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#26 2023-02-27 12:39:35

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,606

Re: Why the Green Energy Transition Won’t Happen

Calliban,

To this day, fuel and salaries are the greatest expenses incurred by any airline service, but the flight time difference for a trans-Atlantic crossing was marginal, your pilots are only allowed to fly for so many hours between crew rest periods (two back-to-back flights across the Atlantic would be forbidden using anything but Concorde, which was the opposite of affordable air transportation), and AGA-33 was as much about increased passenger comfort as it was about reducing fuel costs.  The plane was designed for extra head and leg room not present on today's airliners.  Someone probably saves a few pennies by cramming everyone into a cage, and over time it adds up to a few million here or there, ignoring all the other efficiency and opportunity losses that preclude saving one red cent.  Bean counters should not dictate aircraft design, and engineers who have been "touched by the good idea fairy" need to be summarily fired for saving pennies while squandering dollars.

The design concept is substantially correct, even though it wasn't invented by Airbus or Boeing.  It was intended to show what could be done without radical changes to the way airliners are designed, built, and flown.  Instead, we blew mad money on better engines, which is fantastic, but did little to improve the outlook for the airline industry, because the operating cost keeps going up, up, and away.  The funny thing is that the market kept growing until COVID and COVID response induced recession / depression.

If we built a plane that cut the fuel bill in half, then more people would fly, but the anti-humanists want to separate people into haves and have-nots, so transportation has to be an exclusive luxury only afforded to the independently wealthy.  How else is a blowhard like John Kerry or Al Gore supposed to pontificate to the rest of us when all of us silly "little people" are allowed to fly around in jets like he is?

The entire airline industry is a minor fraction of total CO2 emissions, if the jets were twice as fuel efficient it would be an even more minor contributor, and at some point all the mental masturbation over flying would be recognized as the pointlessly stupid endeavor that it's always been, much like trying to insert batteries into applications where they clearly don't belong.

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#27 2023-02-28 03:18:55

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,572

Re: Why the Green Energy Transition Won’t Happen

Kbd512, looks like you are correct.  The effective lifetime of a commercial jet varies, but is better expressed in cycles rather than years, because airframes take a beating on takeoff and landing.  The industry estimate is 100,000 cycle lifetime.
https://www.airliners.net/forum/viewtopic.php?t=214771

Airbus A319 comes with a price tag of $89.6 million and has 156 seats.
https://www.skytough.com/post/how-much- … plane-cost

That works out at $5.8 per passenger seat per cycle.

Fuel consumption averages 2.1 tonnes per hour, but is obviously greater during takeoff, but less during descent.
https://www.avsim.com/forums/topic/2135 … nsumption/

So a four hour flight would consume some 8.4 tonnes of fuel, or 54kg per seat.  Jet A1 costs about £1.20 per litre, or about US$2 per kg, or about $100 per seat - cycle in this scenario.
https://www.farnorthaviation.co.uk/late … rices.html

So fuel cost outweigh the capital purchase cost of the aeroplane by at least a factor of 10 even for short flights.  Maintenance costs scale with takeoff- landing cycles rather than hours in the air.

This confirms that economy would be better served by improving fuel efficiency, even if it does increase journey time considerably.  A more fuel efficient aeroplane will always win out economically over a more fuel intensive but faster one.  If the slower but more fuel efficient plane is also more comfortable for passengers, it is likely to be a win for them too.

So it is a bit puzzling that none of the major aircraft manufacturers bothered developing the AGA-33 in the past decade.  It would definitely find a ready market in airlines struggling with rising fuel prices.

The energy density of Jet A1 is about 43MJ per kg, which equates to about 4KWh of work in a 33% efficient gas turbine.  That equates to $0.49/kWh of work.  It is possible that an electric aeroplane could compete with fuel costs this high.  But the poor energy density of batteries make it suitable only for short haul flights.  In this environment, recharging time poses a challenge as well.  But there could be a market for the electric aeroplane for short flights of a few hundred miles.  There are situations where flying is still attractive over such short distances.  If you want to travel from London to Dublin, the alternative would be to drive to Liverpool or Holyhead and take the ferry.  London to Amsterdam can be done by train.  But flying in a straight line will always be quicker.  Air pollution and noise pollution are both major health impacts for people living around airports.  Electric could reduce those impacts as well.  So I find it credible that electric aeroplanes could occupy a niche market.  But their applicability is going to be limited to short range flights.

For electric cars, the sheer scale of demand would appear to make EVs impractical as a mass driving solution.  We also appear to be heading into an era where capital is going to be more expensive.  Global supply chains for all of the material components of EVs are also going to be more difficult to maintain in the future, as Peter Zeihan makes very clear.  Scaling up the mining of copper and lithium by orders of magnitude is not realistic in this future.  Demographics are ageing across most of the world now, which implies economic trouble ahead.  Most of the world is going to get poorer and more disconnected in the 21st century.  Transportation under this scenario needs to focus on cheaper vehicles that have lower purchase price and low operating cost.  That probably means smaller, lighter, petrol powered cars.  Emissions reduction should focus on ways of reducing fuel consumption.  That could mean reduced engine power.  Simple technologies that allow braking energy recovery would be a good thing to pursue for the future we are likely to get.  Flywheels could capture braking energy and use it to assist acceleration.  This would allow engine power to be reduced.

Last edited by Calliban (2023-02-28 04:57:30)


"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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#28 2023-02-28 06:02:10

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,572

Re: Why the Green Energy Transition Won’t Happen

Mild steel (pure iron) has 5.73x the resistivity of copper, but its volumetric cost is 22x lower.  As an electrical conductor, copper plated mild steel should have around one third of the cost of pure copper and would be a far more sustainable material.  I wonder how straight forward it would be to substitute coated steel for copper in electrical applications?  Steel would be more cumbersome to use.  It would need to be in the form of insulated bars, rather than cables, because of the threat of corrosion.  Joints would need to be soldered or brazed.  It would have around 5x the weight of copper for the same application.  So it is less suitable for suspended cables.  But in many applications, steel would appear to be an acceptable substitute for copper, especially if long, straight runs are needed along walls or underground.  For wind and solar powerplants, a lot of copper is used to connect geographically distributed generation to transformer stations.  Maybe steel bars could replace some of the huge amounts of copper presently used.  In appliances, where conductors are not subject to bending, copper coated steel could replace copper.

On Mars, iron is far more abundant than copper.  And the surface environment is dry with little oxygen.  Iron would appear to be a more suitable conductor there than copper.  On Earth, it is cheaper, but we would need to be more selective about where we substitute it.

Last edited by Calliban (2023-02-28 06:06:26)


"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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#29 2023-03-01 16:53:09

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,606

Re: Why the Green Energy Transition Won’t Happen

Calliban,

As far as commercial aircraft go, I'm not any kind of expert, but I do know that the two greatest cost drivers are fuel and salaries.  This should surprise no one.  Aircraft purchases are large one-time capital expenditures amortized over 20 to 25 years, with the engines contributing a substantial portion to the total cost, especially when engine maintenance is included.  Avionics and electrical systems are close second these days, followed by airframe maintenance (composites can greatly reduce this, but at greater purchase cost and expensive repairs if damaged in operation).  If those engines can be smaller and lighter while delivering sufficient power, then you will have an overall cheaper aircraft to operate, which drives purchasing decisions.  Engine power is determined payload-to-distance and aerodynamics.  Quite a lot can be done to improve aerodynamics, but it can only ever be optimized for a specific flight regime and payload class.  It would be inappropriate to operate wide bodies half-full, for example.  The employment costs are baked into every business model, and airlines are a service industry so they require lots of people to operate as they do.  IIRC, employment costs are the single largest cost center for the airlines industry, as it as for most other service industries.

FAA.GOV - Aircraft Operating Costs

If total operating cost is what's keeping airlines from being more profitable, then a dramatically more fuel efficient aircraft similar to AGA-33 is what needs to be built.  Paying your pilot / copilot / flight attendants for 1 to 2 additional hours of work per long distance flight is not more money than a 50% fuel cost reduction.  The top speed of AGA-33 is the same as any regional airliner's maximum achievable speed- about 450mph in practice, no matter how fast the jet can theoretically go.  Intercontinental airliners get real high, and then they can fly at 550 to 600mph, but that's with the throttle firewalled and you'd run out of fuel first.  In practice, 500mph to 550mph is as fast as you go to save fuel in case you need to divert upon arrival.  Over long distances, it's 1 or 2 flights per jet per day, maximum, and again theoretically faster speed is largely irrelevant.  A single aircraft can fly to one continent per day, and then fly back if it's US-to-Europe.  US-to-Asia is always 1-way per day.  The 50mph to 100mph of extra speed buys very little, except for drastically increased operating costs.  With that in mind, I'm not saying that AGA-33 is the exact correct solution, but whatever the actual correct solution is, it will look substantially similar to the AGA-33 (a rifle bullet with wings).  Otto Aviation's Celera 500L is also a rifle bullet with straight wings and diesel engine and 5-bladed MT propeller (I have two of them, of a very similar model) that can match the cruise speed of a swept wing and turbofan powered Boeing 737.  LA-to-Narita or JFK-to-Heathrow flight times indicate a 450mph average flight speed.  Since Celera 500L needs shorter runways yet has considerable range and speed, it can also get you closer to your final destination.

I have two prescriptive policy solutions for the larger problem, the first regarding hydrocarbon fuels, and the second viable alternatives to hydrocarbon fuels:

1. If we continue using gasoline / diesel / kerosene, then even if we ignore all other potential or actual issues, eventually we have to make it from scratch using CO2 sourced from the air or water.  That means thermal-to-fuel energy at a massive scale, so only solar thermal or nuclear thermal are viable at the scale required.  The solar thermal solution consumes more steel and concrete, but it's easier to build rather quickly and easier to recycle, so the waste stream is minimized.  The nuclear thermal solution consumes far less steel and concrete, but it's more expensive overall and we would need to build thousands of new reactors across the world.  That narrows the options list to solar thermal, unless the general public suddenly has a change of heart and decides nuclear is the way to go.

If you have a small internal combustion engine combined with a correctly geared transmission, then you can easily get by with 20hp to 50hp for a passenger car.  A car does not need a lot of horsepower to be useful.  It's nice to have and fun, but your ability to use most of it is severely curtailed by existing road laws.   Right-sized engines provide fuel economy averages of 60mpg or better.  This allows someone to drive 15,000 miles per year on 250 gallons of gasoline per driver.  At $3/gallon, that's $750 per year.  If the car weighs 500kg using a plastic chassis, then it can come in at under $10,000 USD, and if you drove it for 20 years, then it's still half the purchase price of a Tesla Model 3.

2. If we're truly going to stop using hydrocarbon fuels, which seems highly unlikely to be perfectly frank, then we need a low-energy resource in near unlimited quantity, which means using air and water.  No other materials (pseudo-materials at that since even air and water have to be filtered, with dust and water removed from liquid air, for example), which is not the same thing as a natural resource (a metal ore, which is not useful in its natural state), are readily available in the quantities required (obtainable in great volume without incredible energy input).  I don't think any of our climate changers have ever thought about how we're going to obtain or replace the energy inputs into steel, concrete / cement, plastics (used by all photovoltaics, all wind turbines, all batteries, all electrical cables except high voltage overhead lines), or other materials.  I'm also wondering how we're going to make roads for electric vehicles without tar for asphalt, for example.

Copper is a contaminant in steel that weakens it considerably, so coating steel with Copper means that we will never recycle that contaminated steel into anything but another electrical conductor wire.  It must be separated out of the waste steel stream or we get unusable steel.

You wouldn't use steel for an overhead electrical cable.  Aluminum is superior for that.  You wouldn't use steel in the windings of an electric motor.  Copper or Aluminum are the only suitable metals, with a strong preference for Copper.  You have greater ohmic (resistance) losses, iron (eddy current) losses, stray losses (unintended conduction), and mechanical losses (bearings) using Iron vs Copper, which is why we use Copper.  Only Silver is ever so slightly better than Copper.  Steel could potentially be used as an electrical conductor for certain types of automotive (conventional vehicles) / industrial / residential wiring, but I would refrain from recycling a steel product containing any amount of Copper.  That said, Copper coated steel wiring is already commercially available, just not widely used.  I suppose it comes down to how easy wiring is to remove and separate.  We do use Zinc or Iron or Aluminum for grounding straps, but stainless steel and Aluminum are the most common.  Brass is actually a weak conductor compared to pure Copper or even Iron, so your realistic choices are Copper, Aluminum, or Iron, in that order.  Your practical electrical insulators are vacuum or air, plastic or rubber, and ceramic.

Beyond electrical systems, compressed or liquid air (LN2 for all practical purposes) is the only material available in the quantities required to power billions of vehicles.  The quantity of metal required to use electro-chemical batteries at scale is not achievable using any known battery technology.  Hundreds or even thousands of years of production at current rates would be required to achieve this over the next few decades, which is why it won't happen regardless of what anyone says or does.  If we ever attempted such a foolish course of action, the CO2 emissions from mining would immediately erase and likely increase our total global CO2 emissions beyond what it would be if we just kept burning things, which is what we have been doing.  I think compressed air, perhaps combined with a hot material like molten salt to increase power density, could even be used to power trains.  They would obviously require more frequent refueling than with diesel, but there's always more fuel available.  Ships are only feasible if the ship is purely blue water operated from deep harbors / ports, but all existing ships would give up substantial cargo capacity, and in all probability would need complete redesign.  A nuclear reactor is a better option for a massive cargo ship.

On average cargo trains seem to consume about 9 liters of diesel per kilometer traveled, which is just over 1mpg.  Given their incredible weight, this is understandable, and is not indicative of how efficient they are at moving cargo, which is better than any other land-based machine and only some very large cargo ships are similar in efficiency.  They have 2,500 or 5,000 / 18,927L (189,270,000Wh gross energy content) gallon fuel tanks.  That's about 66,244,500Wh at 35% efficiency.  That amount of energy equates to 331,222.5L of liquid air, or 662,445L at 50% efficiency.  662m^3 of liquid air is obviously infeasible to store aboard a locomotive, but it equates to a locomotive plus 5 30,000 gallon tanker cars, which are about 60 feet long.  Given that many of the longer cargo trains have 4 locomotives attached, it would be feasible to have 4 locomotives plus 2 tanker cars.  Each locomotive supplies 4,000 to 5,000hp and 60,000ft-lbs of torque for traction.  The most common engines are theoretically capable of 6,000hp but have severe vibration issues, so in practice limited to about 4,500hp.  These machines are 76 feet in length by 10 feet wide and 16 feet in height, so that is the envelope that this new cryogenic steam locomotive must occupy.

If we presume a 62 feet maximum cryotank length, then the locomotive itself can hold about 28,000 gallons / 227m^3 of liquid air, so it has 1/6th the range of a diesel powered locomotive of equivalent dimensions.  Existing cryotank cars can hold 28,000 or 34,000 gallons of cryogenic liquids (LOX / LN2 / LAr).

Models of actual cryogenic liquid tanker cars:
IAPX_1008_REL-01.jpg

IAPX%201028-1037_PROMO_35.jpg

A real Union Carbide liquid Argon tanker car:
640px-Tank_Car%2C_Union_Carbide_Refrigerated_Liquid_Argon_%2810588923296%29.jpg

How efficient or inefficient compressed air appears all depends on how we define efficiency.  If we can't sustain the power system in question, then no matter how efficient or otherwise desirable it looks on paper, it's still pretty useless for replacing anything.  We've achieved astonishingly good electrical efficiency in electric traction motors and electronics, which is great, but all direct electrical energy storage systems remain as wildly impractical as they ever were, at the scale required to truly replace anything.  The energy density of all existing electro-chemical storage technologies is utterly incapable of meeting the demands of a modern energy-intensive society.  Lithium and Sodium metal cannot store the energy required to transition to primarily using them versus hydrocarbon fuels.  If we foolishly attempt to extract every ore deposit, then we will both exhaust those resources long before we meet demand and still not transition off of hydrocarbon fuels.  Worse still, all the money to pursue a workable solution will be gone, irreplaceable time will have been squandered (activity versus accomplishment), and then our positioning to actively pursue a workable solution will be far worse.

I don't want to reach the end of this disaster, only for our village idiots to finally discover counting.

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#30 2023-03-01 18:16:51

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,606

Re: Why the Green Energy Transition Won’t Happen

We already have the technology to do this (we're already powering diesel locomotives using LNG):

LNG on the Rails – Precursor to LH2 on the Rails?

I can't speak to what other countries have or use, but apparently cryogenic liquids have been shipped by rail in the United States since at least 1961.  The first Union Pacific locomotive was powered by LNG in 1994.  Canada started powering locomotives with LNG in 2012.  Powering locomotives with liquid cryogens has considerable "flight heritage" here in North America, and at least some experimentation in Europe.  The tanker cars have even more extensive "flight heritage"- the better part of a century now.  This has primarily been LOX / LH2 / LCH4 / LN2 / LAr / liquid Ethylene.  Since LN2 is an inert gas, DOT rules about flammable cryogens don't apply.

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#31 2023-03-01 19:40:32

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,572

Re: Why the Green Energy Transition Won’t Happen

Kbd512, thankyou for the well considered response.  A six-fold reduction in range for a freight train would be a problem, as it implies that a lot of new stops would be needed, with their own refuelling infrastructure and staffing, just because liquid air is used instead of diesel.  A hybrid solution might work better, with waste heat from the diesel engine supplying the air engine.  If diesel provides half of the power, then fuel consumption is halved.  The engine heat would boost the efficiency of the air engine, so tne range would be half that of a conventional train, instead of one sixth.  And you would only need about one third as much liquid air per tonne-mile, because half of the motive power comes from diesel and the diesel waste heat makes air expansion more efficient.

Then again, freight trains and ocean going container ships are already very fuel efficient.  So they should be relatively insensitive to the price of fuel.  It may turn out that synthetic hydrocarbons are more cost effective when all of the logistical impacts of switching to low energy density alternative are accounted for.  To answer that question we would need an engineering study with a cost-benefit analysis.  That is beyond our resources here.  But from a technical point of view, it is clear that liquid air coukdwork as an alternative to hydrocarbons in these situations.  But the low energy density introduces additional logistical costs thatwould count against it.

Last edited by Calliban (2023-03-01 19:45:25)


"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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#32 2023-03-02 03:54:16

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,606

Re: Why the Green Energy Transition Won’t Happen

Calliban,

Assuming we have the diesel to spare, that would certainly work, but I don't see why you couldn't drag 5 tanker cars behind each locomotive.  Better yet, build locomotives that contain hot water tanks and use tenders to carry the liquid air.  The air can heat the LN2 in the transfer line on its way to the locomotive.  We can use hot water as a heat sink if we need to since we're going to generate plenty of that compressing all that air.  Meanwhile, our merchants of despair are busy trying to entirely do away with hydrocarbon fuels with absolutely nothing to replace it.  I'm trying to come up with working ideas that at least allow most people to not starve to death before they've had their way.

I want to know why all these people with PhDs didn't do enough basic math to know that there wasn't enough Lithium or Sodium or Copper on planet Earth to transition every strictly necessary machine to using electrical energy storage.  I've seen nothing at all that makes me think we have any viable alternatives, or that proposed electric / electronic alternatives are remotely feasible.  PhDs either have blind faith in the ingenuity of people or they've never read a history book to know what happens when energy runs out.  I don't know what they had in mind, but in my estimation farm tractors are strictly necessary for feeding 8 billion people.  There's not enough Lithium for the tractors and trucks to move the food, much less store electricity for a power grid.

I arrived at my proposed solutions by taking stock of what we have in the required quantities that can feasibly operate at the scales that all these other people are talking about them operating at.  The numbers are huge, but the underlying math is quite simple.  How much will it cost?  Where are the resources?  Can we get them in a reasonable amount of time?  Do we already use it at scale?  Is there enough for absolutely everyone?...  I'm not willing to sacrifice anyone to this bizarre new age religion.  If that's the plan, then go back to the drawing board and come up with a better plan.  There have been multiple decades to figure this stuff out.  We pay people good money to sit in rooms all day and think about stuff like this.  Why has so little attention been paid to the basics?  It's like we're planning to fail.

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#33 2023-03-02 05:28:37

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,572

Re: Why the Green Energy Transition Won’t Happen

Kbd512, I think there are two reasons why 'merchants of despair' fail to get the big picture.  The first is that clever people usually tend to specialise.  Taking a PhD doesn't just have the effect of making one more qualified.  It concentrates their perspective into a narrower specialism.  It makes them better able to produce specific solutions, but less able to see a holistic picture.

The second concerns the way that the human brain works.  It forms desires based upon what it finds emotionally appealing.  Symetry appeals to people.  Naturalism appeals to people as well.  People become attached to concepts and ideas that they find emotionally appealing and the logical parts of their brains, end up trying to realise an emotional prejudice and bring their idealisms to life.  We all do it to some extent.  We all operate from a sort of internal mythology, that helps us make sense of the world.  It takes a lot of intraspection and emotional integrity to actually question our internal mythologies.  A lot of people just can't manage it.  Their internal mythology drives them to invent solutions that are looking for a problem.  They end up latching on to real world problems, like climate change, peak oil, resource depletion, etc, as a means of promoting solutions that are developed from their internal mythologies.  For this reason, we collectively end up doing crazy things that end up being non-optimum solutions to problems.  And some peopke end up craving problems that allow them to push their solution.  To an outside observer that doesn't share the internal mythology, this behaviour ends up looking insane.  But it is an inherent design flaw of the human psyche.

Back in 2008, I became aware of the Peak Oil problem.  It is a real enough problem and it was one of the contributors to the 2008 financial crisis.  It was and is something that needs to be managed, if we want to avoid getting poorer.  But a lot of the discussion around it tended towards doomerism and it became a nexus for all sorts of wild ideas.  It provided a problem for idealists to vent their pet solutions onto.  The reality was that the easy oil was getting more scarce and producing liquid fuels was gradually becoming more expensive.  We needed rational ways of improving efficiency and developing alternatives that allowed us to adapt.  The shale revolution was one of the responses to the peak in conventional oil production.  It provided a new source of energy.  When it arrived, many in the peak oil crowd were actually disappointed because by reducing the urgency of the problem, it undermined their personal solution spaces.  This is the sort of mentality that prevents us from finding rational solutions to problems.  It is why we still have a peak oil problem.  And a climate problem.  A lot of people do not want to see these problems solved in ways that undermine their personal mythologies.

Looking specifically at fossil fuels, if we want to find optimum solutions then we need to be careful in scoping the problem.  There are three problems.

The most well known is climate change.  It is in some ways speculative, but it is at least a theory based upon firm physics.  It tells us that humans are changing the composition of the atmosphere and this is having (or will have) some undesirable consequences.  How significant the effects will be is open to debate and we don't really know enough about how the Earth's climate will respond to have much certainty on the scale of the effect.  But generally we can say that it is desirable to reduce GHG emissions into the atmosphere.

The second is Peak Oil.  Fossil fuel resources are like a pyramid, with a small peak of high grade resources and an enormous base of low grade resources.  The best resources are the ones easiest to extract.  They provide the best net energy return.  Unfortunately, as the oil age proceeded, we extracted the easiest and most profitable oil and gas first.  But as time went on, our demand grew and the easiest deposits (shallow, conventional, onshore) are now mostly exhausted.  As we exploit resources further down the pyramid, net energy return declines and the resources and technology needed to get each new incremental barrel increases.  We can think of the oil industry as being a sort of tug of war between conflicting forces.  On the down side, depletion is continuously reducing the grade of what remains and the cost of production.  On the other side, new technology and increasing geographical reach open new resources.  Ultimately, there is no way of cheating the forces of depletion.  Geographical reach has limits.  Technology allows us to do new things, but there is no way of circumventing the poorer net energy return of fuel resources that are 30,000' beneath the sea bed or need to cooked out of tar sand.  So net energy return is declining and fuels are getting more expensive and less profitable to produce.  We need ways of mitigating this problem.

The third problem is about the local environmental impact of producing fuels and mining more generally.  As oil production from shale and tar sands has scaled up, environmental and social impacts have increased.  Producing lower grade resources is more disruptive.  There is no way aroubd that.

The solutions to all of these problems are three fold.  We find ways of using fossil fuels more efficiently.  We find ways of replacing them, either wholly or partially, with alternatives.  Finally, we can find new ways of meeting human needs that don't rely on those fuels in same way.  Railways use diesel more efficiently than trucks.  Solar synfuel replaces diesel with synfuel.  Electric railways replace fuel with electricity.  Hgdraulic capsule pipelines can be pumped by wind directly.  The solution space is almost infinite, which is why we often go down rabbit holes.  There are other desirable outcomes we want to achieve, which can influence the solution.

Last edited by Calliban (2023-03-02 06:20:56)


"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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#34 2023-03-02 11:19:00

Void
Member
Registered: 2011-12-29
Posts: 7,393

Re: Why the Green Energy Transition Won’t Happen

I think you have developed a rather good understanding of the situation and have so further enlightened me.



Here I am referencing human psychology, and not attempting to shove religion down your throats.

Man's Accuser:
https://www.gotquestions.org/Satan-accuser.html

https://www.biblestudytools.com/dictionary/accuser/
Quote:

Easton's Bible Dictionary - Accuser
Accuser
Satan is styled the "accuser of the brethren" ( Revelation 12:10 . Compare Job 1:6 ; Zechariah 3:1 ), as seeking to uphold his influence among men by bringing false charges against Christians, with the view of weakening their influence and injuring the cause with which they are identified. He was regarded by the Jews as the accuser of men before God, laying to their charge the violations of the law of which they were guilty, and demanding their punishment. The same Greek word, rendered "accuser," is found in John 8:10 (but omitted in the Revised Version); Acts 23:30 Acts 23:35 ; 24:8 ; Acts 25:16 Acts 25:18 , in all of which places it is used of one who brings a charge against another.

These dictionary topics are from
M.G. Easton M.A., D.D., Illustrated Bible Dictionary, Third Edition,

This may help define the religious aspects of the social movement which has deployed against humanity, and the solution of problems.

The game of the accusers it to attain benefit from society.  Power and even wealth.

So they need the accusations to stick.  Of course, they do not want the problem solved, as it will disrupt the attempt to have a "Social Movement".

The accusation process currently involves climate, gender, race, and other cultural issues.

One very stupid process in action is about reparations.  Because I am white, I am guilty of what people several generations back are accused of doing.  Even though I did have an ancestor that was i the civil war on the side of the feds.  Don't mix it up the war was between successionist states and the federal government.  Granted, there were north south jealousies.  But the Neuvo Romans always enjoy a divide and conquer story for the public, so they can play their games.

And I am only using this as an illustration.  It is not my banner topic.

If I were required to pay reparations to such a accusation of the previous generations, then why should I not serve a jail term for it?
It is the same idea.

When in fact it is very possible that most black people in this country are part white, and that part white is slave owners.  So, then if we ignore skin color, so called blacks should be paying reparations to each other.

Most slavers in Africa were black, and sold slaves to Arabs and Europeans.

Perhaps Africa should pay reparations to our so-called Blacks?

Perhaps our so-called blacks should pay a gift to Europeans and even Black and Non-Black peoples who decided to suppress slavery here and even in Africa.  Maybe the blacks should pay special fees to the feds for ending slavery, for whatever their reason was.

So, you see, reparations are not my top issue here, it is simply an illustration of how these social movements can bring people to trial who don't really disserve to be accused.

The religious aspects are used by the unholy in most improper ways.

The game is to create an accusation and then to judge, and then to extract power, property, and tribute.

It is not unlike church behavior, but lacks mercy, and is extremely unjust in fact.

So just the same is occurring in the issue of climate change.

I believe that the problems can be solved, but as you have said, that is the last thing they want.  They want to accuse.

As for gender issues, it possible to suggest that there may exist Feminist Xenophobia at this point.

If I have ruffled any feathers, then deal with it.  I will not seek to further argue about these specific items except per so called "Climate" issues.

Done.

Last edited by Void (2023-03-02 11:41:15)


Done.

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#35 2023-03-03 09:59:40

kbd512
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Re: Why the Green Energy Transition Won’t Happen

Void,

It's one thing to be an opportunist who has at least something approximating a solution.  It's quite another to know you don't have the answers or to be so incompetent that it's plainly obvious to ambivalent onlookers that you have no answers.  I would say promising someone something which they believe to be their salvation, when you know you can't deliver anything of the sort, can only be described as evil.

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#36 2023-03-03 21:05:57

SpaceNut
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Posts: 29,309

Re: Why the Green Energy Transition Won’t Happen

One needs to understand a destruction zone that would be required for in the event that a tank did roll off the track and was damaged venting the liquid air since we are seeing the decay of decades of poor to no maintenance which has occurred for the most recent events.

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#37 2023-03-04 04:46:29

kbd512
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Re: Why the Green Energy Transition Won’t Happen

SpaceNut,

We're talking about liquid air and hot water here.  Anything more than a few yards away from the track would not be harmed.  I'd be far more worried about the train derailment than the loss of something that was already naturally present in the environment to begin, albeit not at such a low or high temperatures.  It's not going to start any fires, if that's what you're worried about.

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#38 2023-03-04 18:17:26

SpaceNut
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Posts: 29,309

Re: Why the Green Energy Transition Won’t Happen

Actually, if near human life it could be a problem but as you indicated other than a huge temperature for the air difference to liquify water should be less of an issue other than for a possible drowning. Trees and some plants probably would be ok if nothing strikes them once liquid chilled.

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#39 2023-03-04 19:06:24

kbd512
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Re: Why the Green Energy Transition Won’t Happen

SpaceNut,

Most trains don't derail.  Most cargo arrives at its destination.  If a train is powered by liquid air and hot water used to help expand the liquid air into a greater gas volume to generate more power, then there should be no real environmental objections.  The chances of any sort of catastrophic impact on the environment are non-existent.

This solution:
1. Doesn't require a radical increase in mining of scarce materials
2. Doesn't burn anything
3. If the power is sourced from solar thermal, then there's nothing radioactive being generated, thus no possibility of release

Apart from not satisfying techno-fantasies, what is the actual problem with using thermal systems that can supply the energy in the quantities required, using the two most abundant natural materials we have access to- air and water?

You can't do this with batteries and photvoltaics.  We can't make enough of those to actually replace anything using any current or projected technology.  All we can do with them is radically increase the cost of energy, radically decrease its availability, still fail to actually replace hydrocarbon fuels at any meaningful scale (especially with all the mining we'd need to do), and at the end of the day everyone is left poorer and less able to lead productive lives.

Why should we ever do that to ourselves?

Is there are any desire for an actual solution, or is this electronic-everything nonsense an underhanded attempt to milk an unsolvable problem for all the money and mental capacity that could conceivably be squandered chasing after this mathematically impossible solution, until we finally exhaust all possibility of concocting a viable solution?

That's not an "oops".  You've been told by someone who's done enough basic math to know that what you're after isn't feasible.  I didn't write any rules about how energy systems or the universe works.  I'm working within the rules to try to achieve what our green energy people claim they want.  The fact that my solution is not an impossible task, doesn't mean it won't provide what we need.  It's merely an extension of what the people at Low-Tech Magazine have pointed out to anyone clever enough to grasp what they're getting at.

I'm showing you a better way, I've done enough basic math to know that my proposal does not require impossible quantities of metals, it's a sincere attempt to solve the problem in a way that should be agreeable to the most number of people, and it's my desire to be done with solving the problem so we can move on to building hardware that gets the job done with lowest cost and least environmental impact.

It's not my fault that a bunch of non-viable solutions like electric cars were sold to people without anyone doing their homework to know whether or not their proposals were remotely feasible.  If all you do is consume marketing hype or theatrics without critical analysis, then any old snake oil salesman will come along to take advantage of that.  I'm not a theater major.  I'm in the bean counting business.  If the book says we need 100 beans to cover demand, but we can't come up with half that many, then I report it as the major problem that it is, from my standpoint as one who counts the beans.  You can argue with me about what the book says, but if you can't come up with those missing beans then I report our actual bean count to management.

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#40 2023-03-04 19:58:13

SpaceNut
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From: New Hampshire
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Posts: 29,309

Re: Why the Green Energy Transition Won’t Happen

So now it's about moving the train and not providing a cargo; ok, that changes the safety factors to which I was talking about and yes those means to make energy are green as green can be as I am assuming that the water is closed loop while the air would be vented from the turbine.

Edit this reminds me of running on compressed air topic.

Running on Compressed Air?

I also remember a radiator and solar coming into a closed loop power system which made use of the evening to create the cold sink.

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#41 2023-03-05 04:13:06

Terraformer
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From: The Fortunate Isles
Registered: 2007-08-27
Posts: 3,858
Website

Re: Why the Green Energy Transition Won’t Happen

A crash might not even freeze the area, if the hot water and cold air get well enough mixed in the crash... would suck to be directly in the path, but that's true for *any* train crash. Who knows, maybe they'll ship your corpsicle off to Alcor instead of collecting your ashes.

I wonder , would liquid air transport work best with short range ferries to start with? Get the infrastructure built there, and then we can extend to short range trucks that can take advantage of it to take cargo from the ferry ports to depots. Thinking in a British context, where intracoastal transport is a plausible option and we can get fairly far inland (relatively) with rivers (and canals). Stourport is only 20 miles from the centre of Birmingham. Leeds and Manchester have canals. If we can do quick modal transfers from ferry to truck...


Use what is abundant and build to last

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#42 2023-03-05 07:18:51

tahanson43206
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Posts: 18,137

Re: Why the Green Energy Transition Won’t Happen

Terraformer, this question is NOT for you.  Your post #41 just happened to be ahead of this one.

Someone started this idea that liquid air might be used for energy storage, and I've lost track of who that might have been.  It seems to me that there is an assumption that there is enough thermal energy available at the place where the energy is to be released.  However, I think that assumption is false.

I offer as an example the well known Earth phenomenon of the iceberg.  An iceberg is an example of stored negative heat energy.  In order to melt an iceberg, the Earth must delivery substantial quantities of heat from the surroundings.  By my observation, the Earth DOES NOT supply enough energy to melt an iceberg, except in time frames measured in weeks, months or even years. 

My prediction is that someone trying to run equipment by melting liquid air (better term might be evaporating) will quickly exhaust the available thermal energy and the machine will stop running.

It should be possible for a member with deep knowledge of thermal processes to provide an answer.  My guess is that if this were a good idea it would have been put into practice on Earth already.

There might be a location on Earth where arriving Solar energy could be harnessed at a sufficient rate to evaporate liquid air fast enough to drive a small tool of some kind.

(th)

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#43 2023-03-05 14:47:20

kbd512
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Re: Why the Green Energy Transition Won’t Happen

tahanson43206,

No deep knowledge is required.  I'm sure you could figure this out if you wanted to, but it requires some reading.

The specific heat capacity of water is higher than any other material I'm aware of, at 4,186J/kg per 1°C.  That means it takes 4.186kJ of heat energy to raise or lower the temperature of 1kg of water (H2O) by 1°C.  The specific heat capacity of Nitrogen is 1,040J/kg°C.

A turbine-based air expander (a type of efficient "air motor") is 65% to 75% efficient in practice, which means 65% to 75% of the embodied energy in the flowing gas used for expansion is converted into mechanical work, or horsepower, or kiloWatt-hours if you're one of those silly metric people.  I was initially extremely conservative about the total efficiency of the machine, assuming a 15% to 25% loss.  A good gearbox is 95% efficient, meaning 5% of the input energy is converted into heat instead of mechanical output.

In practice actual efficiency will be much better than the 50% I asserted for sake of conservatism (after all, I'm a conservative, as you well know), and probably closer to 70% if we assume the turbine and gearbox designs are designed by someone who knows what they're doing.  Piston-type air expanders (another type of "air motor", along with gerotors and vane types) are less efficient because they convert more of the gas expansion energy into heat energy, via friction from the piston rings.  Ditto for vane-types.  Gerotors (most frequently used in engine oil pumps) do a bit better, though more complex to machine and still not as efficient as a turbine-type.

So, let's assume that we require 4,500hp (3,356kW) for 1 hour, which is the same maximum gross engine output figure that a modern GE-7FDL powered (a gigantic 16 cylinder diesel engine) diesel-electric locomotive provides.  At 70% overall efficiency, our liquid air / LN2 storage tank, which stores 200kWh/m^3, is providing 140kWh/m^3 in mechanical work output.  This is not how said engine would be run in the real world, but we want to know how much volume of LN2 and hot water (our heat-exchange mechanism) is required to duplicate that feat for 1 hour of run time at "full bark" as diesel engine wizard Gale Banks would call it.

3,356kW / 140kw per 1m^3 = 24m^3

1m^3 of LN2 = 804kg/m^3 of volume at -196°C (just below the boiling point of LN2, which is -195.8°C)

804kg/m^3 * 24m^3 = 19,296kg of LN2

19,296kg / 3,600 seconds per hour = 5.36kg per second (quantity of N2 we must supply to our air turbine to produce 4,500hp)

LN2 expands from 804kg/m^3 at -196°C to 1.251 kg/m^3 at 0°C, so its volume increases by about 643 times.  Each 1m^3 of LN2 at -196°C occupies 643m^3 of volume at 0°C.

Q = mcΔT

Q = 5.36kg * 1,040J/kg * 196 = 1,092,582.4J of energy (that we need to transfer from the LN2 to the water to expand it 643X, which obviously won't remain liquid very long, within the hot water tank car, using a giant radiator assembly embedded in the hot water tank)

We're going to pour in more hot water at every stop and drain out the cold water to be reheated by our solar thermal and LN2 liquefaction plant, in case that point isn't clear.

To lower the temperature of the water requires removal of 4,186J of heat per 1kg per 1°C temperature drop.  In simple terms, raising or lowering the temperature of H2O requires 4 times as much energy as Nitrogen, per unit weight of either substance.

Between the front of the rear and front of the hot water tanker car with its embedded radiator assembly (a gigantic Aluminum car radiator for all intents and purposes, we need to impart or transfer 1,092,582.4J of heat energy per second into the Nitrogen from the hot water, in order to raise its temperature to 0°C, if we run the locomotive's air turbine engine at maximum power output (implies that our cargo train is moving at maximum speed, which of course doesn't happen in the real world for safety reasons).  In reality, the train uses less than half that much power after it's moving at 35mph to 45mph, which is the maximum regulated speed anywhere but the wide open spaces of America in the Midwest.

Assume we're going to take the water temperature of 1m^3 /1,000kg of water from 100°C to 0°C.  To do that, we need to supply...

Q = 1,000kg * 4,186J/kg * 100 = 418,600,000J of energy

How many cubic meters of LN2 do we need to do that?

Q = 804kg * 1,040J/kg * 196°C = 163,887,360J of energy

418,600,000J / 163,887,360J = 2.55m^3

For an "even-Stevens" energy trade, we require 1m^3 of H2O for every 2.55m^3 of LN2 that we heat up by 196°C.  The only form of inefficiency we can have in that process is loosing heat to the environment if the ambient temperature is below 0°C.  If it's above that temperature, then we're recovering heat from the atmosphere, into our hot water tank (the atmosphere is helping to keep our hot water from freezing).  As far as "running out of energy" to power the machine, that won't happen in a properly designed / sized heat exchange system.

Diesel is 37.95kWh/gallon.  Each locomotive has a 5,000 gallon tank.  You get about 35% of that energy in terms of work output, or 13.2825kWh/gallon, or 66,412,500Wh in total.

66,412,500 / 140,000kWh per cubic meter of LN2 raised from 196°C to 0°C = 474.375m^3

Each 30,000 gallon LN2 tanker car holds 113.56m^3 of LN2 (30,000 / 264.172 US gallons per cubic meter), so 4.177 tanker cars to produce equal energy.  In practice, a standard length car is 34,000 gallons, so that "extra" LN2 provides electricity, refrigeration, braking power for the air brakes, etc.

We need 120,000 gallons of LN2 / 2.55 = 47,059 gallons of hot water which remains above the freezing point of water after the energy transfer is completed.  Recall that a car radiator allows us to prevent water from boiling by raising the pressure in the sealed system by 10psi to 30psi, with 15psi to 17psi caps being the most common, so we will raise the temperature above the boiling point, to about 110°C or so.

Why did I assert that we need about 6 tanker cars loaded with hot or cold liquids to equal the range of a diesel-electric locomotive?

Look at the math and tell me why.

If we have 4 of the 34,000 gallon LN2 tanker cars and 2 of the 25,000 gallon hot water tanker cars, then we equal the energy output of 5,000 gallons of diesel fuel.  If we can't supply 5,000 gallons of diesel and we can't come close to providing the batteries required, then we use this alternative, which is 100% completely natural.  It produces "hot" (ambient temperature Nitrogen) and "cold" water.

People who think it's inefficient need to think about what we end up with.  The N2 goes back into the atmosphere, where it's consumed again by the liquefaction plant.  The cold water goes back into the solar thermal hot water tank, where it's turned back into hot water, and then the heat of compression is used to further re-heat the cold water.  It's a perfect circle.  It requires no electronics or even electricity to accomplish.  You can work on the system using hand tools.  You can use Aluminum or stainless steel to hold the LN2, Aluminum for the radiator assembly, and mild steel or cast Iron for the rest of the train.

Recall that steel solar thermal provides 64 times more energy output, per unit of energy input from the Sun, than photovoltaics.  That's because it covers 64X more area, per unit cost.  Cost (dollars spent per unit output) is a proxy for energy cost in real energy systems.  No mumbo-jumbo metaphysical woo woo can change that.  It's durable.  It's recyclable.  It's operable with no advanced knowledge or special tools or technology base.  Every nation on the planet, even the ones in Africa- especially the ones in Africa, can make hot water and air from sunlight.

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#44 2023-03-05 16:01:18

kbd512
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Re: Why the Green Energy Transition Won’t Happen

There is no legal limit on train length in America, but in practice the union laborers who operate the trains assert that trains much longer than 100 cars or a little over 1 mile are unsafe and unwieldy to operate.  Since they do the work, I'm going to take them at their word.  We presently operate trains with up to 300 cars.  A 30,000 gallon tanker car is 60 feet long, so 6 tanker cars are about 360 feet long.  A 1 mile long train would then contain about 88 of those 60 foot long cars.

Air expander turbines have a power-to-weight ratio of about 1kW/kg, so a 10,000hp air turbine would weigh 7,457kg.

GE's 4,500hp 7FDL16 diesel engine weighs 16,216kg for comparison purposes.

That means for "equal engine weight" (ignoring the weight of the engine oil / coolant  / radiator), you have about 4 times more horsepower using a turbine-type air motor.

If we assume that the reduction gearbox will weigh 50% as much as the turbine it's connected to, which is quite reasonable, then we still come out on top by a lot.

So, supplying the horsepower will not be a problem for the air turbine.  It will be a fraction of the size and weight of a diesel engine locomotive.

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#45 2023-03-05 16:33:57

kbd512
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Re: Why the Green Energy Transition Won’t Happen

If we have any other objections to this proposal, whether based upon materials limits, basic math, or just assertions without any prior knowledge, then let's hear them.  We can explore all of them.  We already explored the ice berg analogy.  I was actually expecting some questions about thermal expansion rates and cracking.  Those would be much more pertinent than the objections raised thus far.

An iceberg's heating rate is limited by ambient temperature above the freezing point of water, its surface area and albedo, the albedo of the ocean and heat transfer rate to the sea water, which is also surface area-limited, if it's floating in sea water.  It's a poor example for comparison to a cold liquefied gas, a boiling hot water tank, and an automotive-style radiator embedded in the hot water tank, designed for the formerly liquid Nitrogen to pass through, on its way to the air expander turbine housed in the locomotive.

That's why it takes so much longer for a giant ice cube in the Arctic or Antarctic to melt, than it does to transfer thermal power between two fluids inside a system engineered to do that.  The temperature delta between an ice berg and its natural environment (some place that is very cold to start with, else the ice berg would never form to begin with) is very different.

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#46 2023-03-05 17:37:19

kbd512
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Posts: 7,606

Re: Why the Green Energy Transition Won’t Happen

The reason my proposal is "not a good idea", is that if you can extract diesel fuel from the ground, using the same energy source to supply the input power to rotate those drills, then your EROEI is much much higher with the diesel fuel than liquid air and hot water.  However, basic math and physics still allows you to exploit temperature deltas to do work, which is what all explosively-driven internal combustion engines do, except that they do it by converting hot gas into much much hotter gas to rotate an output shaft.  Apart from that, no other basic physical principles are at play here.

My proposal is basically a "crappy combustion engine" (where no combustion occurs, which is why it's crap), but it's still a lot less crappy than electric machines that only manage an identical power-to-weight ratio using scarce metals mined / transported / refined using gigantic diesel fueled machines, and we would need to increase the production rate of those metals by hundreds to thousands of times, which has never been done before in all of human history.

I am assuming a future where "anti-Carbon fanatics", and others who can't do basic math (screw basic math, they can't even count), have overrun all sensible behavioral norms...  Oh wait, that's already happened.  In that case, my proposal starts to make a lot more sense.

5,000 gallons of diesel fuel contains as much energy as 120,000 gallons of LN2 and 47,000 gallons of boiling hot water.  In other words the diesel fuel's energy density is 33.4 times greater.  This solution is relevant to not burning ANY diesel fuel while still powering the machinery that powers society, which no amount of electronic trash has proven capable of doing thus far.  If we were allowed to burn SOME diesel fuel to expand the liquid air, then the volume and mass of the energy to supply the input heat shrinks by quite a lot, and our heat engine is much closer to 100% efficiency because MOST of the heat would be dumped into expanding the LN2 into a gas.

That is why Calliban proposed doing that instead, because he can also do basic math.  He wants a hybrid, but I want an injector pintle (a blow torch heating the stainless steel tube that the Nitrogen travels through on its way to the locomotive) that ONLY heats / expands the gas, such that only the air expander turbine is providing motive power / acting as the locomotive's prime mover.  That simplifies the drive and makes the machine much lighter.  There are no electric motors or other similar nonsense involved.  We have a hot gas, an expander turbine, and a gearbox to provide torque to the trucks that the locomotive rides on.  It won't satisfy anyone's complexity cravings, but it will work.

I would choose to keep using diesel fuel and to synthesize that fuel from scratch if no more is available in the ground somewhere, mostly because I can do basic math.  Engineers with more uncommon sense than ideology chose to do the same thing.  To satisfy the anti-Carbon fanatics, I am willing to go back to crappy energy density systems that can actually work at the scale required to move all the materials and people that make society function as it presently does.  I can obtain enough metal, sunlight, air, and hot water to make this system work, because the great mass of materials being processed therein, are truly "renewable".

After this system is built at human civilization scale, the product that comes out is the same product that goes in.  Hot air and cold water goes in, and then hot air and cold water comes out.  The sun keeps shining every single day, so the input energy is functionally constant after it's immediately converted into storable hot water and liquid air which we are running through the system every day in mass quantities, so that trains can run, people can drive to work, etc.

We already process wildly more water per year, as compared to hydrocarbon fuel.  Adding cryogenic liquid air to that is not a major imposition, it's choosing truly renewable energy (things we will never "run out of"- air and water) over hydrocarbon fuel.  Our total materials throughput rate is 33.4X higher, but not outside the realm of feasibility.  America used as much as 168,840,000 gallons of diesel fuel per day in 2022.  We need 5,639,256,000 gallons of liquid air and 2,211,472,941 gallons of boiling hot water for equal energy.  We were already using 322,000,000,000 gallons of fresh water per day back in 2015.  I think we can manage.

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#47 2023-03-05 18:10:45

kbd512
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Registered: 2015-01-02
Posts: 7,606

Re: Why the Green Energy Transition Won’t Happen

Anyone who thinks we're going to build enough batteries and photovoltaics and wind turbines to replace combustion engines needs to show the rest of us where they're getting all of their metals from.  It's clearly not coming from Earth.  We need 8 billion tons of Copper alone.  We've mined 700 million tons of Copper since Copper mining began about 6,000 years ago.  All of the world's additional known and estimated Copper reserves (no actual mines built, just an estimate of the maximum amount we could get from a particularly Copper-rich deposit) contain 880 million tons of additional Copper, according to our geologists.  Convince the rest of us that you can come up with enough electrical conductor wire to make your electric dreams a reality.  If you can't do that, then you don't have a solution.  Electricity requires electrical conductors.

I've shown my numbers.  I've shown where they come from.  I didn't make anything up, nor did I come up with it all on my own.  It's all based in basic engineering principles applied to very well known and understood materials- air, water, steel, concrete, and input heat energy from sunlight directly dumped into hot materials (to either produce hydrocarbon fuels or to produce liquid air and hot water), instead of converting it to electricity (a fool's mistake, only committed by people who can't or won't do the multiplication or counting to extrapolate out their solution to human civilization scale).  Their answer to that problem, which they have no workable solution for, is to starve huge numbers of people to death, through energy poverty.  I think their plan is garbage.  Their morals are obviously non-existent.  My math (input energy and total materials requirements) checks out.  Calliban's math also checks out if we decide to use nuclear power instead of solar thermal.  Their math does not.  They're short of all necessary metals by hundreds to thousands of years of production, at current rates, and the mining sector is losing rather than gaining investment dollars, just like the hydrocarbon fuels sector.

We have enough materials to do this, but we need to build the machines now while we still have enough hydrocarbon energy to do it.

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#48 2023-03-05 18:57:10

SpaceNut
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#49 2023-03-06 01:46:32

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 3,572

Re: Why the Green Energy Transition Won’t Happen

Kbd512 has shown that liquid-air and hot water is a plausible energy source for rail freight.  It is similarly plausible for large marine vessels.  The reason this isn't being used at present is that diesel is an established solution that offers better energy density.  The logistics to support it are well established and there isn't a cost advantage to using liquid air over diesel at present.  This is why the Dearman engine has not recieved much attention as a potential replacement for diesel engines.  But the worked examples here show that liquid air is feasible as a replacement for diesel in these applications if the demand arises.

There are advantages and disadvantages to liquid air compared to alternatives.  The advantages would seem to be abundance and simplicity.  Air is liquefied using compression and expansion cycles.  This is a mechanical process.  The compression plant can be made from steels and powered by any prime mover.  Powering the liquefaction plant wouldn't even need electricity.  A wind turbine can power a compressor using direct shaft power.  A solar thermal plant can do the same.  We replace the generator set with a compressor plant.  These are really simple and rugged technologies.  We could instal them at fuel stations in the middle of nowhere and a mechanic can maintain them.  Liquid air is also easily storable for long periods.  An aluminium (could we use fibreglass?) tank can hold it at close to ambient pressure.  If we build it underground then the soil itself provides thermal insulation.  Liquid air can therefore be stored in underground tanks for as many months as needed.

Refuelling can be rapid.  If underground tanks are maintained under slight positive pressure, then internal pressure will push the luquid air through fuel transfer lines.  Filling up a vehicle will be similar to how it is presently done with diesel and refuelling times can be rapid.

The disadvantages with liquid air are its relatively poor energy density and the need for heat transfer to make it work.  Energy density is 0.2kWh per kg, which is only 5% of the work energy density of diesel.  This is roughly comparable to electrochemical batteries.  To provide the heat needed to expand the air, we need either waste heat from an engine, a hot fluid containing stored heat, or heat transfer from the environment.  The first option means using a hybrid.  The second reduces energy density, as we need to carry hot water.  The third limits engine power, due to the need for heat transfer from the surroundings.

Despite these problems, I believe that liquid air holds a lot of promise as one of the systems that we can use in the future to substitute fossil fuels.  It doesn't suffer from the resource constraints that limit the roll out of battery systems.  The systems that make it can be mass produced from common steels and it can be stored in tanks, with relatively high energy density for long periods.  We are heading for a time where global supply chains are breaking down due to declining demographics and shifting geopolitics.  Liquid air is something that can be made locally, using systems that are easy to maintain.

Last edited by Calliban (2023-03-06 02:04:46)


"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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#50 2023-03-06 03:27:07

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,572

Re: Why the Green Energy Transition Won’t Happen

I live in the UK, where solar flux is weak, but the winds are some of the strongest in the world.  Global supply chains are breaking down for various reasons.  Complex systems and components will be more difficult to sustain in a less connected world and we should plan for a future in which more of our manufactured goods are provided locally.  Electronics especially, will be more expensive in the future we are facing.  With this in mind, when meeting our future energy needs, it may be worth examining pre-electrical systems for inspiration.

I am indebted to Kris DeDecker for his work on Low Tech Magazine.  In this article, he talks about how wind power can be made more sustainable.
https://www.lowtechmagazine.com/2019/06 … bines.html

The very largest turbines being produced today, have hub heights of 200m and blade length exceeding 120m.  These turbines produce up to 12MW of power - an enormous amount for a single wind machine.  These large blades must withstand extreme tensile stresses and must therefore use carbon fibre composites.  Unfortunately, these have high embodied energy and are not recyclable.  Small wind turbine blades can be produced from single pieces of wood.  Medium sized turbines in the 100s kW class, can use wooden laminate blades.  These materials have lower embodied energy, can be recycled or burned for heat.  Traditionally, wind mills were compressive structures, with towers made from brick or stone.  These are low embodied energy compared to steel and last for centuries.  Medium sized turbines could still be made in this way.

Another thing DeDecker discusses at some length is mechanical power transmission using rods, jercker lines and ropeways.
https://www.lowtechmagazine.com/2013/01 … kunst.html
https://www.lowtechmagazine.com/2013/02 … stems.html
https://www.lowtechmagazine.com/2013/03 … ropes.html

Mechanical power transmission is still widely used, but is less commonly used for long distance power transmission these days because electricity is less cumbersome.  Since the 19th century, hydraulics and compressed air have developed to allow less cumbedsome mechanical power transmission than was possible using wires, ropes and rods.  In the context of wind power, mechanical transmission of power may come into its own again.  In the 19th century, it was common to attach a wind mill, waterwheel or steam engine to a line shaft running through a workshop.  Individual machines drew power from the shaft using belts.  Some workshops still use this arrangement, but electricity allows more optimised factory floor layouts.  Hydraulics are a more modern mechanical power transmission system that provides all the advantages that electrical systems provide.  If electrical systems become more difficult to manufacture, then mechanical systems using line shafts, rods, hydraulics and compressed air, could link a mechanical wind turbine to a factory.  In this way, wind power is directly converted into and used as mechanical power.  One of the attractive things about this arrangements is that the materials used are brick, stone, wood and carbon steels.  These are all materials with low embodied energy.  They are easily recyclable and these sorts of systems can last for centuries if properly maintained.

Going back to the topic of liquefied air energy storage.  Liquid air is produced by mechanical compression and expansion of air, with interstage cooling.  As the air expands, it cools.  As it compresses it yields heat, which can be removed.  Do this enough times, and air temperature drops below its boiling point.  As this is a mechanical process, it can be driven by mechanical power.  I would propose constructing mechanical wind turbines at power levels of 100-500kW.  The towers of the turbines should be constructed from stone bonded by cement or mortar, allowing useful lifetimes of several hundred years.  The nacelle and blades will be made from wood laminate composites.  The hub, axis and gears will be made from carbon steels.  The horizontal axis of the turbine, will drive a perpendicular vertical steel shaft via a bevel gear.  The vertical shaft will run down the centre of the tower interfacing with a gearbox and clutch at the bottom.  A dozen turbines will be constructed on a line, running north to south.  A trench containing connecting rods will transmit power down the line.  At the base of each turbine, the clutch will interface with a rotating wheel, with connecting rods coupling it through the trench to the wheels in neighbouring turbines.  In this way, several MW of mechanical power can be supplied to a rotating shaft driving the luquefaction plant.  Liquid air would be stored in a large underground tank.

The really interesting thing about liquid air is that lots of it can be stored quite easily in a tank and dirt provides good enough insulation if scale is sufficient.  A combined cycle gas turbine generating 500MW of power would also produce 500MW of waste heat.  Suppose we use this waste heat to evaporate air and produce extra power.  Storing a whole month of power would require 360,000MWh of energy to be stored in liquid air.  That is a tank some 1.8 million cubic metres or a right circular cylinder 132m in diameter.  We have cryogenic tanks about that big already to store LNG.  So something like this could be built.  It would be most efficient if combined with a powerplant producing waste heat, which can then drive evaporation.  In this way, we get twice as much power for each unit of fuel.  It could be even better than that, because we can use the cold air to reduce the compressor work consumed by the GT.

Last edited by Calliban (2023-03-06 04:47:44)


"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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