An abandoned mine in Finland is set to be transformed into a giant battery to store renewable energy during periods of excess production.

The Pyhäsalmi Mine, roughly 450 kilometres north of Helsinki, is Europe’s deepest zinc and copper mine and holds the potential to store up to 2 MW of energy within its 1,400-metre-deep shafts.

The disused mine will be fitted with a gravity battery, which uses excess energy from renewable sources like solar and wind in order to lift a heavy weight. During periods of low production, the weight is released and used to power a turbine as it drops.

  • tunetardis@lemmy.ca
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    11 months ago

    holds the potential to store up to 2 MW of energy

    2nd paragraph and he’s already lost me. It would be nice if tech columnists had the equivalent of even a single semester of high school physics.

    • ISometimesAdmin@the.coolest.zone
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      11 months ago

      I googled Pyhäsalmi Mine gravitricity "2 MW" and EVERY article covering this has also cited 2 MW.

      Now, under Occam’s Razor, what’s more likely:

      1. Absolutely none of the article writers have any clue what the difference between a MW and a MWh is because none of them remember any physics
      2. Some of them could suspect that it’s wrong, but an authoritative source of the claim wrote/said 2 MW capacity when they meant “2 MW peak generation” or “2 MWh storage” (I’d presume Gravitricity, but I’m struggling to find such a source, myself)
      3. One writer miswrote/misquoted as per 2, and everyone is mindlessly recycling that original article’s contents with no attribution or care.

      I don’t know which one it is. But I’d generally lean against 1.

      • tunetardis@lemmy.ca
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        11 months ago

        #2 is certainly food for thought. So the idea is that from a journalistic fact-checking point of view, it is more important to convey the information exactly as it was presented than to verify its accuracy?

        This would explain why science/engineering-based articles are so commonly inaccurate or missing in critical details. The journalist can fall back on saying “I have a recording of an interview with the expert after we downed a few pints at the pub, and I’m just parroting back what he said. Don’t shoot the messenger!”

        • AngryCommieKender@lemmy.world
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          11 months ago

          Just FYI, you need an escape backslant (\) preceeding the octothorpe (#) to not have your entire first paragraph bolded.

            • sugar_in_your_tea@sh.itjust.works
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              11 months ago

              It’s also correctly called:

              • hash
              • pound sign
              • number sign

              But cool people use the bespoke octothorpe.

              The first appearance of “octothorp” in a US patent is in a 1973 filing. This patent also refers to the six-pointed asterisk (✻) used on telephone buttons as a “sextile”.

        • ISometimesAdmin@the.coolest.zone
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          11 months ago

          I’d honestly prefer raw parroting in most cases, even if it’s “obviously” wrong. I don’t want people selectively interpreting the facts as have been conveyed to them, unless they’re prepared to do a proper peer review.

          • nilloc@discuss.tchncs.de
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            11 months ago

            That’s what [sic] is for though. You fact check, and then leave the quote as the press release had it.

            The problem is that most of these articles are basically reprinting of the press release without any editorial additions at all.

            • TwoCubed@feddit.de
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              11 months ago

              I’d wager they let bots crawl articles and have said ai bots rewrite them slightly. Internet journalism is completely lost.

        • neutron@thelemmy.club
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          11 months ago

          Then there’s the issue between scientific jargon that is different from general public use. A scientific theory has a specific definition, but it’s easy for general population to dismiss them as “just a theory”.

      • ISometimesAdmin@the.coolest.zone
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        11 months ago

        Though btw, I also think it’s fascinating the difference if you look up Pyhäsalmi Mine gravitricity "2 MW" vs Pyhäsalmi Mine gravitricity "2MW"

        You’ll get different articles entirely

      • dkt@lemmy.ml
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        11 months ago

        Or just joules per second for power. Eliminate watts entirely. Dumbass unit

        • pcouy@lemmy.pierre-couy.fr
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          11 months ago

          Well, Watts are just a different way to write Joules per second. The unit we should eliminate is {k,M}W.h which introduce a 3.6 factor in conversions to/from the regular unit system

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            11 months ago

            My fave has gotta be kwh/yr/ft². I came across that while researching the lighting requirements for hydroponics.

            • pcouy@lemmy.pierre-couy.fr
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              11 months ago

              Well, it kind of makes sense to give a figure in such an unit. It allows you to quickly calculate how much you’re gonna spend on your electric bill (but only if you’re based in the US), since all weird conversions are already done

          • Hamartiogonic@sopuli.xyz
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            11 months ago

            These cursed time units remind me of the super messy imperial units. Unfortunately, the French revolution wasn’t able to fix that, but it did fix a whole lot of other nonsense.

            • sugar_in_your_tea@sh.itjust.works
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              11 months ago

              What’s even worse is that some units differ between the US and UK, such as a cup. So you can’t even assume the wacky units are even consistent within themselves, you need to know which country you’re talking about.

              • Hamartiogonic@sopuli.xyz
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                11 months ago

                You know, there’s a reason why NASA and the US military use metric units. You just can’t afford to screw these things up because the units are a bit wonky.

          • dkt@lemmy.ml
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            11 months ago

            Yeah but if we all wrote “joules per second” instead of watts we’d encourage everyone to measure energy in joules instead of watt-hours. It’s like speed, we don’t need an entirely separate unit that just means m/s

            • sugar_in_your_tea@sh.itjust.works
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              11 months ago

              It’s especially confusing when trying to size a surge protector. The surge protector uses joules, whereas most devices use watts, and you generally need more protection the more power your devices pull.

    • imaqtpie@sh.itjust.works
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      11 months ago

      That’s a miniscule amount compared to PSH facilities, whether it’s 2 MW capacity or 2 MWh storage.

      It’s a cool concept but practically seems limited to niche applications due to the small capacity. Granted it is a prototype, but it also seems intuitive that pumping large amounts of water would be more efficient than moving solid blocks of heavy material for a gravity battery design.

      • ShortN0te@lemmy.ml
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        11 months ago

        My guess is that that number is simply completely wrong. Bo one would brag about a 2 MW generator or a 2 MWh grid storage.

        The thing is, moving a rock up does not need a huge reservoir. You would only (more or less) need the vertical space

        • imaqtpie@sh.itjust.works
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          11 months ago

          I was thinking that you would need increasingly beefy motors and cables/cranes as the size of the rocks scales. But for a reservoir, you could use the same pump over a longer period of time to store much more energy. It’s also easy to utilize a body of water with a volume much greater than the volume of a vertical cylinder.

    • onlinepersona@programming.dev
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      11 months ago

      Alright, I’ve been to high school but never understood “Wh”. For speed we say “They are moving at 25 km/h aka 25km per hour” --> in one hour the object will have traveled 25km. per indicates division. Same for flow rate (cubic meters per second --> l/s) --> “The swimming pool of 5m³ was filled at 0.5m³/h and took 10h to fill”.

      If something generates or consumes 10W per hour, shouldn’t that be 10W/h not 10Wh? If I hold an object that weighs 100g for an hour, doesn’t that mean I have been exerting myself at the gravitational force of the 100g object for 1 hour --> (100g * 9.832m²/s) / h --> (100g*9.832m²/s) / 3600s and thus the units being g * m² * s⁻² which are joules? How does that equate to “watt hours” Can somebody explain this to me conceptually? It makes no sense to me.

      CC BY-NC-SA 4.0

      • itslilith@lemmy.blahaj.zone
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        11 months ago

        What you’re forgetting is that Watt isn’t a unit of energy, it’s a unit of power, that is energy per time. So you wouldn’t say something generates 1W per hour, you’d just say something generates 1W. And if you multiply that by a unit of time, you get total energy. So an engine producing 2MW running for 5h would produce 10MWh, or 36GJ.

      • tunetardis@lemmy.ca
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        11 months ago

        100g * 9.832m²/s

        That should be 100g * 9.832m/s², or better yet 0.1kg * 9.832m/s² to get a number in newtons (N).

        From a high school physics perspective, holding a 100g object steady for any length of time does no work, since work is force applied over a distance, measured in joules (J). What you do have is gravitational potential energy. Potential energy is the ability to do work, also measured in joules. Once you release the object, then you actually start getting numbers for work and power.

        Power, measured in watts (W), is work done per unit time. So 10W/hr would be (10J/s)/hr. I guess that would be the rate of change of power consumption, if that were useful to you?

        In theory, energy and work should be measured in joules. Simple as that. But this unit of kwh (kilowatt∙hour) has come into vogue, presumably because that’s what power utilities show on the meter outside your house? 1 kW∙hr = 1 kJ/s∙hr ∙ (1000J / kJ) * (3600s / hr) = 3.6MJ. So now we’re back from power to energy consumption.

    • Jo Miran@lemmy.ml
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      11 months ago

      This is one of those ideas that in hindsight seem so simple and obvious that it makes one wonder how nobody thought of it prior. Absolutely brilliant.

        • LanternEverywhere@kbin.social
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          11 months ago

          That’s similar but different in a lot of meaningful ways. Hydro pumping like that requires a relatively large body of water next to a large geographical height right nearby. This new system doesn’t require any water, and it uses a man made hole in the ground that’s already been created and which otherwise would be simply unused

        • seang96@spgrn.com
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          11 months ago

          I read of another it was the same physics but different scenario. I think it was like excess energy moves heavy carts up a hill. When energy is needed, these carts get released and their potential energy from hill and the basic idea of regenerative breaking to repurpose it’s kinetic energy.

        • wewbull@feddit.uk
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          11 months ago

          Yes, and they use lakes of water to have enough mass to make it worthwhile. No weight down a mineshaft is worth it.

        • Jo Miran@lemmy.ml
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          11 months ago

          Not if the energy would go to waste. This is a mechanical battery to store surplus power generation from things like wind and solar.

          • Hamartiogonic@sopuli.xyz
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            11 months ago

            That’s the whole point of grid energy storage. Even if there are losses, it’s acceptable considering that otherwise you would need to burn fossil fuels in a peaker plant to keep the grid balanced. You aren’t supposed to recharge a battery like this with fossil fuels.

          • Honytawk
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            11 months ago

            It wouldn’t go to waste if we were to use “gravity batteries” that have existed for centuries: hydropower

  • wewbull@feddit.uk
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    11 months ago

    2MW is a measure of power, not energy.

    Time for something to free fall 1.4km is about 17s, so the minimum capacity is 34MJ or 9.4kWh in order to make their statements true. $1.50 in electricity.

    • laughterlaughter@lemmy.world
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      11 months ago

      The weight doesn’t have to “free fall” for this to work. It could be a huge boulder that’s lifted a few centimeters per hour. And then it can be dropped a few centimeters per hour when needed.

      • wewbull@feddit.uk
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        11 months ago

        Run the numbers.

        How heavy a boulder? 10,000kg?

        Potential energy is mass x height, so 10,000kg x 1,400m which is 14MJ of energy. Sounds like a lot, right?

        One Joule is a watt flowing for a second and 1,000 watts flowing for 3,600 seconds is 1kWh. 3,600,000 Joules or 3.6MJ. So our 10 ton rock up a 1.4km shaft only stores 4kWhs? 60¢ of electricity?

        Everything is linear here, so even having a 100 ton rock will only get us to half a EV battery.

        Edit: if you’re wondering where the other 90 cents went, this example won’t produce two megawatts. It would only produce about 700 kilowatts.

        • laughterlaughter@lemmy.world
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          10 months ago

          Thanks for doing the math and for expanding.

          The way I see it is: if I gather all the electricity I use to power my appliances in a week and just for one home - my home (fridge, heat, washing machines, vacuum cleaner, lightbulbs, laptop), and use it to lift that rock, how high will that rock get?

          Also, I wasn’t even picturing a rock that small (10,000 kgs in water can be stored half a bedroom of a midsized apartment. Let’s just assume that it would take about the same volume in “rock.”) I was picturing a rock that’s 10m by 10m by 100m tall. More like 10,000,000 kgs.

        • TechieDamien@lemmy.ml
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          11 months ago

          You missed a factor of ten from the gravitational field strength, but still not great. Their heat batteries work better when it comes to heating, but that is mostly limited to just that.

    • ForgotAboutDre@lemmy.world
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      11 months ago

      It will be similar to a big pulley.

      The weight will pull the turbine, the turbine will require a torque to generate current. This torque will act as an upwards force against gravity. This force will slow the fall of the weight significantly. The turbine ‘consuming’ the torque allows the weight to fall.

      The higher the power output the faster it will fall. This will be adjustable. No power out = stationery. A small amount of power out, the descent speed will be tiny. A faster fall a higher power output.

      This won’t be designed to fall at full speed. It’ll be designed for a long slow descent. The theoretical power will likely be much higher. It will be limited by the turbine and wiring capacity that’s rated at 2MW.

      If your calculations are correct it will be able to generate $1.50 a second. It will also consume power that is below market price/free/paid to consume when it ‘charges’. It also provides the utility of stabilising the electrical grid against renewables. Increasing the capability of the grid to support more cheap renewable energy, without the lead time of nuclear or the pollution of biofuel.

    • Crashumbc@lemmy.world
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      11 months ago

      How something be turning a huge ass generator (most likely) AND be in free fall…

      • wewbull@feddit.uk
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        11 months ago

        All solid weight gravity batteries are a scam. The sound good enough to get grant money, but if you run the numbers, they are pitiful batteries.

        To make it worth while you need literal lakes of water.

  • Ekky@sopuli.xyz
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    11 months ago

    Very interesting, and good to hear.

    Though, I’m not sure why they would drive a turbine to drive a generator, instead of just driving the generator directly. Their illustration doesn’t show any turbines either.

    • Jo Miran@lemmy.ml
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      11 months ago

      Just guessing here but I think they are playing with gear ratios. A large turbine with high resistance being slowly turned by a heavy weight could generate power for an extended period of time.

      EDIT: Maybe the shaft is the turbine. Like a big rotating corkscrew.

      • Ekky@sopuli.xyz
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        11 months ago

        And that’s my confusion, why use a turbine (connected to a lift) to turn the heavy weight into a flow of steam or liquid, presumably to convert this flow to electricity using another turbine with a generator connected to it, instead of simply converting the heavy weight to electricity using a lift (or corkscrew) to turn the generator?

        This is, of course, assuming that a turbine only is a turbine when it is driven by steam or liquid.

        I guess the publishers of the article either got the definition wrong, or there’s a less used definition of turbine which I am not aware of.

    • DarkNightoftheSoul@mander.xyz
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      11 months ago

      The turbine is the part that turns potential energy into rotational energy. The generator turns that rotation into electricity.

      • Ekky@sopuli.xyz
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        11 months ago

        But isn’t the definition of a turbine “a type of machine through which liquid or gas flows and turns a special wheel with blades in order to produce power” with the “power” (aka. rotational energy) going to a generator?

        Where does the liquid or gas come from? Isn’t this battery supposed to lift heavy, solid objects?

        It doesn’t outright state that it uses solid weights, but their illustration looks more like they’d use a lift with sand or weights, and not a turbine with liquid or steam:

        https://static.independent.co.uk/2023/01/17/10/mine gravity battery.png?quality=75&width=640&auto=webp

        • DarkNightoftheSoul@mander.xyz
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          11 months ago

          I wasn’t suggesting that a turbine could be used (directly) for sand, I hope you didn’t get that impression, I was just trying to address that commenter’s point of confusion about generators and turbines.

          To your question, a flow is cause by a difference in energy potentials between two connected points in a system; Potential energy causes the gas or liquid to flow through a turbine. The more potential energy, the higher the speed, or pressure (depending). Also, not all turbines drive generators. The output could drive anything where you need rotational input, including a vehicle’s transmission. For a lot of reasons, that isn’t usually done.

          If I understand correctly, the idea is to store something heavy up top, send it down below using the weight of the sand to somehow (unspecified?) generate electricity, then send it back up when there is an excess supply of energy generation, leaving it available to use again when energy production is reduced. Battery really describes this system better than generator, because it’s only a hole in which to dump excess energy and then pull it out (which, in a roundabout turn of events, the “hole” in this instance is above ground, and then you “pull it out” of the hole by sending it back down.).

          All that said, this seems like a boondoggle. I think there’s a lot in this press release that is unsatisfactory, and I’m extremely skeptical that this makes good sense until I see definitive independent proof otherwise.

          • Prismo@lemmy.world
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            11 months ago

            I’m going to preface this by saying, all I know is that know about the subject was one physics class in college… The teacher mentioned Hydro Pump Storage that pumps water into a reservoir when there is an excess of energy generation then releases it through turbines when there is a surge is energy needs on the grid. Wouldn’t this idea work in a very similar way? If so it would seem feasible as about 15% of the UKs STOR requirements are met in this way.

            https://www.nationalgrid.com/sites/default/files/documents/STOR Fuel Type Analysis Summary (By Capacity) - Season 8.5 - Final_0.pdf

            https://www.sse.com/news-and-views/2023/03/britain-s-largest-pumped-hydro-scheme-in-40-years-gets-100m-investment-boost/

            • DarkNightoftheSoul@mander.xyz
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              11 months ago

              Yeah, I was imagining it would probably work better with water instead. Sand can’t be pumped (or turbined lol), and I noticed those many enormous trucks carting the sand around underground which seems to introduce an enormous efficiency loss to the system. Good to see the fundamental concept works well in practice, thank you.

              • Prismo@lemmy.world
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                11 months ago

                Yeh, again I’m not sure how efficient using water is but my instinct says it will be a lot better than any mechanical system as they are generally very inefficient!

          • Ekky@sopuli.xyz
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            11 months ago

            Right, my bad. I thought you were explaining turbines in relation to the post, which would indeed have one attempt to run sand through it if not used with either liquid or steam.

            I also wrote turbine and generator separately, as, as you stated, turbines and generators are not the same. I, in turn, hope I didn’t give the impression that they were.

            I fully agree about the system as a whole better being described as a battery, which usually includes generators of some sort to convert the stored energy back into electricity.

            And yes, this is a rather precarious article, which also is why I wrote the half-question half-joke about unnecessary conversion steps using turbines.

    • Hamartiogonic@sopuli.xyz
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      11 months ago

      The illustration also showed a bucket wheel excavator. Don’t remember seeing that the last time I visited Pyhäsalmi.

    • Hamartiogonic@sopuli.xyz
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      11 months ago

      They’re planning to use the 530 m long secondary shaft at first. The entire mine is a lot deeper, so obviously, there are other shafts too. You gotta start somewhere.

  • blazera@kbin.social
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    11 months ago

    I been promoting this shit for a while now. Energy storage can be surprisingly low tech, it just needs to be built

  • unreasonabro@lemmy.world
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    11 months ago

    Isn’t this a little goofy? It presumes there will be extra electricity. Do you see any sign that we’ll be producing significantly more than we need? All i see is stupid decision after stupid decision. Can’t even build a nuclear reactor these days so barring a fusion breakthrough there are no big leaps to be made. That said, fusion does appear to be coming, but that’d also make this moot and hence silly.

    • s_s@lemm.ee
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      11 months ago

      On-demand (or surge) power generation like this is much different then base power generation like you get from solar, wind or nuclear (or theoretically fusion).

      Long story short, any functional power grid needs both because generation has to match demand, and demand is uneven and wonky.

      The most common surge power source is small natural gas plants. This is a replacement for those.

      It presumes there will be extra electricity.

      There’s always extra electricity. Eg. Solar generates power during the day, charges this “battery” and then powers lighting at night when demand is higher and people need to be able to see.

      • pingveno@lemmy.ml
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        11 months ago

        There’s always extra electricity. Eg. Solar generates power during the day, charges this “battery” and then powers lighting at night when demand is higher and people need to be able to see.

        And this is only set to become more of an issue. Solar and wind are going to be a larger share of the energy mix, but they will still be unreliable. Energy storage, whether physical or chemical, will need to be part of the solution.