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Very simplistically, maybe something like this:
Or maybe this for the vac tank, using concrete with a clay and rubble filling.
Or maybe the tank can sit within a weather proof enclosure, like a shed. This ensures that the clay providing the compressive strength is kept dry. You may notice that I am trying to use as little concrete as possible, as the tank needs to be cheap.
Pumping water instead of air allows greater energy efficiency overall, because water is an incompressible medium. Pumping water therefore minimises heat generation. But it is also presents a problem as concrete and cob, rammed earth and adobe, all lose a great deal of compressive strength when wet. So a good waterproof lining is important.
Last edited by Calliban (2024-09-05 08:39:26)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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Calliban,
We've seen steel compressed gas cylinders used for welding fail during highway crashes. They don't blow entire vehicles hundreds of feet into the air. They can't generate enough force to do that. Heck, even fuel-air explosions with gasoline and natural gas don't do that. Lithium-ion battery explosions don't do that, either. 10 feet, sure. 50 feet, maybe. Some of the most powerful high explosive detonations can toss a vehicle or heavy chunk of metal like the engine block that far, but they tend to rip the vehicle apart, which is worse in some ways. Let's not wildly over-exaggerate any particular danger. A Lithium-ion battery fire is not going to burn a hole through the center of the Earth (China Syndrome), nor will a nuclear reactor meltdown ever do any such thing. The cap or valve on a compressed gas cylinder might get blown that far from the vehicle, but the entire vehicle is not going to be launched into the air, Hollywood style, unless it's done with high explosives. Granted, the energy release from any of these energy stores is fairly spectacular, but it's also a relatively rare event (ignoring severe quality control issues with Chinese products), and we are in fact running H2 powered vehicles on American highways which are laden with highly combustible Hydrogen gas pressurized to 700bar.
On the issue of "range anxiety", I think the "real anxiety" revolves around the myriad of other related issues with Lithium-ion batteries, such as waiting 1 to 2 hours for the battery to recharge on a "fast charger", the fact that the vehicle cannot be left unattended during that process, and all the other supposed benefits which turned out to be pure marketing drivel not tethered to the practical operation of an EV as most people use them. No significant planning process is required to use a vehicle that can be refueled in a matter of minutes.
Vehicles made from the 1970s backwards frequently had a range of 200 miles if they had large displacement V8 engines or poorly tuned carburetors and ignition systems. Some burned so much fuel that you could literally see the fuel gauge needle rolling back while the engine was running. Assuming "range anxiety" wasn't a serious issue back then, it was because there was a gas station every 50 feet and you could refuel your car in about 5 minutes for a reasonable price. You can still do that with compressed air. You get your 200 miles and then you can fill the tank up again in less than 10 minutes.
For the EVs, if you recharge at night from the convenience of your own home, then you're not drawing power from renewable energy in most cases. Unfortunately, this is when it's most convenient to recharge the car, because grid demand and prices are low and you're not using the car. You cannot put your car in your garage, plug it in, and then go to sleep while your car recharges. If anything goes wrong, your house might burn down if you're not present to unplug the vehicle. EVs typically quit functioning entirely if it has an internal electrical short somewhere that the computer detects, which causes it to turn off the car, so then the vehicle cannot be moved to a safer spot where a vehicle fire might be inconvenient but not life-threatening. Worse still, serious failures during operation frequently leave you trapped in a car that might go up in flames, due to "electronic everything", which includes the stupid door handles. Someone needs to accept that not everything can or even should be electronic. Door handles are one example of a device that should remain mechanical forever.
If you routinely fast charge the car, doing so rapidly degrades the battery capacity, decreasing its useful service life and increasing the risk of a thermal runaway that destroys or seriously damages the entire car. If some cell or electronic component within the battery pack fails, you have to replace the entire battery pack. If minor damage occurs during an accident, then the insurance company typically totals the vehicle. An accurate mechanism to evaluate true vs superficial or repairable damage doesn't seem to exist.
If a pressure regulator valve fails in a compressed air car, you don't have to replace the air tank, which is the most expensive part of the propulsion system, nor all the other valves and connected components in the car, in most cases. No power electronics are required to operate the propulsion system. The electronics in a modern car, especially an EV, represent 50% of the cost of the car. If anything but the air tank fails, all the rest of the components can be repaired or replaced in isolation from the air tank, at nominal cost. A pressure regulator valve is a rather cheap and simple part to replace using hand tools. No special skills are required, beyond knowing how to use a torque wrench and how to check for leaks. Special test equipment is not required to "know" that the valve repair was successful. If it was not, then you can both see (using soapy water) and hear the air escaping, as well as monitor the pressure inside the main tank.
As a mechanic, you don't have to worry about being instantly electrocuted by a battery subsystem capable of delivering hundreds of kilowatts to about a megawatt of power. Due to its complexity and materials costs, a very large battery pack is never going to be "cheap" in the sense of it being something you stock on the shelf as a spare part. It's so large and heavy that it's literally integrated into the frame of the vehicle to save weight. Thus, removal is never going to be fast and easy, in the same way the removing an engine is not fast or easy. On top of that, a variety of highly specialized and very expensive electronics diagnostics tools are required to test the entire battery pack and evaluate serviceability. A diagnostics check can be run very quickly in most cases, but that's the extent of how user-friendly maintenance and repair will ever be. It's certainly still doable, but never fast / cheap / easy.
If I roll into a compressed air car repair shop and tell the mechanic I hear a hissing sound from this spot near the tank, he's going to be able to rapidly figure out what's leaking, how badly using a pressure gauge, and how much time and materials it will cost to fix it. There could be other problems discovered after the initial repair, but all the parts except the tank, engine, and atmospheric heat exchange radiator are low-cost bits of mass manufactured metal that you can hold in your hand and replace with your hands using hand tools.
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Gail Tverberg's latest article is well worth reading.
https://ourfiniteworld.com/2024/10/14/o … -even-war/
In her opinion, Climate Change is spin designed to tackle the real issue without publicly acknowledging it: Energy Resource Depletion. The problem is that the politically popular solutions to climate change (wind and solar power) have thus far proven incapable of replacing the abundant low-cost energy provided by fossil fuels during the post-war growth period of the second half of the 20th century.
Growth in OECD countries has been anaemic since 1973. Until the first oil crisis, wages and living standards were growing rapidly. But growth stalled after 1973. Real inflation adjusted wages for the bottom 90% of US workers has not grown in the past 50 years. Wages for the top 10% have grown, but even this growth appears to have stalled. Why is this happening? Wealth is a product of surplus energy. Whilst overall energy production has risen, the Energy Return on Energy Invested (EROEI) of new energy projects is no longer as high as it was for the abundant onshore oil & gas resources that met world demand until the 1970s. The energy cost of accessing new energy has increased steadily since the early 1970s.
Last edited by Calliban (2024-10-22 03:19:32)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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To maintain our present quality of life, an annual per capita energy expenditure of 80 million BTUs per person, equates to 23,445,686Wh per person per year. This is a huge amount of energy to generate using other methods, be it coal, natural gas, liquid hydrocarbon fuels, or sunlight, wind, and water. Frankly, the other methods are hilariously inefficient in terms of input materials required, even when the "fuel" comes from the Sun. The sunlight and wind are "free". The materials required to convert that into electrical or thermal power are not "free", and all of the current methods used to create and process those materials into energy generating machines are incredibly environmentally destructive. Furthermore, all of those "other methods" are not truly sustainable because all of them are artifacts of burning hydrocarbon fuels. That means it's in everyone's best interest to find the least consumptive and most productive methods to generate the energy required to lead a "technologically advanced modern life".
In terms of what we call "high level nuclear waste", the US alone has accumulated 90,000t / 90,000,000kg of "un-reprocessed spent fuel" over the past 75 years of using commercial nuclear power. The reason we don't reprocess fuel is to keep our Uranium miners in business, not because there's a shortage of Uranium or Thorium fuel. If we never mined another kilo of Uranium for the next few centuries, we already have accumulated sufficient fuel to supply ALL of humanity's energy needs. Estimating actual energy consumption can be difficult to quantify, so below I'm also going to include the total US annual electrical energy consumption of 4,000TWh as a measuring stick. Americans consume about 1/5th of the world's energy inputs, which means extrapolating to the rest of the world, using America as a proxy, is very easy to do. Take whatever America consumes, multiply by 5, and that's a reasonably good proxy for global energy consumption of the electrical or thermal variety.
When we talk about "spent" nuclear fuel or "high level nuclear waste", what are we actually talking about?
Each kilogram of spent fuel or high level nuclear waste contains a mixture of U235, U238, U238 transmuted into Pu239 or various other fissionable or non-fissionable isotopes, and lighter elements created during fission. Inside a commercial electric power reactor, there are an incredible variety of lighter daughter products created by fissioning, some of which can actually kill the fission process over time by absorbing neutrons thrown off of fissioning atoms, which could otherwise be used to split other fissionable atoms. These are true nuclear waste products that must be removed during fuel reprocessing. Whenever the "spent" fuel comes out of the reactor, it consists of a bunch of "cracked" ceramic metal pellets in metal cladding. This definition of "high level nuclear waste" actually means "otherwise usable Uranium and Plutonium fuel containing 97%+ of its original energy content". If the neutron poisons could be removed and the cracking didn't matter, instead of 18 months, the fuel could stay in the reactor for about 900 months, and then it truly would be "spent" fuel. Reprocessing includes extracting the cracked fuel pellets from the rods, grinding them into fine powder, chemically or centrifugally stripping the various daughter products and neutron poisons, re-sintering the remaining "good fuel" into new pellets, and sorting them back into a fresh fuel rod based upon remaining energy content. Some fuel pellets require nothing more than stuffing into a new rod cladding because the reaction rate was so low, due to their physical position inside the reactor, which affecs reactivity rates. Until this process has been repeated about 50 times, there is nothing "truly spent" about a load of Uranium fuel extracted from a reactor after 18 months of operation. There is merely accumulated thermal / pressure / radiation damage, along with neutron "poisons" that kill the fission reaction, and fission daughter products, such as radioactive Cesium and Strontium, that truly are "nuclear waste". The swelling that ultimately cracks / destroys the fuel pellets stems from the release of Radon and other trapped radioactive gases, as well as volume expansion from the production of lighter elments during fission.
Approximately 2.5% of our "high level nuclear waste" is "true nuclear waste" (Strontium-90, Cesium-137, Radon, etc) which must be removed and stored over varying lengths of time:
90,000,000kg * 0.975 = 87,750,000kg
The length of time something must be stored, because it's radioactive, is a total misnomer. The shorter the half-life, the greater the radioactivity. The longer the half-life, the less the radioactivity. Radioactive for thousands to millions of years means, "this substance is barely radioactive at all". In all probability, it can't hurt you so long as you don't eat it or inhale it. Isotopes that emit gamma rays or neutrons are the exception to that rule. If you don't make a habit of cuddling up to your spent fuel rods at night, the probability of this kind of waste hurting you ranges between nonexistent and exceptionally remote. Radioactive for 5 minutes to 5 years means, "this substance is insanely lethally radioactive". You don't need to be exposed to it for decades before it might cause cancer in old age. Fatal radiation doses from very short-lived radioactive substances can be accumulated in minutes to hours. This best describes nuclear fuel rods the moment after we shut down the reactor. Inside of a few years, most of the really radioactive stuff has decayed into otherwise harmless elements- but once again, harmless to be in close physical proximity to, not to eat or inhale. If you eat non-radioactive Cesium metal that's never been in a nuclear reactor, it will still kill you. Heavy metals are still heavy metals. Lack of radiation, on top of being a heavy metal, doesn't render them any less intrinsically toxic. In all probability, all such "insanely radioactive" material is so thermally "hot", in addition to being radioactive, that it's kept in a spent fuel pool so it can "cool off" (dump its residual radiation and thermal energy harmlessly). Some notable exceptions include the Cobalt-60 metal rods from nuclear medicine facilities or radio isotope thermo-electric generators, which have killed a literal handful of people through improper disposal. This is far more common in the developing world. The last American killed by radiation from a nuclear reactor died in 1964 or 1965, IIRC. Nobody has died from commercial nuclear power since then, unless they fell off a ledge or ladder or balcony at the power plant, were electrocuted by the electric portion of the plant, or a steam pipe ruptured and cooked them.
Whatever the potential for civil nuclear power is to kill lots of people, such a scenario has never been actualized here in America. We can "what-if" all the possibilities to exhaustion, but at the end of the exercise, exhausted is all we'll end up "being". If a modicum of care and thought is devoted to handling of nuclear materials, they're no more intrinsically dangerous than Lead poisoning of the non-Judge-Roy-Bean variety. The moral of the story is, don't treat radiactive materials like play toys, because they're not. Put them to work for you, the same way we put explosive gases and flammable liquids to work. Oil ended slavery. It's not profitable to use forced human labor when forced machine and materials labor is so much cheaper and benefits everyone (even when it doesn't benefit everyone equally, everywhere, at all times).
UO2, the most common ceramic metal fuel type used in most light and heavy water reactors, is 88.15% Uranium by weight:
87,750,000kg * 0.8815 = 77,351,625kg
Fissioning U235 releases 24,000,000,000Wh / 24 GigaWatt-hours of thermal energy per kilogram of virgin U235. After 18 months, when "spent" fuel is taken out of the reactor, it's only generated 600,000,000Wh of thermal energy. The remaining unfissioned Uranium and Plutonium still contains about 23,400,000,000Wh of thermal energy. Pu239 provides a little less, at 23,000,000,000Wh/kg, but we're going to treat U235 and U238 transmuted into Pu239 as possessing equivalent energy content for evaluation purposes, because all those short-lived daughter products add to the total thermal energy output, and U235 mixed with U238 in a nuclear fuel rod ultimately transmutes fertile U238 into fissionable Pu239. U235 is the only type of natural fuel source that can be used to "make" or "breed" more fuel. For example, if you drop a lump of coal into a gallon of diesel fuel, you don't magically "get" more diesel fuel, merely because the coal contains a lot more Carbon than diesel fuel. In any event, whether we use 24GWh or 23GWh as our energy content figure, the math really doesn't change much, as the back-of-envelope calculation below shows, with regards to our accumulated "spent" nuclear fuel stockpile.
77,351,625kg * 24,000,000,000Wh/kg = 1,856,439,000,000,000,000Wh
77,351,625kg * 23,000,000,000Wh/kg = 1,779,087,375,000,000,000Wh
Whenever this nuclear fuel is "stored" inside a working nuclear reactor, rather than sitting outside on the ground, not only is it a very slim nuclear weapons proliferation risk, it's actually doing something rather useful- generating gobs and gobs of heat energy without combustion.
24,000,000,000Wh per kilogram of U235 / 39,750Wh per gallon of diesel fuel = 603,774 gallons of diesel fuel
A kilo of U235 has the same thermal energy output as an olympic swimming pool filled with diesel fuel.
The actual volume of waste produced is so small that all the spent nuclear fuel in the entire world, after 75 years of commercial electric nuclear power, will fit inside a single football field. Is there really no patch of land in the entire world, the size of a single football field, which we cannot declare "off limits" to everyone?
If one football field per century is "too much", to power all of humanity, then how much CO2 are we willing to release and how many cubic miles of land are we willing to destroy to get at the metal underneath it?
Such a tiny volume of waste could be buried many miles underground, far below any aquifer, if we decided to do that and quit playing dumb games with the waste.
Onwards...
4,000,000,000,000,000Wh per year (4,000TWh) = US total annual electrical energy consumption (about 1/5th of the global total)
1,856,439,000,000,000,000Wh of total thermal energy / 4,000,000,000,000,000Wh per year = 464 years of thermal energy, or 232 years of mostly electrical output with waste heat recovery (combined heat and power). If we convert all of that heat into electricity, then we get 35% to 50% of that energy content as electricity, dependent upon how we choose to generate electricity. Steam will be 35%. Supercritical CO2 will be 50%. Most plants get around half of the energy out through various means, so 232 years is a good approximation for how much accumulated nuclear fuel energy the US has sitting around uselessly at various "spent fuel" storage sites.
350,000,000 people * 23,445,686Wh per person = 8,205,990,100,000,000Wh for all 350 million people per year
1,856,439,000,000,000,000Wh of total thermal energy / 8,205,990,100,000,000Wh = 226 years (covers all energy consumption of all types, for the entire US population)
If nuclear fuel was our only option for reliable power, we are not short of energy to maintain our present standard of living, but it's not even close to our only option at this point. We still have incredible natural gas and oil reserves as long as the person in charge of our government is not canceling drilling permits to commit treason by handing our money to terrorists to appease our pistachios. We still have entire mountains of coal, which should probably be upgraded to diesel and bunker fuels using thermal power input from a nuclear reactor. We have a functionally inexhaustible source of heat energy from the Sun. We have wave action thanks to our moon, which can be used with trompes to compress air. We have hydro power from all the dams, some of which may need to be rebuilt at this point. We have plenty of wind in specific spots.
To build-out the wind and solar energy reserves, we need a LOT of energy input to get the enormous quantities of metals required. That energy has to come from somewhere. It can come from burning coal and natural gas, as it presently does, or it can come from electricity generated by nuclear fuel. At the present time, nobody makes photovoltaic panels using previously manufactured photovoltaic panels. It's not impossible, but it would mean ALL of the energy they generate is consumed by the act of expanding photovoltaic panel manufacturing, which means for quite some time they generate nothing on our electric grids.
To that total for existing Uranium sitting in spent fuel casks, America alone can add around 400,000t of Thorium-232 in known deposits or actual separated Th232 stored in the ground under our deserts at various undisclosed locations. Th232 converted into U233 generats 22,764,000,000Wh/kg. We can safely assume that we can economically recover half of that total as a ballpark estimate, so 200,000t buys us another 502 years of energy. Our Thorium reserves are estimated at 595,000t. If we truly could recover all of that, then 1,494 years. IAEA estimates 13,000,000t of Thorium are recoverable at a cost of $130/kg or less. That would provide for our energy needs for the next thousand years, at the very least. More Thorium is recovered every day during rare Earth metals mining. Th232 may be transmuted into fissionable U233 by sticking it inside a commercial power reactor. The daughter products from fissioning U233 are short-lived, relative to fissioning U235 and Pu239. It's a quirk of the nuclear decay chain for U233 vs U235 and Pu239. However, you still need some U235 or Pu239 to begin transmuting Th232. That seemingly "small change" has a dramatic effect on how long the waste remains radioactive. Almost all of the dangerous radiation is gone in far less than a human lifetime, about the same amount of time it takes for a child to become an adult. We can handle 10 to 20 year sequestration processes quite easily.
We can now passively recover Uranium from sea water, at costs ranging between $400 to $1,400/kg. There's about 4.5 billions tons available. That's plenty for everyone for a period of time longer than homo sapiens have existed. I would also very much like to believe that we will coax fusion into working for our benefit in less than a thousand years. Henri Becquerel discovered Uranium in 1896. It was about 60 years before the first commercial power reactor appeared in the UK, in 1956. The first fusion reaction was discovered in 1933. The first non-weapon fusion reaction in a Z-pinch machine took place in 1951. Our first operable fusion reactor of sufficient size / scale will come online in 2035 and is anticipated to be fully operational by 2039. ITER won't be a power reactor, but it will pioneer all the basic concepts required to run commercial fusion reactors. If some upstart runs a fully functional fusion reactor before 2039, then kudos to them. 60 years from discovering Uranium to a commercial power reactor is a break-neck pace of innovation. Creating sustainable fusion reactions is easily multiple orders of magnitude more difficult, so if we achieve that in about 100 years that is a blistering rate of technological advancement. Either way, we have plenty of energy and time. We're not going anywhere, unless we choose to self-destruct.
If all of 7.5 billion of us consumed energy the way Americans do, and we burn U233 from Th232 only:
7,500,000,000 * 23,445,686 = 175,842,645,000,000,000Wh per year (total primary energy consumption for 7.5B Americans)
13,000,000,000kg * 22,764,000,000Wh/kg = 295,932,000,000,000,000,000Wh
295,932,000,000,000,000,000Wh / 175,842,645,000,000,000Wh = 1,683 years
There are many many more millions of tons of Thorium available, but the Thorium shown above is economically recoverable at today's natural Uranium prices. Thorium is about twice as abundant as Uranium.
Here's how long 4.5 billion tons of natural Uranium would last, if everyone lives like Americans do:
4,500,000,000,000kg * 24,000,000,000Wh/kg = 108,000,000,000,000,000,000,000Wh
108,000,000,000,000,000,000,000Wh / 175,842,645,000,000,000Wh = 614,185 years
You can extrapolate out how long 9 billion tons of Thorium would last.
Divide by 2 or 3 if you wish to account for any inefficiencies, but there's enough energy there to provide heat, food, fuel, lighting, medicine, and housing to 7.5 billion people, all living the way Americans do, for an exceptionally long time. After we crack fusion, we have enough materials here on Earth to last until the Sun goes supernova, although I'd suggest we get serious about finding our next star long before that happens. Maybe we can create a warp drive large enough to move our entire planet. That's how much energy we can get from materials dug out of the ground or filtered out of sea water. Our green goofballs don't want humanity to have access to it, because they're pistachios.
We don't presently collect Uranium from sea water, but we've proven that we can do it, and have done it just to prove that we could. One method using plastic fibers has a cost of $80.70/kg to $86.25/kg. For nations that already have nuclear power, there's enough stored energy in terms of on-hand un-reprocessed fuel to cover the next century or two of operations, even if we didn't mine another kilo of Uranium from all the existing Uranium mines. That means we have fuel galore, but no political will to use it. I suspect that if we run short of energy, the political will to start using the fuel will be "discovered" quite rapidly. No explanation that passes muster has been given as to why we're burning so much coal, oil, and natural gas, when the energy available in Uranium and Thorium is so plentiful. If we reprocess our spent fuel, there is zero danger of ever running out of Uranium and Thorium over the next two million years.
Climate change is either a fraud / hoax of truly epic proportions, or else the same people advocating for the phase-out of hydrocarbon fuels are charlatans to their own cause, pushing fraudulent "non-solutions" that they should be intelligent enough to know cannot possibly function without hydrocarbon fuels, or quantities of batteries we simply cannot make, or nuclear energy providing the backstop whenever natural energy sources run out. Norway has 85%, maybe 90% by now, EV adoption. They only burn 10% less oil. Replacing 100% of the existing gasoline and diesel powered vehicles reduces hydrocarbon energy consumption by 15% at most, if you have oil money from selling oil to developing nations, which you then use to make your own nation appear to be some clean green economy that it's not, never has been, and never will be. At the same time, you drive out all heavy industry, and make virtually none of what you use and consume.
The longer our pistachio-colored climate changing scientologists go without creating an examplar national economy that runs purely on wind turbines and photovoltaics and batteries, the more self-evident their fraud becomes. The utter lack of progress shows they are not serious about confronting their boogeyman. All the "green energy" added has not simply maintained pace with the rate of energy consumption increase as our population peaks. If such an energy system cannot keep pace with increased demand, nor readily contract if less energy is required, then it's neither durable nor scalable. Our pistachios are only serious about using their fraud to continuously extract wealth and resources from otherwise productive economies, for as long as they can possibly perpetuate their green energy fraud.
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