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offtherock,

It's amazing to me that you believe in "peak oil", but not "peak metal".

The metal to make it happen doesn't exist here on Earth.

1MW of photovoltaics uses about 5.5t (5,500kg) of Copper wiring.

Present total global installed electric generating capacity: 9,400,000MW

9,400,000MW * 5.5t/MW * 5,000 (your suggested % increase over installed capacity) = 258,500,000,000t of Copper

700,000,000t of Copper have been mined thus far, from 4,000 years ago to the present day.  Over 95% of that metal remains in use today, so it must be pretty valuable and scarce.

2,100,000,000t of Copper is potentially available in identified deposits.

3,500,000,000t of Copper are potentially available in "undiscovered deposits", which means it may or may not exist.

258,500,000,000t / 5,600,000,000t = 46X more Copper than exists or might exist on Earth

In 2023 alone, 4,500,000,000t of crude oil were produced and 8,900,000,000t of coal were produced.

That means we're going to run out of Copper long before we run out of crude oil and coal.

If we recycle CO2 and water into synthetic coal and petroleum products, something tells me we're far less likely to run out of coal / oil / gas than we are to run out of extractable metals.

If the price was actually heading to zero, then the rates paid by consumers of electricity would also trend in that direction, except for the simple undeniable fact that they're trending in the opposite direction.  The most expensive electricity comes from intermittent sources.  Regardless of how theoretically "cheap" electricity from photovoltaics and electric wind turbines should be, those rate increases accurately reflect reality.

All the metal mining and refining machines on this planet are powered by oil and gas, to include the ones that are electric.  If we're past peak oil, then we're also past peak metal extraction.

One day our peak oil proponents will be proven correct, but nobody knows when, especially them.

Void,

I like low-energy inputs, simple fabrication methods, and truly abundant materials if we're intent on primarily using natural energy generation and storage systems at the human civilization scale.  It's not a "personal preference" type of thing, rather, it's a "Do you actually want to accomplish something worthwhile over a period of time that actually matters type of thing?"  I understand and accept that any truly sustainable energy generating system based upon natural energy flows needs to be long-lasting to minimize energy / labor / capital inputs over time, readily storable for on-demand use, easy to recycle using processes not significantly more complex or energy intensive than initial production, rather than having materials and finished goods repurposed in ways that don't permit replication / duplication of self-similar technology units.  I think reducing rather than expanding our energy generating and storage system footprint is the most sustainable solution.  More than anything else, all of my assertions and proposals are grounded in mathematical and material reality.

A 50% increase in energy efficiency doesn't offset a 10X reduction in energy concentration.  If a proposed solution requires more of a specific type of metal than we've mined in the history of mining, then for all sorts of reasons that solution is a non-starter and should have been politely but firmly dismissed.  Well-thought-out engineering is not magic, and therefore cannot overcome mathematical impossibilities.

The types of solutions I advocate for are as long-lasting as traditional thermal power plants, they're primarily made from large pieces of abundant cold-rolled plain Carbon steel, recycling them involves relatively minor disassembly and re-melt for near-100% recycling rates, and they're deliberately simplistic because complexity is the mortal enemy of sustainability.  The more complex and energy-intensive you make a system that's dependent upon highly refined materials with exceptionally large surface areas for energy collection and storage, the worse it becomes in terms of EROEI, and that's before recycling becomes mandatory.  At some point, that ledger has to balance, or it's not actually sustainable.

Thus far, all we're actually doing is burning more fuel to "create more short-lived electronic stuff".  If that stuff had that qualities I mentioned as important vs the qualities it actually has, then there's at least a chance that we eventually get to stop burning more fuel.  The other notable point I made related to recycling CO2 into hydrocarbon fuels.  The energy density of all combustible fuels is at least an order of magnitude greater than electrical / electronic anything.  All the batteries ever created in the history of battery making, don't amount to more than a few minutes worth of what the world presently consumes, every day, in terms of hydrocarbon fuel energy.  There's an exceptionally good reason concerning why we're "addicted" to hydrocarbon fuels.  They make modern human civilization possible.  Any form of energy storage with a gravimetric and volumetric energy density 10X less than that of pure Carbon is an exceptionally poor energy storage solution- one that's wholly incompatible with merely maintaining a technologically advanced civilization.

Nobody actually wants to regress to a pre-industrialized civilization, to include the people who claim or insinuate that they do.  Without laptops, cell phones, the internet, and private jets, how else would they spread their brain dead ideology to the rest of humanity?  That means combustion is here to stay, at least until we have working fusion reactors.  Even after we have fusion reactors, combustion still makes transport machines more practical.  After we accept that simple statement of fundamental truth, we ought to immediately evaluate and select the best methods for CO2 recycling.

I happen to favor direct conversion of CO2 into pure Carbon powder at room temperature using Gallium-Indium-Copper eutectic.  It's a better use for Gallium / Indium / Copper than photovoltaics, one that incentivizes CO2 capture, storage, and recycling into synthetic fuels.  We then mix the Carbon with water, creating synthetic Coal-Water Slurry.  Since it's not actually "coal", it has no Sulfur or heavy metals.  It's almost completely pure Carbon, which very helpfully "floats to the top" of the Gallium-Indium-Copper eutectic when the CO2 is "bubbled" through a column of that room temperature liquid metal.  If we want a source of pure O2 for Oxy-Fuel combustion at power plants, it provides that as well.  Perhaps best of all, the eutectic mixture is also long-lasting / fairly stable.

The relatively new sCO2 gas turbines greatly exceed the power density of traditional gas turbines.  A child cannot pick up a 10MW steam or gas turbine rotor with one hand.  On top of that advantage, a 50% thermal-to-mechanical power conversion efficiency is not possible until a conventional gas turbine's size / output is 75MW+.  That level of compactness and efficiency makes them usable in ways that our traditional steam and gas turbines never will be.

We'll inevitably want to retain production of gasoline / kerosene / diesel since we have so many machines that consume those fuels, but we have other catalysts capable of producing CO at low / medium / high temperatures as feedstock for the Sabatier reaction vs pure Carbon powder.  That said, synthetic pure Carbon CWS is a non-toxic / high flashpoint / long-term stable fuel suitable for powering ships, trains, and semi-trucks.

In an alternative "modern history", industrialized nations vigorously pursued nuclear power, to the point that right about now the last coal-fired and gas-fired power plants were closed for good, because our electricity and fresh water needs were more than adequately covered.  Unfortunately, our fake environmentalists / real Malthusians convinced large swaths of humanity that nuclear power was the same thing as nuclear weapons.  Sadly, it was far easier to frighten people with the specter of mass deaths from radiation poisoning than it was to convince them of the mass media's fear-mongering.  Large numbers of people were instead subjected to very real air pollution deaths.  These same people, or at least the ones who were not outright advocating for genocide through energy poverty, implicitly encouraged burning coal and gas at incredible rates because there was, and still is, no viable alternative.  The recent Spanish electric grid crash proved that.  France pursued nuclear power, which kept its CO2 emissions lower than Germany.  Germany was and is an ideologically captured nation, so they pursued intermittent energy using photovoltaics and wind turbine farms, so now they're right back to burning lignite.  China and India pay lip service to the idea of reducing CO2 emissions, and they open a new coal-fired power plant about once per week.  America switched to natural gas because we have plenty of gas to spare, the requisite technology base to clear the technological hurdle to widespread implementation, and their ramp-up / ramp-down rates are absolutely incredible, which is ideal for our wild fluctuations in daily demand.

Across a diverse group of pre-industrialized / industrialized / post-industrialized nations with starkly different cultural ideology, politics, energy policies, locally available resources, and favored technological pursuits, there is no actual end result whereby pursuit of any specific policy has resulted in a global reduction in CO2 emissions.  There should be an object lesson in there, somewhere, for our techno-fetishists, yet there's not, because just like the monks in the Monty Python skit, they keep slamming that "good book" into their brain-damaged noggins.  Somewhere between 5 and 10 trillion dollars has been expended to pursue this goal, since the turn of the century.  It's the worst value-per-dollar-spent we've managed thus far.  Nobody "did their homework" on what this would actually cost, where we would source enough of the required materials from, and how feasible that was to actually do.  That means we're gonna burn everything that can burn, until we run out.  Rather than winning that stupid prize, by playing a stupid game, I would greatly prefer we pursued CO2 recycling.  The probability of that at least not making the problem worse, while pretending we're doing something effective, which we're obviously not, is almost infinitely higher than doing what we've been doing.

That brings us right back to why technology choices matter so much, if we're absolutely intent on using intermittent energy sources to supply the bulk of the Total Primary Energy Supply (TPES).  We can still do that in a practical way.  I did enough basic math to show how much of what types of materials would be required to deliver the input energy to synthesize all the hydrocarbon fuels we presently consume here in the US for transportation purposes.  I did not select a "special" type of fuel that was particularly favorable, even though this would be a highly beneficial optimization.  There was no demonstrated requirement to do that.  America represents about 25% of global transportation fuels consumption, but America alone could supply 100% of the transportation fuels consumed domestically and by our allies without a significant land claim.  Using Aluminum-coated steel mirrors to concentrate solar thermal power, the steel demand was about 10% of our present annual domestic steel production, over a period of about 10 years.  Year-over-year demand swings have varied by that amount, so ramp-up / ramp-down of production is clearly long-term sustainable.

That's a starting point for a workable and sustainable energy solution for transportation.  Concrete demand was an even less significant fraction of annual domestic production, IIRC.  I recognize that America, Australia, China, Saharan African nations, and Middle Eastern nations own a lot of "prime real estate", namely deserts, which are most suitable for hydrocarbon fuel synthesis.  I don't see this is as a major issue, since that is where a lot of existing hydrocarbon fuel production and/or consumption already takes place.

The existing "solution", if you could call it that, is that we swap the source of energy generated, stored, and consumed to electricity.  We continue burning everything we can lay a hand to, in order to extract / refine / convert / transport the resources for said electrical / electronic machines.  We make extensive upgrades and 200% to 300% capacity expansions to the world's existing electrical grids, we change how and if / when we use energy to coincide with periods when energy is available, we turn out a new generation of energy generation and storage tech every 25 years or less to remain ahead of eventual equipment degradation / failure, and we mine as-yet unseen quantities of technology metals equivalent to multiple thousands of years of existing annual production rates.  Somewhere along the way we manage to achieve near-100% recycling rates of these hard-to-extract materials that are as finely mixed together in the finished products as coffee and creamer typically are.  At some point, we're supposed to be able to cut back on hydrocarbon energy consumption, but thus far there's been no actual reduction, because we've yet to produce and install the first generation of photovoltaic / wind turbine / battery equipment to generate and store ~70% of the aforementioned TPES.  Individually, all of these separate but related tasks are monumental undertakings, greater in scale than any manufacturing expansion experienced during WWII.  Collectively, they look an awful lot like a plan to fail.  Alternatively, it's a way to continually bilk humanity out of obscene sums of money on the false premise that the desired outcome is realistically achievable.

$10T is enough money to build the machinery to collect, store, and recycle 100% of anthropogenic CO2 emissions, provided that we actually want to solve the problem so we can move on to solving other problems.  After we're no longer mining or drilling for fuels, which implies that we're recycling all of our CO2, then we can discuss whether or not electrification of other parts of our existing infrastructure makes good economic sense.  Suppose we never concoct a better solution, or that a battery with energy density similar to a hydrocarbon fuel is only forthcoming a thousand years from now.  It really doesn't matter at that point.  We're never going to "run out" of recycled CO2 and sunlight over any meaningful timeframe.

The very first thing we should do with power collected from the Sun, including power from wind turbines, is to concentrate it and store it in heated materials or as a compressed working fluid.  Integrating most parts of an electric grid into millions or billions of discrete distributed devices means many of the advantages of centralized infrastructure are lost.  The reason we built small numbers of very large electric generators was that the materials input was about as minimized as it reasonably could be, the inertia provided by massive chunks of spinning metal prevented second-to-second demand fluctuations from taking the entire grid down, and the large scale of individual grid components made them repairable vs replaceable.  The total numbers of discrete components and total complexity was also minimized.  Someone with a grasp of the basics could easily read a schematic containing all of the grid components, run a rather simple test, and determine where a problem existed.  We can no longer do that.

We can optionally use on-demand thermal power for chemical or industrial processes, or convert that heat into electricity, with the express understanding that every energy conversion is an inherently "lossy" proposition.  If we primarily use intermittent energy sources, then we should avoid all unnecessary energy conversions and systems complexity.  Maybe that makes the entire endeavor "less profitable" for people who are interested in who gets money for some specific purpose.  However, the end goals here should be minimization of total energy "locked up" in the energy generating and storage system itself, minimization of special materials and manufacturing requirements, and near-100% recycling of waste products.  We cannot do that in a practical way using existing electronics and electrical equipment.  If we could, then at some point electricity would stop getting more expensive for rate payers as additional layers of electronics and electrical equipment were added to our energy grids.  For what should be obvious reasons, that will never happen.  That is why we need to pursue alternative solutions for consuming and distributing energy from intermittent energy flows.

tahanson43206,

Metals, coal, oil, and gas are all natural resources which have been "stored by Nature".  If growing hydrocarbon foods in the soil vs full artificial chemical synthesis of sugars and starches is not considered "cheating", then neither is mining coal out of the ground.  It's a false double-standard that speaks to a desperate attempt to contort fundamental reality for ideological reasons.  If you need food and fresh water, that primarily comes from the ground.  If you need metal, then you're still talking about digging in the ground.  Similarly, the densest forms of energy also come from the ground.  All the machines that extract and transport bulk resource are only possible because they're powered by fuels that come from the ground.  To replace these underground resources with resources extracted from the air or oceans requires orders of magnitude more energy and materials, which must initially come from the ground, since they don't presently exist in the required quantities.

Onwards...

My personal "favorite" fuel is pure Carbon mixed into water, essentially Coal-Water Slurry (CWS).  It's not prototypical "coal" in the sense that it's not the stuff we dig out of the ground, it's high purity Carbon powder made from CO2 bubbled through a column of Gallium-Copper eutectic, and then mixed into water.  Pure Oxygen is released in that room temperature process while pure Carbon powder floats to the top where it can be easily collected.  The O2 could be retained for Oxy-Fuel combustion, if so desired, given that only compression is required for storage.

We commonly refer to the powder generated by that process as "Carbon Black", which is normally produced by combusting Methane.  Carbon Black is an essential rubber additive found in all motor vehicle tires, Carbon / Graphite is used by most battery anodes, it can serve as the base stock for Carbon Fiber or Reinforced Carbon-Carbon (RCC) for enhanced lightweight motor vehicle components such as brakes.  Last but certainly not least, Carbon Black mixed into fresh water creates a very high flashpoint fuel with much greater gravimetric energy density than any existing battery technology, to include Aluminum-air.  CWS is capable of powering electric power plants, ships, semi-trucks, mining equipment, trains, and passenger motor vehicles using sCO2 gas turbines.  CWS produced in this manner is not a refined petroleum product, nor is it dug out of the ground.

sCO2 gas turbines are high performance / high efficiency external combustion engines, similar in concept to steam engines, except they use sCO2 instead of water as their working fluid, making them about 10X more compact than steam turbines for a given power output.  They're also noticeably more compact and much quieter than traditional gas turbines, which are already quite compact for the power they generate.  Perhaps most importantly, achievable efficiency using sCO2 vs steam as the working fluid is greater across a broader power band.

The refining process for synthetic Carbon Black would start with Direct Air Capture, Direct Plant Capture from sCO2 electric power plants using RamGen to compress the CO2 exhaust effluent into LCO2, or possibly ocean capture methods in countries with access to oceans.  Regardless, acquiring CO2 is not particularly problematic for the parts of humanity that consume the most hydrocarbon fuels.

This is the Google AI answer to how much energy is required to convert Alumina-oxide into Aluminum metal:

Anyone who is truly interested can read more about Aluminum production here:
U.S. Energy Requirements for Aluminum Production - Historical Perspective, Theoretical Limits and Current Practices

The section to read starts on Page 39 of 150 of the above PDF file, and is entitled "5. Primary Aluminum Production".  Since the document contains clickable links that will take you directly to the section of interest, I recommend using them.

Globally, the total input energy ranges between 12kWh and 17kWh per kg of pure Aluminum metal.  Most plants burn coal or natural gas to generate the electricity, but some use hydro dams.  Aluminum smelters run 24/7/365, and absolutely cannot shut down due to intermittent energy sources, else the cost of bringing the plant back online is often uneconomical.

CO2-to-Carbon
Room-temperature CO2-to-carbon conversion facilitated by copper-gallium liquid metal

I will presume that any process which proceeds at a temperature of only 40C doesn't use too much energy.

This is the Google AI answer to how much energy is required to capture CO2 directly from the air:

While ocean capture systems may consume significantly less energy, air capture can be used anywhere there is dense air, which would be everywhere at or near Earth sea level.  Air and power plant exhaust effluent CO2 capture are the most practical options available, with ocean capture being an attractive option which may be more practical for nations with extensive coastlines and infrastructure capabilities, such as America and China.

~3,783kg of water per 1,000 gallons.
3,783kg / 27.8kWh = 136kg of deionized water per kWh
27,800Wh / 3,783kg = 7.348665W/kg

By my math, that means Coal-Water Slurry (CWS) requires about 2kWh to 3kWh per kg of CO2, the pure Carbon production requires very little energy input, plus the energy for the water.  CWS is 60% to 70% coal by volume.

3.79kg per gallon of water * 0.65 = 2.4635kg of pure Carbon

2.4635kg * 3kWh/kg = 7.3905kWh of input energy
1.3265kg of deionized water * 7.348665W/kg = 9.748004Wh of input energy

2.4635kg * 32,800,000J/kg = 80,802,800J = 22,445Wh per gallon of CWS

We should be able to get 50% of that energy back out using a sCO2 gas turbine engine, which will be positively tiny for a car, given that a 250kW turbine wheel is roughly the size of a Silver Dollar.  I presume we'd connect the power turbine to a flywheel, and then connect the flywheel to a geared CVT transmission.  We'll tack on another 15% worth of losses within the drivetrain.  That seems pretty close to reality, since overall efficiency is 35%, about the same as a modern gasoline fueled piston engine.  I'm sure someone will argue with that figure, but they're arguing over well-established engineering principles.

Geared CVT:

Traditional CVTs use belts or chains that stretch and wear out over time, but a geared CVT can continuously adjust its gearing ratio like a traditional CVT while using more compact and durable spur-type gears.

We end up with 7,855.75Wh of mechanical energy per gallon of CWS fuel, and we need to input about 7,400.248Wh of total energy.  We need to add pipeline transport energy costs as well, which will be substantial in aggregate but are also highly variable since they're dependent upon how far the LCO2 and CWS must be pumped.  Additional energy will be expended to transport CWS by truck to fueling stations.  CO2 can presumably be captured from gas or coal-fired power plants to reduce total energy input.  However, the actual refinement process for this "synthetic coal", produced using Gallium-Copper eutectic, comes pretty close to energy "break-even".  Turning Alumina into Aluminum requires 2,000C temperatures.  After more than a century, that's still the basic process for bulk Aluminum production, and it still requires Carbon anodes that produce CO2, regardless of how the input electricity has been generated.  In contrast, turning CO2 into pure Carbon requires 40C temperatures.  That is primarily what dictates how much input energy is required for recycling Alumina vs CO2.

I wanted to use synthetic coal CWS because the fuel is readily storable, not particularly hazardous since it's the same material found in fresh water filtration systems, with the water that this "coal dust" has been mixed into being the only "volatile" part of the fuel.  The Carbon particles don't readily fall out of suspension after they've been mixed into the water.  Since the Carbon is mixed into water, it's exceptionally difficult to accidentally ignite CWS, unlike any other hydrocarbon fuel.  A CO2-derived pure Carbon CWS contains no significant impurities like Sulfur or heavy metals or radioactive gases like Radon.  Recycling atmospheric CO2 into fuel is a truly sustainable process, because CO2 and water is so abundant on Earth, relative to metals.  Synthetic CWS requires only storage tanks and pipeline networks to efficiently deliver the precursor materials and fuel, same as crude oil, gasoline, diesel, and kerosene.  Plain Carbon steels are entirely suitable.  We already pump Methane and Ammonia around the country, so we can also pump LCO2 and CWS just as easily.

If the energy required to convert Alumina into Aluminum can be reduced to something approaching the theoretical minimum energy, then maybe pursuing that option makes more sense.  If Tesla's rechargeable Aluminum-air battery has the energy density of the latest Lithium-ion batteries, then it still results in vehicles that are heavier than existing gas powered vehicles.  sCO2 powered vehicles would use power train components substantially lighter and more compact than all existing gasoline and diesel engines, which means the vehicles could get lighter instead of heavier.  A CWS fuel spill is not particularly hazardous, and could be washed off a roadway with water.  Technically, this high purity Carbon fuel can be ingested in small quantities without much in the way of health effects.  All other common fuels pose health and flammability hazards, to include alcohol.

Teslas use ~250W/mile (not the absolute most efficient but not the worst, either), which implies a 375kg battery at 300Wh/kg at the pack level, for a vehicle with a 112.5kWh pack capable of achieving a driving range of 450 miles.  That's about identical range to existing gas powered compact / subcompact commuter car, none of which are powered by engines that weigh as much as an all cast Iron Big Block Ford engine.  People who are ideologically motivated can try to fight physics all they want, but in the end they're going to pay significantly more money for that excess weight, in terms of purchase and maintenance costs.  Every base model gas powered truck is about $10K to $15K more than a base model gas powered sedan, because moving and transforming natural resources into materials and then components cost money and energy.

That Cadillac Escalade my wife drove more or less proves that excess weight costs a lot more money.  She doesn't drive it anymore.  She drives a Toyota RAV4 now.  For very heavy vehicles, such as BEVs or oversized SUVs, the tires and brakes never last as long as the warranty period says they should and they always cost more to replace, specifically because they're so heavy and made from high embodied energy materials.  Playing a convoluted game of pretend with efficiency doesn't change physical reality.  There have been numerous disingenuous attempts to imply that electricity is "more efficient than Carbon-based fuels", but any time you increase ordering of energy forms you radically increase the energy and materials inputs.  Any purely electrical system based upon photovoltaics, wind turbines, and batteries will require more materials and thus energy inputs than a system based upon chemical energy.

You buy a Tesla, then you accept that you're looking at new tires and brake pads every 12 to 18 months, you're paying 50% than what a comparably-sized but lighter gas powered vehicle costs.  You're never recovering that additional money, in terms of gas money saved, over 10 years of normal driving.  You either accept that at least 50% of your power is coming from burning something, likely closer to 75% if you mostly recharge your BEV at night when you're not using.  Alternatively, you accept that Carbon-based chemical energy requires fewer materials and energy inputs than electrical energy, especially when recycling is an integral part of long-term sustainability.

If theory matched reality, then a country like Norway, where nearly all of the vehicles in active use are EVs, ought to see a 20% reduction in total oil consumption, rather than 10%.  10% would be a very big number for America, but hardly a game changer.  Only big numbers matter, though.  Room temperature CO2 recycling allows us to post very big numbers because a near-100% recycling rate implies that we're adding little to nothing to the atmosphere or oceans over time.  Gradual changes using photovoltaics and wind turbines are already completely overwhelmed by the new coal and natural gas power plants in China, India, and Africa.  The new coal power plants in China alone have already "cancelled out" more than 100% of the supposed CO2 emissions reductions of Western nations from photovoltaics, wind turbines, and batteries.  That's why such solutions are utter nonsense.  They squander lots of time and money while making negative progress towards their stated global CO2 emission goals.  Unless our "green evangelists" are planning to genocide most of the people in developing nations, which would only indicate that they're more profoundly evil than I know them to be, this will continue to be the case.  Recycling CO2 is the best option available, because it's one that doesn't require nonexistent electrical energy storage technology capable of matching the energy density of chemical fuels.

You can't successfully fight physics by continuously increasing the total mass of all vehicles, the energy intensity of the materials required to make them, and the energy generating systems that power them.  Nothing about this Aluminum battery solution requires less total mass of materials than chemical energy.  The grid infrastructure to power a fleet of primarily electric vehicles, without burning something, requires doubling or even tripling of its existing carrying capacity.  Insisting upon the use of intermittent energy as primary sources only increases requirements, which is why all "green energy" systems must be backstopped gas turbines or nuclear reactors.  Electrical systems do not last as long in operation as pipelines and pumps, either.  There's not a week that goes by where I don't see the power company trucks and crews replacing a piece of electrical equipment heavier than a car.  Ignoring all the energy inputs into continuous complete replacement, especially if little of it gets recycled, as is the case for all electronics, is intentionally deceptive.  The only part that's shockingly real is the absurd cost.  Electrical and electronic systems are truly fantastic when they work, but when they don't the only "solution" thus far is complete replacement of whatever failed.  Nobody "repairs" batteries, they replace them.  The fuel-cell-like Aluminum-air batteries might be the only notable exception.

Collectively, all of this new electrical and electronic technology doesn't do what it claims to do, namely reduce CO2 emissions, or merely reduce the rate of increase of CO2 emissions.  Incentivizing CO2 capture and recycling by using simplistic fuels and processes has a much better chance of arresting the rate of increase and drawing down CO2 over time, because CWS can be stockpiled in simple steel storage containers.  Rather than play along with an absurd idea that clearly isn't working, namely consuming more energy and materials to somehow eventually consume less, I'm proposing a more realistic alternative that could work because it uses existing technology.

Here in Texas we're building sCO2 gas turbines to pump our natural gas and to generate electricity.  We needed something better than existing gas or steam turbines or piston engines.  sCO2 provides that "something better".  We spent the past 25 years developing sCO2 tech, and now we're finally seeing the first commercial applications.  As near as we can tell, it actually works, it is meaningfully more efficient than traditional gas or steam turbines, and doesn't require quantities of materials we don't have.

Void,

If a company like Tesla can produce a $25,000 BEV, then good on them.  It will mark their first attempt at manufacturing a common commuter type car to truly compete with similar gas powered vehicles like the Ford Focus, Mazda 3, Honda Accord, etc.  While not as flashy as the higher end models, these vehicles have traditionally been the largest volume sellers.  The Cybertruck could've been a much more popular vehicle if they'd decided to make a traditional looking truck instead of a modern art masterpiece, but I digress.

If this is the genesis of the Aluminum-air battery mentioned:

Recharging it requires about 12X to 14X more energy in than you get out, because the Aluminum-oxide has to be converted back into Aluminum powder.  Energy density is pretty fantastic.  It's essentially a rebuildable fuel cell.  Using it takes away any argument about the battery being more efficient than a combustion engine, because it's not.  A gasoline powered car will use ~937.5kWh of fuel energy to drive the same distance, meaning 500W per mile.  Converting 100kg of Aluminum-oxide powder, back into Aluminum powder, 1,200kWh to 1,400kWh.

The key takeaways from my remarks on this topic are as follows:
1. Energy density is a real world concept with real world implications, not amenable to anyone's ideological beliefs about how it affects every aspect of a motor vehicle design solution.  There are no batteries in existence that begin to approach the energy density of hydrocarbon fuels and there probably never will be within our lifetimes.

2. The monetary cost of BEVs is primarily tied to the energy costs associated with manufacturing and maintaining them.  The embodied energy in BEVs is much higher than the embodied energy in gasoline powered vehicles.  To make costs equivalent, weight must be equivalent and total energy investment must be similar.  The most logical way to do this is to reduce the crushing weight of the battery, but this requires making a battery with dramatically improved energy density.

3. The reason 100% of all EVs in existence use Copper windings in their electric motors is purely related to motor performance and weight.  If the motor used Aluminum windings, then it would weigh more and cost more, because more energy would be required to make it and to move the vehicle it's installed in, simple as that.  Real electrical engineers who design electric motors for EVs have stated as much.  When the electric motor becomes so large as to be similar to the kind installed in hydro dams, then and only then can Aluminum windings be used to save weight and improve performance.

4. The BEV itself is merely the tip of the iceberg, regardless of what battery tech it uses.  It requires electricity from the grid.  This is where the real energy and materials over-consumption becomes a serious problem.  To power everything using wind turbines or photovoltaic panels, and grid-connected batteries is where the real demand for Copper becomes untenable.

If the entire grid was powered by a handful of centralized nuclear reactors, which would not require a complete grid redesign and absurd quantities of additional conductor wiring to deal with Gigawatt-scale power spikes and dips, then converting all the vehicles to electric power makes a lot more sense.  Unfortunately, that's not what we did.  The money to increase grid capacity is going to gas turbines and coal power plants or so-called "green energy" projects that are anything but, since the gas turbine has to run 24/7/365 to prevent daily grid crashes, of the kind seen in Spain under supposedly ideal conditions.

5. No energy is being saved at any point in time using photovoltaics, wind turbines, and batteries.  We're dumping energy into the grid itself for a meager return on investment, and/or burning coal and gas like they're going out of style, which is why, collectively, all of the green energy projects have not resulted in a net demand reduction for coal, oil, and gas.  This relates right back to the Iron Law of Energy Density.  Consumption only declines, temporarily, when consumers are unable to pay.  At all other times, it's beyond obvious that we're driving up the price of energy, reducing grid reliability, and increasing demand for energy.  There are clear benefits accrued to human flourishing by consuming more energy, but no benefits accrued to Earth's natural environment in so doing.

There is no possible way to "save energy" / "become more energy efficient" using energy sources that require orders of magnitude more materials and thus energy input to sustain.  Your LED light bulb consumes less energy, but all the infrastructure required to mass produce LED light bulbs requires more energy input than mass production of incandescent bulbs.  Every LED bulb I've ever used is noticeably heavier than an equivalent incandescent bulb, and made from high energy materials like plastic and Aluminum.  That's why LED bulbs cost more than incandescent bulbs.  To believe that they're "more efficient", you must first partake in a fantasy world where you utterly ignore all the materials and thus energy inputs required to make LED bulbs and you must then presume that fewer bulbs will be made since they last longer and nobody will "leave LED lights on 24/7" because they use less energy.

We all know that in the real world, improved energy efficiency directly causes more energy consumption, "because it's cheaper".  Well...  Define "cheaper".  Cheaper in what way?  On a per-unit basis?  Sure.  In aggregate?  Obviously not.  At some point, if there was any kernel of truth in the claims made by our "green energy" advocates, there would need to be a CO2 emissions decrease, or merely an arrest in the rate of increase, year-over-year.  The more of the wind turbines, photovoltaics, and batteries we produce, the higher our CO2 emissions go.  Funny that.  Only major economic crashes, completely unrelated to energy sources, events like COVID or the 2008 recession from the real estate bubble, have reduced total consumption and thus total emissions.

This doesn't mean we should make everyone poor by not bringing new energy sources online when we need more energy, but we should stop pretending that we're "fighting climate change", or other similarly stupid nonsense, and start being honest about what we're doing- consuming more energy while engaging in a very elaborate "game of pretend".

Void,

We already have solar panels that have lasted more than 8,000 years.  They're called "mirrors".  I'm genuinely curious as to why some of us have yet to discover these seemingly miraculous solar panels, because they've been a part of humanity's technology toolkit long before batteries or combustion engines ever existed.

This YouTube personality who calls himself "The Electric Viking" is delusional if he thinks gas powered cars are going to start disappearing from Texas during the next 5 to 10 years, or merely that BEVs become the majority of new car sales.  People like him think they can cheer-lead their favored power and propulsion solution into existence.  He cannot make peace with the idea that human civilization was built on specific engineering principles not amenable to his personal preferences.  Power and energy density are iron-clad engineering principles that dictate which technologies eventually become practical and pervasive on-demand power and propulsion systems.

A kilogram of diesel fuel contains 39,750Wh of energy.  A modern turbocharged diesel piston engine can extract 19,875Wh of mechanical energy from that fuel.  For a 500Wh/kg battery, that's a 39.75:1 gravimetric energy density deficit ratio.  There are no clever engineering principles able to overcome 40:1 mass ratio increases associated with power / propulsion systems for motorized vehicles.  Unless the gravimetric density of batteries improves by about 40X, the only net result will be a more expensive and less available transportation solution.

Edit:
I should have stated diesel's per kilogram gravimetric energy density value, which is 12,500Wh/kg, but accidentally used diesel's per gallon, which is 39,750Wh/gal.  6,250Wh/kg can be converted into useful mechanical power output.  This is still 12.5X greater than a 500Wh/kg battery, not 40X greater, but my underlying point still stands.  There is literally nothing you can do to make an electric vehicle achieve the same range as a diesel powered vehicle, except by making it much heavier.

Edit #2 (supporting evidence):
The Tesla Model 3 Long Range costs about $56,000, has a 1,847kg curb weight, it's battery weighs 480kg, and it can drive ~310 miles at highway speeds when brand new.

The Mazda Model 3 costs about $25,000, has a 1,400kg curb weight, 13.2 gallon fuel tank and gets 37mpg on the highway, so it can drive ~481 miles on the highway, which is 55% further with 447kg less weight.

Using the current national average gasoline price of $3.136/gallon, if you kept both cars for 10 years, drove the "standard" 15,000 miles per year, and did 3 oil changes per year, the Tesla Model 3 will never "break even" with the Mazda 3 in terms of total cost of ownership.  This would be the case if both the electricity and 12-18 month tire replacements (the maintenance penalty for its excessive weight) for the Tesla were free, which they're not.

Both vehicles are subcompact cars that take you from Point A to Point B.  Anyone on a budget can see how the math of this proposition will work out for them.  Anyone who doesn't care what the car costs, nor how frequently they need to carefully plan their driving route and closely monitor the vehicle's "fuel capacity", isn't significantly affected by their motor vehicle purchasing decisions.  Good for them, but that doesn't describe most people.

Why is the Tesla so heavy and costly?

That's actually a relatively easy question to answer.  That's the performance and monetary penalty associated with poor energy density.  You pay double for 50% less driving range.  If driving range and cost are both irrelevant, then lots of other practical ownership issues are also irrelevant.  I think it's okay to make purchasing decisions that have nothing to do with money, but for vast majority of people who own and drive cars, cost and the practical usability of the vehicle is an issue.  They have to make rational decisions about whether or not they're getting good value per dollar spent.
End Edit #2

More than a century after diesel engines were invented, there are still no practical substitutes for diesel engines.  We should focus more time and effort synthesizing fuels which are free from impurities, designing pistons and valve trains that promote thorough mixing of fuel and air for complete combustion, and optimizing power transfer systems like transmissions.

As shale oil runs out, we should start synthesizing hydrocarbon fuels.  We should do that because it's been achievable using technology that was invented in the 1970s.  We use that same technology to synthesize modern synthetic motor oils from Methane base stock.  If the past century of technological advancement is any indicator, there won't be any new battery technologies that begin to approach the energy density of hydrocarbon fuels.  If all motorized road vehicles used batteries of some kind, oil demand only decreases by about 10%.  If "The Electric Viking" lives to see his dream scenario of 100% electric vehicles, no dramatic change in demand for petroleum products will occur.

Speed-of-Air Pistons did more to improve air quality, through not-so-simple piston crown geometry changes resulting from supercomputer simulations of the combustion process, than the current combination of expensive and failure-prone catalytic converters, urea fluid, and particulate filters.  That "ounce of prevention" proved to be worth more than several hundred pounds of "cure" for large diesel engines.

I wonder what has to transpire before these "electric dreamers" come to terms with the dissolution of their futurism fantasies.  They seem increasingly desperate to ignore technological reality.  I think most of them are in the bargaining phase, though "The Electric Viking" still seems to be in the denial phase.  Regardless, public support and investments into their beliefs are waning as pragmatism gradually replaces hyperbolic techno-fetishism.  Nobody who lives paycheck-to-paycheck is onboard with their plans for the future.

Void,

Even if that Aluminum-ion battery was twice the stated price, it would be a bargain compared to a Lithium-ion battery.  Either these electric vehicles come down in price to something comparable to gasoline engines, without sacrificing all pretense of build quality the way the Chinese manufacturers have done, or they'll never be practical.  They don't need to be rolling computers on wheels, either.  All the optional extras are fine if they don't radically increase cost and work reliably, but quality computers and sensors will never be cheap.  It's the nature of the cutting edge tech beast.  Present day Silicon-based AI chip technology will never be capable of reasoning as a human does because it consumes multiple orders of magnitude too much power to do so.

A human brain computer equivalent is still very much akin to the giant room-filling computers of the 1950s.  It's optical chips or bust, because only full optical computers can reduce the power requirements to something on-par with a human brain- from 20MW to 20W.  After we reduce the input power required to simulate human brain reasoning capacity by 6 orders of magnitude, then lots of things are possible.  I don't know if AGI or "super-intelligence" is even possible, because it presumes we humans have the capacity to create such a thing, but until then we'll never know.  The software required has yet to be written, but we're working on that and initial results look promising.  The software development moves much faster than the hardware tech necessary to run it efficiently.  We have tools now that governments would kill for back when I was younger man.  They probably did and will.

I have a bigger question, though:
How do you coalesce all of this new "wonder tech" into something approximating useful tools for society to put in its tool belt?

A sledgehammer is still a grossly inappropriate tool to use to kill flies.  Sure, it'll work, but that's also a lot of heavy lifting when dealing with the endless stream of day-to-day annoyances.

Beyond that, how do we answer the question of what to pursue?

There are opportunity costs to everything.  We ought to have human-based priorities, such as curing cancers / diabetes / heart conditions, figuring out how to construct energy generating machines, when and where to apply our most advanced tech vs when to simply let slower but "more human" process play out.

Can you even imagine how potentially dangerous biotech will become when we have this new tech?

Everyone worries about nuclear weapons, but even the wildest of men seem to understand that actually using them is a world-ending proposition.  Even after COVID happened, we were still allowing scientists to toy with viruses in labs like children play with their dad's pistol.  All involved ought to know that it can only end badly, and they can't credibly claim that they didn't know what could and likely would happen, yet they do it anyway.  A lot more "adult supervision" will be required for people who are nominally "adults", but "not adults" when it comes to their own field of expertise.  No amount of education is able to inculcate prudence, or so it would seem.  That remains a real and deadly serious problem, even after we develop AGI and all other manner of remarkably powerful tools.

Perhaps the first and most important task for AGI will be to teach people "how to think", where so many humans only taught people "what to think".  On that note, we're going to need to teach AGI the same thing.

RobertDyck,

Regardless, now you can buy one for $10 in 2025.  I posted a link to it.  Grossly exaggerating doesn't help lend credibility to your beliefs.

tahanson43206,

I'm genuinely curious to know if LH2 works better as a fuel than RP1 as you scale-up the size of the rocket to deliver a 100t payload.  I don't have any ideological beliefs about this.  I only care about what the basic math tells us about the nature of the problem.  If LH2 energy economics work more favorably at 100t than 25t, then that's what the ultimate answer is, regardless of what I or anyone else believes about it.  Math won't change to suit anyone's beliefs.

I've done the math on Delta IV Medium and Falcon 9 Bock V to evaluate Total Impulse per kilogram delivered.  I could get more sophisticated with the analysis, but really don't need to.  What it tells me is that for the medium lift payload delivered, RP1 is the fuel of choice.  However, when I look at Delta IV Heavy and Falcon Heavy, I see a clear advantage attributable to LH2.  Delta IV Medium / Heavy and Falcon 9 / Falcon Heavy are the closest "apples-to-apples" real world rockets we have to compare / contrast LH2 and RP1.

For the boosters, I evaluated Total Impulse of each stage at sea level only.  I'm going to use 90% of vacuum Isp, which is pretty standard for booster evluation, and re-run the numbers.  The point to the sea level only evaluation was that if LH2 didn't show a reduction in Total Impulse per kilogram of payload delivered there, then it wouldn't show one with 90% of vacuum Isp, either, since it goes up quite a bit for LH2.  However, what I see thus far seems to favor LH2 for much larger payloads, because the simplistic sea level Total Impulse evaluation for Delta IV Heavy and Falcon Heavy indicates much lower Total Impulse required to deliver a kilogram of payload to orbit, relative to Falcon Heavy.  That means Delta IV Heavy is actually markedly more energy efficient than Falcon Heavy, which is critical for both a SSTO and for any LH2 fueled vehicle to make good economic sense.  LH2 is a premium fuel, easily double the cost of RP1 per gallon.  If we're going to use it, then we need to make a case for why it's more efficient to use it.  For a small payload, we cannot make that case.  For a much larger payload, initial results look very promising.

For a 25t payload or less, LH2 doesn't seem to provide a favorable energy trade, which indicates that the combination of thrust "to get the vehicle moving smartly downrange", as GW would say (what he means is that sluggish acceleration is not acceptable for a SSTO), and cube-square isn't working in our favor for smaller rockets, because the RP1 fueled rocket can be so much smaller and lighter, relatively speaking, that the engine and/or propellant tank mass ratios don't work in favor of LH2.

As with most other things in engineering, everything from gas turbine engine efficiency to economical fission reactors, it appears that scaling laws apply to SSTOs as well.

We finally arrive at an energy economics result favorable to LH2:

Delta IV Heavy Energy Economics Improve Upon Delta IV Medium
447,150,942N-s * 3 (Common Booster Cores) + 124,353,610N-s (DCSS Upper Stage) = 1,465,806,436N-s Total Impulse (both stages)
1,465,806,436N-s / 28,790kg of payload = 50,914N-s/kg of payload to LEO

Falcon 9 Block V Heavy Energy Economics
1,178,870,316N-s * 3 (Booster Cores) + 363,937,025N-s (Upper Stage) = 3,900,547,973N-s Total Impulse (both stages)
3,900,547,973N-s / 63,800kg = 61,137N-s/kg of payload to LEO

50,914N-s/kg  / 61,137N-s/kg = 0.83

1. I take this to mean that the vehicle is very sensitive to thrust performance.   Tahanson43206 set the payload target to orbit at 100,000kg.  Therefore, we want to know the energy economics after we scale-up the LH2 powered SSTO to lift 100t.  There is at least some potential here which indicates favorable energy economics associated with using Hydrogen fuel.  At the 25t payload level or less, RP1 fueled solutions or LH2 paired with solid rocket motors appear to result in much smaller / lighter / equally performant vehicles in the realm of energy economics.  This partially explains why vehicles like Ariane V, Atlas V, and Delta IV Heavy have all failed to compete with Falcon 9 Block V.  For small launchers, no economy of scale is possible.  You either have highly favorable energy economics or the cost of your engines and fuels override whatever minor performance advantages exist.

2. This is an actual desirable result showing a clear advantage in energy consumption required to attain orbit.  Whereas the Delta IV Medium is little better than a Falcon 9 Block V, Delta IV Heavy consumes measurably LESS energy than Falcon 9 Block V Heavy.  Therefore, it must be the case that using LH2 as the fuel of choice doesn't produce the desirable energy economics until the launch vehicle size is scaled-up quite substantially.

3. To make LH2 more competitive, we need better performing engines, such as RDEs, made from somewhat exotic but now much more affordable materials like RCC, in order to minimize engine mass or improve engine TWR, however you prefer to think about it.  RDE alone would result in 150:1 TWR, and using RCC instead of stainless or Nickel-Copper alloys could increase that to 600:1, making LH2 engines suitable for SSTOs.

4. Any reusable SSTO must use CFRP propellant tanks.  No other material is suitable because TPS mass will be added for reentry protection.  However, I was considering the propellant mass fraction of the stainless steel balloon tanks used by the Centaur Upper Stage.  Recent advances in Mangalloy welding make me think that Mangalloy, which has double the yield strength of 304L stainless, could be a lower cost and stronger alternative to fabricate much larger SSTO propellant tanks.  5.1m diameter 304L tanks are clearly doable, but ideally we want 10m diameter tanks.  The Japanese and Koreans have done extensive testing with this material for storage of LNG, LN2, and LH2.  Since they have test data to back up their assertions, I'm going to take them at their word.  Some kind of coating, perhaps Silicon-based, would be required to protect the alloy from LOX, perhaps LH2 as well, but the end result could be relatively inexpensive, strong enough, and light enough.  I was thinking about using steel cable with weldments inside the tank that keep the structure in tension and pull double duty as slosh baffles.  I've never seen this done for this application, but we use it in bridges and other applications.

5. Someone needs to run an analysis to determine what flight trajectories are optimal for LH2 SSTOs, given their lower TWR.  Is there a payload performance benefit to adding some forward / perpendicular velocity during part of the flight within the lower atmosphere, so long as the aerodynamic heating and drag loss is not too severe?  If we're going to use steel balloon tanks, this might be more tolerable.  All LH2 tanks have some external thermal insulation applied so that heat transfer rates remain tolerable.  What kinds of lightweight thermal insulation do we have today?  Perhaps we have something based upon spray-on aerogels that minimize weight and do a better job than polyurethane foam.

LOX/LH2 Propellant for Equal Thermal Output as 1m^3 of Densified RP1 and 1.608m^3 of Densified LOX

NBP LOX = 1,141kg/m^3 (Normal)
MP + 10K LOX = 1,262kg/m^3 (Densified)

37,281MJ/m^3 of RP1 / 10,082MJ/m^3 of LH2 = 3.697778m^3 of LH2 per 1m^3 of RP1
3.697778 * 71kg/m^3 = 262.542238kg of LH2
262.542238kg of LH2 * 6.03 = 1,583.12969514kg of LOX
1,583.12969514kg (LOX) + 262.542238kg (LH2) = 1,845.67193314kg of LOX/LH2 propellant
2,895.78kg (LOX/RP1) / 1,845.67193314kg = 1.568957
LOX/RP1 is 56.8957% heavier than LOX/LH2 for equal thermal output

LOX/LH2 volume increases to:
3.697778m^3 (LH2) + 1.387493m^3 (LOX) = 5.085271m^3 total LOX/LH2 propellant volume
3.697778m^3 (LH2) + 1.254461m^3 (Densified LOX) = 4.952239m^3 total Densified LOX/LH2 propellant volume
4.952239m^3 (Densified LOX + NBP LH2) / 1.608m^3 (Densified LOX + Densified RP1) = 3.079751

Best case scenario, Densified LOX + NBP LH2 occupies 3X greater volume than Densified LOX + Densified RP1 for equal thermal energy output.

Will the propellant tank volume trade for LH2 be quite that bad, due to the much higher Isp of LOX/LH2?

No.  A lighter / faster combustion product means less mass flow at a higher velocity partially equalizes the dramatically lower bulk propellant density of LOX/LH2.  This counts for something, but not enough to favor LH2.

Will a LOX/LH2 powered vehicle dry mass ever be as light as a LOX/RP1 powered vehicle for the same payload to orbit?

No.  The propellant itself will be lighter for equal kinetic energy output and the cube-square law will also partially offset the increased propellant tank mass to store LH2, but the stage dry mass must be higher when using LH2.  There are no two ways about this.

This stage dry mass increase is accurately reflected in the stage dry mass and payload to orbit of Delta IV Medium (all LH2 powered) and Falcon 9 (all RP1 powered).  Both vehicles have very similar stage dry mass, although the Delta IV Medium stage dry mass is higher for both stages, after subtracting the engine mass.  LH2 engines are also heavier than RP1 engines for the thrust output provided, but that's merely another aspect of the compounding problem of low thrust and high stage dry mass.  Delta IV Medium delivers 8,510kg to orbit.  Falcon 9 delivers 22,800kg to orbit.  The fact that the Falcon 9 (549.5t) is about 2X as heavy (with its full propellant load) as the Delta IV Medium (224.6t) has no significant effect on stage dry mass.

549.5t (Falcon 9 wet mass) / 224.6t (Delta IV Medium wet mass) = 2.44657
22,800kg (Falcon 9 payload) / 8,510kg (Delta IV Medium payload) = 2.67920

224.6t (Delta IV Medium wet mass) / 8.51t (Delta IV Medium payload mass) = 26.39248
549.5t (Falcon 9 wet mass) / 22.8t (Falcon 9 payload mass) = 24.10088

The ratio of Falcon 9 wet mass to payload mass is LOWER than it is for Delta IV Medium.

How can that be the case?

The higher stage dry mass of the LH2 powered vehicle (the combination of higher propellant tank mass and much lower engine TWR) offsets more than 100% of its considerable Isp advantage over the RP1 powered vehicle.  This problem would be worse for a SSTO.

The major "clue" that something doesn't add up is the simple fact that the Total Impulse delivered by both stages of the Delta IV Medium, per kilogram of payload delivered to orbit, is only very modestly lower than it is for both stages of Falcon 9.  The only way for that to be true is if the relative propulsive efficiency (total number of Newton-seconds of thrust delivered per kilogram of payload) associated with using LH2 in a real rocket powered vehicle is very similar to RP1.  If that number for LH2 was dramatically lower than it was for RP1, then it's indicative of much greater relative propulsive efficiency.

Delta IV Medium: 67,157N-s/kg of payload
Falcon 9 Block V: 67,667N-s/kg of payload

510N-s of Total Impulse reduction per kg of payload.  That's the extent of what LH2's fantastic "efficiency" provides to a real world Delta IV Medium rocket, which is an almost meaningless figure, because it's equivalent to extending the firing duration of the booster engine(s) in either vehicle for 1.5 seconds or less for either vehicle.  I was expecting a N-s/kg reduction commensurate with the Isp increase of LH2 over RP1 for the engines in question, meaning N-s/kg should be at least 29% lower for LH2.  RS-68A produces a higher Isp at sea level than the Merlin-1D Vacuum nozzle engine variant produces in a hard vacuum.  In real life, RP1's thrust efficiency in a Falcon 9 Block V is less than 1% lower than LH2 in a Delta IV Medium, by computing total impulse delivered by both stages and then dividing by the total kilograms of payload to orbit.  That is spectacularly bad, but only reinforces how important engine thrust and stage dry mass truly are to overall vehicle performance.

If we wanted to make the payload performance of Delta IV Medium and Falcon 9 "equal", what does that imply?

22,800kg / 8,510kg = 2.6792

Stage dry mass is going to increase by about 2.6792X to make a LH2 gas generator cycle engine vehicle "equal" to a RP1 gas generator cycle engine vehicle.  The payload to LEO of Delta IV Heavy, which is about 3X heavier than Delta IV Medium, is only 5,990kg higher than Falcon 9.

Delta IV Medium
26,850kg (1X Common Booster Core) + 3,480kg (5.1m DCSS Upper Stage) = 30,330kg (total dry mass)
30,300kg dry mass / 8,510kg payload mass = 3.56kg dry mass per 1kg payload mass

Delta IV Heavy
80,550kg (3X 5.1m Common Booster Cores) + 3,480kg (5.1m DCSS Upper Stage) = 84,030kg (total dry mass)
84,030kg dry mass / 28,790kg payload mass = 2.92kg dry mass per 1kg payload mass

Falcon 9 Block V
23,600kg (expendable booster core) + 4,000kg (upper stage) = 27,600kg (total dry mass)
27,600kg dry mass / 22,800kg payload mass = 1.21kg dry mass per 1kg payload mass

Falcon 9 Block V Heavy
70,800kg (3X expendable booster cores) + 4,000kg (upper stage) = 74,800kg (total dry mass)
74,800kg dry mass / 63,800kg payload mass = 1.17kg dry mass per 1kg payload mass

How do we make LH2 stage dry mass "more equal" to RP1 stage dry mass?

That's the real question we need to answer to make LH2 a viable candidate fuel for SSTOs.

For a practical purely rocket powered SSTO, what does that mean?

If you insist on using LH2, then you get a lot less payload to orbit (that is not the vehicle itself) for the same stage dry mass.  I can't speak for anyone else, but that looks like a bad trade to me.  All that "potential" thrust efficiency (N-s/kg of payload) amounts to almost nothing due to the poor stage dry mass efficiency, exacerbated by poor LH2 engine TWR.  RDEs and RCC vs metal alloys could potentially solve the TWR issue for LH2 engines, but they cannot reduce the propellant tank mass, which is the largest portion of total stage dry mass.

RobertDyck,

The US does engage in trade, and always has, but it's not a major part of our economy, except for the part that drains resources and jobs to actually buy the products.  If trade was such a great deal, then there would be far fewer people living in relative poverty in America, not more.

I haven't been in a Wal-Mart for many years.  I honestly have no clue where their products are made these days.

Edit:
Back when we still shopped at Wal-Mart, my wife bought dishes, glasses, and other household items (towels, blankets, linen), specifically because they were "Made in USA".

Your parents paid $25 in 1984 for a device which I can buy for $10 in 2025:
EZ DUZ IT - USA Made Can Opener - $9.95

It's available on Amazon with a $4 markup.  There are other American-made can openers which are also available for less than $25.

I feel like you were a little over-zealous in typing out all those zeroes.  You're "off" by a factor of 10.

Purism's US-assembled Smart Phone with US-made Electronics and US-sourced Materials:
Purism Liberty Phone

Purism's 128GB Liberty Phone: Starts at $1,999
Apple's 128GB iPhone 16 Pro: Starts at $999

Edit #2:
Most of the Apple mobile chips are now made in the US before being shipped to China for final assembly into iPhones and other Apple products, then shipped back to the US.  TSMC moved their chip fab to Arizona citing security concerns about having all of their factories in Taiwan.

Edit #3:
Amprius now has 500Wh/kg Lithium-ion batteries, which are made in Brighton, Colorado.  This is far in excess of what the present iPhones have in them, but will obviously help power the next generation of mobile devices.  Purism could source their batteries from Amprius, for example, because their batteries are user-replaceable by design.

Yes they are and I just proved it.  Actually, the real world market economy just proved it.  I didn't have to prove anything.  You should've done some basic research before making your outrageous claims, but you didn't because basic research wouldn't support your claims.

RobertDyck,

Isn't President Trump doing Canada a favor by encouraging Canada to seek more profitable trade deals with other nations?

Yes, free trade has been so "good" for Americans that since offshoring of American manufacturing jobs began during the 1970s, real wages haven't increased, relative to inflation, except ever so briefly during President Trump's first term in office.  We're all too stupid to notice that we're somehow getting "poorer" despite all those "cheap" goods pouring in from overseas.  In other news, water is no longer "wet".  Sorry, but all the pathetic attempts at "jedi mind tricks" no longer work on people who have to choose between rent, food, gas money to drive to work, and health care.  Free trade has been great for rich people- just one more way to exploit desperate people elsewhere in ways they're not allowed to here in America due to labor laws.  For everyone else, it's become yet another "utopia".  I can buy lots of things I don't need with money I don't have, but I can't buy an appliance that lasts longer than 5 years.

When you pay your neighbor to make something you truly need (need vs want, endless choice vs meaningful choice), the benefit is that he gets to use the money to support his family, you get your coffee machine, and because his company actually makes coffee machines, any coffee machine manufacturing innovations are likely something that our fellow countrymen get to benefit from, rather than someone living in a foreign land.  I don't need or want an internet connected coffee machine with 50 different settings and more lights than a Christmas tree.  I could care less if it sings to me in the morning.  I'm buying it because I want a hot cup of coffee in the morning.  If it can do that, reliably, for the next 20 years or so, then it was something worth spending my money on.  It wouldn't matter if it costs $100 vs $50 when it lasts 4X longer because it's not loaded with useless features nor made from the cheapest materials imaginable.

The US didn't engage in enough trade immediately before and during the Great Depression for trade to make much difference to the overall US economy.  For starters, most Americans couldn't afford imported goods.  We didn't export much, either.  Productive output nonetheless decreased by half and investments fell to near-zero.

This popular line of argumentation about Smoot-Hawley is frequently used to explain the worsening of the Great Depression, yet there's clear evidence that trade was never a sufficiently large part of the American economy to explain away a 10 year long event.  To this day, trade continues to be a minor part of the overall US economy.  The real issue is that when it comes to making things that truly matter, all the raw materials inputs required to create the machines, we largely stopped doing that.

We're not allowed to open new mines, smelters, and other heavy industry inputs required to make things in quantity.  The Democrats are largely to blame for that.  We tried to open a Lithium mine and they did everything in their power to prevent that.  The same applies to coal, oil, natural gas, and lumber.  I'm willing to meet Democrats half-way on the lumber issue by growing our own bamboo in the Southern US because I don't want all of our tress cut down, either.  You won't find anyone who thinks cutting down all the trees is a good idea, except maybe the green energy advocates who want to clear-cut forests for their wind and solar projects.

Green energy tech is finally dead because they fixated on so much stuff that simply did not matter and imported all of it from overseas.  They could've built solar thermal power plants that operated 24/7/365, and the fact that they used more steel and concrete would've been shrugged off as acceptable because they last for 75 years like any other thermal plant and require the type of maintenance that ordinary people can do.  More electricity without having to burn something is more better, but only when you get it through sustainable means and it's boringly reliable.  That's not what they did, and now there's no more money to finish the over-arching idea, because they're focused on meaningless details while ignoring the important ones.

All that potential, all the money, all that intellectual effort... squandered.  That's the real travesty.