.
arghwhat 6y ago
Batteries do not replace power generation capacity directly. They can, however, be configured to cover huge surge loads for short moments, or smooth out small discrepancies over a longer span, in more or less the same footprint. If you want a GW of coal, you need a GW plant, whereas with batteries you can decide between a gigawatt-hour or a 1000 megawatt-hour using a similiar footprint (scale to capacity of chosen technology). This reduces the need for significant unclean backup capacity, and either decommissioning them or reducing their usage.
jillesvangurp 6y ago
Your assumption that we need that much storage is simply wrong. This pops up in just about any article on HN mentioning batteries. Somebody will jump to the wrong conclusion that we need to provide massive amounts of battery storage and that therefore we need coal/nuclear/etc. (i.e. really expensive ways to generate energy) because buying so many batteries is obviously stupendously expensive. It's a popular argument with nuclear proponents and with the fossil fuel industry. The reasoning roughly goes like this: wind and solar capacity varies because wind doesn't always blow and the sun doesn't always shine. This is very obviously true of course. Except these effects are local, temporary and typically result in a reduced capacity rather than a complete collapse. You always get some output out of solar panels (except at night). And wind turbines might stop spinning but it's extremely rare for that to be a continent wide thing. Offshore wind is pretty reliable. Also these effects are kind of predictable via weather forecasts so we can plan for them. Same with seasonal patterns. Simple cables rather than batteries are the key technology that we need. And we mostly have that in place already. The grid connects power plants via cables. So, we can compensate for local dips in power with remote peaks. What matters is the collective performance of the grid. That still fluctuates but not nearly so dramatically that you'd need a lot of battery. E.g. the European grid is very connected. So, you might get power from Norwegian hydro, North Sea offshore wind, German on shore wind, solar plants in Spain, France, Germany, etc. or any of the gazillions of solar panels on people's houses. And of course there are coal, gas and nuclear still on the grid as well (for now). All of that failing 100% at the same time is simply not a thing. Not even close. It's not something grid operators plan for. It might dip by 20-30% but it might also peak by that much. And it's likely to average out over time in a very predictable way. All that means is that we need to have a little more capacity. 2x would be overkill. 1.2 to 1.3x plus some battery will probably do the trick. Batteries on the grid are intended for and used exclusively for absorbing short term peaks and dips in both supply and demand. Short term as in hours/minutes; not days or weeks. They are very good at that. This is why modest amounts of lithium ion batteries are being used successfully in various countries. These batteries can provide large amounts of power (MW/GW) for typically not more than a few hours. The reason that is cost effective (despite the cost of these batteries) is that taking e.g. gas peaker plants online for a few hours/minutes and then offline again is expensive and slow. And of course with cheaper wind and solar providing cheap power most of the time, gas plants are increasingly pushed in that role because they are more expensive per kwh to operate. Gas plants on stand by still cost money. And turning them on costs more money. Batteries basically enable grids to have fewer (and eventually none) of those plants. These gravity based batteries have the same role. It's a cheaper alternative to lithium ion batteries. Currently, clean energy is the dominant form of energy in many countries already (e.g. Europe, China, parts of the US). In some countries it's well over 50%. This proves the point because these grids don't feature a lot of battery currently and the combined capacity of peaker plants (i.e. not operating continously) is far smaller than the presumed need for batteries. If you were right, these countries would be facing massive blackouts all the time as their dominant form of energy disappears for days/weeks on end. That's obviously not a thing.
hutzlibu 6y ago
"Also, we already have gravity-based systems, only nature does all the work of raising the payload for us in gaseous form, and we let it fall in liquid forms. But it takes so much dam place" We actually also do have self created gravity-based systems, where we also do the work by ourself, to have a energy storage on demand: https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... They work reliable and with big capacity since the very beginning of electricity. The only problem is ... scale. You cannot just build them where you want them. You need rivers and height differences. Unless you create such systems completely artificial and there are plans to do so, but that will be very expensive. edit: here is a paper (in german) discussing such possibilities, to create a artificial pumped-storage out of the remains of surface mining https://epub.wupperinst.org/frontdoor/deliver/index/docId/7211/file/WP194.pdf https://epub.wupperinst.org/frontdoor/deliver/index/docId/72... edit 2: and my opinion is, that I am not a fan of complicated solutions, like the originial solution from the article seems to be, which is also stated as "The technology is still “incredibly immature” There are solutions to make batteries without rare elements. They just don't reach the energy density of lithium based ones, but that is not really a problem, when you have them stationary. So if you could scale up production of these and in the end, have a big battery in every home/factory connected to the grid - you would have a stable grid without any need for gas- or coal powered backup.
- dopidopHN 6y ago
  Side note on what is currently existing with gravity. The suiss folks are gaming the west European energy market this way. When the French produce too much nuclear energy, the German have leftover and stop buying it 100%w Price go down. Swiss buy it cheap and pump water in their dam system with it. Inevitably, the french grid align and produce a bit less. Price goes up slightly. That when the suiss comes out, release the water into a turbine system and sell the energy for a higher price that what they bought it for to German, French and Italian grid. I can’t even be mad at them. They have the perfect setup. But you need the Swiss alp and climate to do what they are doing. And being freaking Swiss. Source/Context from a Swiss news paper : le temps, in French They describe that « system » and apparently it’s being disturb in recent years with the evolution of the German market. https://www.letemps.ch/economie/barrages-suisses-vendre-eston-arrive https://www.letemps.ch/economie/barrages-suisses-vendre-esto...
prof-dr-ir 6y ago
> But it takes so much dam place. Does it? If you use iron instead then we only need to know that it has eight times the density of water. Multiplying a volume by eight is not a lot; it's only twice the size in length, width, and depth. So let's imagine replacing a typical hydroelectric power station [0] with a 'gravicity' system. Supposing the same depth you need a system of about one third of its length and its width and then fill it to the brim with iron. And of course do not forget to install cranes that are able to lift this iron to another space about 200m lower and back up. By the way, for concrete blocks it would only be a volume factor of 2.5, which would mean about 36% more in length, width and height. All in all, the amount of space that can possibly be gained with these systems seems pretty minimal to me. [0] https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_Station https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_... Edit: care to explain the downvotes?
- deleted 6y ago
  [deleted]
audunw 6y ago
It's a common misconception that energy storage needs to handle all the power needs of an area for a significant time. The most immediate need for energy storage is frequency regulation, and short hours-long dips in power output. If we can solve that we can scale renewables very far. For days-long dips in power output, it's probably better to keep some gas power plants on stand-by. I think many areas of the world has enough of them to handle these needs already. To make it sustainable, they could be switched to using renewables fuels, like hydrogen or ammonia made from electricity. We're going to need a shit-ton of those kinds of fuels for trucks, ships and airplanes anyway, so setting aside some of it for backup power wouldn't be a huge problem. For seasonal variations, I think trash burning power plants is a reasonable solution. Sweden and Norway has some of them, and they also provide heating to nearby homes. I mean, yeah: first of all we should reduce, reuse and recycle. But eventually our trash become unrecyclable, and burning it seems to be the best option. Modern facilities seems to be able to extract almost all harmful compounds from the waste then. There are also experiments with carbon capture from these plants, which in a fully renewable world could make them carbon-negative, and become one of several tools to help reduce CO2 in the atmosphere again over time. And of course, nuclear would be a great help. If it can be made cheap enough again, it can be used for seasonal variations. But we're still going to need renewables. So we still need energy storage for frequency regulations and minute/hours-long dips in energy output. Nuclear power plants are NOT a good solution for that.
- martinald 6y ago
  Not true in northern European countries. The problem isn't day to day regulation, it's the massive demand in cold snaps in winter (when there is very little wind generation - cold weather tends to have little wind). You're talking balancing 20-30GW of additional demand with little solar/wind generation for weeks/months - probably at least 1TWh of storage required for the UK alone. Keep in mind this will only get worse as heating demand is switched from natgas to electricity.
  - cogman10 6y ago
    This seems like a "running before we can walk" statement. Until we can handle day to day problems, it seems weird to worry about edge cases. I imagine as we transition to renewables and storage we will still have fossil fuel peeker plants to handle these sorts of snaps. It won't be until our power storage is far more beefed up that we'll shut those down, and that will take years.
throwaway189262 6y ago
> as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land use. This is just false. Every wind turbine I've ever seen uses 50 square feet on a farm or cattle ranch. Not once have I seen a wind farm where the land underneath isn't still used for it's previous purpose. And at least in US we have enough farmland to power entire US with wind. And that's not counting rapidly growing offshore wind power. Which uses no land at all
- tarsinge 6y ago
  Resources are also construction material, that’s where wind get its bad ratio.
  - throwaway189262 6y ago
    Construction material is a meaningless metric. If you compare coal or gas plants you need to consider the materials they consume and infrastructure needed for fuel transport. This is a big number, many times the material used for the plant itself. The only meaningful comparison is material used vs solar. Once these things are built they use near zero resources. For everything else you have to keep mining shitloads of material forever. How much coal do we have to mine for coal plants? How many gas wells and pipelines for gas plants? What about transport? How much does it take to mine and process all the uranium into fissile isotopes for nuclear? With wind and solar you plop the thing in a field and get years, maybe decades of energy with no input. I'm convinced that all these land use and building materials costs studies are just FUD funded by the fossil fuel industry.
    - lai-yin 6y ago
      Sorry but you don't get to discount wind turbines' ecological damage just because no more mining is involved post-construction.
      - throwaway189262 6y ago
        It does far less damage than any other source of power. Unlike solar, it uses no space. Unlike fossil fuel and nuclear, it uses no continuous inputs. Coal and gas plants use many times their weight in materials for a lifetime of operation. Nuclear probably does too because the massive waste involve in uranium refining. What do you suggest as a greener power source than wind?
fighterpilot 6y ago
> As usual everyone is fixated on price when the real hurdle will be scale If it's way too expensive (and there's no obvious way to reduce costs), then scalability is irrelevant, which is probably why people are fixated on it. We need both scalability and price to be favorable.
ClumsyPilot 6y ago
Maybe our expectation that we can match generation to consumption with storage, is just plain wrong. Maybe all we need is to have massive overcapacity of renewables - if we have 10x more solar than we need, even the most cloudy day will still provide power.
kjrose 6y ago
You are absolutely dead on right. We need to stop trying to bang on a model that isn't working and be willing to think even more outside of the box. All of this is essentially ways to create hydroelectric plants without the water. If we can find a way to create more of them without massive disruption it'd probably be the most effective. We need to find a solution that isn't just based on good wishes.
onecommentman 6y ago
10E6 shafts is not a scary number. There are about 10E7 active oil wells in the US. https://www.eia.gov/petroleum/wells/ https://www.eia.gov/petroleum/wells/ There are 10E8 private water wells in the US. https://www.epa.gov/privatewells https://www.epa.gov/privatewells So 10E6 sounds practicable and, as discussed previously, may be a significant overestimate of actual need. Suspect 50 year life cycle costs and various environmental and political externalities would be substantially lower for gravity-based solutions. But who knows? Concrete requirements? About 10E10 tons of concrete are consumed worldwide each year. https://concretehelper.com/concrete-facts/ https://concretehelper.com/concrete-facts/ Again, 10E6 doesn’t look so big, but might involve some engineering cleverness. But 10E6 big, capital intensive, fairly generic things can justify a lot of engineering cleverness in that one generic design. Geotech would need a lot of thought.

by rakoo 6y ago

pedrocr 6y ago

That's the wrong comparison. We don't need to replace generation capacity with the same capacity of batteries. Batteries don't generate any electricity after all. We need batteries to smooth out differences between demand and generation. The total amount we'll need is very much still up in the air. Better interconnects, good use of existing hydro, overbuilding renewables, shaping demand, are all other ways to balance loads and guarantee enough power at all times, all of which reduce the need for batteries.

ben_w 6y ago
I think[0] we should probably be aiming for a few hours of storage, even with every affordable grid interconnect (which would help a lot with short winter days). We use less power at night — and some of what we do use is incentivised by lower nighttime electricity costs from power plants that don’t scale down well — but I expect we will continue to use some at night forever. For the sake of Fermi estimation, I assume average electricity use in a developed nation is 1kW/person, and that average all-forms power use in the same is 5kW/person. Transportation is almost certainly going to be batteries or synthesised fuels like hydrogen, and can only be backed by gravity storage if you have the kind of beamed power that would be banned by international treaty on the grounds of being too easily weaponizable[1]. If you’ll permit me to assume grid interconnects and lower nighttime demand than at present due to different pricing incentives, we might be able to need a mere 3kW-hours/person of electricity storage per night. Using the lifetime cost estimates in the article, 3kWh/person/night is about $0.51/person/night for gravity storage and $1.10/person/night for LiIon. Neither is bank-breaking, but cheaper is better. However, the volume required is a different question: 3kWh of batteries has a volume of 4.3 to 12 litres, while 3kWh of gravity storage is 1.1 metric ton kilometres[2]. You can make the distance required smaller by using more mass, but if I assume the average home mass is about 200 tons, you’d still have to raise the entire building 5.5 meters every day to store the same energy as a backpack of batteries. I do not expect construction on this scale to be the optimal solution in general, despite it being a very good idea in some specific cases such as hydro dams and preexisting deep shafts. [0] Armchair opinion — I’m a software engineer not a civil engineer. [1] Assuming they’ve read or watched any Larry Niven, the Bobbiverse, The Expanse, Babylon 5, or the news at any point in the decade following the second week of September 2001 — 'A reaction drive's efficiency as a weapon is in direct proportion to its efficiency as a drive.' [2] http://www.wolframalpha.com/input/?i=3kWh%2F%289.8m%2Fs%2Fs%29%20in%20%28metric%20ton%20km%29 http://www.wolframalpha.com/input/?i=3kWh%2F%289.8m%2Fs%2Fs%...
- Retric 6y ago
  Large scale hydro electric dams are already large scale batteries across months. The specific day of the week energy is released is not particularly relevant let alone time of day. 6.6% of US electricity is from hydro, assuming 2/3 flexable your looking at 4.4% of daily power demand or ~1 hour of full grid storage every day is already built. Excess capacity is required for storage to work and reduces the need for energy storage. But, once you start talking excess capacity, transmission dramatically reduces the need for storage. Assuming storage costs say 2x as much as wind generation then building excess wind capacity is worth it until ~1/2 of a wind turbines output is wasted. Thus if we are looking at 3kWh of storage that can be banked at any time of the day we are looking at a lot of excess capacity, yet somehow still supposed to have a 3kWh per night deficit.

FooHentai 6y ago

I did a bit of scratch math with the notion this might be more suited for individual, home power storage rather than grid supply - You need something in the order of a 5m tall tower bearing 73 tonnes to store 1 kilowatt hour (even then, ignoring conversion losses). So that's the weight of ~ten class-4 fully laden heavy trucks. Once you can get it up in the air then the higher you can go you're doubling your storage in a linear fashion. Hoist one of those trucks to 50 meters (perhaps you have a handy cliff in your backyard) and you've stored as much as the ten trucks did at 5 meters. So yeah scale seems hard, but the low technology/materials requirements and potential for gradual scale-up make this worthy of deep investigation. I think there's a lot of wandering off into dead-ends as far as limitations go though - Solutions that depend on a lot of concrete pouring, for example, are a no-go if the end goal is reducing atmospheric carbon.

chris_engel 6y ago
Hm, you also need to consider that 5 trucks can have a much higher combined output than the 1 truck 5 times as high. The storage might scale this way but not the output when demand is high.
- rsa25519 6y ago
  > Hm, you also need to consider that 5 trucks can have a much higher combined output than the 1 truck 5 times as high. How so?
- SagelyGuru 6y ago
  You can make that one truck descend five times faster, giving the same output.
  - randallsquared 6y ago
    "...for a given drop rate" seems implied. There will be a maximum drop rate that is supported by the machinery being built, and it seems reasonable, though not mandatory, that a 5x weight system will be designed to handle more generation than whatever it's 5x of.

arghwhat 6y ago

Batteries do not replace power generation capacity directly. They can, however, be configured to cover huge surge loads for short moments, or smooth out small discrepancies over a longer span, in more or less the same footprint. If you want a GW of coal, you need a GW plant, whereas with batteries you can decide between a gigawatt-hour or a 1000 megawatt-hour using a similiar footprint (scale to capacity of chosen technology). This reduces the need for significant unclean backup capacity, and either decommissioning them or reducing their usage.

jillesvangurp 6y ago

Your assumption that we need that much storage is simply wrong. This pops up in just about any article on HN mentioning batteries. Somebody will jump to the wrong conclusion that we need to provide massive amounts of battery storage and that therefore we need coal/nuclear/etc. (i.e. really expensive ways to generate energy) because buying so many batteries is obviously stupendously expensive. It's a popular argument with nuclear proponents and with the fossil fuel industry. The reasoning roughly goes like this: wind and solar capacity varies because wind doesn't always blow and the sun doesn't always shine. This is very obviously true of course. Except these effects are local, temporary and typically result in a reduced capacity rather than a complete collapse. You always get some output out of solar panels (except at night). And wind turbines might stop spinning but it's extremely rare for that to be a continent wide thing. Offshore wind is pretty reliable. Also these effects are kind of predictable via weather forecasts so we can plan for them. Same with seasonal patterns. Simple cables rather than batteries are the key technology that we need. And we mostly have that in place already. The grid connects power plants via cables. So, we can compensate for local dips in power with remote peaks. What matters is the collective performance of the grid. That still fluctuates but not nearly so dramatically that you'd need a lot of battery. E.g. the European grid is very connected. So, you might get power from Norwegian hydro, North Sea offshore wind, German on shore wind, solar plants in Spain, France, Germany, etc. or any of the gazillions of solar panels on people's houses. And of course there are coal, gas and nuclear still on the grid as well (for now). All of that failing 100% at the same time is simply not a thing. Not even close. It's not something grid operators plan for. It might dip by 20-30% but it might also peak by that much. And it's likely to average out over time in a very predictable way. All that means is that we need to have a little more capacity. 2x would be overkill. 1.2 to 1.3x plus some battery will probably do the trick. Batteries on the grid are intended for and used exclusively for absorbing short term peaks and dips in both supply and demand. Short term as in hours/minutes; not days or weeks. They are very good at that. This is why modest amounts of lithium ion batteries are being used successfully in various countries. These batteries can provide large amounts of power (MW/GW) for typically not more than a few hours. The reason that is cost effective (despite the cost of these batteries) is that taking e.g. gas peaker plants online for a few hours/minutes and then offline again is expensive and slow. And of course with cheaper wind and solar providing cheap power most of the time, gas plants are increasingly pushed in that role because they are more expensive per kwh to operate. Gas plants on stand by still cost money. And turning them on costs more money. Batteries basically enable grids to have fewer (and eventually none) of those plants. These gravity based batteries have the same role. It's a cheaper alternative to lithium ion batteries. Currently, clean energy is the dominant form of energy in many countries already (e.g. Europe, China, parts of the US). In some countries it's well over 50%. This proves the point because these grids don't feature a lot of battery currently and the combined capacity of peaker plants (i.e. not operating continously) is far smaller than the presumed need for batteries. If you were right, these countries would be facing massive blackouts all the time as their dominant form of energy disappears for days/weeks on end. That's obviously not a thing.

hutzlibu 6y ago

"Also, we already have gravity-based systems, only nature does all the work of raising the payload for us in gaseous form, and we let it fall in liquid forms. But it takes so much dam place" We actually also do have self created gravity-based systems, where we also do the work by ourself, to have a energy storage on demand: https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit... They work reliable and with big capacity since the very beginning of electricity. The only problem is ... scale. You cannot just build them where you want them. You need rivers and height differences. Unless you create such systems completely artificial and there are plans to do so, but that will be very expensive. edit: here is a paper (in german) discussing such possibilities, to create a artificial pumped-storage out of the remains of surface mining https://epub.wupperinst.org/frontdoor/deliver/index/docId/7211/file/WP194.pdf https://epub.wupperinst.org/frontdoor/deliver/index/docId/72... edit 2: and my opinion is, that I am not a fan of complicated solutions, like the originial solution from the article seems to be, which is also stated as "The technology is still “incredibly immature” There are solutions to make batteries without rare elements. They just don't reach the energy density of lithium based ones, but that is not really a problem, when you have them stationary. So if you could scale up production of these and in the end, have a big battery in every home/factory connected to the grid - you would have a stable grid without any need for gas- or coal powered backup.

dopidopHN 6y ago
Side note on what is currently existing with gravity. The suiss folks are gaming the west European energy market this way. When the French produce too much nuclear energy, the German have leftover and stop buying it 100%w Price go down. Swiss buy it cheap and pump water in their dam system with it. Inevitably, the french grid align and produce a bit less. Price goes up slightly. That when the suiss comes out, release the water into a turbine system and sell the energy for a higher price that what they bought it for to German, French and Italian grid. I can’t even be mad at them. They have the perfect setup. But you need the Swiss alp and climate to do what they are doing. And being freaking Swiss. Source/Context from a Swiss news paper : le temps, in French They describe that « system » and apparently it’s being disturb in recent years with the evolution of the German market. https://www.letemps.ch/economie/barrages-suisses-vendre-eston-arrive https://www.letemps.ch/economie/barrages-suisses-vendre-esto...

prof-dr-ir 6y ago

> But it takes so much dam place. Does it? If you use iron instead then we only need to know that it has eight times the density of water. Multiplying a volume by eight is not a lot; it's only twice the size in length, width, and depth. So let's imagine replacing a typical hydroelectric power station [0] with a 'gravicity' system. Supposing the same depth you need a system of about one third of its length and its width and then fill it to the brim with iron. And of course do not forget to install cranes that are able to lift this iron to another space about 200m lower and back up. By the way, for concrete blocks it would only be a volume factor of 2.5, which would mean about 36% more in length, width and height. All in all, the amount of space that can possibly be gained with these systems seems pretty minimal to me. [0] https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_Station https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_... Edit: care to explain the downvotes?

deleted 6y ago
[deleted]

audunw 6y ago

It's a common misconception that energy storage needs to handle all the power needs of an area for a significant time. The most immediate need for energy storage is frequency regulation, and short hours-long dips in power output. If we can solve that we can scale renewables very far. For days-long dips in power output, it's probably better to keep some gas power plants on stand-by. I think many areas of the world has enough of them to handle these needs already. To make it sustainable, they could be switched to using renewables fuels, like hydrogen or ammonia made from electricity. We're going to need a shit-ton of those kinds of fuels for trucks, ships and airplanes anyway, so setting aside some of it for backup power wouldn't be a huge problem. For seasonal variations, I think trash burning power plants is a reasonable solution. Sweden and Norway has some of them, and they also provide heating to nearby homes. I mean, yeah: first of all we should reduce, reuse and recycle. But eventually our trash become unrecyclable, and burning it seems to be the best option. Modern facilities seems to be able to extract almost all harmful compounds from the waste then. There are also experiments with carbon capture from these plants, which in a fully renewable world could make them carbon-negative, and become one of several tools to help reduce CO2 in the atmosphere again over time. And of course, nuclear would be a great help. If it can be made cheap enough again, it can be used for seasonal variations. But we're still going to need renewables. So we still need energy storage for frequency regulations and minute/hours-long dips in energy output. Nuclear power plants are NOT a good solution for that.

martinald 6y ago
Not true in northern European countries. The problem isn't day to day regulation, it's the massive demand in cold snaps in winter (when there is very little wind generation - cold weather tends to have little wind). You're talking balancing 20-30GW of additional demand with little solar/wind generation for weeks/months - probably at least 1TWh of storage required for the UK alone. Keep in mind this will only get worse as heating demand is switched from natgas to electricity.
- cogman10 6y ago
  This seems like a "running before we can walk" statement. Until we can handle day to day problems, it seems weird to worry about edge cases. I imagine as we transition to renewables and storage we will still have fossil fuel peeker plants to handle these sorts of snaps. It won't be until our power storage is far more beefed up that we'll shut those down, and that will take years.

throwaway189262 6y ago

> as a single wind turbine, which is already one of the worst ratio of power output per quantity of resource and land use. This is just false. Every wind turbine I've ever seen uses 50 square feet on a farm or cattle ranch. Not once have I seen a wind farm where the land underneath isn't still used for it's previous purpose. And at least in US we have enough farmland to power entire US with wind. And that's not counting rapidly growing offshore wind power. Which uses no land at all

tarsinge 6y ago
Resources are also construction material, that’s where wind get its bad ratio.
- throwaway189262 6y ago
  Construction material is a meaningless metric. If you compare coal or gas plants you need to consider the materials they consume and infrastructure needed for fuel transport. This is a big number, many times the material used for the plant itself. The only meaningful comparison is material used vs solar. Once these things are built they use near zero resources. For everything else you have to keep mining shitloads of material forever. How much coal do we have to mine for coal plants? How many gas wells and pipelines for gas plants? What about transport? How much does it take to mine and process all the uranium into fissile isotopes for nuclear? With wind and solar you plop the thing in a field and get years, maybe decades of energy with no input. I'm convinced that all these land use and building materials costs studies are just FUD funded by the fossil fuel industry.
  - lai-yin 6y ago
    Sorry but you don't get to discount wind turbines' ecological damage just because no more mining is involved post-construction.
    - throwaway189262 6y ago
      It does far less damage than any other source of power. Unlike solar, it uses no space. Unlike fossil fuel and nuclear, it uses no continuous inputs. Coal and gas plants use many times their weight in materials for a lifetime of operation. Nuclear probably does too because the massive waste involve in uranium refining. What do you suggest as a greener power source than wind?

fighterpilot 6y ago

> As usual everyone is fixated on price when the real hurdle will be scale If it's way too expensive (and there's no obvious way to reduce costs), then scalability is irrelevant, which is probably why people are fixated on it. We need both scalability and price to be favorable.

ClumsyPilot 6y ago

Maybe our expectation that we can match generation to consumption with storage, is just plain wrong. Maybe all we need is to have massive overcapacity of renewables - if we have 10x more solar than we need, even the most cloudy day will still provide power.

kjrose 6y ago

You are absolutely dead on right. We need to stop trying to bang on a model that isn't working and be willing to think even more outside of the box. All of this is essentially ways to create hydroelectric plants without the water. If we can find a way to create more of them without massive disruption it'd probably be the most effective. We need to find a solution that isn't just based on good wishes.

onecommentman 6y ago

10E6 shafts is not a scary number. There are about 10E7 active oil wells in the US. https://www.eia.gov/petroleum/wells/ https://www.eia.gov/petroleum/wells/ There are 10E8 private water wells in the US. https://www.epa.gov/privatewells https://www.epa.gov/privatewells So 10E6 sounds practicable and, as discussed previously, may be a significant overestimate of actual need. Suspect 50 year life cycle costs and various environmental and political externalities would be substantially lower for gravity-based solutions. But who knows? Concrete requirements? About 10E10 tons of concrete are consumed worldwide each year. https://concretehelper.com/concrete-facts/ https://concretehelper.com/concrete-facts/ Again, 10E6 doesn’t look so big, but might involve some engineering cleverness. But 10E6 big, capital intensive, fairly generic things can justify a lot of engineering cleverness in that one generic design. Geotech would need a lot of thought.