[HN Gopher] Gravity batteries try to beat chemical ones with win...
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Gravity batteries try to beat chemical ones with winches, weights,
mine shafts
Author : hheikinh
Score : 213 points
Date : 2021-04-24 05:42 UTC (17 hours ago)
(HTM) web link (www.sciencemag.org)
(TXT) w3m dump (www.sciencemag.org)
| SarbinBracklur wrote:
| The numbers in this article seem off. 250kW (peak power) for 11s
| (time at peak power) is 2.75 MJ. That's only about 51 10000mAh D
| batteries. Of course, the peak power of the gravity battery is
| much higher than the chemical batteries, but still.
| Ekaros wrote:
| I wonder what is the limit when this kind of storage would only
| consist of single steel cable. As at certain point weight of
| cable is so big that it can't support even itself anymore.
| [deleted]
| joss82 wrote:
| The system bring talked about here can deliver 250kW during 11
| seconds max.
|
| That is LESS than 1 kWh of energy storage.
|
| I hope it's not the one on the picture otherwise their cost
| estimates are way off and two orders of magnitude larger than
| current lithium batteries, even taking into account battery
| replacement.
|
| Another problem would be the ever-lowering price of batteries
| comparing unfavorably against this good old tech with stable or
| raising costs (human costs tend to rise over time)
| nixpulvis wrote:
| I had the same thought. They do make it clear that this is a
| demonstration, but I'm curious how this scales with larger
| weights and heights; both in capital cost, and efficiency.
|
| I'm also curious if anyone's seen a good comparison to
| hydro/dam based gravity batteries? Or even to the gimmicky
| sounding electric train based ones I've read about before?
|
| My understanding is that anything near or past 90% efficiency
| gets very hard to achieve, but perhaps there are special cases
| where this isn't true?
|
| Finally, I'm also curious how these compare to flywheels, which
| offer a similar style of energy storage, but with rotational
| potential instead of gravitational.
|
| Storage is clearly one of the largest barriers to large scale
| adoption of many renewable sources of power we have. And,
| chemical batteries raise a lot of valid concerns in terms of
| safety and environmental impact.
| apetrovic wrote:
| How efficient the system is? If, say, the machine uses 100KW to
| lift the weight, what's the output?
| alexchamberlain wrote:
| Between 80% and 90%.
|
| See https://gravitricity.com/technology/
| kvutza wrote:
| Could they make it a space elevator?
| choeger wrote:
| Stopped reading at a total cost of more than $300 per MWh for
| batteries.
|
| Quick back-of-the-napkin calculation: Car batteries come in at
| less than $100/KWh. They're good for at least 1000 cycles at 80%
| capacity. That gives us at least 0.8MWh for a 100$ investment.
|
| It's very, very unlikely that initial construction of the site
| and operational costs more than triple that price.
| alexchamberlain wrote:
| Their marketing has the LCOS of those 2 solutions the other way
| around - $171 for Gravity, $367 for Litium Ion batteries.
|
| See https://gravitricity.com/technology/
| PeterisP wrote:
| Too bad they don't seem to provide the actual report anywhere
| (and neither does ICL), they just quote a single chart from
| that without any details. This feels fishy to me - I'd want
| to look into the cost basis they used, as a key problem with
| comparisons against batteries is that the battery cost has
| changed so much over the recent years (halving every 5 years
| or so), and many studies quote their battery price
| calculations on older reports that are now off by a large
| multiple.
|
| $367 of LI batteries at year X is $171 of LI batteries at
| year X+5 and $86 at year X+10, so it's important to look at
| what the X is in their study. And of course, we should
| consider that chemical battery costs are expected to decrease
| in the near future, while the cost well-established
| mechanical components would stay stable.
| alexchamberlain wrote:
| Whilst I agree the components of a mechanical battery are
| probably going to stay stable, I think Gravitricity have an
| opportunity to commoditise the design and install near
| sporadic renewables like wind.
|
| Bias: I participated in their crowdfunding campaign.
| _rpd wrote:
| Here's what the article says about cost:
|
| > For a 25-year project, he estimates that Gravitricity would
| cost $171 for each megawatt-hour. Jessika Trancik, an energy
| storage researcher at the Massachusetts Institute of
| Technology, says that number is aspirational and still needs to
| be supported with field data. But Schmidt's calculation of the
| lifetime cost per megawatt-hour for lithium-ion batteries,
| $367, is more than twice as much. Flow batteries, a promising
| grid-scale technology that stores charge in large tanks of
| liquid electrolyte, come in at $274 per megawatt-hour
| o_p wrote:
| This doesnt account the short duration of batteries, I have to
| replace them every time they go past their lifetime, so in the
| long term their cost is much higher
| PeterisP wrote:
| The heavy machinery with moving parts lifting thousands and
| thousands of tons is also going to need maintenance and
| wear&tear replacements. The problem with scale is that all
| these proposed gravity batteries need much, much more
| machinery than an equivalent pumped capacity pumped hydro or
| chemical battery plant.
| polypodiopsi wrote:
| Out of interest: do you have experience with mechanical
| engeneering or is this more of a common sense speculation?
| simion314 wrote:
| You should finish reading or find a similar storage company
| that sells batteries and see how much they charge.
| imtringued wrote:
| The only savings grace with these gravity systems is that they
| could last 100 years. Gravity is a very poor of storing energy.
| Height is limited by practicality. Reusing old mine shafts is
| just a code word for unaffordable. You need to increase the
| amount of mass that you move around, therefore your system
| should be infinitely scalable. By limiting yourself to
| mineshafts you have reduced the scalability option and the
| entire project becomes a scam.
| billytetrud wrote:
| Car batteries don't last decades. Multiply that $100 by 5 years
| and you can see how the price racks up
| kurthr wrote:
| What you have described would last for 1000 days used to even
| out daily (solar) power demand/supply. So for a 25yr capability
| it would cost 8x more? I would hope not, and I think you could
| get 3000 cycles by restricting temperature and
| charge/discharge, but that still requires 2.5-3x higher cost
| and puts this solution as very competitive with current battery
| solutions.
| choeger wrote:
| The cost was given purely in terms of MWh.
| cheschire wrote:
| I wish that cost basis wasn't the only consideration when
| evaluating energy storage, but we're so accustomed to money
| being the great equalizer that things without a financial cost
| associated are often overlooked.
|
| What is the $/MWh cost associated with mining for, recycling,
| and disposing of battery components? What about the third order
| effects of centralizing control over the fuel source within
| only a handful of countries[0]? What's the $/MWh of the
| political shifts?
|
| I can't safely make assumptions about why you personally
| stopped reading after cost came up, but it seems to be a common
| reaction at this point. "Show me the money!" tends to end most
| conversations about energy these days.
|
| 0: https://unctad.org/news/demand-raw-materials-electric-car-
| ba...
| darawk wrote:
| Not to disagree with your underlying point, but I think it
| might be more constructive to frame the problem as a failure
| to internalize the costs, rather than a focus on money.
| Ultimately we do need a fungible way to compare solutions,
| and money is the simplest way to do that. We just need to
| figure out how to effectively internalize those externalities
| to the price.
| wizzwizz4 wrote:
| Cost functions have an implied ethical system behind them.
| Using money is just waving your hands over it and going
| "well, money is _objective_ , so we don't need a value
| system" - but there's still a value system there. It's like
| "machine learning" in that regard; there's no magic.
| darawk wrote:
| Money is just a fungible unit of comparison for types of
| value, nothing more.
| Qwertious wrote:
| In that case, gas plants are the best peaker option in
| most places as in most place CO2 and methane emissions
| cost $0.
| axiolite wrote:
| > What is the $/MWh cost associated with mining for,
| recycling, and disposing of battery components?
|
| A fraction of the cost of the batteries, naturally.
|
| > What about the third order effects of centralizing control
| over the fuel source within only a handful of countries[0]?
|
| The lead in car batteries is one of the most recycled
| materials on the plant. Your link is talking about lithium,
| not lead. Lithium-ion batteries only make sense in portable
| applications like cell phones and electric vehicles where
| weight is a major consideration. In stationary applications,
| heavier batteries like lead-acid are infinitely more
| practical.
| f6v wrote:
| > What is the $/MWh cost associated with mining for,
| recycling, and disposing of battery components?
|
| A chemical battery is rather compact, imagine how much stuff
| you need to build a gravitational mega-structure.
| stavros_ wrote:
| I agree.
|
| There's so much bullshit in mainstream energy analysis;
| there's too much incentive. Energy is central to civilization
| - what we use, where and how we get it, how we use it, how
| much of it there is and when we can use it - change any of
| those variables, change the shape of the entire civilization.
|
| Yet the conversation around energy technologies is entirely
| dominated by dollar cost. This obfuscates so much, and lends
| a false equivalence to pricing/market/financial mechanisms -
| it implies that if something can be sold cheaply (low price)
| then it can be produced/extracted cheaply (low cost).
|
| We are quite capable of, and actively involved in, stealing
| from our futures (high cost) in order to achieve low prices
| in the present. The economic externalities of our energy
| usage don't go away - by definition, that which is finite and
| we use now to do this, cannot be used later to do that.
|
| That energy we'll one day need to feed ourselves, and heat
| our homes, and supply our medicines and materials? We're
| using it, right now, to make a shitload of disposable, toxic,
| plastic shit. Junk nobody needs that we'll convince them they
| want anyway.
|
| And why are we doing this mad, insane, thing? Because we're
| convinced it doesn't matter, we're convinced the price of
| energy will always be low. We're convinced we're not the ones
| paying the costs.
|
| Apologies for going full doomer on y'all.
| https://pics.onsizzle.com/oh-i-made-myself-sad-me-
| irl-242092...
| danans wrote:
| > That energy we'll one day need to feed ourselves, and
| heat our homes, and supply our medicines and materials?
| We're using it, right now, to make a shitload of
| disposable, toxic, plastic shit.
|
| We should limit it's use to making medicines and materials
| instead of burning it to heat our homes and propel our
| cars.
|
| Not only does the latter consume a lot more fossil fuels,
| it does so by dumping a lot more CO2 into the atmosphere.
| Plastics consume 14% of global petroleum production today
| [1].
|
| We could ban all the "disposable, toxic plastic shit"
| tomorrow (and I agree that we should find ways to create a
| less disposable culture) and we would still have a huge CO2
| problem caused by fossil fuel powered space heating,
| transportation and electricity production.
|
| 1. https://e360.yale.edu/features/the-plastics-pipeline-a-
| surge...
| imtringued wrote:
| The problem with batteries is that there are a bunch of grid
| storage chemistries using abundant elements that can scale to
| 1 GWh but there is almost no demand for grid storage only
| chemistries so lithium wins by default because it piggybacks
| of other developments.
| inglor_cz wrote:
| This could give a new purpose for abandoned mines all around the
| world. The shafts already exist and are no longer in use, they
| would only need some repairs.
|
| I grew up in one such city, there were "covered holes"
| everywhere.
| inasio wrote:
| Gravity and electromagnetic forces are somewhat similar, they
| both have infinite range, decay as 1/r, one key difference is
| that the electromagnetic force is 10^36 stronger than gravity
| [0]. Just for that reason I'm always immediately skeptical of
| projects of this type.
|
| [0] https://en.wikipedia.org/wiki/Fundamental_interaction
| labawi wrote:
| On Earth, gravity has a bonus of a free massive side plate. As
| a battery, it might work better on Jupiter and unusable in free
| space, but it still stores orders of magnitude more energy than
| we use, in abundant cheap materials. I liked the trains-on-
| hills project - seems easy enough to build in large quantities
| and stores reasonable amounts of energy.
|
| With electromagnetic, we are barely capable of scraping a bit
| of energy from the surface without the device self-destructing.
| Even in superconductors, only a fraction of electrons whizzes
| around and even high-energy plasma is a mixture of both
| charges.
| flal_ wrote:
| Yet, gravity is strong enough to initiate nuclear fusion at the
| core of stars, or create black holes... That 10^36 argument is
| non sensical to me.
| tryonenow wrote:
| It's about energy density. Generally you can fit many orders
| of magnitude more energy in the same physical space when
| storing energy electromagnetically. The comparison implies
| some assumptions but the point stands. It's space
| inefficient.
| andijcr wrote:
| it is strong enough at the scale of a star, on earth my foot
| electromagnetic repulsion against the floor is enough to
| counteract all of the planet pull
| imtringued wrote:
| Are you suggesting we should build a bigger planet?
| f6v wrote:
| We should have been smaller people with fewer needs.
| sscarduzio wrote:
| Would you say a magnetostatic (rather than gravitational)
| potential energy storage offer better performance?
| runeks wrote:
| Here's an idea: what if -- instead of digging a deep hole into
| the ground -- we use the tower of a wind turbine as the vertical
| space in which the weight is raised/lowered?
|
| A wind turbine is already equipped with a generator, so it'd be a
| matter of building some sort of "switch" which would make it
| either: (a) generate electricity using the turbine, as per usual;
| (b) raise the weight using the turbine, thus not producing
| electricity; (c) generate electricity by connecting the weight to
| the rotor/generator, while lowering the weight.
| masklinn wrote:
| > Here's an idea: what if -- instead of digging a deep hole
| into the ground -- we use the tower of a wind turbine as the
| vertical space in which the weight is raised/lowered?
|
| First, there's not really any room in there, wind towers are
| built for the job, we don't add twice the amount of steel and
| an elevator shaft for funsies.
|
| Second, even if there were some room it would be
| inconsequential, you need a _lot_ of crap very high up to get
| significant amount of energy.
|
| As demo, let us take the largest turbine available right now
| and lift _the entire thing_ up and down its tower.
|
| The Haliade-X has a hub height of 150m, a 600t nacelle, and
| 165t blades. In normal operations it's rated for 14MWe.
|
| 765t at 150m is 250kWh. You can get electric buses with larger
| battery packs than that. For reference, US households use about
| 29kWh/day.
|
| That's the issue with gravity: it's really not that strong, so
| to store significant amounts of energy you need either
| ridiculous amounts of weight (hence dams and pumped hydro which
| can manage unfathomable weights), or extreme height difference
| (hence... still dams, pumped hydro a bit less so I think).
|
| As a point of comparison, Bath County (the largest pumped-
| storage station in the world) has a hydraulic head of 270~385m
| and the upper reservoir stores 44 _million tons_ of water.
|
| Now taking in account that you can't really empty the entire
| thing, that it's not perfectly efficient, etc... Bath has a
| storage capacity of "only" 24GWh, it's not actually moving 44
| million tons up and down 400m.
| thirdlamp wrote:
| What if we used load bearing batteries as part of the tower
| structure?
| Scoundreller wrote:
| I was thinking what if we used buildings built on jacks as
| our source of mass. Big one are largely built on pilings
| anyway, and even small ones on softer ground.
|
| Going to be a lot of flexing though.
|
| Nice thing is that some of the "inefficient" heat may be
| usable on-site: and you may get compressed air as an output
| that could be usable directly.
| masklinn wrote:
| > I was thinking what if we used buildings built on jacks
| as our source of mass.
|
| Then you've got no height. Plus buildings are not _dense_
| so it 's a pain in the ass, and when (not if) the jacks
| fail you're out a building.
| jacobolus wrote:
| It's amusing to think of whole houses getting jacked 100
| ft into the air on giant stilts during the middle of the
| day when solar panels are operating, then slowly dropping
| to release the stored energy in the evening/morning.
| wott wrote:
| :-) Perfect for quarantine.
| yongjik wrote:
| I don't know how much a typical house weighs, but
| assuming 100t, raising it by 30m will give you potential
| energy of ... 8.2 kWh, or about $1.6 in today's
| electricity rate.
|
| Gravity is weak.
| meepmorp wrote:
| Turbine fires would turn into something really special.
| billytetrud wrote:
| What about using batteries as the weight to lift?
| masklinn wrote:
| You risk damaging the batteries and you make maintenance a
| pain in the ass. If you've got that amount of batteries,
| just put them on the ground the normal way.
| f6v wrote:
| > That's the issue with gravity: it's really not that strong
|
| The weakest of all forces, isn't it?
| mbreese wrote:
| Does that matter though? If it is weak to extract energy
| with gravity, then it should also be weak to "charge" the
| system against gravity. The weakness may push these systems
| to less "instantaneous" loads, but I don't see why it would
| necessarily be bad to use gravity storage (as opposed to
| another mechanical method like pressure).
|
| I'd love for someone to explain more though.
| dahfizz wrote:
| It's just impractical. You only need a 21x21 foot square
| of ground covered in solar panels to generate the same
| amount of electricity this does.
|
| It doesn't make sense to invest so much land, machinery,
| and labor into something that generates and stores so
| little energy
| zestyping wrote:
| Because gravity is so weak, in order to store a
| meaningful amount of energy, the lifted object has to be
| very heavy or very high. Building large tall structures
| is expensive, and we just don't have objects that are
| dense enough to make the system small.
| mbreese wrote:
| Okay, so the question isn't "can you get out what you put
| in", but rather "is the amount of energy you can store
| worthwhile"?
| tatref wrote:
| It depends on the distance
| bluGill wrote:
| We should always hold out for some new discovery that is
| weaker.
| FigmentEngine wrote:
| Design forces are very weak...
|
| btw anyone saying that gravity is weak should try getting
| of this planet...
| dmoy wrote:
| Yes, by many, many, many orders of magnitude.
| thirdlamp wrote:
| This could be something more like a planetary gearbox or a
| differential that can connect 3 systems (e.g. gas engine,
| electric motor, wheels in a hybrid car). But if requirements
| are too different 2 generators may be the better option.
|
| The tower would probably need reinforcements for the additional
| weight, but I have no idea about the magnitude required.
| thehappypm wrote:
| I've always been surprised that there is no product wind
| turbine with a guaranteed power output, that is, a turbine with
| an embedded battery. Sure it would cost much more, but in some
| applications steady power is worth it.
| masklinn wrote:
| > Sure it would cost much more, but in some applications
| steady power is worth it.
|
| It would cost much more and be way more complicated & less
| reliable than... just getting the two separately and using
| battery grid storage on the output of the windfarm.
|
| Even for a backyard turbine it wouldn't make much sense, for
| maintenance reasons you'd want to manage your turbine and
| storage separately, and if, say, you add solar panels, you
| want that to feed into your battery bank as well.
| DavidPeiffer wrote:
| Wind turbines use the tower to take parts to the top for
| maintenance. Regardless, you'd need to dramatically increase
| the wall thickness of the tower along with the foundation for
| the additional load, to the point it probably wouldn't be worth
| it.
|
| Bad math, let's say we can use a lead weight 2 meters in
| diameter, 3 meters tall (107,000 kg) with 120 meters of drop
| available.
|
| All of that gets us 35 kWh, or 0.035 megawatt hours of energy.
| Compared to a 2 MW turbine, it's a negligably small amount of
| stored energy, even if we scaled every dimension up by a factor
| of 2 (getting us to 0.28 MWh).
| patall wrote:
| Funny how people tell you that that this does not make any
| sense at all, but here it is:
| http://www.naturspeicher.de/en/naturstromspeicher.php
|
| (Yes, I am aware that it is not storing the water at the top :)
| patall wrote:
| Furthermore, there exists the opposite concept of replacing
| water with air deep in the sea: https://www.iee.fraunhofer.de
| /en/research_projects/search/20...
| dumbfoundded wrote:
| I think it'd be more efficient to use a massive flywheel for a
| wind turbine. That flywheel could then be the battery and each
| turbine would come with their own.
| sollewitt wrote:
| We already have pumped hydroelectric storage, it's used as a load
| balancer on some national grids.
| _rpd wrote:
| pumped hydro is great, but requires uninhabited geography of a
| type that is in short supply in many nations.
| drran wrote:
| We can use underwater bubbles to pump air into, or displace
| water in lakes/sea with something with large volume and very
| lightweight.
| mbar84 wrote:
| Since scale and locality is such an issue here, I wonder if there
| are any concepts for integrating such a system in new mid-rise
| buildings. Similar to an elevator shaft, but with a weight of
| depleted uranium instead of the passenger car.
|
| You're digging for the foundation anyway, maybe maybe the
| marginal cost to dig a few meters deeper is worth it. You're
| building with a crane anyway, maybe the marginal cost to build a
| steel frame tower on the roof is worth it. It's certainly not a
| mine shaft, but perhaps better than nothing.
| jb775 wrote:
| It's crazy how little we understand about gravity if you think
| about it. It's a perpetual energy source right in front of us,
| but we never really think about it, and can barely offer a basic
| explanation as to what powers it. It even impacts _time_
| itself[1] for christ sake. I think better understanding gravity
| is the solution to all human energy needs. (interesting to note I
| have heard stories of disappeared scientists who made
| advancements in gravity research years back)
|
| [1] http://thescienceexplorer.com/universe/how-gravity-
| changes-t...
| exporectomy wrote:
| You shouldn't repeat unsubstantiated rumors like that. Can you
| even name these disappeared scientists or know anything at all
| that could be used to verify those stories?
| jb775 wrote:
| If you dare to venture, need to follow _deep_ rabbit holes.
| Look into: work of Harold Aspden (and his coworkers &
| previous research partners), plancks equation origins and
| drop offs, dewey larson physics, piesel electric effect
| origin and drop offs, the adams motor, ellen brown, what
| maxwells equation actually determines and where it
| selectively _isn 't_ being used
| bigsparky wrote:
| I think you are getting unwarranted downvotes. If you are
| someone with a dislike of information you can just ignore
| it... downvotes unnecessary.
| thaumasiotes wrote:
| > It even impacts _time_ itself for christ sake.
|
| I was under the impression that this is an effect of force
| generally, nothing to do with gravity in specific.
| function_seven wrote:
| > _It 's a perpetual energy source right in front of us_
|
| It's not. Once something has fallen down, it can't fall down
| again.
|
| To draw energy from the gravitational attraction of 2 bodies,
| you must first separate them. That consumes energy.
|
| On second thought, I suppose tidal energy fills the bill.
| Extracting that energy is really exploiting the Moon's motion,
| using gravity as the "conduit". Not strictly perpetual, but
| essentially so for our needs.
| tshaddox wrote:
| Isn't tidal energy just harnessing some of the existing
| gravitational potential energy of the Moon-Earth system,
| which is roughly similar to any system that harnesses energy
| from a massive object falling due to gravity?
| eraserj wrote:
| But again, slowing tidal currents must be drawing energy
| from somewhere until there is none left.
| Xylakant wrote:
| It basically draws energy from the moon orbiting earth.
| It could theoretically alter that orbit, but given that
| the moon/earth system has a lot of mass, the timescale
| for that to happen is extraordinarily large.
| tshaddox wrote:
| That's exactly what it's doing. It's slowing down Earth's
| rotation and speeding up the Moon's orbit (i.e. moving
| the Moon further from the Earth).
| jb775 wrote:
| But that "something" keeps being pulled down until it is
| stopped/blocked by something (e.g. the ground). Gravity _is_
| perpetual relative to the source of the gravity. It 's just
| that our surroundings change and give the illusion of gravity
| changing...i.e. we don't "run low" on gravity
|
| I don't think Maxwell's Demon is 100% solved.
|
| Tidal energy could play into it, some underwater tides deep
| in the ocean are insanely strong.
| t0mas88 wrote:
| You're confusing force with work. Gravity is a perpetual
| force, but a force doesn't generate energy.
|
| To generate power you need gravity to move something
| downwards, releasing the potential energy. And when that
| thing hits the bottom of the shaft you've used up all the
| potential every that was stored in it.
| nl wrote:
| > It's crazy how little we understand about gravity if you
| think about it.
|
| We understand most things about it
|
| > It's a perpetual energy source right in front of us,
|
| No it's not. It's a good way to store energy but in no way is a
| source.
|
| > and can barely offer a basic explanation as to what powers it
|
| It's not something that has power. It's a consequence of
| entropy.
|
| > It even impacts time itself
|
| You sound surprised by this? Given relativity it would be more
| surprising if it didn't.
| jb775 wrote:
| IMO you grossly overestimate the amount humans know about
| things.
|
| Science is basically a stream of updated realizations that
| the previous "known" things were actually wrong.
| rcxdude wrote:
| and you vastly underestimate it
| kingsuper20 wrote:
| I underestimate it and overestimate it.
|
| Excuse me, I'm off to build a battery out of a bank of
| leaf springs.
| f6v wrote:
| > We understand most things about it
|
| In a classical mechanics sense - yes. But the waves were
| detected just couple years ago.
| Gauge_Irrahphe wrote:
| The technology isn't incredibly immature. On the contrary, it's
| understood to the tiniest detail. If it doesn't work, it won't
| work.
| PurpleFoxy wrote:
| Isn't pumped hydro a realistic solution? There should be a
| massive amount of energy in moving all that water up a
| mountain.
| ascorbic wrote:
| Pumped hydro's main drawback is that it has very specific
| requirements in terms of geography.
| walshemj wrote:
| Limited places it will work and you cant just flood valleys
| and displace the residents anymore in the west.
| bluescrn wrote:
| Pumped storage hydro makes far more sense. Which is why it's
| already in use.
|
| Maybe the efficiency can be improved upon with a small-scale
| 'gravity battery', but water has massive advantages when it
| comes to scaling it up, as well as being able to combine it
| with traditional hydro, where nature moves much of the water
| for you.
| RosanaAnaDana wrote:
| Plenty of issues with hydro, but in the grand scheme of
| things, it does seem like by far the most accessible,
| actionable, least polluting option.
|
| I've often wondered what scale of a system would be
| required to power a fully off the grid home at say 30kwh/
| day, for say, 6 days? I'm imagining a tank based system
| with two tanks where the fluid is effectively just
| exchanged (so one doesn't have to account for the
| environmental impacts of a dam or for losses due to
| evaporation)..
|
| After some googling: https://www.edie.net/library/Using-
| pumps-as-turbines-to-gene...
| rakoo wrote:
| 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):
|
| > 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 wrote:
| 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 wrote:
| 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%2
| Fs%...
| Retric wrote:
| 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.
| audunw wrote:
| 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 wrote:
| 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.
| bjourne wrote:
| Homes in the UK are poorly insulated, likely due to a
| previous over-reliance on fossil fuels.
| https://www.theguardian.com/environment/damian-carrington-
| bl... Better insulation and switching to district heating
| where applicable could yield massive savings.
| amluto wrote:
| District heating still needs heat to come from somewhere.
| Admittedly, low grade heat like is used for heating can
| be stored for days in the form of hot water in insulated
| tanks.
| cogman10 wrote:
| 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.
| canadianfella wrote:
| People freezing to death isn't an edge case.
| f6v wrote:
| > This seems like a "running before we can walk"
| statement.
|
| Europe tries to be at a forefront of green energy. No
| sun/wind is a real issue there, not just an edge case.
| silon42 wrote:
| Yup, where I live there can be 3 months of fog/clouds...
| meaning minimal wind / sun.
| oauea wrote:
| Global warming will resolve that issue soon enough.
| cogman10 wrote:
| Right, and my point is that they aren't going to
| decommission all backup power until they are at the point
| where sun/wind/storage can actually be relied on for more
| than just the good days.
|
| We have a long trip to get there, so why worry about a
| once in 3/5 year event? We wouldn't go a year without
| fossil fuels and say "Ok, that was it! Demolish all the
| plants right now!"
| Qwertious wrote:
| Arguably, if a gas plant hasn't run for a year then it'll
| go bankrupt and shut down pretty soon.
| Dylan16807 wrote:
| In a system where it's a backup, it shouldn't be both
| independently owned and have revenue tied only to use.
| ms4720 wrote:
| A cold snap like that can happen every 3-5 years, think
| really cold February. If you don't have the capacity to
| handle it people will die and lots of things will break.
| It is not an edgcase
| martinald wrote:
| It's actually worse than that, there are many days in
| winter in the UK with high demand and virtually no
| solar/wind output. But obviously a really cold snap would
| be even worse (and as you said isn't an edge case - even
| if it is look at the damage that happened in Texas when
| it wasn't accounted for)
| raverbashing wrote:
| Agree. See Texas for an example.
| cogman10 wrote:
| It is when we aren't running 1 year on pure renewables.
| Let's worry about events that happen every 3 to 5 years
| when we've got 1 year of renewable only figured out.
|
| It will take years before this is potentially a problem
| and by that time we'll likely have gone through a few
| cold snaps.
| ericd wrote:
| Wrt cold snaps being a big problem, it seems like we could
| just massively insulate dwelling and improve our energy use
| auditing, if it became necessary? Vacuum insulation panels
| are a bit pricey, but they're crazy insulative for the
| thickness. If we're willing to deal with thicker walls,
| there are a variety of other options that are downright
| cheap (shredded newspaper, for example).
|
| We've been designing around super cheap on-demand energy
| for a while now, but we did manage before that.
| ianai wrote:
| I'd just build the generation out to that maximal use case.
| During the off peak times power a desalination, hydrogen,
| or other energy intensive plant.
| martinald wrote:
| The problem is the UK sees maybe 1-2GW of renewable
| generation sometimes in winter while demand is about
| 50GW. So you'd have to overbuild 25x to cope with these
| days.
|
| Keep in mind the UK already has about 30GW of solar and
| wind potential nameplate capacity. Your suggestion would
| result in a requirement of 700GW of solar and wind to be
| installed. On windy and sunny days would result in
| probably 350GW of generation, at least 300GW more than we
| need.
| eloff wrote:
| All the while the north sea with it's wind is right there,
| and the Sahara with it's sun nearby too.
|
| Some investment in long distance power transmission would
| go a long way towards smoothing out the grid.
| im3w1l wrote:
| Importing energy from Sahara comes with serious
| geopolitical issues. Do you really want to commit to
| peacekeeping in a huge area of Africa? Keep in mind that
| oil can be stockpiled much more easily than electricity,
| stockpiles that let you weather small storms. Importing
| electricity means being on top of every hint of a blip.
| eloff wrote:
| There are many countries in North Africa of varying
| levels of stability and many locations for potential
| underwater transmission lines.
|
| If Israel can build natural gas pipelines to Italy, I
| think we can handle a subsea electrical cable.
|
| You don't want all your eggs in one basket, but this
| seems like a poor excuse for having zero eggs at all.
| after_care wrote:
| Long distance power transmission is a significant
| political and military liability, not to mention a
| fantastic terrorist target.
|
| We cannot guarantee that the UK will be at peace with
| every county between them and the Sahara forever. Hosting
| the power line would grant significant political or
| military leverage.
| eloff wrote:
| You don't want a single point of failure. Having multiple
| lines across a geographic space is the way to go.
|
| It's a big upfront investment, but it could be much
| cheaper than storage at scale.
|
| I think ultimately you want power transmission stretching
| from the UK to Japan so as the sun moves the power
| generation continues.
|
| I imagine it will happen one day, because it would seem
| to make so much sense, but this is something governments
| could make happen a lot sooner if they put their mind to
| it.
| VBprogrammer wrote:
| > It's a common misconception that energy storage needs to
| handle all the power needs of an area for a significant time.
|
| You are only looking one half of the problem. Wind power in
| the UK has a power factor of about 35%. What that means is to
| meet the average demand from the UK electricity grid we'd
| need not install 3 times as much Wind Power as the demand.
| This is borne out in the current figures, we have some 25GW
| installed wind power for an average of about 6GW supplied. If
| we have enough renewables to meet the demand on average, a
| windy day across the UK is going to result in a glut of
| power.
|
| If we don't have ways of storing that modestly efficiently
| then our only choice will be to take turbines out of service,
| increasing the overall cost.
| kstenerud wrote:
| Actually, almost none of our trash is recyclable (despite
| what you've heard). Plastic is particularly bad, and it's
| only now, with China banning import of "recyclable"
| materials, that we're finally seeing just how much of a farce
| it is.
|
| Burying it is a form of CO2 sequestration. Burning it just
| releases it into the atmosphere.
| kortex wrote:
| But it's already out of the ground. I'd rather burn 1T CO2
| worth of plastic trash made from oil and prevent 1T CO2
| worth of coal or heavy oil being extracted and burnt. Not
| that it's 1-to-1, point is burying plastic is probably less
| net carbon vs burning.
| kstenerud wrote:
| Sure, provided that the burn efficiency is high enough.
| FooHentai wrote:
| 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.
| berkes wrote:
| I can imagine this tech all packed up in a standard 40ft
| shipping container and dropped on premise.
|
| This would be rather simple tech, that can supplement solar
| and wind on your farm, lodge, campsite or island. Another
| piece in the puzzle for smaller scale independence.
|
| Not to replace metropolis-scale energy demands, as
| grandparent implies, but to smooth out fluctuations on
| hourly, household scale.
| marcosdumay wrote:
| I imagine chemical batteries would be easier to ship and
| install, and require less maintenance. I really can't
| imagine any mechanical system that involves plugging and
| unplugging a load (or anything more complex than that) to
| be useful at small scales.
| arbitrage wrote:
| I think you are drastically underestimating the density of
| bulk metal.
|
| Trucks, while impressive as an illustration, are not quite
| dense enough to be practical or applicable in an energy-
| storage scenario.
| tekstar wrote:
| This exists at least in one place, with trains on a hill in
| Nevada.
|
| https://aresnorthamerica.com
|
| "ADVANCED RAIL ENERGY STORAGE"
| jodrellblank wrote:
| > " _a 5m tall tower bearing 73 tonnes to store 1 kilowatt
| hour_ "
|
| By comparison, a pint of gasoline stores about 4 kilowatt
| hours.
| BenjiWiebe wrote:
| Too bad we can't just synthesize gasoline with electricity
| at a decent efficiency.
| chris_engel wrote:
| 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 wrote:
| > 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 wrote:
| You can make that one truck descend five times faster,
| giving the same output.
| rakoo wrote:
| The total available energy in such a system is defined by
| m * g * z
|
| where m is the mass and z is the elevation difference. It
| doesn't depend on the speed at which it goes down
| randallsquared wrote:
| "...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 wrote:
| 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 wrote:
| 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.
| ephbit wrote:
| Sounds like you're mostly unaware of the issue that trying to
| compensate region, country and sometimes even continent wide
| lows/peaks would require many gigawatts of transmission
| capacity in the form of cables in arbitrary directions. Even
| if the European grid is well interconnected it's painfully
| far from handling such situations.
|
| And that is not even accounting for the fact that right now
| only a small proportion of total energy use is transmitted
| electrically, which means that with future energy generation
| becoming greener being strongly tied to having more
| solar/wind (which is also electrical), there will anyway have
| to be a massive increase in grid capacity.
|
| > Currently, clean energy is the dominant form of energy in
| many countries already (e.g. Europe, China, parts of the US)
|
| Just not true. Yes, some countries are (Iceland is one of the
| few) but most European countries are far from what you claim.
| Maybe you meant energy transmitted as electricity instead of
| all energy.
|
| See https://ec.europa.eu/eurostat/statistics-
| explained/index.php...
|
| Quote: > In 2019, renewable energy represented 19.7 % of
| energy consumed in the EU-27, only 0.3 % short of the 2020
| target of 20 %.
|
| > The share of energy from renewable sources used in
| transport activities in the EU-27 reached 8.9 % in 2019.
| berkes wrote:
| Thanks for the clear explanation.
|
| I'd like to add that with the rapid electrification of car-
| and soon truck and ships- fleets, we are already rolling out
| that giant battery-pack, as we speak.
| fighterpilot wrote:
| > Somebody will jump to the wrong conclusion that we need to
| provide massive amounts of battery storage
|
| +1 for the post, but I don't see this that much.
|
| Whenever I see the debate come up, it's when someone is
| directly comparing the cost of solar to nuclear/natgas
| _without_ factoring in the additional cost of batteries and
| DC lines, which obviously leads to an invalid (or at least
| incomplete) comparison.
| VLM wrote:
| The cheapest "energy storage" is bandwidth and demand based
| billing.
|
| The required battery storage cost to guarantee my 3 KW
| electric clothes dryer could theoretically operate 24x7 when
| needed after three weeks of cloudy windless weather at
| midnight is staggering. The alternative is demand based
| billing and program my dryer to never accept a KWh that costs
| more than say, seven cents. On a minute by minute basis I
| don't care if my "hour" dryer cycle takes 65 minutes because
| a cloud passed overhead and it slept for five minutes. Its
| also worth considering that "in theory" people who design for
| max theoretical load MUST assume my clothes dryer will run
| for 24 hours a day 7 days a week, when in practice I have
| never done more than five hour long loads of laundry in a
| row, and that was after traveling out of country for two
| weeks (after zero electrical demand for 14 days)
|
| Even data centers can do stuff like vmware vmotion running
| virtual hosts off a cloudy cloud data center to a sunny cloud
| data center with no user interruption.
|
| The idea that the wall outlet is an infinite source of energy
| is going away, or if its demanded for a hospital operating
| room or nuclear power plant or something, those KWh are going
| to cost like $5 or something similar and that's just how its
| going to be. Its not going to be that much suffering; right
| now my multi KW airconditioner instantly starts up when the
| thermostat says go, and in a decade maybe the electric
| company contract says it's guaranteed to start within the
| next ten minutes 99% of the time, and that sounds like a nice
| deal if it cuts my bill in half and eliminates CO2 output.
| ephbit wrote:
| Problem is: how are you going to convince great numbers of
| people to alter their daily routine that might also be
| quite synchronized across a country's population?
|
| Like tea time in the UK where apparently millions of people
| turn on their kettles (2 kilowatts each) in synchrony to
| get some hot water.
|
| What if they also like to cook something with their stove
| (another 2 KW) to get a nice dinner, around the same time?
| kjrose wrote:
| 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.
| ClumsyPilot wrote:
| 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.
| hutzlibu wrote:
| "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_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/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 wrote:
| 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-
| esto...
| marcosdumay wrote:
| You mean they are selling large scale storage and managed
| to turn a profit?
|
| That sounds great. They are first, but as we deploy more
| renewables, we'll need much more cases like this.
| jdmichal wrote:
| > Price goes up slightly.
|
| How much of a swing in pricing are we talking about here?
| Because that storage mechanism is maybe 80% efficient. So
| the price swing would have to be at least that big to break
| even. And in that case, if they are helping to smooth out
| swings in demand that are that large... Sounds like they're
| providing a valuable service.
|
| https://en.wikipedia.org/wiki/Pumped-
| storage_hydroelectricit...
|
| EDIT: Keep in mind that electricity is entirely fungible.
| This is no different than the Swiss turning on a power
| plant when prices are higher. Except it would probably be
| too expensive to have a power plant just sitting there idle
| when the price isn't "high enough".
| PeterisP wrote:
| > it would probably be too expensive to have a power
| plant just sitting there idle when the price isn't "high
| enough"
|
| This is exactly what is done, and pretty much inevitably
| must be done - grids need spare capacity that can be
| relied on to spin up rapidly when demanded, that's
| usually done by gas turbine plants.
| hutzlibu wrote:
| Maybe I do not understand it fully (ne pas parle de
| francais), but where do they game the system?
|
| You buy cheap when you have storage and sell expensive when
| demand goes up. Pretty much how the market should work?
|
| This way there is incentive to balance it out (by creating
| storage) - and in this case stabilize the grid.
|
| When the grid would become more flexible, so even
| homeowners can do this with their solar panels and big
| batteries - then this should be net gain for everyone, no?
|
| Unless gaming it, with big money, destabilises it. So some
| safeguards probably should remain.
| bjourne wrote:
| It's not gaming the system, it is arbitrage. However, it
| is pretty terrible for producers unable to exploit price
| swings. E.g a nuclear plant produces electricity at a
| fixed cost and may sell it at a loss when the price is
| low, but recoups the losses when the price is high. Since
| arbitrage smooth out the price peaks, it damages
| nuclear's profitability. One could say that's too bad for
| nuclear, others (nuclear lobbyists) say that regulation
| is needed to prevent electricity arbitrage.
| xboxnolifes wrote:
| If the fixed price nuclear uses is too low to be
| profitable, then it must be raised.
| aquark wrote:
| If nuclear can offer sustained cheaper than average
| generation then the market would allow a long term fixed
| price contract -- they shouldn't need to sell their full
| output at spot rates. Consumers that want predictability
| could buy on these contracts.
| throwaway189262 wrote:
| > 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
| waynecochran wrote:
| The problem with wind is storing the energy. I live in the
| Pacific NW and when you drive through the Columbia Gorge you
| see hundreds of these windmills. I have have visited the Wild
| Horse Wind facilities and they store energy using batteries
| -- terrible. The dams below can back up water, but wind blows
| whenever is may. The dams also provide safety from flood, a
| waterway, recreation, ... windmills just pollute the sky,
| kill song birds, and can not produce energy on demand nor
| store it effectively. Talk to engineers for Bonneville and
| they mock the windmills.
|
| If they are going to use wind why not pump water up from the
| Columbia River up to the top of the surrounding hills? Use
| the potential energy at least.
| jasonwatkinspdx wrote:
| You misunderstand the impact of the dams on the ecosystem.
| Salmon are hanging by a thread in the Columbia, and only a
| very aggressive hatchery program has kept them from
| collapse.
|
| Essentially all buildable sites have already been built,
| and there's a growing awareness some existing damns need to
| come down. The Gorge is not some great untapped resource
| for pumped storage that people were too distracted by wind
| power to discover.
| kleiba wrote:
| In places with cold winters, it is often forbidden to
| approach wind turbines because of the risk of falling ice.
| throwaway189262 wrote:
| The turbines are all in fields, useless scrubland, cattle
| ranches, and the ocean. Humans don't hang out in these
| places anyways
| lai-yin wrote:
| Land AND resource use. Just because a single wind turbine
| takes up a small patch of land doesn't mean it's not
| extremely resource intensive. Case in point: https://twitter.
| com/extrachelle/status/986599367049179136?s=...
| throwaway189262 wrote:
| So? How much resources does it take to mine thousands of
| tons of coal a day, or billions of BTU of natural gas?
|
| With solar and wind, you put it up and you're done. No more
| inputs. It chills in the field.
|
| With coal and gas you're feeding shit tons of material into
| it every day. And you always need more, for the life of the
| plant.
|
| It's bonkers you think the amount of steel and concrete
| that go into a turbine are anywhere close to comparing to
| the raw materials other power sources consume.
|
| Turbines require steel and concrete. So does every other
| building above 5 floors
| michaelbuckbee wrote:
| I was curious about total life cycle CO2 output and found
| an study in Nature.
|
| It looks like:
|
| - Hydropower + Bioenergy -> 100 gCO2eq kWh-1
|
| - Traditional fossil fuels -> 78-110 gCO2eq kWh-1
|
| - Nuclear, Wind and Solar -> 3.5-12 gCO2eq kWh-1
|
| https://www.nature.com/articles/s41560-017-0032-9
| tarsinge wrote:
| Resources are also construction material, that's where wind
| get its bad ratio.
| throwaway189262 wrote:
| 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 wrote:
| Sorry but you don't get to discount wind turbines'
| ecological damage just because no more mining is involved
| post-construction.
| throwaway189262 wrote:
| 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?
| wizzwizz4 wrote:
| > _Unlike wind, it uses no space._
|
| Unlike solar?
| throwaway189262 wrote:
| Lol yeah
| yunohn wrote:
| Please link to a source/calculation where a wind turbine
| uses more resources than a coal plant to build. I mean,
| you can even do napkin math and see that there's no way
| multiple buildings and vast mining infrastructure take
| less material than a turbine farm.
| rakoo wrote:
| If you want to take a coal plant, you have to compare it
| with something that's comparable.
|
| A coal plant is a 1000MW machinery. A wind turbine is in
| the order of 10MW. Also, turbines have a very low
| capacity factor so you have to double them to guarantee
| their output and combine them with storage. So it's 1
| coal plant vs 200 turbines at the very least.
| fighterpilot wrote:
| > 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.
| prof-dr-ir wrote:
| > 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_...
|
| Edit: care to explain the downvotes?
| [deleted]
| guerby wrote:
| "But Schmidt's calculation of the lifetime cost per megawatt-hour
| for lithium-ion batteries, $367, is more than twice as much"
|
| This is ridiculous.
|
| I'm charging right now my EV from a 14 kWh 16S LFP pack which
| costed me $1400 tax paid and delivered.
|
| LFP properly managed will do minimum 3000 cycles, so that's 42
| MWh for $1400 which gives $34 per MWh out of the battery.
|
| Note: 5kW 48V inverter cost $500.
| tralarpa wrote:
| > 14 kWh 16S LFP pack which costed me $1400
|
| Wow, that's amazing. But why are home battery systems still so
| expensive? I see system prices in the range of $700 to $1200
| per kWh. Even on aliexpress, it's minimum $550/kWh. Is the
| inverter so expensive?
| guerby wrote:
| Niche market so high markup to pay for the maker margin and
| the seller margin.
|
| I found the vendor by following:
|
| https://diysolarforum.com/
|
| https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q
|
| DIY Solar Power with Will Prowse
| audunw wrote:
| Battery does not just degrade with power cycles. It also
| degrades with time. Not sure about the numbers for LFP, but
| it's something you need to take into account. For some areas
| time may be a more important factor than cycles. If it does a
| full cycle every 3 days or so, it'd take roughly 25 years to
| reach the cycle limit.
|
| It's also important to remember that capacity will be reduced
| gradually. After 25 years both the energy storage capacity and
| power output of batteries will be seriously reduced, while the
| gravity-based system will most likely still be at full
| capacity.
|
| I still think the estimate may be too high. Especially taking
| into account that these systems will compete in the future at a
| time where battery costs will be lower. But it might still make
| sense to build gravity based systems for a while to make sure
| all the lithium we mine goes to batteries for transportation.
| BenjiWiebe wrote:
| In 25 years, a mechanical structure with tons of force on
| moving parts is going to be needing some maintenance, too.
| ardit33 wrote:
| It is over 25 years, I don't think your battery will last 25
| year. You probably have to replace it 3-4 times over that
| period of time. A mechanical system can last that much, even
| more, with minimal maintenance.
| kragen wrote:
| You may have accidentally responded to the wrong comment. The
| comment to which your response has been attached already
| takes into account the limited cycle life of batteries.
| guerby wrote:
| And I didn't take into account that a third of the paid
| price was shipping, and that battery prices are dropping
| like a rock:
|
| https://pubs.rsc.org/en/content/articlelanding/2021/EE/D0EE
| 0...
|
| Re-examining rates of lithium-ion battery technology
| improvement and cost decline
| goldenkey wrote:
| And these systems are way larger, more dangerous (wind) and not
| as efficient as magnetic bearing flywheels.
|
| https://en.wikipedia.org/wiki/Flywheel_energy_storage
| frankus wrote:
| One of the downsides (or maybe double-edged swords) of kinetic
| energy storage is that it's relatively easy to accidentally get
| all of the energy out at once.
|
| A stick of butter and an 2-tonne truck at 216 km/h both
| "contain" about 1 kilowatt-hour of energy.
|
| The butter could maybe burn your house down but the truck could
| easily kill a couple of dozen unprotected humans in a fraction
| of a second.
| goldenkey wrote:
| Flywheels made for energy storage are vacuum chambered and
| surrounded by very very dense material, made to withstand any
| accidents. So it isn't an issue.
| xyzzyz wrote:
| Yeah, if you do the math, it turns out that you need
| impractically large weights lifted to unreasonable height.
| Like, suppose you're lifting 100 ton weight 100 meters high.
| That's a rather large and heavyweight system. How much energy
| you can store this way? Less than $5 worth of electricity, as
| it turn out.
|
| This is basically the same as pumped water storage, but instead
| of immense amount of water you can pump between very large
| reservoirs, you're limited to one solid weight that's too light
| to store nontrivial amount of energy, but heavy enough to be
| significant problem from engineering perspective. It just
| doesn't make practical sense.
| labawi wrote:
| That's why you should use trains, which can safely go a few
| km high in good terrain.
| ecpottinger wrote:
| Great, now calculate how much a flywheel system that stores
| that much energy will cost vs cheap concrete blocks. Magnetic
| bearings and large vacuum chambers do not come cheap.
| tchvil wrote:
| How about to retrofit wind turbines? They are tall, strong,
| and empty inside.
| masklinn wrote:
| > How about to retrofit wind turbines? They are tall,
| strong, and empty inside.
|
| It's still basically piss-stakes: the largest wind turbine
| right now (14MWe Haliade-X) has 765t sitting on top of a
| 150m tower, so let's say you keep the 150m tower, rejigger
| it so it can move a 765t weight up and down the shaft
| without crumpling, and add your weight (a lead weight 4m in
| diameter and 5.4m tall), how much energy does that store?
|
| 250kWh, 2.5 teslas, or a medium-large electric bus battery.
|
| And it's not like you can add that to a working turbine:
| the tower was set up for 765t not 1500, and you need space
| for the crane.
| Mulpze15 wrote:
| Yes, the math does not look good. I remember dreaming about a
| house that could go up and down like this. Then I went to buy
| a AAA battery... same. That said, if they can manage to find
| that 1km shaft in an old mine like they hope, and put some
| crazy amount of weight and make it work, that would be
| impressive and cool.
| ObscureScience wrote:
| Too me, pumping water seems like a pretty good solutiuon. If
| you are located on the coast, and can move let's say a
| million tons something like 100-200m up, that's not trivial
| and doesn't seem that impractical.
| [deleted]
| travisjungroth wrote:
| Now I want one. Home powered by solar and a flywheel is so
| retro-future. How does your house get electricity? Oh, power
| from the sun gets this flywheel spinning super fast and then it
| slows down and powers the house all night.
| goldenkey wrote:
| The heavier the flywheel, the less rpm you'll need for your
| storage requirements. Not sure how efficiency factors in. But
| yeah, would be awesome!
| [deleted]
| 3dee wrote:
| Ares is another gravity battery system. They run electric trains
| up a hill to store energy.
|
| But looking at the size of the project, I have a hard time
| believing this is viable.
|
| https://aresnorthamerica.com/
| lebuffon wrote:
| I think this guy is onto something...
|
| Liquid metal batteries will be better than gravity storage IMHO.
|
| https://www.youtube.com/watch?v=NiRrvxjrJ1U
|
| First commercial scale system is going live in 2021 so we shall
| see how it works out.
| xutopia wrote:
| I don't understand how that would be feasible... wouldn't the
| battery need to be kept at a really hot temperature somehow to
| function?
| isoprophlex wrote:
| So, let's look at doing this in a distributed manner: giving
| every household their own gravity battery. A 1 m3 cube of
| concrete weighs 2400 kg; moving this over 6 meters yields (mass *
| gravity acceleration * height) = 140 MJ, = 39 kWh. Lets say 34
| kWh after accounting for energy losses.
|
| A european household uses approx 3500 kwh/year; americans use
| upwards of 10000 kwh/year.
|
| Clearly such a slab of concrete will comfortably allow buffering
| an entire day's worth of power, and then some.
|
| Edit: fuck me I'm dumb. Off by a factor 1000. 39 watthour in that
| cube, not 39 kWh. Ignore everything I said.
| _ph_ wrote:
| An European household rather uses 10-20kWh/day, usually closer
| to 10. The question is, what is cheaper, to build a 6 M tower
| that can lift 2 tons of concrete or a nice Lithium battery pack
| which uses a lot less volume too?
| isoprophlex wrote:
| Considering that i messed up by a factor 1000, a battery pack
| is probably cheaper than a 6 km high tower...
| prof-dr-ir wrote:
| 140 kJ, not MJ [0]. So you'd need a thousand of these cubes for
| 39kWh. But you can also just raise your single cube by 6km.
|
| [0]
| https://www.google.com/search?q=2400+kg+*+10+m+%2F+s%5E2+*+6...
| isoprophlex wrote:
| O wow. Off by only three orders of magnitude. How
| embarrassing, thanks for the correction!
| iandanforth wrote:
| Ok, ok, everyone, I've got it. It's great. As you know, two _meh_
| ideas together make one _galaxy-brain_ idea so here it is.
| Gravity batteries + vertical farming.
|
| This is so amazing I'm just jittering over here. So what are big
| shafts filled with before they are shafts? _Dirt_! What do plants
| need to grow? _Dirt_! So what you do is ... wow this is great ...
| what you do is you take the dirt out, then you make this big
| battery thing a stack of _dirt shelves_ that go up and down and
| while they are going up and down they _also_ grow plants in the
| dirt.
|
| So now you have a big field of these dirt stacks going up and
| down and in the middle you have a big farmers market. Money from
| dirt _two_ ways. God how is this not already a thing.
|
| Problems solved. Done.
| f6v wrote:
| Peak HN, right here.
| timonoko wrote:
| If you pump one cubic meter of air 100 meter deep, the energy
| stored equals a tonweight at 100 meter up. That is 9.81 kJ aka
| 2.7 Wh. This is inifinitely scalable and suits flat places like
| Australia.
|
| One and only minor problem is how we prevent the 2.7 GWh energy
| storage, which is 1E9 m^3 aka one cubic kilometer inflatable
| container, not rupturing or raising up.
|
| But otherwise ingenious nicht wahr?
| accrual wrote:
| Higher materials density = higher energy density of the overall
| system. The more you're lifting (e.g. iron, steel, tungsten) the
| more you can get out in a smaller space. Kind of a cool way to
| increase the energy density.
| toast0 wrote:
| Lead in an appropriate container is probably a good idea.
| Tungsten is denser, but lead is less expensive.
| imtringued wrote:
| Materials density is irrelevant, materials abundance and
| scalability is far more important. The more you spend on dense
| materials, the less money you have left to actually store
| energy.
|
| We use pumped hydro because water is basically free and it is
| infinitely scalable depending on geography. Meanwhile the
| proposed system is limited by the size and existence of
| mineshafts. In other words this is a dead end.
|
| Energy vaults is impractical but it at least tried to solve the
| scalability problem by taking advantage of the fact that the
| energy storage grows quadratically with the length of the crane
| arm. Assuming it is possible to actually build that system in a
| sealed tower to protect it from the elements (wind makes the
| control problem almost impossible). Given a large enough energy
| vaults system there will be a point where its advantages
| massively outweigh its downsides.
|
| Going one step further, you could carve out a large cylinder of
| rock out of the landscape [0]. By using wiresaws you will only
| need to cut the surface area of the cylinder out. At this point
| your material costs are approaching 0. The only challenge is
| sealing the walls of the hole and sealing the walls of the
| cylinder to turn the system into a giant hydraulic cylinder.
| Storage scales with the fourth power of the radius. Considering
| the theoretical performance of a gravity storage system
| anything that is below r^2 scaling is just laughable, which is
| why the mineshaft idea will ultimately fail.
|
| [0] http://eduard-heindl.de/energy-storage/energy-storage-
| system...
| kerbobotat wrote:
| Does it need to expend the energy to winch it up? Would it not be
| simpler to have a set of these weights, and a ramp system to
| deliver them to the top, and use vehicles to unload at the base
| and drive them back to the top to be hooked up again in sequence?
| Surely there would be less energy loss moving it up a ramp than
| fighting gravity in a vertical shaft to winch it directly
| upwards.
| JBorrow wrote:
| No, gravitational potential energy is linearly proportional to
| the height over which you raise the weight.
|
| http://hyperphysics.phy-astr.gsu.edu/hbase/gpot.html
| GuB-42 wrote:
| Not the first time I have heard of gravity batteries, and with
| the exception of dams, they all look unconvincing.
|
| To make a comparison, there is a human-scaled variant of the
| concept in the GravityLight by Deciwatt. The concept is clever,
| it involves lifting a bag of rocks to get a bit of light for 20
| minutes. But if you run the numbers, it is tiny. As the name of
| the company suggests, the generator outputs 0.1W, enough to power
| a 15lm LED. For 20 minutes you need to lift a 12.5kg bag 1.8m.
| That's around 0.03 Wh per lift. By comparison, a good 18650
| battery is around 13 Wh, about 400x more.
|
| As a niche product, GravityLight is not a bad idea, but it is
| telling that their new product, NowLight operates the same way,
| but they replaced the bag of rocks by... a 18650 battery.
|
| Back to the topic, it looks like that "drop a weight in a mine
| shaft" idea does worse than what you can do with a single Tesla
| car, which have more energy storage and more power at the wheels.
| Plus, it is cheaper and you get a whole car with it.
| robertlagrant wrote:
| Gravity based battery, stuffed full of lithium ion batteries?
| amanzi wrote:
| No - it's just storing potential energy.
| ChainOfFools wrote:
| yeah this sounds like a pendulum but geared on the y axis
| instead of the x. in fact a pendulum seems more practical
| since it doesn't need a shaft, just an enclosure. I suppose a
| pendum is itself is just a special case of flywheel anyway.
| montag wrote:
| Covered with solar panels and shaped into a giant flywheel?
| arketyp wrote:
| Floating on the ocean catching waves.
| swagasaurus-rex wrote:
| Converting H20 -> H2 and storing it in fuel cells
| julienfr112 wrote:
| With a heavy water thermonuclear reactor
| raverbashing wrote:
| Maybe the solution is using very dense material. Like nuclear
| power plant waste.
| Ekaros wrote:
| Or then we could use lot more of this pretty cheap, pretty
| available, pretty easy to handle stuff that we have mature
| technology and understanding for. Namely water. Only thing is
| that need nice reservoirs on top and bottom. The shaft it
| self can even be narrower and less sturdy...
| o_p wrote:
| what if you lift ion batteries instead of iron
| exporectomy wrote:
| If it's cheaper than batteries, adding batteries will just make
| it less economical.
| RosanaAnaDana wrote:
| What about pumping water up hill into reservoirs?
|
| I know not every where is suitable for reservoirs but this seems
| pretty obvious. Run renewable to pump the water up hills, all the
| 'battery' components of the tech are well established. You're
| creating additional benefit by storing potentially potable water.
| It seems like the tech for water storage/ transport/ regeneration
| to electricity is all pretty well figured out. I'm thinking some
| place like the Columbia gorge where there is high capacity for
| wind and for hydro.
| PicassoCTs wrote:
| The cheapest gravity storage is capable of holding itself up.
|
| Which is why vertical glaciers are so tempting. Its just ice, you
| pile it up, in large columns, with a puddle of water beneath.
| Energy is extracted by warming the water and taking part of the
| pressure to a turbine.
|
| Energy is added by pumping and freezing water on top, while the
| extracted heat is stored in a side tank for later usage.
| Insulation against heat prevents energy loss for longer times.
| Four T-beams hold up the freezing machinery on top. Storage grows
| with demand. If the ice starts to deform, added carbon-flakes,
| can increase tensile strength. Pressure in the pool is kept via
| onion-seals
|
| https://imgur.com/iCg9LzY
| amanzi wrote:
| This is a clever system. I remember reading about a similar
| system in Australia that used excess solar power to lift giant
| concrete bricks, and then these bricks were lowered to the ground
| in the evenings to drive generators.
|
| Not sure if this is the same one I read about, but it's the same
| concept: https://energyvault.com/
| binbag wrote:
| It's talked about in the article. But it doesn't talk about the
| impracticalities.
| blueblisters wrote:
| Wasn't Energy Vault debunked as being too impractical? Here:
| https://youtu.be/NIhCuzxNvv0
|
| These guys "solve" the wind and control problem by digging a
| 300m deep pipe for the weights.
| audunw wrote:
| You should not use Thunderf00t as an authority on this. He
| has no clue what he's talking about. That seems to be a
| problem in general, he doesn't actually do much research on
| the topics he talks about. So unless he already has some
| understanding of the topic, he doesn't provide much insight.
|
| He seems to think Energy Vault is an alternative to pumped
| hydro, which it is absolutely not. They're not solving the
| same problem.
|
| Pumped hydro is best suited for regulating power over
| days/weeks. You do not want to use it to do frequency
| regulation or regulate power fluctuations over hours/days. In
| fact, in Norway, where there's a whole lot of hydropower, and
| now an increasing amount of wind power, they're considering
| putting battery storage inside hydro power plants. This may
| seem really stupid until you understand that constantly
| regulating the output of a hydro power plant up and down
| wears down all the parts of the power plant much faster, and
| can cause issues for life in the river downstream. So it
| actually makes a lot of sense, since the hydro power plant
| has a good grid connection and may have some spare areas for
| batteries.
|
| Batteries and solutions like Energy Vault are primarily
| intended for frequency regulation and short term storage, and
| that covers most of what's needed to help balance renewables
| in most areas.
|
| There's a bunch of other serious flaws in his reasoning too,
| such as thinking that a marketing-material picture of Energy
| Vault next to wind turbines means that they actually propose
| putting Energy Vault towers right next to wind turbines,
| rather than just an illustration that the Energy Vault helps
| regulate output from renewables.
| throwaway189262 wrote:
| This is an obvious scam if you do the math.
|
| Assuming the full scale version delivers peak power for 11
| seconds like the prototype, 2MW peak power would be 6 kilowatt
| hours of energy.
|
| That's terrible. We're taking about dropping hundreds, maybe
| thousands of tons down a mine shaft to get the same amount of
| power as $700 of lithium batteries you could carry in a backpack.
| For instantaneous loads you're way better off using flywheels,
| which we've already had for decades.
|
| Gravity is weak, literally. The only realistic use case for
| gravity generation is hydro power. And MAYBE reverse hydro power
| where we put giant gas bags underwater and they make energy
| floating up
| DissidentSci wrote:
| Is anyone trying to implement that gas bag idea? Not one I'd
| heard of before
| 015a wrote:
| I think an important thing to note about gravity batteries is
| how environmentally friendly they are, even relative to lithium
| ion batteries. Lithium mining is an insanely tight bottleneck
| in LI battery production, mostly outsourced to countries where
| we don't think much about it (Australia is a big one right now,
| but in terms of untapped reserves, Chile Argentina and China
| are all huge). They require complicated manufacturing processes
| that are centralized into maybe four or five advanced
| manufacturing companies around the planet.
|
| When speaking about LI packs, especially to enterprises
| deploying them at grid scale, their expected life has to enter
| into the equation. Maybe 15 years? 25? So, millions up-front,
| and millions more every couple decades; its not an impossible
| sale, but relative to other options (like hydro storage, which
| is excellent but also limited to areas with existing
| reservoirs) its not obviously the best option.
|
| They may be better, but I don't feel that means gravity
| batteries don't have a place. The mechanical pieces to raise
| and harvest the energy likely aren't carbon-zero, but the
| weight itself can be built out of anything. They don't
| experience leakage of stored energy over time (barring a
| failure of the retention system keeping the weight elevated)
| (though, obviously, there is loss in the addition of energy to
| the storage, as the machines which raise the weights are not
| perfect). They can be reused essentially indefinitely
| (excepting continuing upkeep of the retention and raise/harvest
| systems, and proper weather protection of the weight). Their
| failure mode is "falls", which can be designed far, far safer
| than a typical LI pack failure of "explodes in a fire that
| literally cannot be put out". None of the systems in-play are
| particularly technically advanced, and a ton of the cost is up-
| fronted. There's a lot of reasons to think they will represent
| a component of green energy storage in the future; likely not
| as large at LIo packs, but the world is a big place.
| Youden wrote:
| > This is an obvious scam if you do the math.
|
| Reading the rest of your comment, I'm not sure you did the math
| yourself...
|
| > Assuming the full scale version delivers peak power for 11
| seconds like the prototype
|
| The prototype is a 4-storey tower (i.e. less than 20m).
|
| > That's terrible. We're taking about dropping hundreds, maybe
| thousands of tons down a mine shaft
|
| A mine shaft can be expected to be significantly deeper than a
| 4-storey tower is tall.
|
| So it seems you've invalidated the assumption upon which your
| argument is based in the paragraph immediately following it?
|
| > the same amount of power as $700 of lithium batteries you
| could carry in a backpack
|
| From TFA itself, they estimate they can offer a price of
| $171/MWh, while Lithium-ion batteries cost $367/MWh.
| Dylan16807 wrote:
| > From TFA itself, they estimate they can offer a price of
| $171/MWh, while Lithium-ion batteries cost $367/MWh.
|
| With absolutely nothing to explain the cost estimate, so you
| can put away "TFA" thank you.
|
| A system like this with only a single weight is going to be a
| huge amount of work to set up each unit of capacity.
|
| Also looking up the info I can find, I think they're
| calculating that rate over a 60 year lifetime.
|
| Edit: Uh, did I say something offensive?
| hn_throwaway_99 wrote:
| Agreed. I'm glad that people and companies are trying different
| solutions for our energy challenges, but I see so many examples
| where the _basic physics_ make these solutions impossible to
| scale, that it seems like these are primarily just schemes to
| suck government money.
|
| Gravity solutions like these will _never_ be feasible, because
| as you point out, gravity is just plain too weak of a force. I
| mean, it looks like pumped hydro will be viable, but when you
| think of the sheer mass of water that can be pumped behind the
| Hoover damn you realize stacking a bunch of bricks is
| ridiculous in comparison.
|
| There was another recent article on HN about a giant tidal
| generator, and I was glad to see the top comment pointing out
| that basically over 50 years all these tidal projects have been
| failures (at least when it comes to ever being able to provide
| decent power in a fashion that shows it can scale).
|
| It's time we start calling out these schemes for what they are,
| because they take funding away from solutions that we now we'll
| need _now_ to fight climate change.
| ionwake wrote:
| Please excuse me if I am terribly ignorant.
|
| In my head, liquid must be easier to play with than a solid.
|
| So displacement of water or air should be done.
|
| The displacement of air, being pumped into a balloon under
| water seems like a great idea.
|
| I know many solutions must have been thought of, but is the
| inflate balloon under water , then let it float up - the most
| efficient way of storing energy?
|
| Lithium batteries wear out, but are more energy dense and so
| arent comparable ( regardless of size).
|
| Forgive me for ruminating I think this is a problem with an
| already identified solution though?
| Kenji wrote:
| I'm Swiss and I've been following this "technology" since its
| inception. Yes, it is a scam, I agree 100%. The maths never
| checks out, every engineer in this country knows this. We are
| all ashamed.
| samatman wrote:
| Well, maybe not rocks in a mineshaft. Probably not rocks in a
| mineshaft.
|
| But Advanced Rail Energy Storage?[0] Different story, has
| potential (bad pun, I know). There are some nice synergies,
| like a system such as this can reuse the generators from a
| decommissioned coal or natural gas plant.
|
| It can definitely play a part in a broad-spectrum energy
| policy.
|
| [0]: https://aresnorthamerica.com
| sdenton4 wrote:
| 'Switzerland-based Energy Vault wants to use a multiarmed crane
| with motors-cum-generators to stack and disassemble a 120-meter-
| tall tower made of hundreds of 35-ton bricks, like a Tower of
| Babel that rises and falls with the vagaries of energy demand.'
|
| This sounds amazing. It's like the repetitive, seemingly-
| pointless behavior you see in the background in videogames...
| dang wrote:
| Past related threads:
|
| _Gravity Energy Storage: Alternative to batteries for grid
| storage_ - https://news.ycombinator.com/item?id=25650551 - Jan
| 2021 (167 comments)
|
| _Gravity-Based Energy Storage Begins Trials 2021_ -
| https://news.ycombinator.com/item?id=24337537 - Sept 2020 (2
| comments)
|
| _To Store the Wind and Sun, Energy Startups Look to Gravity_ -
| https://news.ycombinator.com/item?id=22394154 - Feb 2020 (2
| comments)
|
| _Lifting rocks as a form of long term energy storage_ -
| https://news.ycombinator.com/item?id=21736607 - Dec 2019 (1
| comment)
|
| _Gravity Battery_ - https://news.ycombinator.com/item?id=6750276
| - Nov 2013 (1 comment)
|
| _Gravity Battery Concept_ -
| https://news.ycombinator.com/item?id=6739349 - Nov 2013 (72
| comments)
|
| Others?
| rafaelturk wrote:
| I realy like the design of this baterry: Its simple, easy to
| build and mantain.
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