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Long Duration Thermal Energy Storage to Prevent Wasting Solar and Wind Energy

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The Malta energy storage system takes electricity, converts and stores that electricity as heat, and then converts it back to electricity to be redistributed on the electric grid. In charge mode, the system operates as a heat pump, storing electricity as heat in molten salt. In discharge mode, the system operates as a heat engine, using the stored heat to produce electricity.

40% of the solar and wind power that is generated is wasted. Malta uses steel containers to hold heated salts. This could store 40% of the solar and wind energy that is wasted and return 25% of that amount or 10%.

It seems like they will use the electricity to heat salt and then convert heat stored in the salt back to electricity when needed. This would likely be 35-55% effective in either direction. The total system might be 10-15% efficient. However, the energy would otherwise be wasted.

Malta Inc, Google X alumni company, was funded for $51 million and has a breakthrough long term thermal energy storage technology.

SOURCES- Malta
Written By Brian Wang, Nextbigfuture.com

115 thoughts on “Long Duration Thermal Energy Storage to Prevent Wasting Solar and Wind Energy”

  1. The NACC-FIRES guys wanted to mate a nuclear plant with a CCGT, and their storage actually was electrically resisitive brick sensible heat thermal store inside a a high air pressure silo, the idea being dump grid energy into the bricks, and send compressed air in the gas turbine to the silo first to pick up heat before heading back to the turbine to either runs as is or with makeup natural gas combustion, with the HRSG having some interconnectedness with the nuclear plant side as well.

    On a home basis, something conceptually similar but in a smaller format would be interesting. Capstone microturbines have a large fixed recuperator heat exchanger block for exhaust heat recovery, so extending that functionality wouldn't be too hard, but capstone turbines might be too big for most homes (their CHP types usually target businesses). I wonder if small scale thermoacoustic rigs could be scaled down to home sized rigs, similar to Aster thermoacoustic rigs with the bidirectional turbine for power generation.

  2. Wow, that's flat out scary. I'm assuming the insurance covered that at least, since it wasn't your fault…

  5. If your solar satelite is 60 km diameter and the recieving rectenna is 1 km you're beaming more 60^2/1^2*20% efficiency = 72 000% of solar insolation (AKA death ray).

    Even if you decouple them, that limits you to a solar collector area of ~1 km in diameter for each 60 km in diameter you put in space.

  6. Just the diffraction limit alone makes the receiving rectenna on Earth a Chernobyl exclusion-zone sized area.

  8. "Holy cow!.. An answer! Wow!" So, the great expert on SSP just learned where they are proposed to be located. Are they in Space?

    3 hours ago "OK, now I've read through the first paper". About beacons. Finally!

  9. You seem to agree with Criswell as to the LSP radar size, assume 1 KM target. So, it is not absurd, but part of the 1 cent per KWe plan. Why not? The size is too small for 20-200TWe, so more than one is needed, btw. $$$$$ the bigger the scale!!

  10. You may find it interesting to note that larger radars are needed for more accurate pointing. Perhaps the plans may account for that? Have you checked? Have you informed the military of your stunning work in this field?

  11. My best data is that all these smart people are doing really stupid stuff for 50 years, and publishing the results, OR, you are wrong somewhere. It is your neurotic attitude that is the problem, dude. I let you fester, by withholding info sometimes, just so others will get the clear idea of your method. Did you ever get the nano coating on the battery electrode figured out? Another case where you go on and on without even looking at what people show you. And are wrong from the start.

  12. Given that there are several variants being discussed, all far more advanced than what was there in the 70s, which is where the initial idea was approved my most, you are alone in your claims. You must show something! Don't demand stuff from me, you are the one who is wrong, as current phased array GEO comm sats prove. Or simple radios, for that matter, also power beaming. Everyone else is improving the system, you are making a fool of yourself. It is a tested testable claim.

  13. OK Dan, I've perused the article, and none of the demonstrated power transmissions come even close. We are talking about at max a couple of kilometers, with the possible exception of the northrop grumman experiment, the results of which seem to be secret.

    So from your source, the technology is orders of magnitude away from where it would need to be for LEO power beaming and does not seem to improve. Demonstrations in the 90's are roughly equivalent to demonstrations in the 2010'ths.

  14. Interesting bit: I was correct how the beacon technology works.

    Basically, you phase lock the element transmitter wave to the incoming wave phase. (se my reply to Dennis above).

    The pointing accuracy – how well the power beam is aimed at the beacon source – is a proxy for the limits of how well the beam divergence could be set when it would be limited only by the emittor ability to replicate the incident beam phase.

    And, the only number I could find in the review article from 2013 (Dennis first source) was 0.1 degrees, i.e. two orders of magnitude worse than what would be required for LEO power beaming.

    So, the beacon technology removes the absolute blocker in terms of phase control, but what has been demonstrated is still two orders worse than what is required. Unless, of course, you have some other data.

  15. OK, now I've read through the first paper, and it turns out my guess was correct, it *is* phase locking the output phase of the emittor element to the input beacon wave. Let's call this RMS phase noise in this context.

    So it all comes down to just how well the mixer can detect the phase difference between the incoming beacon wave and the local oscillator and how well the phase difference can be fed back to the emitter amplifier.

    Here is an interesting bit: the "pointing" accuracy will give you a proxy for the limits that the RMS phase noise will give you. If your phased array can transmitt the beam back (with the help of the beacon wave) with 0.1 deg accuracy, then your beam divergence cannot be better than this when using the same phase detectors and feed-back network.

    Note that the actual beam divergence will be the "worst" of the limits set by the RMS phase noise (se above) and the number of emitters (and no doubt aditional limitations).

    And the only experimental data point in the first reference is 0.1 degrees (se reference 26 in the reference list), i.e two orders of magnitude worse than what would be required for LEO power beaming.

  16. I see no reason lithium ion batteries should come down that low, as there is huge demand for using them in vehicles, and as energy density increases, the uses will also increase which means even more demand. Larger drones for flying humans around will be made to the tune of over 5 million a year, then there is more traditional aircraft, mining equipment, farm equipment and robots.
    It is batteries that have the short life. Something like 3,000 cycles. That is a little over 8 years if the system is used every day.
    Electric trains are low maintenance, mostly just greasing the axles, and keeping the paint protecting against rust. The concrete itself should last indefinitely. A glass glaze would insure that and have zero maintenance.
    I would use concrete ties, stainless spikes and plastic coat the sides and bottom of rail as well. That should last over 100 years.
    You should need 5 or less people for daily operation once built.
    Land use is a nonissue, at least for the US and all but the most crowded countries.
    If we banned lead starter batteries for cars, the price of lead should plummet, as over 70% of lead is used for that. That might make it viable to put the lead in the concrete, making the cars heavier, lowering the center of mass making a derailment much less likely, and store more energy. The lead could also be sealed say by dipping it in plastic before it goes into the concrete. That should make it perfectly safe indefinitely.

  17. Thermal storage is cheap but it is also inefficient. Batteries are better. We just have to find ways of making them cheaper.

  19. Got that right: I make a point of NEVER leaving my wife without kissing her, and telling her I love her, because, if I don't come back, I want that to be the last thing she got from me.

  20. Good to hear that you came through. Best of luck with recovery, and I hope we'll read more of your comments from now on.

  21. We have different perspectives. From your point of view I'm incapable of doing research, and from my point of view you have zero technical knowledge/understanding of the system you are rooting for.

    Be that as it may, but if I'm incapable of understanding the theory, then it becomes all the more important to see real world results. Even if you don't understand the system Dan, perhaps you would know of some empirical results regarding beam divergence? And power transmitted?

    I will happily admit to having been wrong if you can provide *any* empirical data of beam divergence that shows that it *may* work. Any empirical data, Dan…

  22. Wondering if low-temp solar thermal in parallel might be worth considering, as source for the heat pumps. In theory you could cool your PV panels, also making them a bit more efficient, and use that heat as input to the heat pumps. Though maybe cooled PV panels would cost more than simply using separate and cheaper (and maybe larger area) thermal collector panels, after installation and maintenance costs are included?

  23. I doubt you could possibly understand the level of stuff going on now with these things. You cannot do simple research.

  24. "1) Real-Time Steering Problem:With regard to a), retro-directive beam control systems have recently emerged as the most reliable techniques to guarantee an accurate beam steering in WPT applications [8], [17], [22], [40],[41]. Such systems are based on the emission of a coded pilot signal from the receiver toward the transmitting array, which is used as a reference to steer the beam back-wards [23], [40], [41]. In such a framework, the steering problem can be formulated as follows [23], [41]." pg 1466 of Dennis' first cite. These are highly advanced versions of the 70s idea, but the pilot or beacon was always there. Can't work otherwise w/o extensive computer work.

  25. Do you have a link to the "beacon" solution? Since you have not explained how it works, I can only guess. And my guess is that you phase lock your individual emitters to the beacon wave.

    This would transform the problem to a phase noise and jitter problem of the phase locked loop. And the requirements on the phase noise and jitter might still make it impossible, but I don't know that for a fact. The devil is in the details. The locking time of the loop needs to be faster than any mechanical motion – such as vibration – of the emitter…

    Here is is crucial to know what has been demonstrated. This would tell us how well they have been able to lock the emitters to the beacon wave (if that is indeed the method) and by extension, how well a future (larger) system could possibly work.

    Do you have any data of achieved beam divergence at all, Dan?

    Also note that even if the system is technically *possible*, it might be prohibitely expensive. If I am correct about requiring 3.6 billion emitters – and phase locked loops – from LEO, then this would surely make it really expensive…

  28. Thanks for replying, Brett.  My health seems to be returning, (wasn't The Plague, thank the lesser gods).  

    Its a funny thing … you go in, they want to see your heart, tell you to schedule an angiogram, you do that, go in, get left by your wife to come back a few hours later, and suddenly its 3 days later, and apparently the tip of the roto-rooter came off, and something sprung a gasket, and the lil' gremlins wearing arterial snorkels went on strike, and you need to take enormous horse tablets, twice a day, or you'll die.  Or worse.  

    Yah know?  

    Kind of like taking a nice early afternoon drive, and having the semi-truck 100 feet behind you crashed into by ANOTHER semi truck from the opposite lane, shutting down the freeway in both directions.  Life … without any help of our own, can turn on you. That accident-not-incurred was a veritable HAIR away tho'.  

    Be well, Brett. 
    Kiss the people who matter, or shake their hands heartily.  

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  31. Peaking pricing may be up there, so running a plant in peaker mode might make sense (though really, at that point you are splitting hairs between dispatchable baseload and peaking for that particular plant). Also, in theory, you could also act as a grid storage energy sink when you have excess grid baseload to be absorbed.

    I suppose the calculus in terms of storage, is whether diurnal storage to level out reactor output to reduce the size of the reactor, or overbuilding steam plant equipment to spin up to peak loads. Favoring peaking means you have idle steam turbines.

    For reference, CCGT is commonly used for peaker plants, but the steam side of the plant (fed by the gas turbine heat recovery steam generator) trails gas turbine spin up by 30 minutes as the steam plant warms up.

  36. The beacon is for the problem of timing everything, as you say would be impossible without it. That is why it was touted as a safety measure in the 70s and beyond, you need the beacon! So no prob with the diffraction? The emitters are going full bore, and need more than diffraction requires, for power load, so they are split up into independent stations. $$$ come from them. I will let you and Dennis take credit for solving this problem in a new and unexpected way. His doc covers this extensively, but you have to interested.

  37. I did read about the 40 years of service life, but since I put the maintenance cost to zero during all this time, I figured it would even out. Perhaps this was wrong.

    But even so, if battery prices come down to 30 USD per kWh – and I know this is a big "if" – then this system really looks both expensive and excessive in terms of land use. Plus, you would have a much, much, faster pay-back time for the batteries compared to the rail system. Much better from an investor point of view.

    I have to admit, though, that it would be kind of cool to have huge, lumbering trains to store energy. Forever moving in an automatic pattern. Kind of like a gigantic art installation or or a steam punk world.

  38. As I understood it, the beacon helps with aiming but it does not remove the requirement to control the phases of each emitter element.

    In my answer to Dennis above, I have listed that a LEO array would require 3.6 billion emitters where each emitter is "delayed" by ~10^-16 seconds compared to the adjacent element. For an L5 array you would need 360 billion emitters and the emitter-to-emitter signal delay would be ~10^-17 seconds.

    Clearly such small and precise time delays are technically impossible.

  39. I just wish for you to either address the phase requirement head on or stop spamming about power beaming/space solar at NBF. As simple as that.

    And if someone is truly "doing" space solar, please provide a link. Even the military have a few crackpot projects so you would have to read what they have actually achieved to know if there is something "there".

    Example. Remember how Northrop Grumman promised to solve fusion in a few years with their "compact fusion reactor"? And did it work? Nope… [1]

    (1)
    https://www.nextbigfuture.com/2018/08/lockheed-compact-reactor-is-100-or-more-times-worse-than-initial-claims.html

  40. Dan, the angles have nothing to do with the diffraction limit. It has to to with the beam width. The angles I list are the "cone" angles of the beam. Also listed as HPBW (Half Power Beam Width).

    LEO is ~36 000 km above the earths surface. So the cone angle should be – given a 1km x 1 km rectenna target – arctan(1/36000). How is that not 0.0016 degrees?

    For L5 and moon the distance is 384 000 km so the angle is arctan(1/384000), right? And when you punch the numbers you get 0.0016 degrees and 0.00015 degrees respectively. Is this wrong in some way?

    Do you not agree?

  41. I could not find the beam width from those two articles. But here is an easier one [1].

    In equation 15, they find that the HPBW (Half-Power-Beam-Width) scales linearly with the the number of element emitters (in 1D). 1 deg requires 100 elements (in 1D).

    In our case, we would like HPBW of 0.0016 and 0.00015 respectively (GEO and L5 locations), which would mean ~60000 and ~600000 emitters in 1D, or 3 600 0000 000 and 360 000 0000 000 emitters in 2D respectively. Each emitter would be lambda/2 = {@2.5 GHz} = 0.12 m apart, making the first antenna ~7km x 7km and the second 70km x 70km. Neither will come cheap.

    The phase requirement for each antenna would be given by equation 2 in [1]:

    delta_Phi = pi*sin(theta)

    We need the beam to be within the rectenna field, so we need to point the beam with an accuracy better than 0.0016 degrees and 0.00015 degrees respectively. Using these angles as theta above, yields:

    delta_Phi = pi*2,77*10^-5 deg (GEO)
    delta_Phi = pi*2,6*10^-6 deg (L5)

    respectively.

    In the time domain, these angles correspond to:

    delta_Phi = pi*2,77*10^-5*(1/f)/360 s (GEO)
    delta_Phi = pi*2,6*10^-6*(1/f)/360 s (L5)

    in seconds:

    delta_Phi = 9.7*10^-17 seconds (GEO)
    delta_Phi = 9.1*10^-18 seconds (L5)

    It's just plain impossible from a technological standpoint.

    (1)
    https://www.analog.com/en/analog-dialogue/articles/phased-array-antenna-patterns-part1.html

  42. You should stop worrying about me, and go to the various people who are already doing what you say cannot be done, military esp. It is not my duty to educate you on things that have been intensely discussed for over 50 years. You are unfamiliar with the basics. Do you have anything useful for this task, saving the Earth?

  43. Mr. G, if you know whom I mean, verified this long ago. The equation is simple, but most seem to make an error of 100*, for some reason. You are talking the basic diffraction limit, right? This has been challenged many times, it never changes.

  44. Holy cow!.. An answer! Wow! Only goes to show that there is a first for everything.

    And it also shows that space solar is not going to happen. For GEO, you need a dispersion cone angle of 0.0016 degrees and for L5 – which is at the same distance from earth as is the moon – you need 0.00015 degrees.

    Not going to happen.

    Both these numbers lead to technically impossible phase requirements on the emitters and a rediculous number of emitters in the phase array. Unless, of course, you can present your own estimate of these two parameters or link to a "professional" estimate that counters my claim. Feel free to provide either at any time, Dan….

  45. Rectennae are ~ 1 KM dia, LSP radars ~ 60 KM dia, which meets diffraction. Power of beam is 20% solar, but could go to 2% and still work. You are welcome.

  46. Hi Jan,

    I think the system could last for 30 years. Large turbines usually have a design lifetime of 30 years.

    One of the advantages of this approach is that you can increase the amount of storage by just increasing the size of the tanks and the amount of molten salt and antifreeze. The power output would be the same, but the storage duration could increase.

    There is an economy of scale here. The price will go way down as the storage duration increases. If you want to increase the duration of storage, you just increase the amount of antifreeze liquid, which is extremely inexpensive. The steel needed to build the storage tanks gets smaller and smaller per unit of liquid stored as the tanks grow larger and larger.

    The expensive parts are the power equipment (turbines, etc) which remain the same for longer duration storage.

    Ultimately, the energy is stored in molten salt and antifreeze liquid, which is always going to be cheaper than lithium ion batteries.

    Anyway, that was what I inferred. It's possible I am mistaken about something.

    -Tom S

  48. Not remotely as exothermic as molten sodium and water, though.

    To be honest, I'm not fond of molten sodium reactors. Molten salt reactors make more sense to me.

  49. They are different parts of the energy supply. Power beaming, moving photons instead of electrons or, ugh, molly queues, replaces the conduction lines we mistakenly call "transmission" lines, and can work with nuke energy just fine, altho it shines when used to balance variable supply and load. You want Space Solar, which power beaming leads to naturally, to replace nukes, as it is also steady supply, unlike Earth solar or wind. Now, THERE is a good idea!

    http://www.searchanddiscovery.com/pdfz/documents/2009/70070criswell/ndx_criswell.pdf.html

  50. Says right in the document 40+ years for lifetime. But I think that is a low estimate. It should last much longer than that. There are many electric locomotives still working after more than 100 years. They just put them in museums because newer ones are more powerful or more efficient.
    And if it was proportional to their 50MWh facility it would be 3,000 Acres for a GWh or 12 km2 not 14 km2. And I would lay odds that they have quite a bit of room on either side to put in several more tracks without even expanding the land set aside for them. And 3,000 acres in the middle of the Southwest is trivial. $1.5m: https://www.landsoftexas.com/property/3231.79-acres-in-Terrell-County-Texas/9888623/

  51. "If you imagine one cycle per day for 10 years, after which the system has to be replaced" That is ABSURD! You could use the system for 200+ years. You might have to replace an engine now and then, but that is cheap compared to the whole system cost. The cars move slow and the track is strait, so wear on wheels and rail should be minimal.

  52. I like pumped storage. But you are quite limited with where you can put it. And there is a large footprint, even if it is pretty natural looking. It is more of an issue just with how much land is being taken up. And if the lake formed is shallow, you are going to be evaporating a lot of water adding to inefficiencies. In the Southwest we don't have a lot of water to spare…unless we pumped ocean water. The Salton Sea would be technically possible, but would be very expensive (140+ miles of aqueduct) and chemicals from farm runoff getting released into the Gulf of California would not make environmentalists happy. But there are suitable hills all over for the trains.

  53. Off by an “order” of magnitude?  10×?  Each power operator has their own magic box of formulæ to evaluate the buy-do-not-buy decision for available power. When either the extant supplies or the near projected supply-vs-demand situation implies 25¢/kWh is a good option, they'll take it in a heartbeat. Likewise, when supplies are flush, 5¢/kWh is hard to sell.  

    This reality allows for all sorts of niches to be filled.  If all you can produce is 35¢/kWh recovered heat-energy … and make a bit of a profit … then you'll only have opportunities on maybe 1% to 2% of the total yearly power company input ledger. So, there becomes the scale calculation for how big an operation it makes sense to build.  

    AFTER that come the pölïtically motivated and 'dirty' subsidies. Subsidies, local politician talking points, greenie sit-ins, grade school co-education possibilities.  Selling snake oil, banapple gas and uncut opals.  

    Such basically nefarious gambits have paid for a LOT of pork-barrel 'deals'. Huge solar reflective systems in the middle of deserts that produce a couple of megawatt hours, then are allowed to idle-into-non-working-ness. 

    Point being, there is straight economics, and politicized wishnomics. 25¢/kWh might be just fine under the latter. 

    ⋅-⋅-⋅ Just saying, ⋅-⋅-⋅
    ⋅-=≡ GoatGuy ✓ ≡=-⋅

  54. Just the diffraction limit itself at the frequencies involved (e.g. microwave windows like 2.6 GHz) makes space solar senseless even if it was technologically feasible.

    Regardless of whether you are beaming 1 W or 10 TW, at a given level of efficiency the recieving rectenna diameter needs to be Chernobyl exclusion-zone sized. You can't have people in the second or third lobe of the airy disc pattern either if you are beaming any kind of reasonable amount of power. Grids are ~the size of a US state so that's at least some 50 odd permanent Chernobyl exclusion zones in the US that must be evacuated.

  56. Concentrated solar thermal is expensive, unreliable and unsuitable outside deserts.

    The only solar thermal that might make sense is simple water-heater/pool-heater type.

  58. Supplying energy predictably at peak times is worth a lot more than supplying dispatchable base load power, is worth a lot more than supplying random "negative demand" undispatchable power like wind and solar usually does.

    Old, amortized plants in the middle of their bathtub curve will always be cheaper than new plants.

  59. But you do need a secondary loop in a sodium cooled reactor. Molten salt makes sense to use in the secondary loop, because it won't react explosively with molten sodium or water.

    Once you have a secondary salt loop, the storage system is a relatively trivial addition. ("Relatively")

  61. "In particular, it appears that a full-scale SPS-ALPHA, when incorporating selected advances in key component technologies should be capable of delivering power at a levelized cost of electricity (LCOE) of approximately 9¢/kilowatt-hour." Also, for larger scales needed for global weirding solution, launch of product makes no sense. Launch factories. However, for starting scales, there are many cases where cost is *no object*. Do it!

  63. Mankins has sent a little power in Hawaii, I believe. He is against LSP for some reason, claiming it only has one huge beam as perhaps a sat would? The distribution of power is as big a deal as the collecting of it is. Hello Texas!

  64. "a simple thing as space solar orbital height." For most, GEO is assumed. LSP (have you heard of it?) is same as L5, obviously.

  65. For the 4th or so time, the beacon gives exactly the info you need to send the return signal. The cost of the arrays is only feasible if you are using them at max power, as is needed for 20-200 TWe. In that case, the lunar arrays are too small, and more have to be built to handle the load. $$$$ result.

  66. Dan, if you want me to prove that nukes work, I can provide you ten links within minutes. And that is because it is well known and has been demonstrated in real life.

    It is not well known that you can reach 0.016 degrees of beam divergence with a phased array for beaming microwave power. As far as I know, it has not been demonstrated. And that's why you cannot provide any link.

    Now, what bothers me is that you are not even curious. It doesn't irk you that you might be spamming NBF with calls for a technology which may or may not be technically impossible. But you don't care. It's unimportant that you don't know any technical details of the projects you cite, what they believe is possible or what they have demonstrated. The navy is throwing money down a hole and that's all the proof you need.

  67. I'll read your links, but to answer your question. I have looked at the number of emitters necessary and phase difference between each emitter to reach a beam divergence for moon solar (beam to earth) and for geosynchronous orbit beaming. In both cases the requirements were literally technically impossible. By orders of magnitude. And, I don't have to know the precise cost of each emitter element to know that 10^12 emitters (moon solar) would be outside of any budget. Impossible phase requirements and exorbant cost (10^12 emitter elements for moon solar).

    Of course, I could be misstaken when I made my calculations using the wikipedia phased array equations, which is why I would welcome any professional estimate of just how many array emitters you would need to reach a given beam dispersion and the phase requirement. It could also be the case that space solar entails much lower flying installations – hundreds of kilometers instead of thousands of kilometers – which might or might not put the phased array within the limits of the technically possible.

    But it is impossible to get Dan to answer any numerical question about phased arrays or even such a simple thing as space solar orbital height.

  68. It is possible and has been tested, though not yet at orbital distances. The term to google is "retro-directive wireless power transmission." This paper from 2013 looks like a decent technical overview:

    http://www.cs.columbia.edu/~lierranli/coms6998-10SDNFall2014/papers/WPT1.pdf

    NASA's report on SPS-ALPHA doesn't go into much detail on WPT but does claim that it works and isn't too far off from being ready for SPS, and estimates full system cost at 20 cents/kWh using then-current tech at pre-SpaceX launch pricing.

    https://www.nasa.gov/directorates/spacetech/niac/2011_Practical_Solar_Power_Satellite/

    (Side note, I'm wondering how you estimated costs, for a technology you believed to be nonexistent.)

  70. Why, though? Once you're already using molten salt, storing more of it is relatively cheap. Certainly a lot cheaper than if your system didn't use it to begin with.

  71. Eh, solar updraft towers don't require direct sunlight, and could benefit from a bit of energy storage. But clouds don't just diffuse light, they obstruct it, too; You may tend to underestimate the degree to which they do that, thanks to human eyes being very good at adjusting to light levels, but a cloudy day can reduce general illumination by as much as 90%.

  72. Nice to have you back! Long time, no see.

    One place thermal storage really shines, is in electrical heating where the pricing is variable. You can dump heat into the storage, (Often just a stack of bricks or bin full of rocks.) when electricity prices are low, and extract it at times when the price is high. And thanks to the fact that you want the heat AS heat, you don't incur conversion inefficiency.

    I'd been pricing out such a system back in 08, when I had to drop the idea and move due to the economy. It was easily cheaper than the propane heat I was relying on at the time.

  73. I'm actually a nuke activist, and think coal power is an environmental abomination.

    But not because of the CO2, because the fly ash is nasty stuff.

  74. Ask the military, they are doing it. Your question about elements proves that you have not even seen the graphics, as Criswell obviously has more advanced hardware than simple elements you are thinking of. Hint: see the doc!

  76. Why are you asking me that question? I'm not claiming that it's possible nor desirable. Are you confusing me with someone else? I'm the guy arguing over the phased array, remember?

  77. It's the person doing the "claiming" that has to provide proof. Gobblins are not "proven" to exist until someone links to a definitive debunking of them; it's the job of the gobblin believer to provide evidence of their existence.

    Likewise, it's your job to provide evidence that space solar works, since you are claiming that it does.

    How about a straight answer for once, Dan? Your estimate of number of transmitter elements and thier phase difference?

  79. No, there are no details in the CNN blurp. Nothing to answer my questions. How high was the satellite orbiting? What percentage of the transmitted power reached the target? What was the beam divergence? Were they even using a phased array or was it a parabolic dish?

    It's a huge difference between beaming from 200 km height and 36000 km height. Presumably, any real system would be positioned at geosynchronous orbit (36000 km height), or at least thousands of km height as to never be in the shadow of earth. If not, please tell me at what height the space solar system should be placed.

    But I did find out that the pilot beam has nothing to do with beam divergence. Nothing. It's only function is to make sure that the power beam is directed towards the target, i.e. aiming. Why did you bring it up at all, when you knew that it did not answer my concerns, Dan?

    And I am still waiting for you to even give a hint of how many transmitter elements are necessary for the (space solar) phased array and what the phase difference between elements need to be.

  80. "100% renewable energy goal will require a massive buildout of grid infrastructure to get energy from the windy plains or offshore wind farms over long distances to cities where electricity is needed."

    Any ideas on how to do this?

  81. "Jaffe and DePuma are experimenting with sending the energy back down to Earth as microwaves, hitting the correct destination using a technique called "retro-directive beam control," where the energy beams wouldn't be transmitted until a pilot signal from the terrestrial receiver is locked in at the orbiting panels. Jaffe "also allayed any future fear that bad actors could use the technology to create a giant space laser," CNN reports." The Week U.S. scientists have shown it's plausible to power the Earth from solar panels in space Peter Weber Wed, February 24, 2021, 7:34 AM The beacon is always mentioned as the reason the beam cannot focus accidentally. You "reverse" it to hit the target.

  83. You don't explain what you mean and provide no links, Dan. What is the mechanism by which the "beacon" would make the power beam narrow? Links to navy announcements, links to "beacons" in the context of power beaming.

    Furthermore, you have yet to provide a single estimate of the number of transmitter elements in the (power beaming-) phased array and the phase difference between the elements. You still avoid the question.

  85. All you show is that you are unaware that these systems use beacons. Which was pointed out in at least two of the responses you did not read, apparently. Which were the perfect response to your otherwise valid point. The recent Navy power beaming/Space Solar announcement mentioned this, as did presenters in the 70s, describing Glaser plans.

  86. It would be, if it were a powerful laser WW II searchlight. You could stand in front of radars in WW II and get warm, from the "power" being "beamed" into your body. As sailors reportedly did. See pg 5 again of the above cited Criswell publication for refresher info.

  87. I assume Thorium was written up as the way forward back in the late 1960s or something when Uranium was thought of as rare, expensive, and likely to run out fairly soon.
    Under those circumstances it's a good idea.
    But you can't rely on technology assessments from half a century ago. So many of the basic assumptions have changed since then.

  89. Come on Dan, to say that radar is the same as power beaming is like saying that a world war 2 searchlight is the same as a laser defense system.

  90. As an example, assume a heat pump storage system that uses a heat pump for charging and a turbine for discharging, as the Malta system does. If the heat pump has a COP of 2 (equivalent to 200% efficiency), and the turbine has an efficiency of 35%, then the combined round-trip efficiency would be 70%. Heat pumps become less efficient, and turbines more efficient, as the temperature difference increases. As a result, the combined round-trip efficiency could never exceed 100%. As a practical matter, 70% round-trip efficiency could be achieved.

    This system seems plausible, inexpensive, and low risk. It uses molten salt and antifreeze liquid as storage media, and those materials are extremely inexpensive. The system also uses common, widespread components like heat pumps and gas turbines. An efficiency of 70% is tolerable. I'd say they have as good a shot as anyone.

    -Tom S

  91. Hi Brian, I usually love your site, but you are wrong about this one point.

    Heat pumps frequently have more than 100% efficiency and sometimes more than 300% efficiency. Sometimes this is called a "coefficient of performance" to avoid the confusing terminology of efficiencies over 100%. For example, a heat pump with a COP of 2 is equivalent to 200% efficient.

    The maximum efficiency of a heat engine is the inverse of the maximum COP of a heat pump, both operating at the same temperature difference. As a result, the theoretical maximum round-trip efficiency of heat pump storage is 100%. Of course, that theoretical maximum will never be reached. However, round-trip efficiencies of more than 70% are definitely feasible with heat pump storage.

    -Tom S

  92. I'v not written in a while, but this seems like a good topic to return. 

    There are 4 basic problems which every energy-production-and-storage system aims to address, when you reduce all the pölïtically motivated chatter to “the money”.  

    № 1 — Modest (ideally minimal) production cost, including land, fuels, maintenance
    № 2 — Modest (ideally near-zero) distribution, storage, levelling, cycling costs
    № 3 — Modest environmental, safety, aesthetics, insurance, 'stink-eye' factor costs
    № 4 — Modest complexity, unreliability, operations and repurposing costs

    As a 'practicing computer scientist and electronic engineer', I tend to amortize EVERYTHING cost-wise, and turn it into a constant comparable number, per system.

    If this almost hopelessly inefficient storage-and-recovery system delivers free waste energy for less than 15 to 25 cents a kilowatt hour, WITH the cost of acquisition, pad, operating staff, regulatory hoops, insurance, management and so on, well .. .then it might be worth pursuing. Otherwise, taking ALL the factors in play, it is worth near nothing.

    Just Saying,
    GoatGuy

  93. At 10% overall efficiency there cannot be a price advantage, at it automatically makes this solution almlost 10 times more expensive, not to mention that there are more beneficial alternatives approaching 100%. Makes you wonder how often our "free market" is willing to channel resources to the obviously not to the most profitable and beneficial course of action.

  99. nuclear and cleaner natural gas coal are always the best solutions, solar and hydroelectric and geo thermal are great for certain locales too… i never under stood wind.. its ugly and kills birds and seriously unreliable

  100. No Dan, radar is "not the same thing" as power beaming. If you get 10 deg cone angle on your radar beam, you are fine. There will be a returned radar reflection from your target even if the beam is much larger than your target.

    Not so for power beaming. You need a cone angle so that none of you power beam ends up "outside" of your rectenna.

    To beam from geosynchronous orbit you would need 0.0016 degrees cone angel on you radar beam to target a 1 km rectenna field. Going for a 10 km by 10 km field will only make it marginally better; 0.016 degrees cone angle instead.

    I've shown you earlier that achieving such a beam angle is technically imposisible for the wavelengths that we are talking about. But if you do not believe me, why don't you provide your own estimate of how many phased array elements would be required and the phase difference between each array element?

    It's really sad that you don't actually respond to these points. You just pretend that I never raised these objections and keep spamming almost every NBF-post with advices about using power beaming. And you keep propping up that old chriswell "pamphlet" as if it addressed any of the points I raise. It does not.

  101. On a larger, more important point, the really sad thing here is that you don't even realize you are neurotic, quite common. Thus, you don't even realize you can be cured. primaltherapy dot com.

  104. It would be more cost effective to not build the windmills in the first place, and instead build something that is a lot closer to 100% reliable.

    Solar can be reliable if sited in the right area. From a 'global warming' standpoint, though, does it actually make sense to lower the albedo of deserts in order to generate power?

  105. Well, nobody knows about power beaming, since it would require technology which is not possible and costs which are rediculous. We've been through this allready, but you've not learned anything. It's really sad.

  106. Well, they state that the system could potentially store one kWh for 168 USD capex. If you imagine one cycle per day for 10 years, after which the system has to be replaced, this would increase the cost of the electricity by about 4.6 cents per kWh, or stated differently, double the cost of electricity. Plus, the system requires about 14 km2 per GWh. That's quite a lot.

    Batteries, by contrast, are getting cheaper by the day. By 2030, lithium batteries will – at least if you believe Tony Seba – cost about 30 USD per kWh. At those prices, 168 USD per kWh seems really expensive. But allready today, lithium batteries cost less than 100 USD per kWh. Of course the complete system is more expensive than the cell prices alone, but the "overhead" should be reduced with size. I.e., when building a 10 GWh back-up plant, it will probably be less than 50%. After all, going from cell to pack in a vehicle requires less than 50% more spending than the costs of the cells by themselves.

  108. Solar thermal really needs to be located in a desert. PV still makes some power if there's cloud overhead, but thermal can only focus direct sunlight, not diffuse light through cloud. It's also about three times more expensive per watt installed, last I checked.

  109. I'd lean towards MSRs, V2G, and hydrogen electrolysis. During times of high electrical demand, reactors drive heat engines, and fuel cells use H2. During times of low demand, heat from reactors enables steam electrolysis by renewable electricity. V2G, and home storage arbitrage energy over the short term.
    It's all about giving users/producers/arbiters price signals, and letting them act in their own best interests.

  110. If x% of your solar energy is being wasted, why not build x% fewer solar panels, and replace them with concentrated solar thermal. You save a conversion step, expensive & environmentally damaging to make & recycle PV cells, and get more energy. Solar => heat is almost 100% efficient with the right absorber.

  111. Energy conversion is always a loss. Just build batteries and inverters capable of load following.

  112. The advances in both H and power beaming are coming fast. Either one completely solves both intermittancy and variable customer load problems. Together, they can replace our vulnerable grid system.

  113. The Echogen system does the same thing and is based on a supercritical CO2 power cycle that actually commercially exists.

    The Malta system is just a model. They've never built anything.

    If it was my money, I'd spend it on nuclear reactors like the Natrium design. Minimal regulated equipment, built-in thermal storage to enable flexibility of power output without flexing the reactor.

  114. I suppose if they could throw one together for some $X per kilowatt hours it might be worth it, provided it lasted for a long time and had low maintenance costs. I recently saw a video about pumped hydro storage; those systems, while difficult to locate, are built to LAST.

  115. "The total system might be 10-15% efficient. However, the energy would otherwise be wasted." Unless they somehow knew about power beaming, or H production.

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