What will replace aircraft when the petrol/oil runs out?

Factual Questions
21

Not going to refute you, but one should remember that biofuels at $5-7/gallon depend on farm equipment and fuel trucks running on $1/gallon (or whatever) diesel fuel.

One worry in Norway is that we’re too dependant on oil, but there are a few factors that are often forgotten. As long as we don’t run out way before the rest of the world we’ll:
a) Have less and less oil, which will be worth more and more as the reserves dwindle.
b) Still have lots of hydropower in a market where any kind of power is worth more.

Personally I think humanity should try to use the boon of “easily accessible” fossil fuels to make improvements to the world that will benefit our descendants, instead of mostly for fun and profit. But that’s just me. :smiley:

22

eburacum45,

There have been several studies on hyrogen as a fuel source for commercial aircraft.

The good news is that you’d only need to equip a few hundred fueling statoins within the USA, rather than millions for replaceing auto/truck fuel. The infrastructure costs would be comparatively minor, perhaps enough to avoid the chicken-and-egg deadlock.

The bad news is that hydrogen, even cryogenic liquid hydrogen, contains a LOT less energy per unit weight and per unit volume than jet fuel / kerosene does.

Aircraft are very highly optimized vehicles now and even if we ignore the cryogenic issue, simply filling the tanks with magically liuid room temperateu hydrogen would result in range reductions of 50% or more. The result woul dbe catastrophic to the viability of present models. even setting aside the almost-certainty that the fuel would cost more per unit energy.

So hydrogen-fueled aircraft would need relatively bigger staorage tanks. That weighs more, and causes more drag, which leads to a bigger aircraft, which in turn need more fuel to go a given distance, so you need bigger tanks which weigh more, and causes more drag, which leads to a bigger aircraft, etc.

I’m not saying you get a runaway feedback loop, but I am saying the aircraft design process routinely iterates feedback-decay problems like that and very often the impact of 1 pound gained here is 5 pounds gained total before we settle on another stable equilibrium where all the factors balance.

Bottom line: Hydrogen-powered aircraft would be larger, heavier, lesser range, and/or carry less payload than their kerosene burning cousins. All of which increases their relative costs.

Overall I agree with Sam Stone’s version of the economic future. We can and will replace oil with something as the price climbs.

But we should all bear in mind that significantly higher energy prices are just like higher taxes; they simply act as a brake on other forms of economic activity.

23

But you could say the same thing about them and their descendants, and so on. Your philosophy doesn’t allow anyone, ever, to have fun. :smiley: :smiley:

24

Of course it does, just not fun based entirely on fossil fuels. There are other kinds you know. :wink:

25

It seems a shame to abandon airplane travel because the kerosene in fossil strata becomes depleted;
As I have said before there is energy galore in our solar system; apart from solar power and geothermal heat there is millions of years worth of deuterium and He3 just out of reach…
All we have to do it gather the rather thinly spread bounty and bring it to our old planet somehow.
Perhaps a ground based transport system would be more effective, such as an evacuated tube railway system.

But airplanes are fast and flexible, so we shouldn’t abandon them.
There must be alternatives to kerosene as a fuel, but if not - it will have to be manufactured.

Here is a nice picture of a hydrogen fuelled jet airliner- you are right, it does look a bit bloated…
http://www.phoenixproject.net/lh2airport.htm
so does this one;
http://europa.eu.int/comm/research/growth/aeronautics-days/pdf/posters/cryoplane.pdf
And yes, I was wrong;, not for the first time; kerosene has a density twelve times as great as liquid hydrogen, even though it gives less power; so the big first stage of the Saturn V was filled with LOX/ kerosene after all.

I though you guys would have pick that one up…

26

Not quite. At least in the mid-west, both 100LL and 80 octane are still available, although 100LL is by far the more common.

Also, internal combustion/piston engines do not require leaded gasoline/petrol to operate - as demonstrated by automobiles for some decades. There are conversion-to-unleaded kits available for the smaller aviation engines (at least the Continentals) although the pistons and cylinders do wear out sooner after conversion. There are also aircraft engines available that were designed to run on premium-grade unleaded automobile gas/petrol and I have, in fact, flown behind such engines.

At this point, if unleaded gas disappeared tomorrow the technology is there to make the conversion for at least the lower end - 2 and 4 seat - of the piston fleet to either engines that don’t require leaded fuel or to diesel (diesel engines for small planes are, according to my information, being tweaked to run on jet fuel and not road-vehicle diesel, the idea being jet A is already available at most airports). The biggest problem would be supply and demand - there aren’t enough ready-made engines or parts or qualified personnel to install them at this point in time. The writing has been on the wall for some time, however, and the problem(s) is being worked on.

The other big problem involves regulations - the FAA only certifies certain engines for a particular airframe, and it would be a big headache to jump through the hoops to get permission to put a different engine into a plane. Some folks have done it already, so it is possible, and if the entire fleet needed re-tooling they might make a blanket ruling on it - something like in airplane A engine Q can now be replaced by engine Z.

27

Actually, the way I understand it, we tend to convert lots of otherwise unusable or un-economical fractions into gasoline or other fuels- that’s what a “catalytic cracker” does.

http://www.premcor.com/oilrefining.asp
http://www.premcor.com/cracker.asp

Otherwise, we’d be stuck with just certain cuts off the distillation column that are suitable for gasoline, jet fuel, diesel, etc…

I see no reason that we couldn’t run a similar process to convert lots of the middle fractions from refining into different compounds more useful for plastics and lubrication.

28

Besides airplanes, I seem to (vaguely) remember hearing about an idea something like, mag-lev bullet trains traveling in vacuum tubes. They could attain very high rates of speed. Did that idea end up too far-fetched? Too expensive?

29

re: Plastics. New plastics can be made from plant sources, for example:

http://www.dow.com/dow_news/prodbus/2000/20000111b.html

and

http://www.nsf.gov/bio/pubs/arabid/arab-pl.htm

The first plastic materials were made from plants, i.e. celluloid, cellophane, rayon

and acetate:
http://www.celaneseacetate.com/index-a/wa_index/history_of_acetate_filament-acetate.htm

Linoleum is also made from plant materials.
Re: Oil and airplanes
I’m not that old, but I remember as a kid when air travel was a luxury, something reserved for transatlantic flights, etc. It won’t be such a big deal when it becomes expensive again and people will fly less as a result.
I worry more about the cost of food and distribution.

Uranium is a limited resource, (50 years supply) and reactors that could reuse nuclear waste would take at least 20 years to come online.

I’m wondering how all of our coal reserves are going to handle the increased transportation energy demands of a world where the population of China is going to be owning automobiles, in addition to the conversion of our existing transportation infrastructure.

Oil has subsidized population growth in the form of increased food production. (fertilizer, machinery, harvest, distribution) What happens when those cheap portable energy inputs (oil) are no longer available?

30

Why do you easily foresee such a bacterium?

31

World population growth is slowing already, and total population will actually begin to decline within the next 50 years or so. So the simple answer is that population growth will cease well before cheap portable energy inputs (oil) are no longer available.

The world produces far more food than it needs now, even with wasteful parctices like feeding grain to cattle. And production is incraesing. A decrease in fuel isn’t going to present any threat in the sense that people will be going hungry.

With the use of fast breeder reactors, reclamation from tar sands and oilshales and other as yet uninvented technologies there is no reason to believe there will ever be any energy shortage that will lead to starvation. Whether it wil result in a decline in air travel is another debate, but food won’t be aprobelm.

32

Say hello to the Autogyro Pilot. :slight_smile:

33

Ummmm…hello.

How does this relate? :confused: :dubious:

34

Not true. It is estimated that there are about 11million tons of mineable uranium, enough to last for almost 200 years at current rate (not allowing for breeder reactors). It has to be mentioned, though, that the mining costs for much of this would be a lot higher than today. The amount of easily obtainable uranium is at present only enough for 20 years at current rate of consumption.

All according to this report from the World Energy Council.

35

Because I’ve been following developments in bioengineering somewhat, and it’s not a great stretch to imagine a bacteria that either makes iso-octane directly, or else makes other hydrocarbons that could be easily catalyzed into into it. IIRC, the key is making the bacteria resistant to the toxicity of its own excretions.

36

Nitpick: one bacterium, two or more bacteria.

37

Considering there are organisms that live in Diesel oil, this might not be impossible.

The potential of biotechnology is vast;
I personally don’t see any real reason not to collect the bounty of sunlight using genetically modified plants, for fuel, food and material production;

however some environmentalists would prefer that the unmodified ecosystems of our planet should not have to compete against designer crops.

Ah well; another conundrum.

38

Looks like we’ve found someone who hasn’t seen Mad Max 2: The Road Warrior.

39

OK, fair enough, although I was speaking in the plural anyhow, I likely wasn’t using something correctly. :confused: Do you have something to discuss regarding the actual topic I brought up? r-DNA origin insulin producing bacteria? Oil-eating bacteria? Organisms that flourish in extremely hot and toxic springs and black smokers?

40

Yes, I already asked why you thought it was likely that such a bacterium could be developed, and you answered it. See above.