Stacking concrete blocks is a surprisingly efficient way to store energy

[maybe yes, maybe no ~ctm]

From Quartz

Thanks to the modern electric grid, you have access to electricity whenever you want. But the grid only works when electricity is generated in the same amounts as it is consumed. That said, it’s impossible to get the balance right all the time. So operators make grids more flexible by adding ways to store excess electricity for when production drops or consumption rises.

About 96% of the world’s energy-storage capacity comes in the form of one technology: pumped hydro. Whenever generation exceeds demand, the excess electricity is used to pump water up a dam. When demand exceeds generation, that water is allowed to fall—thanks to gravity—and the potential energy turns turbines to produce electricity.

But pumped-hydro storage requires particular geographies, with access to water and to reservoirs at different altitudes. It’s the reason that about three-quarters of all pumped hydro storage has been built in only 10 countries. The trouble is the world needs to add a lot more energy storage, if we are to continue to add the intermittent solar and wind power necessary to cut our dependence on fossil fuels.

A startup called Energy Vault thinks it has a viable alternative to pumped-hydro: Instead of using water and dams, the startup uses concrete blocks and cranes. It has been operating in stealth mode until today (Aug. 18), when its existence will be announced at Kent Presents, an ideas festival in Connecticut.

Concrete plan

The science underlying Energy Vault’s technology is simple. When you lift something against gravity, you store energy in it. When you later let it fall, you can retrieve that energy. Because concrete is a lot denser than water, lifting a block of concrete requires—and can, therefore, store—a lot more energy than an equal-sized tank of water.

Bill Gross, a long-time US entrepreneur, and Andrea Pedretti, a serial Swiss inventor, developed the Energy Vault system that applies this science. Here’s how it works: A 120-meter (nearly 400-foot) tall, six-armed crane stands in the middle. In the discharged state, concrete cylinders weighing 35 metric tons each are neatly stacked around the crane far below the crane arms. When there is excess solar or wind power, a computer algorithm directs one or more crane arms to locate a concrete block, with the help of a camera attached to the crane arm’s trolley.

energy-vault-landscape_colorcorrected

Once the crane arm locates and hooks onto a concrete block, a motor starts, powered by the excess electricity on the grid, and lifts the block off the ground. Wind could cause the block to move like a pendulum, but the crane’s trolley is programmed to counter the movement. As a result, it can smoothly lift the block, and then place it on top of another stack of blocks—higher up off the ground.

The system is “fully charged” when the crane has created a tower of concrete blocks around it. The total energy that can be stored in the tower is 20 megawatt-hours (MWh), enough to power 2,000 Swiss homes for a whole day.

When the grid is running low, the motors spring back into action—except now, instead of consuming electricity, the motor is driven in reverse by the gravitational energy, and thus generates electricity.

Read the rest of the story here

Company Website

H/T HotScot

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292 thoughts on “Stacking concrete blocks is a surprisingly efficient way to store energy

  1. It takes more energy to lift the block than what is gained when the block is lowered. Consequently, it is a net energy loser. What makes this profitable? Is it because power plants are allowed to coast down and maybe there is an energy savings there? Just curious

      • Pumped hydro could be placed almost anywhere, even in the middle of the Sahara.
        If the reservoirs are stacked and located below ground all that is needed is digging to create the negative space then filling one reservoir with water.
        Since the reservoirs are stacked a minimum amount of space is needed and since they are below ground no mountains are necessary.

      • Simply pumping water back up over the dam works too but it is so positively absurd they hide the stupidity of it by creating artificial reservoirs in a bit of sleight of hand. Except for the excess dissolved gases in the water passing through the penstock twice, it is not functionally different than pumped storage. It is done for the singular purpose of increasing demand on off-peak (cheaper) energy to increase the cost to consumers of that energy, and to resell that energy during the daytime when it is more expensive. It is of course a net consumer of electricity, and nothing short of a scam.

        • “It is of course a net consumer of electricity, and nothing short of a scam.”

          This is an example of the widely accepted fallacy that forms the foundation of socialism. Hundreds of millions of lives have been lost because of this sort of thinking.

          In his book covering the subject, “The Wealth of Nations,” Adam Smith described it this way: “It is not from the benevolence of the butcher, the brewer, or the baker that we expect our dinner, but from their regard to their own interest.”

          If by some magic Smith’s “invisible hand” would cease functioning tomorrow, the majority of people would be dead in less than a year.

          • Does that mean “Only the power companies can reduce the efficiency of their production processes while turning a greater profit and raising the cost to consumers”?

      • PUMPED HYDRO ==> In the US, this makes money because they use cheap “excess” electricity to pump the water up and then make electricity with it (sending it back down through the turbines) when electricity prices are higher due to demand,

        In the solar/wind powered grid, this is even better as one can pump the water up when the wind blows and/or the sun shines (creating excess electricity), absorb that excess power pumping up, and then recover most of that energy again when need to balance the grid with very little run-up time.

        • Clockwork generator ==> My teen-aged son, while in high school in the Dominican Republic, designed a clockwork generator (and/or water pump) system that was a water tower (tank at the top) (or just tower), with pulleys and a clockwork catchment that controlled speed.

          In the morning, the villagers would all play tug-of-war and jointly pull a weight to the top of the tower. When released, the clockwork ran a fly wheel that ran either the pump or a small generator for 12 to 18 hours. When the villagers returned from the fields in the evening, they pulled the weight back up again. Human power stored for the night.

    • All energy storage mechanisms have a net loss. The trick is finding the one with the least loss.

      I think the idea has merit. Most proposed systems have loss due to heat (springs, compressed gas), or loss over time (electric capacitors). This one seems to have less, but you need a lot of mass.

      Water is easier, but you need to consider geography and whether or not the water is needed downstream.

        • Lawrence, I agree.

          Also I cant see where the author of this paper has taken into account the dangers of sacking unreinforced blocks in a wind zone.

          No doubt he will produce a further paper in designing a block that will not blow over in the wind.

          Cheers

          Roger

          • um … but … Li batteries already solved this problem in a box that fits in the backyard shed.

            The problem is price, not mechanism.

          • Many of the blocks in the columns of the Acropolis in Greece have been standing for thousands of years.
            One source of energy loss is that required to direct and control where the stacking occurs during the energy discharge phase. And with each subsequent level less energy is produced as the fall length is lessened by the size of the prior block

          • Since the device is picking up blocks from random locations and putting them back down in random locations, there’s no way to use guy wires to prevent those blocks from swinging in the wind while being lifted or lowered.

          • BryanA, the fall length is lowered by twice the height of a single block, since the next block to be picked up will be lower as well.

          • The ancient Egyptians developed an excellent block stacking system on roughly this scale. They built pyramids.

        • The idea of using a train up a long slope is being developed, so we’ll see. But both the train and pumped hydro need a hill. The advantage I see of this idea is that you can build one anywhere, any flat land, and it has a small footprint unlike a big water reservoir.

          • Lossy, but every method is, and also complicated and expensive to build and maintain.
            How much energy is needed to make that thing, and make sure it is working properly?
            It does not appear to be something that can be built and ignored while it operates.
            The first thing that bothered me was when the article stated that some such method is required to allow for using less fossil fuels, and that solar and wind are required for this to occur.
            One word reply to that notion: Nuclear.

      • Just a software engineer (not a “real” engineer) here, but it seems to me pumped hydro would be more efficient in the discharge phase (assuming efficient turbines) but less efficient in the “charge” (load) phase. There would be more losses pumping a fluid (water) uphill than lifting the blocks, methinks (depending on the efficiency of the motor and rigging pulleys). In any event, some losses would be tolerable as long as having the storage capacity made the overall grid (and combination of generation sources) sufficiently stable.

        • Pumped hydro is more efficient, and dirt cheap, depending what is used to pump it.

          A clever homeowner could install solar panels, a small wind turbine, a few storage batteries and a “pumped” hydro generator/storage unit (if he has access to a “gravity flow” water source) …… and he would always enjoy “free electricity” even when the Sun wasn’t shining and the wind wasn’t blowing because his “pumped” hydro system would keep right on working unless the water froze.

          To construct a “pumped hydro system”, all that is needed is a “water ram” (or trompe), a large storage container, water pipe and a hydrologically driven generator.

          And you can either build yourself a “water ram” or purchase yourself one.

          Just “click” the above hyperlink iffen you are not familiar with a “water ram”.

          • FWIW according to the U.S. Energy Information Agency, in 2017 “Pumped Storage Hydropower” accounted for -0.2% of U.S. electricity generation. Quote:

            “Pumped storage hydroelectricity generation is negative because most pumped storage electricity generation facilities use more electricity than they produce on an annual basis. Most pumped storage systems use fossil fuels or nuclear energy for pumping water to the storage component of the system.”

            As I mentioned, expected inefficiency can be justified by the critical function of baseload enhancement provided. Grid stability is the single most critical requirement. But if we weren’t forcing unreliable renewables on the grid, we wouldn’t need inefficient storage schemes at all!

          • Pumped storage hydroelectricity generation is not constructed for the purpose of saving money (cutting expenses) …….. but for the purpose of making money (a profit).

            Buy power when the price/kw is low ……. and sell power when the price/kw is high.

      • Meh. Just another convoluted scheme to try to justify undependable “renewables” when we’ve already had dependable electric-generators for nearly a century.

        • Agree 100%.
          Subtle messaging in the article states that some such method is required in order to use less FFs.
          No, it is not.

        • Yes, coal, oil and gas are proven, long lasting energy storage mechanisms. On top of that they’re completely natural and also produce plant food as a by-product. A win-win-win.

        • Was thinking this throughout the whole article and comments. Good grief. Nuclear is perfect, but it’s been made ” too expensive ” on purpose. Modern coal is very good. NG is good. But small nuke plants are the likely future. Humanity needs a generation to die off first… the ones that demonized nuclear power because they hated ” the man ” and just wanted free sex and smoke pot and drop out.

          • “a generation to die off…the ones that demonized nuclear power because they hated ” the man ” and just wanted free sex and smoke pot and drop out.” I think you’re referring to what we now call “snowflakes”.

    • Paul: You’re asking the wrong question. Energy storage always costs more than using it at the tap. The question is, does it cost more to store it, than to less 100% of it go to waste. So the idea is to get some net amount back that pays off the cost of storage and release.

      Anyway, I am a green energy skeptic myself.

      • Ah, So although storage is always less efficient due to friction, heat loss, etc., simple laws of physics, the question is does it make sense to store (more expensive) energy than to lose it all when it is created during low usage times?

        • The question should be two fold:

          1) does it cost more money to store the excess energy than the value of the energy that would have been lost.

          AND (a big and)

          2) Can you retrieve the stored energy when the value of that energy is increased?

          On point 2, if you can get the energy back when the cost of energy is at a premium, such as peak demand, then the case for storage improves.

          This solution is much different than solar and wind which are unpredictably available…

          • Now you’re thinking. I have done or at least participated in a number of thermal energy storage applications, and one plus for the idea is that it can be significantly cheaper to build a thermal storage system than to buy an additional chiller (for example). Then the chillers do extra work when the load is low (which just so happens is usually when rates are lowest since almost everyone on the grid experiences the same load profile), to put some into storage, to be used to “top-up” when the load hits a peak. This sort of system provides a viable return on investment where demand charges are especially high. The thing is, as noted elsewhere, it provides an assist for dispatchable power because it does take some planning and scheduling of the equipment run times, they can’t be turned on or off in a blink, like when there’s a wind gust, followed by NO wind.

          • Red94ViperRT10 : As an aside, I think the earlier vipers, like yours, were gorgeous. Much cooler than the newer improved more powerful ones. Just sayin’

          • I’m going to go with None of the Above.

            Use the undependable energy (aka “renewables”) for desalinization of water.
            Use nukes for powering a modern technical society.

        • Power plants are ‘load following’ so they do not ‘need’ storage. Storage allows utilities to run their cheaper generators at full capacity off peak and then use that power during peaks rather than more expensive units. Plus pumped storage makes for beautiful water reservoirs – as where we reside – Smith Mountain Lake VA. …and tourism….and recreation….and fishing tournaments….and bird habitat for great blue herons, eagles, ospreys…. Yeah – do the pumped storage thing. You won’t regret it.

          • Shawn — correct. The Smith Mountain Lake reservoir actually uses more electricity than it makes. The purpose is to run the fossil-fuel/nuke plants more efficiently — run them at higher loads (more efficient) at night to power the generator/motor pumps to fill the lake and then those pumped-storage generators assist the FF/nuke units in the high-demand daytime periods. The “gross” flow thru the Roanoke River that feeds the lake is actually quite small and a straight-thru hydro plant there would generate very little. The pumped-storage reservoir at Mt Storm, WV operates similarly.

          • beng, small correction. There is a coal-fired power station at Mt. Storm, but no pumped storage.The pumped storage facility is in Bath County, Virginia. At 6,000 MW, it is one of, if not the, largest in the world. I have visited both sites.

    • Of course it is a net energy loser. All energy storage systems are. Perpetual motion machines don’t exist.

      The real issue is how does the efficiency of this compare to the efficiency of competitive systems, or more importantly, account also for life cycle costs.

    • “It takes more energy to lift the block than what is gained when the block is lowered. ”

      Darn, really, I thought they came up with a perpetual motion machine. 😉

      • Theoretically, the energy stored as gravitational potential energy is exactly the amount needed to lift the load.
        The losses come from friction and moving the blocks horizontally and the mechanism that prevents swaying…plus all the computers and servos that are needed to operate the whole thing. Et cetera.
        Add in the cost and energy to build and maintain it, mine, refine, and manufacture each of the components, including a whole hell of a lot of CO2 producing concrete…
        ( And…yes, I know that concrete is said to absorb that CO2 back over time, maybe.)

    • All energy storage methods are net energy losers. Entropy always wins. That doesn’t mean that they can’t be useful.

      But this one seems unlikely to be worth it. 20 MW/h isn’t that much. A small Nat Gas peaking plant would be much, MUCH cheaper to build.

      ~¿~

      • And the concrete would cost a significant amount (plus all the CO2 released making the concrete). Motors are fairly efficient at lifting things – 85% or so, which is probably better than the pumped hydro. You just don’t have the scale needed to really store very much energy. You would need one of these for every four or five large wind turbines.

      • Makes it energy for the consumer more or less expensive than traditional ways of energy production?
        Society has only progressed when energy became more abundant and therefore cheaper for larger groups of people.

    • Even charging a car battery has a net loose of 10%. What makes it profitable is that i’ll have also energy stored in the battery when my generator is turned off during daytime.

      • And it is perpetually 10 or 50 years down the road. The TRUE perpetual motion → The goal post is always moving. Just a few billion more dollars and we will have it.

    • Yes, there is always a loss of energy in every operation , even in hydrostorage, including water evaporation. With this concrete block system the upper blocks have more energy than the lower blocks, so the energy production of the system tapers off as it gets low. That might be a lot like the water level of a hydrosystem dropping, but the lowest blocks will have little energy. Energy losses in the crane operation will not be inconsequential. Now, let’s consider inclement weather and the vagaries of wet concrete blocks, frozen blocks, ice locking them together, and blocks overloaded with ice. No such system is simple.

      • It would make more sense to use an inclined railway with a linear motor in the blocks fed by power from the rails. The efficiency of a crane and the multiple problems created by wind and wear and cables and connectors are pointless. Just have the tonnage go uphill when there is spare power and run them downhill one by one, three by three or another number that matches the demand. Unlike the tower, all the masses would reach full potential.

        Suppose one sent 100,000 tons up a 100m tall hill to a plateau. That is 10 GJ of potential energy = 2.77 MWH. Now consider a 300 hill: 8.33 MWH. There are many places with a 600 m drop that are not suited to pumped hydro without building tanks.

        That mass is only 700 rail cars. 2500 cars with a 600m drop stores 60 MWH worth of power. Could it be feasible? At $200,000 per MWH, lithium batteries (with a relatively short working life) would cost $12m. That’s cheap.

        Compressed air and pumped hydro are still cheaper by over half. Compressed air can be stored anywhere. In a hybrid system, the compressed air can be used to burn natural gas with very high specific power. Rather look to that.

        • If you live in the U.K. you will know that you couldn’t use trains to store energy here because at weekends – when you most need the energy – they don’t function and you only have a bus replacement service.
          Come to think of it they probably wouldn’t work a lot of the rest of the time either because of signalling and line problems. Did that sound too bitter and twisted? Sorry.

          • Moderately,
            No – you do not sound too twitter and bisted.
            I have the enviable position as a former [Ta-dah!] user of Southern Railways.
            You have it spot on!
            [And you could have added ‘the wrong sort of snow/rain/sunlight’; union problems; and early Victorian infrastructure, not to mention management that does cause raised eyebrows at their ‘decision-making’ prowess!].

            Auto – now retired!

      • “The system is “fully charged” when the crane has created a tower of concrete blocks around it”

        Doesn’t this mean that your “fully charged blockery” is flat on the bottom?

    • Minimum loss of energy is required.
      Some decades ago as a student of electronic engineering I used to walk daily by Tesla’s museum in Belgrade. On numerous occasions I went in to look at the exhibits with the Tesla’s electromagnetic egg being favourite.
      https://www.flickr.com/photos/jup3nep/6146549391/lightbox/
      Here you can see it in action : https://youtu.be/Ec4u4BfS4tE
      In the energy storing device the egg would be replaced with a huge heavy metal cylinder housed in a super-cooled vacuum chamber, with small modification to the circuitry it would be forced to levitate.
      All electrics (again with superconductivity arrangement) are outside the chamber. With no mechanical transmission, gears, bearings or even air friction, etc. the cylinder could be progressively accelerated to many tens of thousands rpm, with minimum loss of energy.
      When power is switched off the cylinder will keep rotating with slow de-acceleration but this time generating electric current with minimum loss of energy mostly required for maintaining superconductivity of electrics and the rotating cylinder.

      • Flywheels have been proposed many times for energy storage, in vehicles and static. They have many advantages over gravitational potential systems like this one. I don’t know why there is so little interest for them.

        • Three problems.
          1) You need a huge flywheel to store usable amounts of energy.
          2) If the bearings go, all of that energy is released over a couple of microseconds.
          3) Cost

          • no, while generating current the electro – magnetic coupling acts as brake. With no bearings and transmission gearing, in vacuum and a super-conductive set-up efficiency would surpass any other electro-mechanical system with incomparably lower maintenance cost.

        • I think people have even proposed flywheels for usage in cars and other vehicles, but the potential for disastrous consequences is very high.

        • IIRR, flywheels were used to power jitneys going between villages in Switzerland. I’m not sure what the outcome was. They may still be in use, for all I know.

      • Check out http://beaconpower.com/

        “Beacon’s proven flywheel storage systems respond instantly to store or deliver precise amounts of power whenever it is needed. Examples of high-value, high-cycle applications requiring power for a short duration include frequency regulation, frequency response, and smoothing and integration of variable output renewable generation such as solar and wind.”

        http://beaconpower.com/wp-content/uploads/2014/03/flywheel_cutaway.jpg

    • Government makes it profitable. Most folks will buy the cheapest energy. Only modern governments make these schemes through mandates, price controls and the associated graft and corruption that accompanies government.
      One might say the best of the worst would be the cheapest but, again, modern government only has the yardstick of compliant, uneducated, rather feckless voters to convince. Thus, efficiency and cost control is simply not an issue.

    • Off the top of my head, I can’t think of any energy storage system that does not require more energy to charge the system than you will get out. Which one were you thinking of that would be so much more efficient?
      The purpose is to store energy for when the charging system is unavailable.

    • This concrete elevator idea is only feasible in a world where we produce renewable energy a low demand periods. This energy is essentially useless . So you can store energy that you didn’t need to produce in the first place. Makes sense if you forget the fact that you spent a fortune building tha capacity you didn’t really need.

    • The storage operator buys base load power, at base load rates, to raise the concrete blocks. The base load operators may even sell their power at a discounted rates, as running the equipment during a short period of low demand is cheaper than shutting down and restarting.

      When the storage operator can sell the energy at a rate that covers the losses from inefficiency and overhead, the costs are covered, but the goal is to sell the energy at peaking rates. As more power storage comes on line, the price of peaking power goes down, but so long as the stored energy is less expensive than gas turbine generators and diesel generators, they can still make a worthwhile return while lowering overall electricity costs.

      The costs are comparable to the costs of hydro-electric projects, being mostly concrete with some rotating machinery.

    • I disagree. Given the varying nature of electricity demands, we have to build for the maximum capacity (plus margin) to meet demand. If we have efficient storage, we can build to the average demand (plus margin) instead. That is entirely ignoring renewables.

      The question is whether it is cost effective.

      • “The question is whether it is cost effective.” That depends on how “cost effective” is calculated. Electric provider rates are higher when demand is high which covers the cost of “pumping water up hill to store it”(usually at night) when demand and rates are lower. Arkansas Panhandled project is a good example.

      • cost effective???? What does that have to do with it? It is a solution to some problem and would engender some form of subsidy. And what would the cost of manufacturing the blocks add? Even though it is a one-time expense.

        • As of construction worker points out above, it can quite easily pay for itself if power costs fluctuate enough, which they seem to these days. No need for subsidies.

          • The entire storage ‘issue’ is about affordability otherwise Li storage could do it now (isn’t it queer how every one in the new renewable-energy church went all quiet about Li storage being the ‘solution’?).

            Wildly fluctuating electron prices is in the opposite direction of affordability, it’s in the direction of ruination and destruction of domestic business, employment and economy, which is why masquerading greenies in concern-troll mode push it.

            The best storage is the ‘Strong’ nucleus force.

            Releasing it does not require storage at all (oh damn, now they is ripping up our raison detre!).

            It’s entirely affordable and has been for 60 years. And it’s very abundant.

            It’s the greens who merely claim storage is required, so this whole concept should be ruthlessly regarded with bucket loads of skepticism for the red-kipper it has been all along.

            We already use affordable batteries for portable stuff, which is what cranes and concrete blocks aren’t.

    • Exactly! There is already a far more effective method of energy storage: a pile of coal is a perfect energy storage device, when electricity is needed someplace, burn the coal, make steam, turn a turbine, generarate said electricity! (Non)problem solved!

      • A pile of coal take many hours to start producing electricity. Even a well engineered plant running standby needs time. Hydroelectric comes closest to being a perfect storage device.

        • Hydroelectric is solar powered and the energy is conveyed by the water cycle. The energy source is approximately infinite and highly reliable, and self-distributes. We don’t need intermittent (low reliability) wind and PVC energy conversion and storage schemes. And we need to stop fretting over having over-capacity at night. There’s a reason China is converting the Himalayas to hydro farms.

    • Here’s an even better solution:

      1. Build your wind power system.
      2. Build your back-up system consisting of 100% equivalent capacity in gas turbine generators.
      3. Using high explosives, blow your wind power system all to hell.
      4. Run your back-up gas turbine generators 24/7.
      5. To save even more money, skip steps 1 and 3.

  2. Gravitational storage seems to be an attractive idea. There are a number of schemes. One involves a train loaded with concrete blocks.

    Pumped hydro works and is economically applied all over the world. Various other gravitational storage schemes have been proposed. It seems to me that if they were going to be viable, one of them would already have demonstrated that. ie. If people have been working on something for a long time, and it hasn’t worked yet, it probably won’t work.

    • Gravity is the weakest of all the four (allegedly) separate ‘forces’.

      Why avoid using the strongest and most efficient storage mechanism/force at all?

      Why would one lobby to, or choose to (non-returning, unsustainablyand non-renewably) invest’ in the weakest force mechanisms, when you already have affordable and proven economic access to (just some of the existing capabilities and options, with much more to come) of the strongest force and energy provision means economically available to us?

      Because the greenie-nasties will always insist on us using the least efficient, most uneconomic and lowest mass-energy delivery options available. Thus our greenie-nastie holly-voluntary meta-‘saviours’ will always distract with a completely false non ‘problem’, to talk-up their loser-option(s), and to talk-down the most efficient, most affordable and most economically viable options, which would do the most good for the most people (and actually save people and the environment for real).

      • 1) Ever tried grabbing a typical heavy rock (say over 250 lbs) to hoist it up, or let it down?
        2) Ever tried stacking and unstacking typical rocks?
        3) “Rocks” of the size/mass contemplated for the crane approach in the above article are not readily available at most of the sites where one would want to place an energy storage system such as that proposed in the article.

        • This particular comment was about trains being driven up hills.
          A trains full of rocks would be a lot cheaper than ones full of concrete blocks.

          • Rocks might work, but one has to account for the packing factor of the rocks, which in turn decreases their effective density when loaded into a railcar compartment. One option to minimize voids between loaded rocks would be to crush them down to pebble size (or smaller), but then one would need all the infrastructure of rock crushing to make these loads. This would be above and beyond the cost of extracting the “rocks” from the ground.

            I won’t bother to do the research and cost estimates to see if this approach would be better overall than just manufacturing the reinforced-concrete blocks.

  3. And we don’t need a patent office because everything conceivable has been invented already. [A real statement by a real government official.]

  4. An unsupported tower of concrete blocks. Wouldn’t that work great in an earthquake zone.

    Apart from that, wsbriggs has it exactly right.

  5. Why wouldn’t you just lift a single weight to a height, like twisting a rubber band, or better yet, pump fluid to a height…

    • “Why wouldn’t you just lift a single weight to a height”

      The weight would be enormous, that means very big, very expensive bearings and a geartrain on a very big motor.

    • Big rubber bands might be better and cheaper than this method.
      We used to use them to power airplanes, and they were small rubber bands.

  6. I’m wondering if this plan has been run by a few actual megascale crane operators? They seem to think this whole thing can be automated. That doesn’t jive with what I know of from tall building construction.

    ~¿~

    • It can be automated but that requires a large safety exclusion area where no humans are allowed. In Nova Scotia this area would be 1.3 times the height as a minimum… so 136meter diameter given the 120 meter height. That is a very large footprint.

        • That exclusion zone would be for simple falling objects in an unattended automated system. After some thought, following the link to the article and a critical look at the drawing of the system I think that is the most minor problem it would face.

          The drawing seems to show the arms length as 1/4 the height of the tower and unstayed. As a tower crane they are trying to avoid flex in the mast by lifting two loads on opposite sides but are neglecting the sag in the arms under load. Cranes aren’t my specialty but I have family in that industry so have some small awareness. This thing is an accident waiting to happen, automated or not.

          This group is talking about managing costs by using waste materials to save on cement, i.e. low strength, brittle blocks. Even if everything works as planned the repeated handling will degrade the structural integrity of the blocks, leading to one failing.
          If it fails while suspended the uncounterweighted load will topple the crane. It may(likely) fling the remnants a large distance, think trebuchet. I would want one within a country mile of me.

  7. Sand is cheaper than concrete and weighs about the same. Shell blocks of sand?

    Anyway, the idea has merit if the investment is private and not subsidized.

    But what will this do to the futures of scarce sand?

    • Good points eyesonu. But but, there is the added benefit of all that CO2 from concrete production… so I’m leaning towards the concrete block truly green solution.

      • eyesonu writes: “But what will this do to the futures of scarce sand?”

        Shhhh… don’t let the Saudis get wind of this. They might try to corner the market on sand before their oil reserves run out.

        Oh, wait….
        .
        .
        .
        If this can be done without production subsidies and sold to willing buyers without subsidies, I’ve got nothing against the idea.

    • I like the sand idea. And it doesn’t have to be in a container. There are lots of ways to move loose sand up and down. As many have pointed out here, the requirements for using gravity for storage are (1) cheap and (2) safe. I’m sure that there are many ideas cheaper and safer than lifting concrete blocks.

  8. The main issue with any sort of energy storage tied to an energy producer is that you have to oversize the producer to supply the demand PLUS deliver energy to be stored. Thus, the energy producer is more expensive to begin with. Then you add even more expense of the energy storage, which doesn’t produce anything while energy is being stored. How can this ever be cost-effective? It seems an energy producer that works all the time, always wins… unless you’re selling those oversized energy producers and storage units!

    • Actually, pretty much the opposite, see my comment above. (I’m playing like I’m Nick Stokes. I have no enthusiasm for this idea myself, but I’m trying to keep everyone honest in their comments.)

      • Do you mean the one at November 16, 2018 at 7:33 pm?

        Exactly so. You need enough generation available to cover your peak load. If the geography is right, it is cheaper to provide some of that generation in the form of pumped hydro. link It works. It saves money. We’ve been doing it for more than a century.

  9. Nature did daily solar energy storage for us many millions of years ago. And some ignorant people actually think a few concrete blocks can power a technological society 24/7 for times when the sun doesn’t shine for days, or when the wind doesn’t blow for weeks. Sad.

    • One of these will power 200 homes in a country that does not use a lot of power per person.
      But the really big users use far more than a few thousand homes.
      And how many of these are needed for even one medium sized city, of which we have many.
      Enough solar and wind to supply our needs is flat out impossible.
      That should be the real conversation, and until it becomes the conversation, they are just wasting our time and money.

      • Typo of course…2000 homes were specified, although as noted the Swiss use a minimal amount of electricity, as compared to Americans for example.

    • Maybe not a house, but a CCA might want to play in the energy markets in the future as managing the grid in March and October is going to be a bit of a challenge.

      At those times a lot of curtailment occurs on the CA grid.(1) and “Storage” is noted as one of the “solutions” (3) to the problems associated with having to pay some generators to not produce or pay out of state users to take the overage if it can’t be curtailed physically (2).

      1) http://www.caiso.com/Documents/HistoricalCurtailment.pdf
      2) http://www.caiso.com/Documents/MarketPerformanceReportforMarch2018.pdf see “Figure 17: Renewable Curtailment by Resource Type for jan 17 through March 18 data and Figure 48 shows the daily price frequency for prices above $250/MWh and negative prices in FMM for PACE, PACW, NEVP, AZPS, PSEI, and PGE. The cumulative frequency of prices above $250/MWh inched down to 0.16 percent in March from 0.21 percent in February. The cumulative frequency of negative prices rose to 2.46 percent in March from 1.99 percent in February.”
      3) http://www.caiso.com/informed/Pages/ManagingOversupply.aspx#dailyCurtailment

  10. Concrete block energy storage: Has anyone bothered to calculate the energy storage capacity of this gadget, compared to burning a ton of coal in a power station? Measley, I bet.

  11. It’s worth checking some basic arithmetic here. Lifting 100 of these blocks 100m does store about 1 MwH, so their claim of 20 MwH storage seems feasible. Presumably there would also be some flywheel storage to smooth out transitions.

    And 20MwH is a useful contribution to running a grid. The Tesla battery in South Australia can store 120 MwH, and has done a good job in stabilising the grid. It also makes quite a lot of money by buying power when it is cheap, and selling at a better price. On that basis alone, it will pay off quite soon.

    • The concrete block idea doesn’t have the ability to respond in micro-seconds like SA battery does.

      Can’t see how it can do anything for grid stability.

        • “You can run it with a flywheel. Then it responds just as quickly as any other generator.”

          Either that or it will take time to spin up the flywheel. Can’t have it both ways.

        • “You can run it with a flywheel. Then it responds just as quickly as any other generator.”

          Or, if it is not running and you have to start it it, the flywheel will take time to spin up to operating speed.

          • And dangerous.
            Rejected as a means of storing power long ago due to the uncontrollable destructive potential of a damaged unit.
            At least a fire can be put out.
            Try grabbing a massive wheel spinning at thousands of rpms.

    • Nick Stokes

      For once I’ll dare take you on , you being an educated guy and me not.

      So we have basically inefficient wind turbines/solar panels/name your poison producing intermittent electricity to wind up a primitive (and I mean really primitive) energy storage device.

      These will blight the environment and the land usage to gain any meaningful level of power is simply staggering http://www.rationaloptimist.com/blog/wind-still-making-zero-energy/

      Now, split hairs if you like, but Matt Ridley is not too far off the mark and my contention is that whilst we are disappearing down the burrow hole of science for the sake of science (wind turbines, solar panels and concrete blocks) the point is being missed that after 20 years of these futile attempts to reinvent the wheel, we still have a square wheel, producing single digit percentage amounts of global energy.

      And I’ll make this point once again; to my knowledge there is not a single empirically derived, acceptable, scientific field study which demonstrates that atmospheric CO2 causes the planet to warm. Yet somehow accepted wisdom is that we pursue inefficient energy schemes, such as this, expecting to replace the 85% of global power provided by fossil fuels.

      I’m all for innovation but wind turbines are 14th Century technology. Pumped hydro only works because of massive land appropriation but, even that’s not on the scale of turbines and solar, and it can only work as load balancing, it’s not a viable power producing solution on it’s own. Unless of course a country is going to be littered with massive, expensive battery installations and renewables.

      Seriously, what level of battery power would it take to provide for Sydney for a week in the event of a typhoon when turbines and solar couldn’t work? Assuming no fossil fuel backup of course.

      Nor do I accept News.au as a reliable source of scientific analysis and I’m dumbfounded you posted the link.

      • I once worked out how long that wonderful(ly) expensive battery could power South Australia. Even if it were possible to use the energy it contained all at once when full, it would be able to power SA for a full three minutes. I recall it was a long time before reports actually gave an energy value instead of power, so I couldn’t work out of for a while.

        I know it’s not supposed to power the whole state, but this provides some perspective.

        • Zig Zag Wanderer

          So from that, a battery around 3,360 times the size of the existing installation by my calculations to power SA for a week.

          I wonder how long it would take renewables to charge that up?

      • Eventually we will need to replace Coal and Gas with something. Once all available coal is mined and all available gas and oil are fracked. It does make sense to develop and test other methods now while it can be done using cheap reliable energy sources to create them but it doesn’t make sense to foist them on civilization until they are truly needed…which they currently are not

        • But wait. Don’t we have enough uranium and thorium to last until the sun goes red giant? After that, we can use solar. We’ll be inside it.

        • We have over 400 years till oil and gas run out. Coal maybe 3 times that.

          I’ll let my 12th generation grand children worry about that problem, using technology that none of us have even dreamed of yet.

          • Bingo again, Mark.
            Whatever we need when that time comes can be figured out by people with far more knowledge and more advanced tech than we can imagine, unless you figure that we know as much as people a few hundred years, or even several decades in the future.
            Has that ever been true in the past?

        • Not if you believe in the abiotic nature of oil and natural gas/methane. You just have to develop the technology to drill 5-10 miles deep into the Earth’s crust.

          • I do not know about that, but I am sure that the estimates for the total amount of fossil fuels in the earth are very low.
            They always have been low, and that trend has not changed AFAICT.

    • The information that was released by Neoen a couple of days ago… makes it very clear the previous government’s implementation and delivery of the battery was incredibly messy and overly expensive,” Energy Minister Dan van Holst Pellekaan told ABC Radio Adelaide.

      “It actually costs taxpayers’ money. There’s a cost of $4-5 million a year to have the battery in place … There are more costs than that involved.”

      Such a “good job.”

    • 20 MWh is a ludicrous contribution to any reasonably sized grid. One or two minutes production for a normal-sized nuclear or fossil power plant. It can do some good in “stabilising a grid” for a minute or two if you have a gas turbine that can take over afterwards.

      When South Australia bought that battery with big fanfare they also bought five 50 MW gas turbines. But that was done quietly.

  12. I vaguely remember reading about a system that used excess energy to lift a very heavy weigh using pistons.

    The energy could then be regained later.

    This was probably some 20-30 years ago.

  13. Pumped storage in the U.S. can handle relatively small amounts of energy. And this concrete block gizmo can only store 20MWhrs, a piddling amount in grid terms – what the typical nuclear reactor can produce in less than 15 seconds. Pumped storage was not created to provide power when none was available, but to store cheap baseload power for those hours when demand exceeded the baseload generator’s capacity and to avoid what was back then very expensive peak load power from natural gas. Stored power has no abulity to replace unreliable power, which can disappear for hours, days, even weeks.

    • The idea has merit. Comparable to pumped storage and available everywhere even without land elevation differences. However there will always remain the 4 main problems of green energy
      1) Because of the intermittency, you will always need fossil fuel backup because what will drive the pumped storage of a flat system like this? You will need fossil fuels to get the bricks back down when the sun isn’t shining or the wind isnt blowing. Or you will always need fossil fuels to guarantee no blackouts nor brownouts.
      2) Land use is already bad enough with renewables. This just creates further land use .
      3) Stability issues on the grid and spinning losses will always remain as well as the huge life cycle costs of green energy.
      4) As soon as you start to remove the green subsidies, green investment will dry up.

      • “The idea has merit.”

        I agree, at least as a thought experiment. Plus it really goes to show two things. The first being how low density renewables really are, and how we have come to expect grid power to just always be available, without really realizing how much energy is actually in the grid every second as evidenced by how many concrete blocks it would take just for 20 MW/hr. Last Sunday Nov 11th, the USA mainland grid consumed 198,495 MW/hr average per hour that day, but on Monday, the lower 48 consumed well over double at 469,009 MW/hr per hour. And the vast majority % of that currently comes from fossil fuels. Which is the 2nd point. It is really a good thing that we are still no where near peak oil, firstly, and secondly, it is even better that CO2 not only isn’t dangerous for climate, but it is the invisible gas of life. How is it that CO2 has become so demonized and labeled pollution is just beyond words. You couldn’t have made this up 50-60 years ago when I was a kid.

        • Look no further than the mentality espoused by the supposedly intelligent and educated jackasses that pretend to be our betters.
          We have a few of them right here telling us what is what.

  14. Of course, the very best way would be to somehow store solar energy as a transportable substance of some sort, even being able to use that transported substance to power the transportation system.

    Some sort of substance that combines readily with atmospheric oxygen, perhaps. ?

    Even better if that chemical can be used for other purposes, such as growing food etc

    Can anyone think of such a substance ?????

    • Ummmmmmmmmmmmmmmmmm Is it something that starts with a C and when combined with oxygen, Al Gore and the whole Democratic party believes that it is a pollutant and yet it comes out of his mouth every time he speaks.

      • Carbon Engineering in Squamish, BC is trying to do this extraction of CO2 out of the air directly, and then use someday use surplus renewable electricity to break it apart and adding hydrogen to create liquid fuels. Or something close to that. If it can be developed wholesale someday without subsidies, and has a round trip efficiency over 66%, it may have some application for creating high density liquid carbon fuels. Would maybe be real handy on Mars, if rocket fuels were required, and had an abundant source of electricity.

        http://carbonengineering.com/

        • We already have some things that pull the 4 molecules out of 10,000 out of the air which are CO2, and they are entirely self-replicating, run on solar energy, and can be put anywhere on earth that it is not freezing cold all year…provided they have some water.
          The larger models produce wood out of the carbon dioxide, and many of the smaller ones produce actual food people can eat.
          As a bonus, the emit pure oxygen as a waste product of the reactions.

          • I was thinking an exotic application that might make sense, such as Mars where there is plenty of CO2, and you needed to make rocket synfuels such as hydrogen or liquid oxygen or kerosene. Or even just everyday common jet fuel. If you have plenty of electricity, then the knowledge to be able to modify the carbon chains could be real handy. I am not opposed to any R&D. And I am not opposed to gardening as per your recommendation, but I fail to understand your point given I was talking about Mars and manufacturing rocket fuels directly out of CO2.

    • Fred250, here’s an idea for you: use water. It is very safe, easily transportable and has other purposes. “Store” electrical energy by dissociating the water into its hydrogen and oxygen components. Then when you need to recover that stored energy, recombine the hydrogen and oxygen and recover the electrons released in the recombination process. I don’t believe there are any practical limits to scaling this technology.

      Why, I think I’ll go so far as to call this concept a “fuel cell”.

      No charge for this.

  15. This would be a very intermittent power supply. Every time a block is dropped at the bottom, energy would be needed ( and non created ) while the crane block ( head ) is returned to the top. Cranes blocks do not lift quickly.

  16. https://www.theengineer.co.uk/issues/march-2015-digi-issue/pumped-storage-a-new-project-for-wales/

    This article suggests an efficiency pump to generate of 70% to 80% – significantly better than even ccgt
    Also new builds may be in the offing.

    Pumped storage: a new project for Wales
    12th March 2015 12:00 am
    A new pumped storage scheme for emergency electricity generation is to take shape in North Wales’s

    With the highest mountain in Wales as its centerpiece, Snowdonia’s natural beauty is a magnet for some six million visitors a year. The same glaciated geology that helps make Snowdonia so valued as a wild place also makes it attractive as a location for grid-scale electricity storage.
    Dinorwig, currently Britain’s largest pumped storage scheme at 1.7GW, was built there on the northern shore of Llyn Padarn near the town of Llanberis. But that was 30 years ago.

  17. All green energy projects should be auditted for embedded carbon. I suspect that even if this could be made to work reliably over a reasonable time horizon, the embedded CO2 in all of those concrete blocks will erode its green credentials to nothing.

  18. What do you do with the blocks when the storage plane goes belly up? I say use it as the endoskeleton of an amusement park.

    • Brilliant invention. It uses the idea of material strength and gravity to produce energy. Now if we could only get a non polluting stove and source of energy for those 3 billion people who are forced to cook with dung, wood, charcoal, and other biomass.

  19. My friend in Pahrump, NV, said this:

    “There is already a plan in place near Pahrump to pull a train load of boulders up a long slope and then let it coast back downhill to recover the stored energy. If what I have heard is true, the BLM has already granted permission for this project to take place on public land to the southeast of Pahrump.”

    Pahrump is about 50 mile from the Ivanpah solar generator.

    • The Ivanpah solar power facility???

      I thought most knowledgeable people were already disgusted with its poor overall efficiency and low capacity factor. [According to Wikipedia, the facility’s overall energy conversion efficiency = energy output / intercepted solar energy = 1,045,967 MW*h/yr / 6,621,720 MW*h/yr = 0.15796 or less than 16 percent.]

      Why are they now looking for ways to further make it infeasible (I understand Ivanpah’s electricity cost is more that $0.20/kWh output, but I don’t know if that is an LCOE cost that takes into account the $2.2 BILLION cost of the boondoggle).

  20. “The trouble is the world needs to add a lot more energy storage, if we are to continue to add the intermittent solar and wind power necessary to cut our dependence on fossil fuels.”

    Umm, let’s just stop wasting limited resources building and installing less efficient and more expensive power sources.

  21. Taking ugly to a new level.

    “A 120-meter (nearly 400-foot) tall, six-armed crane stands in the middle”

    “The total energy that can be stored in the tower is 20 megawatt-hours (MWh), enough to power 2,000 Swiss homes for a whole day”

    So a small town of 10,000 homes would require five of these concrete monstrosities, per day.

    Before taking into consideration that these ugly monstrosities are forty stories tall and only fulfill one purpose.

    “When there is excess solar or wind power, a computer algorithm directs one or more crane arms to locate a concrete block”

    Oh!
    Great, a concrete trickle charged latent energy source that only works off of excess electricity produced by wind mills and solar sources. Sources that rarely produce more than 25% of their baseplate capacity.

    Wonderful!
    Forty story tall stacked concrete lincoln logs with giant cranes, surrounded by thousands of desolate acres of land with wind mills and solar arrays crowding out humans and wildlife.

    • “The total energy that can be stored in the tower is 20 megawatt-hours (MWh), enough to power 2,000 Swiss homes for a whole day”

      Apparently the Swiss homes use very little power, like 417W in average. According to worlddata.info it seems to be 788kW per capita on average. So more like 1,000 homes.

      Crabby calculations all in all, as one must assume that these storage device probably need to be giant as lakes and cost trillions, as we need months of storage if “wind” is taking over most of the production.
      As a child I had these kind of wheat dreams too.

    • You’re not thinking fourth dimensionally. They could be forty storey tall apartment blocks filled with climate refugees. Two birds with one stone.

      Come, come, fellows. This whole thread is a joke, is it not?

  22. Extra idea, free.
    Have a small reservoir of water nearby. Build a tank around the concrete blocks. Fill it with water so when the blocks are down, so they are buoyant and easier to lift while some parts of them are still under water. Empty the tank before the cycle when the weights come down. Adds another control mechanism because you can pump and recover energy from the water system like it is a mini hydro system for short term fast response load following. This is knee jerk inventing, so be kind. Geoff.

    • Geoff,
      Are you saying your free idea was “knee jerk inventing”, or that the stack of blocks idea was “knee jerk inventing”?

      SR

      • The free idea was, in the way of “Never give a sucker and even break”, though the basic concrete block proposal is trivial and insignificant when compared to larger concepts like “Why do so many greens oppose nuclear powered electricity while promoting windmills?” or “Why is there an innate impulse that drives people to align with the stupidity of the green movement?” Geoff

  23. Concrete (Portland cement) production is just behind fossil fuel in anthropogenic CO2 emissions.

    So sure, let make a many megatonnes of new concrete blocks to SaveThePlanet.

    • We can use steel instead. Also produces oodles of CO2 being manufactured. Come to think of it, all that concrete has got to be reinforced. With steel rods. And those cranes must be built of pretty fancy steel.

  24. So how much solar and wind energy is really used and how much is wasted? We don’t know. All we do is quote peaks but we don’t know how much is actually used because we can’t toggle between fossil fuel and renewable generated sources efficiently enough to measure. No? I see this as a viable solution for niche applications and has advantages over current batteries. The low tech simplicity and cost makes it ideal for third world applications where 24X7 availability isn’t an issue. Bury some of it and put a building over the top and you help mitigate the weather and earthquake issues. Local materials could be used for the dead weight. Unfortunately I don’t see anyone caring about providing electricity to those that don’t have it.

  25. Oh come on, seriously?

    Concrete has a density of about 150 lbs per cubic foot and water is about 62 lbs per cubic foot. So the rhetoric about concrete being able to store so much more energy is really only about 2.5 to 1. Take a look at the scale of pumped hydro and you’ll suddenly realize that even with a 2.5 to 1 density advantage, this system still needs an AWFUL lot of concrete in an AWFUL lot of towers to get to grid scale.

    There’s a second claim in the article, which is that there are only 10 countries that have built pumped hydro storage. I haven’t fact checked that, but it is most likely one of those things that is technically accurate and totally misleading. Every hydro electric dam is also a hydro storage facility without pumping. In a grid with multiple sources, the flow rate from the dam is ratcheted down when other sources are over producing, and the water backs up behind the dam for use later. No loss from pumping the water uphill because you simply didn’t let it down hill in the first place. When other sources under produce, the hydro dam is simply ratcheted back up to fill the gap.

    Novel idea, kudos to them for that. But a stunning leap in energy storage it isn’t, and doubtful that it will be economical.

    • Hey I know! Blocks of gold! 1200 lbs per cubic foot, now we’re getting a decent density advantage, nearly 200 to 1! Plus we have lots that costs nothing to get. We just stop storing it as bricks in Fort Knox and instead store the same bricks in one of these contraptions.

      There may be a security risk I haven’t quite figured out yet….

  26. The solution to an expensive inefficient environmentally destructive unreliable ‘renewable’ energy generator is to add an expensive inefficient environmentally destructive ‘storage’ system?

    Yup. Sounds like a plan.

  27. If the solar and wind guys had been paid on the basis of Firm on demand power when required they would have figured this minor problem out by now. Concrete blocks, hydraulic accumalators or flywheels…this isn’t rocket science either. And wasting precious state of the art batteries for grid storage is really stupid, not to mention expensive and wasteful.

    Unfortunately, the market got saturated with subsidies and priority access to the grid with solar and wind. Because these types of renewables are low density and non reliable, these means the dams are spilling water as they have to ramp up and down, or the coal/gas baseload gets shuffled off to the spot market at next to worthless rates. That was a fundamental error that rewarded all non firm renewables with firm prices and grid access while making baseload pay the price. Should be the other way around, without any subsidy. Necessity is the mother of invention.

  28. So who wants a bunch of these 400′ towers scattered around the city? One for every 2,000 homes? How ugly would that be? Even though they are made out of concrete they can’t be cheap to build! Creative idea but just plain ugly. Who wants one of those in their neighborhood?

  29. Well we can come up with all sorts of storage ideas. How about hydrolyzing water and storing the hydrogen on a high peak. Recombine with oxygen in fuel cells and let the resulting water flow down hill through a turbine. You get a three for: heat to drive a turbine, water to drive a turbine and electricity from the fuel cells. Yes, I’m just pulling this out of my … you know.

    • I’m not any kind of boffin like you lot, but work in a power station and am interested in the subjects raised on this site. Bear, I can’t find fault with “hydrolyzing water” theory. As you say, split the water when there is over generation and use the hydrogen as fuel.

      • The fault is the same for all storage methods: Inefficient thermodynamics, scalability, cost to build and maintain…

  30. You know me, I’ve done too many engineering projects to not run at least some back-of-the-envelope calculations. The problem that I see is friction at the pulleys.

    Each pulley in such a system adds about 10% to the force otherwise needed. Now, these blocks weigh 35 tonnes, so you’re gonna need maybe 5 pulleys at the top sheave and 5 pulleys at the hook end.

    The total force required to use the pulley system is 1.1 per pulley, raised to the tenth power, or about three times the force required in a friction-free situation.

    Next, you have the inefficiencies in the winch and transmission. Each of those is on the order of 95% efficient on a good day, combined maybe 90%. So it looks like it will take on the order of four times the force to lift the block up. That’s 25% efficiency.

    Now, we could reduce that by using heavier wire rope … but then the energy needed to bend the wire rope at the pulleys goes way up.

    So … let’s be generous and figure we can lift the blocks at 50% efficiency. However, that’s not the end. The pulleys sap energy on the way down just as they do on the way up. If it’s 50% to lift it, it will be on that order of magnitude when it goes down … so throughput efficiency is likely on the order of 25%.

    Now, are those numbers solid? By no means. It’s a back-of-the-envelope calculation designed to see where a problem might lie. But I’ve doubled the one-way calculated efficiency to allow for that in part. If the one-way efficiency actually is 25%, overall throughput efficiency will be much lower.

    In any case, these numbers indicate that there MAY be a real problem with the efficiency of the system.

    Finally, what do they claim the efficiency of the system is?

    90 percent!

    90% … gotta tell you, I’m not buying that for a minute. The motor/generator plus the transmission alone would make the throughput efficiency much less than that. It’s very unlikely that the motor/transmission/winch combo has greater than 90% efficiency. If you have that going both in and out, which you would, that would give a total throughput efficiency of 82% … and that’s with frictionless pulleys and friction-free wire rope …

    Regards to all on a smoky, smoky day. Carr fire smoke still covers central California.

    w.

    • Willis,

      Excellent treatise. I mentioned motor and pulley efficiencies, but with no napkin to hand. Accepting at face value your dismal figures for the weight system: Knowing that pumped water systems are currently in use, what do you reckon is the efficiency of that approach? Obviously the turbine generators have been developed for along time in hydroelectric dams, which as we know provide significant cheap power in good locations. But it seems to me pumping water uphill must incur some major losses.

    • While pumped hydro can have an efficiency as high as 70%-75%, I think you are probably right about the inefficiency of the pulley sheaves in this proposed contraption. They may even get too hot to work proper due to all the heat being generated in the friction. If it is that inefficient, even say 50% round trip, that is a lot of thermal heat being created in the sheave/rope/transmission losses both ways full time. The motor/generator will have its own losses, at best 91%-92% overall efficiencies for that, also both ways so there is at least 20% off the top in a super efficient motor/generation system and electrical wire/transformers that we already have. If you can’t get a total 70%-75% round trip efficiency, it probably isn’t worth doing.

      Since this is a thought exercise now, and fun to think about, perhaps floating hollow concrete blocks up a narrow pipe in a pumped water column could kill a few birds with one stone, in that a buoyant cement block gets a lift up for fairly efficient inputs just pumping water in and after buoyant displacement for lifting the concrete blocks, that water power is recaptured, but now you have the heavy concrete block at the top of the tower. Then the concrete block can be utilized in a reverse hydraulic gravity pump/generator the same way, and cool the hydraulic oil. Just thinking of how a canal lock works at the Panama Canal is really staggering how much dead weight of a massive loaded ship can be lifted with ease. Of course, they are utilizing a higher head water to work both ways, so is ‘free’ in that sense, although I wonder if there is still something here that improve efficiencies with these concrete blocks up to 75% efficiency, if we just tinker and modify things around a bit? There is no free lunch, but maybe some dessert. Doesn’t hurt to think…

    • Willis, I think I figured this one out, we build Eco-friendly cable-car systems on the tops of all significant mountains (especially volcanoes … they are potential energy ‘renewables’) and get useless unemployed greenies to fill the cars with rocks, then release the car under gravity to let a cable turn a pulley attached to a generator.

      Presto!

    • Perhaps if they use a synthetic line something like a PowerPro that fishermen use for salmon, most of the bending and unbending inefficiencies go away? That Power pro is petty strong stuff, and very supple, it must be a close to as strong as steel. For regular crane hoisting, efficiencies don’t really matter and steel is the way to go, but maybe where efficiency counts they’ll use something else.

      • Spectra or Dyneema are the names of this material. Claims to be many times stronger than steel. Its is expensive.

      • Scotty, that might help … but I don’t think it will make the problem go away. What I’d like to see but haven’t found is anything resembling an engineering-level study of the actual efficiency. They claim 90% round-trip efficiency, but I’m not seeing how that is even remotely possible. That would imply that the entire motor/transmission/winch/cable/pulley efficiency is sqrt(0.9) = 0.95, and that’s not happening.

        w.

    • Willis, I find your efficiency figures to be startling. I have no idea if they’re right. I find it hard to believe that anyone making a serious proposal like this and claiming to be expirimenting on it would be unaware of frictional losses. They did give an estimate. I would assume it included things like this. But I suppose stranger things have happened (e.g. hockey stick).

      • Thanks, Canman. I found their efficiency figures to be startling. They claim net 90%. For that to be true, they’d have to achieve 95% storing the energy and 95% releasing it.

        However, I don’t believe that just the motor-generator / transmission / winch part of the system can achieve a 95% efficiency. To do that, each of the three parts would have to achieve 98% efficiency … not happening. And that is NOT including the frictional losses in the flexing of the cable and the turning of the pulleys …

        Real-world large electric motors are at around 92% efficiency.

        Winches have three types of gears—worm, spur, and planetary. The most efficient are spur gears, at about 75% transfer efficiency (transmission plus winch). See here for details.

        That gives a total efficiency for the two of 70%. HOWEVER, that’s 30% loss going in and 30% loss going out. This gives a combined efficiency of about 50% …

        Now, if you went to ultra-high efficiency motors and gears you might get 80% for the combined system, which would give you 80% * 80% = 64% for the combined system … not including cable and pulley losses.

        So I have no clue where their claim of 90% efficiency comes from.

        My best to you,

        w.

  31. I remember a Popular Mechanics article back in the day when I was young (pre-teen — 50 years ago) and my father read it avidly. It suggested a huge flywheel be installed under the house to capture wind power. When needed the motor that powered the flywheel would draw energy from it, reversing the generating process. I never saw that implemented either.

    • It has been done. There are flywheel energy storage systems. As a matter of fact every electrical grid is a huge flywheel storage system. The rotating masses of the turbines and generators are crucial for system stability since it buys time to take action when there is a failure, or at least time to limit a failure to a part of the grid.

      This was what actually caused the system-wide failure in South Australia. Wind turbines have asynchronous generators because they are cheaper, but this means that their rotating mass is useless. So when there was too much wind power and too little conventional power in the grid there was no longer enough rotating mass (=time) to do anything when there was a largish point failure and the whole system went down.

  32. ‘The trouble is the world needs to add a lot more energy storage, if we are to continue to add the intermittent solar and wind power necessary to cut our dependence on fossil fuels.’

    Wut? Storage does NOT fix wind/solar intermittency. Storage is a fake solution; it solves nothing.

  33. It doesn’t have to be a tower of blocks, it could be a hole in the ground, any hole in the ground will do, for example a vertical shaft. -The dreadfully nasty deep mining coal industry has lots of relevant experience in this regard.
    A hole in the ground solves the wind problem and the visual intrusion, but now we may have problems with ground water ingress.
    OK, It doesn’t have to be solid concrete blocks (like the gold idea, but lead works too) into a hole in the ground, it could be a compressible fluid into a deep high pressure reservoir. A gas with a phase change to liquid under pressure would be good. – That dreadful nasty oil industry has lots of relevant experience in this regard.
    Is it 1st April already?

  34. What about instead of storing excess energy what about using it productively to say melt aluminum when energy demand is low and shutting down the plant when energy supplies are low.

    Plants could easily be designed to take advantage of differing production rates.

    • “Plants could easily be designed to take advantage of differing production rates.”

      I suppose that is the reason plants take such extensive precautions to ensure an uninterrupted power supply.

      Generally speaking process industries handling large volumes of very hot substances (steel, aluminum, glass) do not take kindly to power interruptions. The most extreme case is a float glass factory which in practice has to be completely rebuilt after a power failure.

  35. This is essentially a gravity-battery. I admit its a cute idea, but I can now envisage more poor home state of Texas covered in these monstrosities as well as those wind farms up on the hills. Its one thing to build a wind farm over a corn field, and quite another to ruin beautiful rugged landscape. But I can see another use for these cement blocks…they can program the computers to cover up all the dead eagles and bats the wind farms are leaving about.

    I think I will keep my bet on coming up with better chemical battery storage over this idea. There is just too much to go wrong…think way one of our 200″ MPH tornadoes could do to all these loose blocks… (You don’t believe me, go watch some you-tubes of cars and trucks flying about some of the big tornadoes).

    Speaking of gravity-battery storage…there are a lot more locations for hydro than you might imagine, assuming costs are no object (so let’s call it green and costs don’t matter anymore). You just need to build a large sea-water storage area in an estuary, let the tides partially fill it and use “excess power” to pour more sea water into it. Then, when tides are lower you can let the water out through turbines. Yeah, lots of problems, but it would work near almost any coast…until the hurricane hits at least.

    Hey! I know, let’s build nuclear power plants that run all the time and don’t have these issues… They can be hardened against hurricanes and tornadoes, and they don’t kill all the birds or bats either. OK, silly idea.

    • yeah, I HATE what they’ve done to Texas… other places too, but I live in Texas and it’s horrible. In 20 years they’ll have big contracts to take them all down because a younger generation of kids will have grown up to detest the sight of the folly of the Government-subsidy farms.

    • Robert of Texas

      I think some con man in Wales attempted something like this. I understand the British government eventually threw the idea out.

  36. Hopefully this scheme has been proto-typed. Concrete blocks have alot of friction and are not easy to move around. If they have prototyped this and upscaled it in tests then the data should speak for itself. Otherwise it sounds like a pipe dream… just an experienced EE speaking.

  37. This system can be easily compared to pumped hydro storage, which is currently the most economical form of energy storage. The amounts of energy storage are proportional to the density of the material and how high it is lifted.

    One little realized aspect of hydro storage is the astounding amounts of water that are used. Take Hoover Dam, which has a hydrolic head of almost 200 meters (about 600 feet — perhaps a third higher than a 40 story building). How much water do you have to lift that 200 meters to run a 100 watt lightbulb for an hour? I come up with about 180 kg or 50 gallons. That makes 500 gallons per kilowatt hour.

    Now cement is about three times as dense as water and iron about 8 times as dense — well within an order of magnitude. Of course you can increase energy stored by increasing lift height. By any measure, you’re talking huge amounts of material.

    • You are very close at 100 watts theocratically where gravity is 9.81 before all losses. (98.1 watts)

      So a teeny bit less = 69 watts net (after losses) for 180 L water dropping 200 M over an hour x Water to Wire (WTW) efficiency.

      180 Kg/litre /3600 seconds/hour=.05 Liter per sec Flow x Head x 6.9 WTW losses
      .0005 lps x 200 M x 6.9 (all losses in WTW). =69 watts per hour Net

      But I suspect you forgot the losses, so almost exact in theory: a bit less at 69 watts in practise for 180 Kg of water falling 200 M over an hour with losses.

        • Dang autocorrect…this fancy new Apple MacBook Pro…I wish it could read my mind, and is so handy 99% of the time. It even still looks real close re-reading after you point it out. Nah, gravity isn’t a religion..lol at least for most of us.

  38. The load ALWAYS matches demand – within fractions of percent. IPOs are experts at planning and manipulating the various generating sources to insure that happens. When load does not match demand frequency fluctuates, generation too low & shed load, demand too low & shed generation. Too fast or too slow in response and bad things happen, distribution breakers open, generators trip.

    Generators are usually most fuel efficient in a range around the design point. Backing off load increases the heat rate/decreases efficiency (100 * heat rate, Btu/kWh/3,412 = eff, %) and $fuel/MWh goes up as does emissions.

    So, do the incremental fuel savings of maintaining optimum loads pay for installing & operating storage?

    Look around. If it did, it would. It doesn’t.

  39. Won’t work. Storing energy goes slowly. Retrieving energy, however, must be extremely fast in order to balance the varying demand on the system. Waterbased balancing systems have a zero to full power lag of a few seconds which can only be achieved when the medium is a liquid. Concrete is not a liquid. The only alternative to water would be Mercury, lots of it.

  40. This fully renewable world that we are supposed to be “transitioning” to is going to be one fugly place isnt it.? There is no end to the junk these people want to litter over the land and seascapes

  41. Clock makers solved the problem centuries ago. Put the weight inside the 400ft wind turbine tower. The turbine lifts the weight when the wind blows and when the wind stops the weight falls and drives the turbine (not the blades) It worked for winding up clocks in the 19th century. If you lubricate the system with unicorn oil to remove friction and use three parts of Hubris to one of cement for the weight to make it denser you have the perfect system. Patents pending.

  42. I think there is some confusion about energy storage, pump storage is not about storing ‘excess electricity’ (More correctly excess generation capacity, which should be the normal state of affairs for 24 hours a day, this spare capacity is used to fill the upper dam at times of low demand) to compenste for demand exceeding generation capacity. It’s purpose is to allow the grid to cope with sharp peaks in demand which there is insufficient time for the dispatchable generators to increase output to match. Dispatchable power plants react automatically to load variation and this is seen by the variation in frequency. Increase in load drops the system frequency, turbine governors open up the steam valve to get the frequency back up and vice versa. A large increase in load causes a greater drop in frequency which pump storage can be used to compenaste so minimising frequency drop.
    What is impractical and very expensive (Even if battery costs are lower) is to use storage in the grid to compensate for lack of renewable generation on a large scale. It is not the answer for renewable generation variability due to the very large capacity required to do that.

  43. A well balanced, reliable, stable
    and flexible electric network does not need any
    energy storage.

    With wind and solar, energy storage is simply silly at the very least.
    In proper consideration of time, there is not any efficient or any minimal
    required stable sustained production, let alone any actual meaningful
    extra surpluses for storage.

    Put simply, in case of wind and solar, “non production” undermines the
    “extra surplus” over time, especially when considering that wind and solar
    tuned and operationally connected to the grid continually 7/11.

    Of course, wind and solar do increase instability and inflexibility in the grid.
    Of course this will lead to more consideration for grid energy storage.
    But it only be considered as grid storage by the grid for the grid, as means
    to keep paying more and more the wind and solar, for less and less,
    and efficiently and very successfully keep increasing artificially the
    electricity tariffs and payments.

    Crapier the grid more and more in need of considering energy storage…
    and less and less efficient and more costly it becomes…regardless what
    you add and hang on it, either trains or concrete blocks or else.

    cheers

  44. Having been struck by lightening at age=12, me and elektrikery have an understanding.
    We have biiiiiig respect for each other and are endlessly amazed at what each of us can, and does, get up to.

    This impinges upon magnetism, strictly electro-magnetism, as you don’t get one without the other unless nothing much is happening- a-la static electrikery.
    Moving elekrikery is all about the GHGE of course, = transmission lines & media, impedances, short circuits, open circuits, reflections, standing waves, energy transmissions & absorptions depending on any and all of those things.

    A fantastic trick guaranteed to get *most* people wondering involves 2 identical capacitors. Things with ‘capacity’, that is they store energy. Manifests as ‘voltage’ – apply a voltage to a capacitor and it ‘stays there’ after you remove the voltage source.
    The energy stored follows a familiar sort of rule, it goes as ‘half C times V squared’
    C = Farads and V = volts to give energy in Joules

    The Trick involves 2 identical capacitors, one charged to voltage v and the other not charged at all.
    Work out the energy in that system. (half CV squared)
    Then, connect the 2 in parallel using as perfect a piece of wire as you can (imagine)
    You will get 2 capacitors (value= 2C) and each will have half the original voltage
    Now work out the energy stored and you will find exactly half of it has ‘disappeared’ – the C value doubles but the V-squared value goes down by a factor of 4

    Where did the energy go?
    Answer please……
    Where Did The Energy Go?

    Remember, you can do this experiment with perfect capacitors and perfectly conducting pieces of wire and The Energy *still* disappears..

    And so it is with this sort of system. You are moving blocks of stuff, energy goes as velocity-squared and they are being accelerated and decelerated. Their motion (velocity akin to voltage) is being shared, exactly as happens with the capacitors. Energy loss or flat-out disappearance is the name of the game.

    Just as in the GHGE, as combination of mechanical motion (temperature) and electricity (radiation, long wave, short wave, down welling upwelling, whatever welling radiations and energy)

    Energy is not trapped, it is not stored, it weasels its way any and every way that it can.
    At Light Speed.
    *Only* in Science Fiction will you *ever* catch up with it.
    (Or inside supercomputers and the GHGE)

    • sigh. an extra “2” snook in there
      (energy eh, what’s it like? If even a self proclaimed genius like me can get it wrong so what hope have the rest of you?)

      Should= You get ONE capacitor of value = 2C

      • Double sigh, despite your correction. There is no missing energy in your Gedankenexperiment. Energy is conserved. It is true that the total capacitance of two 1 farad capacitors connected in parallel will be 2 farads and that the electrical energy originally stored in the single charged capacitor (at voltage V) will be equally divided between the two capacitors upon connecting them in parallel. But you are wrong in asserting that the voltage across the connected pair will than drop to 1/2 V. Instead, it will drop to (1/sqrt(2))*V, or 0.707*V.

        • Peta is correct – energy is lost during this experiment. If the wire has any significant resistance, then the I^2.R loss during the current spike (with exponential decay) will exactly account for the loss. With zero resistance wire, there will be an arc at the moment of contact, with energy loss as light, heat, RF radiation…

    • It goes back into surrounding space from where it came.

      Space is a ‘battery’, harnessing the forces is how you make temporary withdrawals from that battery.

  45. Another ridiculous ‘solution’ to a self-created problem.

    Anyway, everyone knows masonry is an excellent way to store energy – it’s called UHI, and is vastly more significant in the actual temperatures that the vast majority of people in the world experience, than the supposed role of CO2.

  46. The tower will topple at wind speed of 65 kph. The concrete blocks are not fastened. Only their weight provides stability against wind force. Bending torque calculation:
    Assume: clockwise torque = weight of blocks, anti-clockwise torque = wind force
    when clockwise torque = anti-clockwise torque, tower is stable and will not move
    when clockwise torque < anti-clockwise torque, tower is unstable and will move and topple

    concrete block = 1 m x 1 m x 1 m, concrete density = 2400 kg/m^3, stack height = 120 m
    weight of stack = 2400 (9.81) (120) = 2.83 e6 N
    torque arm = distance from center of mass to pivot point (edge of block) = 0.5 m
    clockwise torque = 2.83 e6 (0.5) = 1.41 e6 N-m

    wall area = 120 m x 1 m = 120 m^2, air density = 1.225 kg/m^3, wind speed = 18 m/s (65 kph)
    dynamic pressure = ½ (1.225) 18^2 = 198.45 Pa
    wind force = 198.45 (120) = 23,814 N
    torque arm = distance from center of wind force to pivot point (edge of block) = 120/2 = 60 m
    anti-clockwise torque = 23,814 (60) = 1.43 e6 N-m

    clockwise torque < anti-clockwise torque at 65 kph wind speed, tower is unstable and will move and topple

  47. A lot people older homes have 8 or 10 inch water well pipes that were drilled over 100 feet deep but have been abandoned for city water. If you made a ten inch cylindrical lead slug (or some other metal) that weighed a ton, couldn’t you store energy the same way, with a lot less infrastructure and complexity, and no worries of wind toppling it, by lowering it up and down in that pip

    • The weight still reaches the bottom, leaving you in exactly the same state you would be in had you never built the storage system.

    • Even with lead you need some 300 cubic meter of such slugs pro house. The idea is not efficient at all.

  48. All of this reminds me of people recommending using teaspoons to dig the foundations for skyscapers to save on using fossil fuels. It works, but’s foolish and makes the people coming up with it look desperate. Next, we’ll have dung burning stoves with massive filters to make the exhaust “safe”. However, since the stove don’t use fossil fuels, they’re will be praised, subsidized and probably worshipped. Combining 21st century lives with 14th century practices results in a sad failure. What a comment on our loss of science and understanding of the real world, eclipsed by worship of “alternate energy” to “save the planet”.

  49. The idea is not really feasible. A typical one-family house in Europe requires around 90kWh (a week worth of consumption) of energy storage to smooth out unreliability of the renewable sources.
    Now, suppose we use blocks with density 2.6kg/l, 1m block height, 10m working height. How wide will the tower be? The answer is – 20m in radius. Much bigger than the actual house. Not really feasible.

    • In fact I can go out right now and buy a 90kWh Li-Ion battery for 25k€. Will such 40m wide and 11m deep tower full with cement blocks and cranes be cheaper than 25k€? I seriously doubt it.

    • When centrally produced electricity becomes unreliable, people will acquire their own production capability. Like a diesel generator. They are not going to buy limited carry through capacity – they will still need their own generating capacity.

      The homeowners’ dilemma is identical to the power companies’ dilemma. Storage does not solve the problem.

      The duration of wind/solar outages are unknown. Days of storage is prohibitive, obviously not feasible. As you approach 100% renewables, you approach requiring infinite storage. Infinite storage will require infinite power supply to charge it up.

  50. we’ll have dung burning stoves with massive filters to make the exhaust “safe”. However, since the stove don’t use fossil fuels, they’re will be praised, subsidized and probably worshipped.

    Funny you should say that.

    https://www.breitbart.com/politics/2016/03/29/the-dirty-story-behind-hillary-clintons-clean-cookstoves-campaign/

    carbon credits. It states: “In addition to being one of the fastest growing offset types in the voluntary market, cookstoves credits are selling for some of the highest prices observed in the voluntary carbon market.”

    If Clinton becomes president, her energy policies will likely enact a cap-and-trade system or a carbon tax—which would suddenly make her cookstove project profitable.

  51. I think I get it; this is a contest right? To see who can find a way to make this already bad idea worse while making it sound even better to the renewables crowd?

    This is a tough challenge, but here’s my go at it:

    One obvious drawback of the original plan already mentioned by others is we’d have to build a whole bunch of these towers, further dotting the landscape with low-density energy systems. Why not get double use out of the 100-meter towers we’re already building to host wind turbines? Build the towers a little stronger and the concrete base a little bigger and you could incorporate a lift system for a heavy concrete collar surrounding the tower.

    Advantages:

    1) It’s decentralized — each turbine has its own energy storage system built in.

    2) It eliminates transmission losses as the surplus output of any single turbine is captured right there.

    3) It scales automatically with new wind capacity.

    4) It requires no more footprint than the turbine itself.

    5) The heavy lift capability can also be used to get people and replacement parts up and back down for maintenance activities.

    6) You get the power for the lift with a simple mechanical takeoff from the turbine shaft itself, avoiding the efficiency loss of the rotation -> generator -> electricity -> electric motor path. Likewise to get power back just use the falling concrete block to keep the turbine shaft spinning when there isn’t enough wind.

    When a given turbine has more wind energy than electrical demand, tap the surplus mechanical energy from the turbine shaft and lift the concrete weight up the tower. When a given turbine is not producing enough power to meet demand, tap the potential energy of the concrete weight and make it spin the turbine faster.

    If an individual turbine has already lifted its weight to the top and still has excess wind energy, surplus electricity could be used to spin other turbines whose weights are not at the top.

    OK, let’s see someone top that!

    • And when every single wind turbine is equipped with such a system, you’ll get roughly 1GWh storage capacity for, say, Germany. Currently Germany has pumped storage of 40GWh. Do you think 1/40 of this is worth the costs? Hardly.

    • TOP IT?

      Simples.

      With a donut of concrete surrounding the wind turbine tower we have a readily available flat surface not needed for anything else to which we can attach SOLAR PANELS. These can by themselves provide more than enough electricity to power ALL the control electronics of the whole system thus increasing the input/output theoretical efficiency to 101%.

    • “Build the towers a little stronger and the concrete base a little bigger and you could incorporate a lift system for a heavy concrete collar surrounding the tower.”

      Actually, if one wants to lift a single mass equivalent to the hundreds of “small” concrete blocks of the originally proposed multi-crane system, then that 100 meter wind turbine tower is going to have to be ENORMOUSLY stronger (i.e., much more massive). Look up “Euler’s critical load” for the buckling of columns in compression. It basically says that, for a fixed tower height and given construction material, the minimum area moment of inertia of the tower cross section must scale in direct proportion to the load being hoisted, including the weight of the wind turbine on top, to avoid the tower buckling.

      I’m sure this is the reason for the original proposal to use many relatively small masses as opposed to one (or several) much larger masses.

      • Ooops, typo . . . “if one wants to lift” . . . not “if one want’s to lift”

        I really long for the day that posters once again have the option to edit their own posts after the fact.

  52. First problem. When excess energy exists, it needs to be used, NOW.
    Moving a crane and using it to grab a block will take multiple minutes of time.

    Secondly, I’d love to see how well this contraption handles even a moderate breeze.

  53. Just use sodium ion batteries, as storage. Dirt cheap, and stable, as these schemes go. You can have some Lithium ion as a faster capacitor.

  54. Why everytime stacking concrete blocks.

    Lift and sink the whole neighborhood erected on a ground plate.

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