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#1 2020-08-06 14:24:42

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Escape to Mars after we trash the Earth?

An interesting article by Alice Friedmann on the apparent impracticality of colonising Mars.  I would be interested in what others here think of her article.

http://energyskeptic.com/2020/mars-is-n … o-save-us/


"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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#2 2020-08-06 14:55:40

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Escape to Mars after we trash the Earth?

I would think that we would be going as having learned not to trash the place.
But its going to a hard habit to change from doing things that are easy that destroys ones surroundings.
For things that might be harder to do for extending where you live.

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#3 2020-08-06 15:05:18

Terraformer
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From: Ceres
Registered: 2007-08-27
Posts: 3,800
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Re: Escape to Mars after we trash the Earth?

Bah. What does Mars offer in the way of nickel for the vast Nickel-Iron batteries we'll need to transition to solar power?

I wouldn't take Biosphere-3 to be indicative as anything, other than that sealed terrariums don't work and that any small ecology needs active management.

"Likely" and "possibly" do a lot of heavy lifting in her article. "We don't know what's here, so let's assume they're dragons and not go." No, it's a sign we need to do proper experiments, not that space colonisation is a pipe dream.

But I'm a Lunatic anyway, not a.... Mars Hare? The perils of a multi month long journey don't apply to it, and it's far easier to come up with an economic justification (the same for 'settlements' on the ocean - resource extraction, tourism, science research). We go to Mars once Luna has paid and paved the way to it.


"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony

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#4 2020-08-06 20:59:27

kbd512
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Registered: 2015-01-02
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Re: Escape to Mars after we trash the Earth?

As near as I can tell, Alice Friedemann is another one of those merchants of despair that Dr. Zubrin warned everyone about.  People like her keep repeating their ideology as if their dogma has any meaning beyond their own three pound universe.  We do not, at this time, have anything approaching a like-kind replacement for oil and gas, which is why we continue to use it.  We can't do X, we can't do Y, and we can't do Z.  Well then bubba, you just about covered everything we can actually do.  If Alice is as smart as everyone else thinks she is, then she can invent her way out of her ideological conundrum instead of complaining about the problem.  That takes real intelligence and real effort, though.  Complaining is easy.  Inventing fundamentally new technology is hard.  It's always been that way and probably always will be that way.

Every time we try to advocate for going up the energy density pyramid, from hydrocarbons to nuclear power, people with more ideology than actual knowledge of how nuclear technology works do their best impression of the Luddites.  For those who haven't read much history, the Luddites were people from England who destroyed the machinery of mass production because they were worried about weaving looms putting them all out of work.  Who wants their kids to go to school when they can be working on losing their next finger in a textile factory?

The entire reason for going to Mars is to explore and to colonize the planet.  If humans live on 2 or more planets, then the possibility of a singular event wiping all of us out goes down dramatically.  If we live on 3 or more planets, something truly cataclysmic would have to happen to kill us all.  The astute will note that the dinosaurs aren't around to be a party to this debate because a giant rock fell from the sky and did in a day what global warming never will.  Whether or not Alice is capable of realizing what humans can do when they actually mean to do something is irrelevant.  Anti-humanists are a dime a dozen.

What is abundantly clear is that whenever the "experts" venture far afield of their area(s) of expertise and start commenting on things they clearly know little to nothing about, they give education and title a bad name.  When we were first sending humans into space, the same goofy beliefs about what would happen to those men were espoused by people who thought too much and knew too little.

It's just so very tiring hearing the same nonsense repeated by the same sorts of people.  Why we would ever listen to them is beyond my understanding.  If you think you can, then you're probably right.  If you think you can't, then you're equally liable to be right.  Ugh!

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#5 2020-08-07 04:31:20

Calliban
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From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Escape to Mars after we trash the Earth?

I think the 'merchant of despair' label is a misleading way of looking at people that talk about resource and ecological issues.   It is likely to lull you into a false sense of security.  There is a tendency to think that just because certain people have latched onto these problems, therefore the problems themselves must be entirely false.  It is an intellectual trap.  This has led to a bizarre mental polarisation in Western politics.  The left are using ecological problems to try and make the case for their vision of sociopolitical revolution.  People on the right seem to have fallen into the trap of assuming that just because people on the left shout loudest about these problems, they must be fake con tricks that aren't real at all.  Hence, the absurd efforts to avoid accepting basic physics when it comes to the science of climate change.  Both camps manage to draw the wrong conclusions.

Fossil fuel depletion and climate change are real enough problems.  Fossil fuel depletion especially, is now exerting a definite drag on economic progress for all industrial nations.  It isn't that we are running out of reserves as such.  It is more that the energy and resources that need to be invested to mine fuels from weaker resources is increasing progressively with time.  This is reducing the prosperity of the average person, because it is surplus energy that drives the real economy.  Outside of the pseudoscience of economics, the real economy is a thermodynamic machine.  What we call wealth is real goods and services, that are generated by the action of energy on matter.  Less energy means less wealth.
Our problem is as painfully simple as that.  But somehow, that simple piece of logic has gotten lost due to the predominant understanding of the economy as a financial system, rather than as an energy system.  Most Americans are poorer now than they were in 2000.  Fossil fuel energy depletion is slowing down average Chinese growth as well and the world is drowning in debt that will never be repaid.   Money is only ever a claim on the products of surplus energy in the real economy.  And that surplus energy is now declining.

But it is wise to keep in mind that many people exploit these issues to push another agenda.  What I find most conspicuous is that the people that tend to latch on to these problems and shout loudest about them, are the very ones that stand in the way of practical solutions.  As Kbd points out, the impact of fossil fuel depletion could have been far less significant if the growth of nuclear power had not been impeded by far-left green idealists.  The same is true for climate change.  It would not be the problem that it is if nuclear power had been allowed to orderly replace coal and natural gas power plants.

Greta Thunberg is the most sickening example of a far-left cause junkie.  She stands on the podium expressing outrage at the global leadership for having stolen her dreams and future because they have not swiftly stopped burning fossil fuels and filled the world with wind turbines.  This silly bitch wouldn't even be alive without fossil fuels.  It would be very difficult if not impossible for Sweden, with its weak soils and cold cloudy climate, to produce sufficient food for 10million people without fossil fuel powered agriculture and fishing.  And without diesel, Sweden could not have imported much food either, assuming that other countries (also without FF powered agricultural systems) had any surplus to trade.

One might expect that Greta Thunberg, with her moral outrage against continued fossil fuel production, would be the first to support the building on new nuclear power stations in Sweden and elsewhere.  But no.  A clear indication that an important issue (climate change) is in fact being used by this puppet and her string pullers to push a larger political agenda, that in reality, has nothing to do with climate change.  The reason these people are so opposed to nuclear power is that the last thing they want is solutions to these problems.  They want to use them to sell you an entirely different way of life, along with a sociopolitical revolution.  A real solution that doesn't require such deep changes to your way of life, is actually a pain in the arse to these people.  That is why they are so firmly against nuclear power.  It undermines what they are offering.  One of the first things that the Clinton administration did in the early 1990s, was shut down the Integral Fast Reactor programme in the US.  Nothing was more dangerous to the far-left cause than an inherently safe nuclear  reactor, that used so little fuel that it was practically a perpetual motion machine.  Climate change is simply a convenient tool for these people.  It would be a mistake to simply assume that it isn't a problem at all though, simply because these people are using it.

But I have digressed from the topic considerably.  The problems that Alice Friedmann discusses are real enough.  But they are generally exaggerated and presented in a way that makes the concept look more impractical than it actually is.  They are presented as impassable obstacles, rather than challenges that can be overcome with technological solutions.  That pretty much sums up all of her work in my opinion.  She starts with the opinion that something isn't going to work and then presents eloquent arguments to back up her case.  If she had started with the opposite point of view, she could have made a convincing case just as easily.  Her material is a good example of sophistry.  At the end of the day, she doesn't want solutions to the problems she is writing about.  Someone writing four or five centuries ago, could have written much the same things about colonies and plantations on the American continent.  They would have cited Atlantic storms, scurvy, hostile natives, uncertain soil conditions, climatic extremes, untamed local fauna; all as evidence that American colonies were a bad idea.  And the problems they wrote about would have been real enough.

Alice Friedmann is a member of the ecological-left.  These people are opposed to space colonisation for the same reason that they don't like nuclear power.  If we establish supply routes for rare minerals and other resources that do not rely upon mining the Earth, then it is one more reason that we do not need the sort of social, political and economic solutions that these people are selling.  In the case of Mars colonisation, it is not difficult to present the sort of argument that she has, because the problems involved are undoubtedly formidable and will stretch human ingenuity in their solution.  This does not make Mars colonisation a bad idea.  The correct conclusion then, is not that problems aren't real, but that we do not need far-left idealists and their socialist revolutions for getting the job done.

Last edited by Calliban (2020-08-07 06:24:24)


"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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#6 2020-08-07 11:43:05

kbd512
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Re: Escape to Mars after we trash the Earth?

Well...  At least Alice can do some basic math, so maybe I'll read some more stuff on her website to see if she has any actual solutions, rather than complaints.  Thus far, I've seen lots of complaints and scant mention of feasible solutions, apart from the usual "kill the poor people by mandating mass abortions" crapola that the anti-humanists are so fond of.

From her "Energy Skeptic" handbook:
A Sodium-Sulfur battery that could store 1 day of electricity for the US would weigh 450 million tons, cover 923 square miles, and cost 41 trillion dollars.  That's clearly not practical, so solar and wind and batteries are not going to work without a miraculous new battery energy density improvement.

Whereas, if that same battery was 10 times more energy dense for the same cost, then it'd only be 4.5 million tons, cover 92.3 square miles, and cost 4.1 trillion dollars.  That's slightly less infeasible, yet probably still grossly unrealistic.  Hopefully, we're beginning to appreciate the scale of the battery energy storage problem here.  People who aren't being deliberately obtuse fully recognize that even this "1 day of energy storage battery" is an absurdity.

She indicates why she thinks nothing significantly better than Lithium-ion is on the horizon, yet says she doesn't understand how batteries actually work (a "sure sign" of an "expert"), along with why it is that increasing the cell voltage of a Lithium-ion batteries is not very practical.  It's not completely infeasible as she seems to suggest, but it does require the introduction of some fairly toxic heavy metals (not a major problem for Lead-acid, apparently, because we recycle better than 90% of those).

Now that we all know that this "battery for everything" is a bunch of unmitigated stinky brown stuff, maybe we can stop pretending that battery powered trucks or electricity grids are the answer to anything, except how to strip even more resources, destroy more of Earth's environment, cause more pollution, and ultimately not solve a damn thing.

However, Alice seems to be missing something important, as it relates to trucks.  They're not using all of the engine's power at all times, despite the fact that the engine is built to deliver it, if demanded by the driver.  Increasing the displacement of an engine increases fuel burn because keeping a heavier rotating mass in motion requires greater fuel burn (both at idle and any other rpm range).  In most cases, maximum thermodynamic efficiency is achieved at WOT (wide open throttle).  However, fuel economy under varying loads is generally not.  There's a "fuel island" that most intermittent combustion engines like to "sit on" for best fuel economy.  Believe it or not, you can make a large displacement gasoline fueled aviation engine turn in some numbers very reminiscent of a diesel engine's brake-specific fuel consumption, but you also have to demand a lot less power from the engine than what you get at WOT and most pilots like "going fast".

The "basic physics" she refers to provides a solution to her conundrum:

Presuming well-designed and properly inflated tires and a good level paved road surface, tire drag is 1.6% to 2% of vehicle weight at 70mph.  Every part of the tire has to flex as it passes under the axle.  A railcar produces 1/9th or 1/10th of that drag force at equivalent speed because its wheels don't flex.  Aerodynamic drag force at 70mph is 23.5lbf/ft^2 for every square foot of frontal area of the vehicle under power.  For any vehicle, but especially a lightweight personal transport vehicle, aerodynamic drag force is considerable and typically more than rolling resistance.  Now you know why Tesla's engineers spent so much engineering effort on reducing the drag coefficient.  The Cd of a Tesla Model 3 is 0.23 and he frontal area is 23.9ft^2.  Those are impressive numbers, BTW.  Many bullets don't turn in a Cd that good.

23.9(frontal area in square feet) * 0.23 (Cd) * 23.5 (pounds of constant aerodynamic drag force at 70mph per square foot; doesn't change for different vehicles; only changes with elevation and temperature- atmosphere is thinner the higher you go) = 129.1795lbf (pounds of drag force that the motor must overcome to keep the vehicle at 70mph)

Now we add to that the rolling resistance / drag force produced by the vehicle's tires (this increases with increasing speed, but increasing tire pressure has a drastic effect on rolling resistance; the engineering toolbox website has a good graphic that shows the curves for tire inflation pressure and speed)

0.02 (rolling resistance coefficient at 70mph) * 4,100lbs (Model 3 mass with the 75kWh battery) = 82 pounds of force from rolling resistance

129.1795 + 82 = 211lbf

That's the drag force that the electric motor and battery have to overcome to keep the Tesla Model 3 at 70mph.  More power will be required going up a hill and less power will be required going down a hill.

The equation for horsepower (1 brake horsepower is 550ft-lbs/sec) required would be as follows:

211(pounds of force to overcome) * 102.667(fps at 70mph) / 550 = 39.386hp = 29.37kW

In other words, a Tesla Model 3 with the 75kWh battery pack could maintain that speed for 2.55 hours or 153 minutes.  Please note that for maximum range, according to mileage claims, you obviously can't travel at 70mph, because aerodynamic drag force goes up dramatically as speed increases.

So, kbd, what's "the solution":

1. Drive at 55mph.  The double nickel saved lives and it drastically reduced aerodynamic drag, which is typically the dominant factor affecting the power requirement for a highway vehicle.  Power to overcome drag goes up drastically with increasing velocity.  You can only reduce Cd and frontal area to a certain point, so going slower is the most practical option for saving fuel.  That's what the physics says.

2. Decrease rolling resistance of the tires.  There's clearly a limit to this and if the tire doesn't grip the road sufficiently well (provide adequate traction), then you have a drifting machine more than any type of usable grocery getter (Model 3) or grocery hauler (Class 8 heavy duty truck).

3. Use a form of power that does not require keeping a heavy rotating mass in motion, such as a high temperature diesel fuel cell, which can be 70% to 80% efficient.  This single change is the greatest possible improvement to fuel economy of the heavy trucks that keep a technologically advanced society supplied with goods and services.  It's hard to underestimate how this affects fuel consumption, since rolling resistance force is tied to weight.

If a diesel engine converts 35% of the fuel into mechanical power, then 16.1MJ/kg.  If a diesel fuel cell converts 70% of the fuel into mechanical power, then 32.2MJ/kg.  The fuel cell also produces half of the emissions for the same amount of mechanical work.  If the highly aerodynamic diesel engine powered DOE "Super Truck" was getting 12mpg, then a high temperature diesel fuel cell truck of the same design will be getting 24mpg with the same load and a the same speed.

Apart from drastic expansion of the railways, there isn't any other practical way.  Reduce the drag force (to a point), increase tire inflation pressure (to a point), and use a more fuel efficient "engine" to provide power.  That's it.  That's all there is to it.  No "magic" can or will happen here.

Whereas a 600hp Class 8 diesel engine is in the 4,000 pound range, a high temperature fuel cell would likely weigh less than 660 pounds.  Since it consumes half as much fuel, a single 50 gallon fuel tank can take you 1,200 miles.  The national average 7mpg for a class 8 truck requires 172 gallons of fuel to go the same distance, which is another 830 pounds of weight add to the tractor (plus another 100 pounds or so for the tankage), so the fuel cell powered vehicle is 3,000 pounds lighter in terms of "engine weight" alone.  If each wheel has its own electric motor, then we're looking at saving at least another 1,000 pounds of transmission and drive train weight, so we either gain payload or reduce fuel consumption by decreasing rolling resistance.  All in all, we're looking at knocking 4,000+ pounds of weight off the tractor with the fuel cell.  This doesn't require using lighter materials, either, it's just the mass differential between a large high duty cycle ICE and a high temperature solid oxide fuel cell.  The truck chassis will still be steel with Aluminum wheels, same as nearly all new big rigs.  For on-road use in spring or summer months or places where it doesn't snow or ice up frequently, super singles do contribute meaningfully to improved gas mileage.  CNT fabric sidewalls would nearly prevent blowouts.  We can play endlessly with aerodynamics, but the most practical solution is to drive a little slower.

The final solution is to build more railways anywhere there isn't water, because physics simply won't accommodate any magical thinking about the relative efficiency of flexible vs non-flexible wheels.  US Army studies showed (every single time they re-do "the test", looking for a different result that physics won't accommodate) that wheeled vehicles up to the 10t weight limit can generally get better fuel economy off-road than tracked vehicles, but after that the use of tracks (especially rubber band tracks) saves fuel because the tracked vehicle design ends up exerting lower ground pressure for a given payload, therefore reduced rolling resistance.  That little "discovery" and "re-discovey" and "re-re-discovery" was solely due to rolling resistance between wheels vs rubber band tracks in an off-road environment.  Again, physics doesn't care about what toys the boys want to play with.  It says what it says, does what it does, and it's not changing to accommodate anyone's ideology or feelings or burning desires.

Want to know why we still make and use diesel combustion engine powered trucks?

Nothing that changes the math affecting the power requirement to move a given load a given distance has appeared, with respect to battery powered vehicles and the current battery technology is woefully insufficient to move Load X to distance Y at Rate Z.

We, as in all of humanity, live in a country called "Derpistan".  In Derpistan, the locals don't like math.  They much prefer their religion of choice.  One religious group thinks diesel ICE's are the answer to all of life's energy problems and the other thinks that batteries and solar panels solve their energy problems.  Both groups wave their magic wands, recite their religious dogma, and...  NOTHING CHANGES AND NOTHING FUNDAMENTALLY "BETTER" APPEARS!  Well, derpity-doo-dah all the live long day.  Maybe one day we'll collectively realize how much precious time has been wasted chasing down non-solutions.  You go up the power-to-weight and efficiency ladder whenever you start demanding more ton-miles per unit of fuel (of whatever type) expended, not down.

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#7 2020-08-07 16:55:45

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 3,352

Re: Escape to Mars after we trash the Earth?

Kbd, that is impressive.  There are a few limitations on solid oxide fuel cells that might require you to modify your concept, but SOFC trucks deliver enough of an improvement in fuel economy that it would appear (to me at least) that they should allow us to stay ahead of the surplus energy cliff for a long time to come.  Just a couple of things:
1. Realistic efficiency for a SOFC is closer to 50%.  Still a big improvement on compression ignition engine, especially when reduced engine and drive train weight are accounted for.
2. SOFC is very vulnerable to damage from sulphur in fuel.  The fuel needs very low sulphur content.
3. As a high temperature device, there will be warm up time.  The truck should maximise distance travelled between rest stops.
4. Hydraulic recovery of braking energy could improve fuel efficiency even more.  For big trucks operating in urban conditions, it could allow a 40% reduction in fuel consumption.  Probably a lot less for long haul.

SOFC sounds like a good option for powering a Mars vehicle.  That would be especially true if could use hydrogen and CO2 in the fuel cell.  I seem to remember that hydrogen will reacte exothermically with CO2.

I don't think grid battery energy storage is taken seriously by anyone as a potential solution for long-term lulls in renewable energy production.  What it can actually achieve is to provide enough energy storage to allow CCGTs to be brought on load, if the windfarm drops off of load.  That is where battery storage is useful.  You don't need days or even hours of grid storage for that.

Thermal energy storage could also be valuable as it has generally low capital cost compared to other options.  It means storing hot water in insulated tanks.  In power generation concepts, heat is usually stored in concrete or rock masses.  This is then used to generate power using a steam cycle (S-CO2?).  Works best in combined heat and power mode.  Typical energy storage density is 0.5-1MJ/kg, which is about the same as batteries.  The difference is that rock and concrete are cheap as chips, it is the steam generating plant that costs money in this case.

Last edited by Calliban (2020-08-07 17:34:26)


"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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#8 2020-08-07 21:29:46

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Escape to Mars after we trash the Earth?

Take Me to Mars

There is no doubt that humans are going to Mars. It is simply a question of how and when.

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#9 2020-08-07 23:07:53

kbd512
Administrator
Registered: 2015-01-02
Posts: 7,362

Re: Escape to Mars after we trash the Earth?

Calliban,

1. I'm reasonably sure that the US Army's SOFC program manages 70% to 80% efficiency using CHP and they're designing these things for off-road trucks and generators for base power.  They don't baby their equipment, either.  Anything incapable of withstanding a reasonable level of abuse won't see a field trial.  In any event, there are a number of ways to improve electrical efficiency and cell life, which includes recirculation of exhaust gas through the cell to extract more power from the un-reacted Hydrogen gas in the exhaust stream.

More Efficient, Longer-Lasting Solid Oxide Fuel Cells

2. The US Army has also come up with materials that are tolerant of high Sulfur content in poor quality JP8 fuel.  You do get more NOx emissions with SOFC, but less PM2.5.  In my opinion, higher quality fuels are worth the extra refining cost because they make design of the rest of an internal combustion or fuel cell solution so much easier.

3. True, but there's a solution to this problem and the one actual unresolved issue with fatigue from thermal cycling as well.  Surrounding the fuel cell with appropriate insulation or a molten salt heat source to prevent rapid temperature fluctuations will greatly increase service life.

NASA may have solved the thermal cycling issue with a mechanical solution:

High Power Density Solid Oxide Fuel Cell

2.5kW/kg and 7.5kW/L

A 600hp / 448kW class 8 truck fuel cell "engine" would therefore have a cell volume of 2.1 cubic feet and weigh 179.2kg / 395 pounds.  That would easily fit between the frame rails of the tractor, even with insulation and everything else included.  I used my mass estimate based upon "standard" 2kW/kg SOFC technology and increased that by about 50% for sake of durability.  There's little reason to think that we couldn't make the solution "bomb proof" by generously beefing up the design, on account of how much lighter it is than a diesel engine.

The fact of the matter is, these things are tiny and maintain better power-to-weight ratios than gas turbines up to 1.5MW or so.  That accounts for nearly all land vehicles by numbers, many diesels for boats and backup generators for ships, all light aircraft (defined as 10,000lbs or less here in America).  I'm guessing that the fuel economy improvement would cover the mass differential for virtually all land vehicles outside of some very specialized one-of-a-kind industrial equipment for mining and construction (where slightly increased power system mass would likely be negligible anyway).

The pilots I know couldn't care less if the power going into the prop is provided by a gas-powered four-banger, a fuel cell, or miniature purple ponies.  They'd welcome electric motors for "smoother than a gas turbine" operation with open arms.  The electric motors for aircraft have already been perfected and they work beautifully, as long as you can supply the kilowatts.  The pilots who have flown them have nothing but good things to say about them.  Their only complaint is that the batteries can't supply the power for very long.  Fuel cells could change that.  For this to happen, fundamentally different thinking is required and fuel efficiency needs to become a national priority.  The technology needs to be industrialized, plain and simple.

For larger ships and power plants, there's still a possibility of using co-generation techniques to improve fuel efficiency:

FUEL UTILIZATION EFFECTS ON SYSTEM EFFICIENCY IN SOLID OXIDE FUEL CELL GAS TURBINE HYBRID SYSTEMS

4. Since electric motors are already incorporated as a part of any fuel cell solution, it would also make sense to use the motors as generators to assist with braking.  Four 112kW motors are the ultimate "Jake brake", but without the obnoxiously loud noise.  Vehicle accessories like power steering, AC and heating, hydraulics or pneumatics to assist with braking or acceleration, could also be pressurized using waste heat from the fuel cell, as you already noted.

I actually have a specific tractor design in mind that integrates the fuel tank with the chassis, a tubular design that utilizes otherwise wasted space and provides a smoother ride using independent suspension.  It would have 4 super singles instead of 4 super singles and a pair of steering wheels.  The drastic weight reduction of the tractor using the fuel cell makes this practical since there's not a 4,000 pound motor out front and another 1,000 pounds of drive train components.  I think the Ford F-Vision design is pretty close to the right idea, but the batteries are not suitable for highway use because they simply don't have the energy density required.  The F-Vision has a 300 mile range using its onboard battery.  Note that the Nikola Motors Nikola 1 design uses a PEMFC with 100kg of onboard hydrogen storage and that provides a 500 to 750 mile range, and 1,000hp or 2,000hp for acceleration using an onboard 250kWh to 1MWh battery, and it has a dry weight of 18,000 to 20,000 pound range (or much more than that with the 1MWh battery).  Nikola Motors said that if they were to add a 3MWh battery pack to provide equivalent range to the Hydrogen fuel cell powered truck, it would add approximately 30,000 pounds of weight to the vehicle, which basically makes it unusable as a heavy duty truck for carrying typical loads on most existing highways.

Batteries may be all the rage for small cars and there's great utility in battery powered micro cars for daily driving, but for heavy duty highway trucks the need for fuel cells is pretty obvious.  While drivers are driving, they're getting paid, thus time and therefore money is at play.  Most people want their product delivered yesterday as well.

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#10 2020-08-08 03:04:34

Terraformer
Member
From: Ceres
Registered: 2007-08-27
Posts: 3,800
Website

Re: Escape to Mars after we trash the Earth?

I think we should also be doing a lot of work on coal-water slurry fuel. If we can burn coal in a diesel engine, not only does that open up new opportunities for biomass (there's no obvious reason it wouldn't work with charcoal), it allows us to start using coal for some load balancing tasks.


"I'm gonna die surrounded by the biggest idiots in the galaxy." - If this forum was a Mars Colony

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#11 2020-08-08 07:31:31

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Escape to Mars after we trash the Earth?

Coals main issue is sulfur content for the creation of acid rain.

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#12 2020-11-14 13:09:54

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Escape to Mars after we trash the Earth?

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#13 2021-04-25 12:49:52

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 28,750

Re: Escape to Mars after we trash the Earth?

I am not sure that anyone even noticed the trash cleanups of the local communities as part of the Earth Day week end...

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