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

Factual Questions
1

or perhaps the question can be worded:

What alternative forms of transport will become available to the masses to replace the cheap, rapid global air transport offered today when aviation gas becomes too expensive?

The current models of global oil output (taking into account new efficiencies and new discoveries), indicate that oil production after 2050 will start dropping below 1950’s levels. And that is with much greater demand. Whether the models are accurate or not, in the next 50 years avgas has got to be getting very expensive.

I dont want to debate the details of the modelling, but am after information on the current and foreseeable technologies that will allow continued cheap global air transport. The world will be a very different place without cheap air travel.

Will people have to travel by boat or dirigible?
Can planes run on natural gas?
What about other energy sources?

2

The discussion is moot without accurate modeling.

If Boeing, Airbus, Pratt & Whitney, General Electric, Rolls Royce, Allison, Bombardier, Cessna, the U.S government, and others believe that fuel will be scarce in 50 years, then they will fund research to find economical alternatives. If these companies are not pursuaded that such a need exists, then the status quo will continue.

3

All is most certainly not lost.

First off, gasoline will be available, via conversion of methane, biomass, and energy crops. The cost and availability will not be even close to what we have now, but even now IIRC one can make gasoline or jet fuel from corn at a cost of about $5-7/gallon delivered (don’t quote me on it, I don’t have a cite available. Please feel free to refute me). So if worst comes to worst, we will still have jet fuel.

That future is a long, long way away. Advances continue every month on bioengineering and technology. I could easily foresee a bacteria that eats corn or wheat and excretes either gasoline or hydrocarbons very close to gasoline - or which can be easily converted to it. I can also foresee fast-growing energy crops that have twice or three times the yield we currently have. It is possible that in 2050, jet fuel from biomass may cost about what it does now in 2003 dollars.

4

Back in the 1940’s Germany had a fully functional aircraft that ran on concentrated hydrogen peroxide, hydrazine hydrate and methanol with a top speed of 600 kph. There were a few problems, such as an irritating tendency to blow up without warning and highly corrosive fuel, but there’s no question that airplanes not only can fly with alternative fuels, they have. By the way, here’s what the little devil looks like. I don’t think we’re likely to move to bifuel rockets for commercial aviation, but the point is that there are alternatives to “petrol”.

The Europeans have a fully functional diesel engine for small piston aircraft, available not only in Europe but also (I believe, as of last year) in the US. Diesels can run on alternative fuels, although not as efficiently. Presumably, one could tweak a diesel design to obtain maximum efficiency from a particular fuel other than petroleum derieved varieties. Or maybe not - it’s not an area where I have great expertise - but the point is that there is already on-going research into more fuel-efficient airplanes.

It would be enormously expensive to alter the current fleet to accept different fuels, but if the alternative was giving up air travel I think we’d do it.

5

Synthetic fuels can be made from any hydrocarbon source and energy - some processes like Thermal Depolymerization look like they could replace petroleum without actually costing all that much more.

6

The OP and others inadvertantly combine two very distinct fuels:

“Avgas” is a high octane gasoline/petrol product burned in the internal combustion (“piston”) engines of small private planes. It used to be available in 4 leaded grades and over the last 30 years has slowly morphed into essentially one unleaded grade today, at least in the USA.

It may well die out in a few years because the formulation is expensive and it needs a completely separare production and transport infrastructure. As the volume dwindles, the overhead costs are skyrocketing. A crisis of supply of some sort is widely predicted within 10 years, having nothing to do with the availability of crude.

The other fuel is “jet fuel”. It’s burned by airliners of all sizes, including the smaller propeller-driven planes with 20-50 seats as are commonly flown by the big airlines’ feeder partners.

That fuel is essentially filtered kerosene with a couple of special chemicals added to limit water absorbtion. It has a much lower inherent cost of production than avgas, as well as no problem with dwindling demand.

As to possible synthetic sources, the heavier kerosene is much easier to make than avgas. As well, turbine (“jet”) engines are pretty forgiving about what they burn. With a few minor tweaks they’ll run acceptably on diesel or biodiesel today.

The regulatory hurdles are large, but swapping commercial mass-transportation aircraft to an alternate quasi-diesel fuel source is not a major engineering problem at the airplane end. Building the infrastructure to manufacture the needed volume of alternate fuel, now that’s a different matter, and one I’m not qualified to comment on.

Economics are another matter. In the US at least, airlines make profits with jet fuel at US$0.50/gal. At US$0.80/gal they’re losing money. Fuel is roughly 1/3rd of total operating costs, and if fuel was US$ 5.00/gal, the cost of tickets would have to rise 3x or more. That’d have a chilling effect on demand that makes the last 2 years’ recession/terrorism-driven doldrums seem like a boom.

And that’s ignoring the feed-forward effects of the price of all other inputs going up as everyone in the supply chain grapples with their fuel costs.

With due respect to the OP, a 5-10x bump in fuel prices will be so disruptive to the entire economy that it’s impact on the airlines is small stuff around the edges.

The good news is that while it’ll happen pretty quickly once it starts, it won’t be an overnight spike, a la the OPEC-induced crises of the '70s. It’ll be expensive and disruptive to retool that quickly, but it won’t be impossible. I HOPE :-o

7

Here is an article that includes information on Diesel aircraft engines.

(I haven’t kept up with avgas changes – I just call the fuel truck and tell them how much I want.) The most common avgas is 100LL. I read once that “Low Lead” avgas actually has more lead in it than did regular leaded mogas.

8

One thing to note is that technologies to convert coal and natural gas into gasoline, jet fuel, lubricating oil, etc… are already here, and WELL on the way to being profitable.

According to this article on GTL/Gas conversion technologies, teh breakpoint for GTL technologies vs. crude oil prices is around $20/bbl.

This ain’t that high, folks- the current price is somewhere around $30/bbl(West Texas Intermediate). In other words, they could be synthetically creating all manner of stuff right now and making profit off of it. And that type of stuff is more environmentally friendly- little sulfur!

I don’t have a cite, but I seem to recall that we have coal and natural gas enough to last a LONG time relative to petroleum reserves. Plus there are lots of currently uneconomic reserves out there that would be utilized if prices rose enough.

I don’t think there’s much to worry about in any kind of reasonable time-frame.

9

Screw the gasoline, the jet fuel, the heating oil. We can burn damn near anything, given enough money.

When the oil runs out, what do we do without plastic?

10

Return, sensibly, to gutta percha.

I wish we’d do it now as the Third World needs a cash crop.

11

The airline industry will be the least of our worries, if the Olduvai Theory proves correct:

http://www.dieoff.com/page224.htm

The theory claims Industrial civilization will last about a century, starting from 1930. About 2030 the world will be in an increasingly rapid decline back to the Dark Ages.

12

That’s a preposterous theory. For one thing, it neglects to account for things such as nuclear energy, Fischer-Tropsch GTL or coal conversion, more efficient electrical devices and transmission systems, renewable sources, etc…

Basically all that’s going to happen when petroleum production starts to become too expensive is that other sources will become viable. Prices may go up, but there won’t be mass permanent blackouts- there’s too much money to be made providing electricity for that to happen!

13

When, when the oil starts to run out, the cost of producing new plastic will rise, possibly making it more expensive than recycling existing plastic. Most plastics can be melted down and recast pretty easily, but for now producing new plastic remains less expensive. There are a few exceptions, like plastic soda-bottles and whatnot, that can be collected and reused pretty easily, but a lot of our plastic packaging currently goes straight into the nearest landfill. If oil got sufficiently expensive, picture mandatory recycling laws (or higher deposits on soda-bottles) to encourage citizens to return their plastic for re-use, instead of tossing it.

14

That’s just they expected you to say, from the first sentence of the Abstract:

I’m personally suspicious of any theory that contains (let alone starts with) a description of the amount of resistance it has encountered. That strikes me as a blatant attempt to play on my sympathy for the underdog, rather than trying to win me over with sound reasoning. It’s saying, in effect, “Look at all the mean people we’ve upset. That must prove we’re on to something.”

I think it’s as likely (if not more so) that a theory is challenged because it is flawed and not just because it ruffles the feathers of the status quo. I’m amused by one of the closing sentences:

How many “Industrial Civilizations” has the author analyzed? What’s his baseline? Atlantis? Mars? The author simply doesn’t recognize that energy has become a commodity, like steel or grain or pork-bellies, and that boom-and-bust cycles are natural. But I guess a theory that doesn’t involve apocalypse won’t get you much attention.

Short-term, I’m hoping the widespread advent of LEDs will replace incandescent light bulbs completely. That alone in a major city can be a huge energy savings. The fossil fuels saved by lower electricity demand can be used to keep the airplanes flying, until something better comes along.

Long-term, I hope controlled fusion plants start popping up all over the place.

15

LSLGuy wrote:

The reason I am interested in the affect on cheap air travel in particular is that there are a range of obvious alternate energy sources for other forms of transport and power consumption. With air travel it seems we are a bit more resticted with the technology.

I suppose the question comes down to how costly the new fuel will become once the infrastructure is set up to support it.

Hopefully the biofuel or GTL solutions wont be so expensive that countries like Australia become even more distant.
LSLGuy thanks for the clarification of the difference between avgas and jet fuel. I always thought they were the same. I just read this document on aviation fuel compositions.

16

When oil passes peak production and reserves begin to fall, the price will rise.

As the price rises, several things will happen: First, people will start to conserve more without the government forcing them to. You hate SUVs? Fine. Wait until gas is $10/gallon, and that problem will solve itself.

As oil increases in price, previous unprofitable wells will come online, adding to the supply. The tar sands in Alberta are massive, and they’ll start to be exploited.

As oil increases, at some point the price curve will climb past nuclear, and wind, at which point you’ll start to see major moves towards those power sources. Solar may come into play later.

In the meantime, the high cost of energy will spur for-profit research into alternatives.

LONG before we run out of oil for plastics and lubrication, oil will be too expensive to be burned in cars. Once cars stop burning it in mass quantities, there will be enough left over to supply other industries for a long, long, time.

We will never run out of energy. We won’t run out of oil, either. Our infrastructure will mutate, adapt, and continue rolling on. Economic growth may take a hit as we absorb the cost of rising energy prices. On the other hand, perhaps there will be a new breathrough.

But we’ll never run out of energy. We know how to make lots of energy without oil. Nuclear, solar, wind, geothermal, ocean currents, biomass, you name it. We don’t use these sources today because oil is cheaper. That will eventually change.

17

I agree with you Sam. Oil as energy will become more expensive and end up just producing plastics, pharmeceuticals, specialty chemicals etc. But remember this question is specificaly about aircraft.

The thing is we have an energy source that is currently
very cheap and has
high energy/mass,
and thus perfect for running aircraft.
There is plenty of it around (even though we are consuming it at a tremendous rate).

The energy source to replace it will have to have the same advantages. Running out is not the issue, it is cost. The GTL technology sounds promising (in terms of cost). Technological improvements on biofuels would have to be good - in 50 years the world population will have increased from todays 6 billion to 9 billion - thats a lot of hungry people competing for the crops.

We have heaps of coal. Could jet fuel ever economically be derived from coal? Una?

18

As I understand it, we’ll still be making quite a lot of oil-based fuels, because when oil is used in other industries the refining process produces fuel anyway. In the 1800’s, gas was burned off as waste.

There might be enough production to provide aircraft with fuel, if everything else stops using it. The price of flying would go up substantially, though.

19

Ach;
Liquid hydrogen got Saturn V to the Moon;
I’m sure the hydrogen in the sea could be used in aircraft transport systems of some sort.

to get the energy to extract this hydrogen you could use the long promised fusion plants, which might be available by the time the oil runs out; otherwise I am sure modern technology could produce safe fission plants…
most of the danger involved in fisson energy production occurs at the mining stage, as I understand it, and mining radioactive material safely drives the cost up,
so does arbitarily high standards of radioactive waste disposal.

other options include coal, OTEC, solar photovoltaics, geothermal, wave and tidal power, perhaps wind power and biomass energy production.

The Earth is bathed in 18,000 times as much energy (from the Sun) as we currently use; there is a billion times as much available in the solar system as a whole.

There is no way that this planet can ever run out of energy; although the cost of that energy may change, there are economies of scale which should result in a far more energy intensive culture than we now experience.

None of this will happen overnight, however, and there is a non-trivial chance that we might not develop the post oil economy in time.

SF worldbuilding at
http://www.orionsarm.com/main.html

20

I think the key word is “economically”. Right now, no. But in the future…relative to a tightening supply, I’m sure the answer will be “yes”.