Military Plans Tests in Search for an Alternative to Oil-Based Fuel

The idea of alternative jet fuels has come up a few times, I thought this would be of interest.

Note: "The United States is unlikely ever to become fully independent of foreign oil, Mr. Aimone said, but the intent of the Air Force project is "to develop enough independence to have assured domestic supplies for aviation purposes.""

[Edited 2006-05-13 22:27:03]

Didn't South Africa successfully develop fuel from coal during the 80s? Can't find a reference but I remember reading that they had a program due to the international boycotts. I suspect it wouldn't be commerically feasible (yet), but it would be a good idea to have some degree of self sufficiency.

Quoting Lumberton (Reply 1): Didn't South Africa successfully develop fuel from coal during the 80s

They may have. The Nazi's invented the process during World War II when the Odessa Oil Fields were bombed. The name of it is the Fischer-Tropsch method. Currently, Gov. Brian Schweitzer of Montana is proposing gasifying coal in that state. Here's the link to the story:
http://www.billingsgazette.com/newde...08/02/build/state/25-coal-fuel.inc
Quite the idea really, I'd be in support of it.

-Copa

Quoting Copaair737 (Reply 2): The Nazi's invented the process during World War II when the Odessa Oil Fields were bombed.

Now that you've brought that up...

I know the Allies did bombing raids in central Germany on synthetic
fuel factories in 1944 I think. Do you know from what materials these
fuels were being processed; and more importantly, what happened to
this technology?

Quoting Copaair737 (Reply 2): Quite the idea really, I'd be in support of it.

Many thanks for the link and info, Copaair737! What are we waiting for???

As crude oil becomes more and more expensive coal will become the main source for liquid fuel. This fuel is exactly the same as the fuel out of oil, it is just more expensive to produce. It is also estimated that there is about 3 times more coal than there ever was oil. The largest amounts of coal are found in Western Europe.
The proces and chemical reactions to make liquid fuel out of coal are well known it's just the factories that need to be build or adapted. At $70 a barrel for crude oil it is equally expensive to use coal or oil to make fuel. If the price of oil rises further you will see companies investing in coal to fuel factories. It is just a matter of time.
It is also possible to make fuel out of organic material (waste, crops).
Both fuels can then be mixed. In Germany this happens already, they add ethanol (made from sugar cane) to diesel to make bio-diesel.

Possibilities enough to to produce the same kind of fuel we use today for decennia to come... The price will depend on the production cost of course.

Sjoerd

[Edited 2006-05-14 01:18:16]

Quoting Lumberton (Reply 4): Many thanks for the link and info, Copaair737! What are we waiting for???

Too make sure the investments won't suddenly get undercut if OPEC decides to lower oil prices through increased production.

I think to make any alternative fuel strategy work, both minimum oil price levels for domestic consumption as well as an oil content tax on imports of other goods to avoid having domestic producers be under cut by producers in nations who have a minimum price below that of the domestic price.

Quoting Sjoerd (Reply 5): The largest amounts of coal are found in Western Europe.

Sorry, Sjoerd. This doesn't jive with what I'm seeing on the web.
http://www.geohive.com/charts/charts.php?xml=en_coalres&xsl=en_res
This says that the U.S. has the largest reserves, followed by:
Russia
China
India
Australia

Quoting Lumberton (Reply 7): Sorry, Sjoerd. This doesn't jive with what I'm seeing on the web. http://www.geohive.com/charts/charts.php?xml=en_coalres&xsl=en_res This says that the U.S. has the largest reserves, followed by: Russia China India Australia

Yeah that should be correct. I remembered the inforamtion I gave from what I learned at the university. I got it wrong then, maybe Western Europe has the highest concentration for a certain area.
There are also big differences between the quality and accessibility of coal, maybe it had something to do with that.
Whatever the case the world will not run out of fuel (the one we know today) soon.

Sjoerd

[Edited 2006-05-14 01:42:01]

[Edited 2006-05-14 01:54:26]

Lumberton,

That doesn't take into account accessability. Most of the coal deposits in the U.S are not yet accessable, (No infrastructure, remote areas) ditto Russia, China, (most of it is under mountains), same with India, and all Aus's deposits are in the middle of nowhere. Most of Europes coal fields are shallow draft (relatively easily reached and mined and already easily accesible by road and rail) and are already being mined as we speak, and have been for 30-40 years.
So I think that's where Sjoerd was coming from. Coal isn't cheap when you have to build new mines, roads, railways, etc. to reach it.

This link is interesting as well, it gives a pretty different picture. Must have been Eastern Europe I wanted to refer to. It also shows how much more coal there is left.

http://www.rudrumholdings.co.uk/second_level_pages/ff2.htm

Sjoerd

Quoting ZE701 (Reply 9): That doesn't take into account accessability. Most of the coal deposits in the U.S are not yet accessable, (No infrastructure, remote areas) ditto Russia, China, (most of it is under mountains), same with India, and all Aus's deposits are in the middle of nowhere. Most of Europes coal fields are shallow draft (relatively easily reached and mined and already easily accesible by road and rail) and are already being mined as we speak, and have been for 30-40 years.

Not to belabor this, but strip mining, i.e., surface mining, is a huge industry in the U.S. I grew up in western Pennsylvanis (eastern U.S.) and strip mining was quite
common, as well as deep coal mining. Much, and I mean quite a bit, of the U.S. coal is accessable by either surface or deep mining. And most of it is bituminous coal.

Here is another link that addresses accessability:
http://www.eia.doe.gov/kids/energyfa...ts/sources/non-renewable/coal.html

Quote: Coal miners use giant machines to remove coal from the ground. They use two methods: surface or underground mining. Many U.S. coal beds are very near the ground's surface, and about two-thirds of coal production comes from surface mines. Modern mining methods allow us to easily reach most of our coal reserves. Due to growth in surface mining and improved mining technology, the amount of coal produced by one miner in one hour has more than tripled since 1978.

[Edited 2006-05-14 02:07:42]

Fair enough Lumberton. You know more than me about US matters, I'm just going by what I learn from press sources. Hopefully I'm more accurate with the other countries, it's just that I don't see any big figures for coal production for anything above and beyond Europe so I was just backing up my Belgian friend. Thank you for correcting me.

Quoting Sjoerd (Reply 10): This link is interesting as well, it gives a pretty different picture. Must have been Eastern Europe I wanted to refer to. It also shows how much more coal there is left.

Well it combines Eastern Europe and FSU (Former Soviet Union?). The previous link showed Russia with world's second largest coal reserves, so it is another way of presenting essentially the same data.

Quoting ZE701 (Reply 12): Fair enough Lumberton.

Not a problem at all! I am simply amazed that we can't get any momentum in the U.S. (and elsewhere) to start developing this resource. If there was ever an issue that begs for government backing, it's this one IMO! But then again, we can't even get another refinery built here.    If the USAF can get something rolling over here then I'm all for it.

Quoting Lumberton (Reply 14): Not a problem at all! I am simply amazed that we can't get any momentum in the U.S. (and elsewhere) to start developing this resource. If there was ever an issue that begs for government backing, it's this one IMO! But then again, we can't even get another refinery built here. If the USAF can get something rolling over here then I'm all for it.

This is because it's still cheaper to use oil (with the existing refineries), even with the high oil prices. When the price of oil rises more the investment in new factories and development becomes worth it. The process of making fuel out of coal is well established.

Sjoerd

Quoting Lumberton (Reply 13): Well it combines Eastern Europe and FSU (Former Soviet Union?). The previous link showed Russia with world's second largest coal reserves, so it is another way of presenting essentially the same data.

Correct.

Sjoerd

Quoting Lumberton (Reply 14): Not a problem at all! I am simply amazed that we can't get any momentum in the U.S. (and elsewhere) to start developing this resource. If there was ever an issue that begs for government backing, it's this one IMO! But then again, we can't even get another refinery built here. If the USAF can get something rolling over here then I'm all for it.

The biggest problem is, that to equal the daily consumption of oil that the U.S. uses today( 20 million barrels a day),we would need to build 140 such plants. At 7.5 Billion apiece,you do the math.

Quoting Copaair737 (Reply 2): They may have. The Nazi's invented the process during World War II when the Odessa Oil Fields were bombed. The name of it is the Fischer-Tropsch method. Currently, Gov. Brian Schweitzer of Montana is proposing gasifying coal in that state. Here's the link to the story: http://www.billingsgazette.com/newde...08/02/build/state/25-coal-fuel.inc Quite the idea really, I'd be in support of it.

The Nazi's actually used both coal and oil shale to good effect during WWII. Given that the US has the largest reserves of both forms of energy, we are in good shape long run.

Quoting Sjoerd (Reply 5): As crude oil becomes more and more expensive coal will become the main source for liquid fuel. This fuel is exactly the same as the fuel out of oil, it is just more expensive to produce. It is also estimated that there is about 3 times more coal than there ever was oil. The largest amounts of coal are found in Western Europe.

Try the United States, followed by eastern europe. In the US is in Colorado, Wyoming, and then some of the mid eastern states. Hardly inaccessible.

Quoting Lumberton (Reply 14): Not a problem at all! I am simply amazed that we can't get any momentum in the U.S. (and elsewhere) to start developing this resource. If there was ever an issue that begs for government backing, it's this one IMO! But then again, we can't even get another refinery built here. scared If the USAF can get something rolling over here then I'm all for it.

I keep hoping that the USAF or some other millitary unit says "we garuntee 50BB at $50 a barrel to kickstart liquefied coal or oil shale. Oil shale is more likely since that can be refined to Jet A.

Quoting Sjoerd (Reply 5): The price will depend on the production cost of course.

Quoting Sjoerd (Reply 15): This is because it's still cheaper to use oil (with the existing refineries), even with the high oil prices. When the price of oil rises more the investment in new factories and development becomes worth it. The process of making fuel out of coal is well established.

This is exactly right.

The fallacy that the USA itself can't be energy independent is promoted by two groups at opposite ends of the spectrum: energy companies and environmental groups.

Enviro groups try to stop any exploitation of new sources while energy companies perpetuate the current import model because it allows them to be less careful about environmental impact.

The thing is, there is a certain price point where the oil in various areas of the USA becomes viable, where oil shale and oil sand are viable, where coal fuels are viable.

The oil companies don't want to invest in the infrastructure to get to it, because the return would not be worth it (getting oil from the mid-east is WAY cheaper). And the Arabs know this too, so whenever the oil price reaches a point that the investment WOULD be worth it, the price of oil magically drops to below the point where it makes sense to use something besides crude.

The record oil company profits shown recently should be used to invest in non-mid-east based sources of fuel around the world, in stable places, but it won't be unless they feel assurances that the new world order is constant, that oil will remain at $70 or higher for the foreseeable future.

And frankly, the best long term energy policy the west could have is to perpetuate hostility in the middle east, because once the infrastructure is built to become independent of oil, that region loses it's grip on the world stage.

Which is why OPEC won't let it happen, or at least hasn't let it happen in the past. They've exerted pressure to remind the rest of the world why they are important in the past, then pulled back prices as a reward. Which is why no airline truly believes that $70+ oil is here to stay, because historically, it's just not sustainable, at least for OPEC. We'll see if it's really a new world or not.

Boy, you know something is expensive when even the United States Air Force is looking for ways not to pay for it...

Quoting Sjoerd (Reply 5): In Germany this happens already, they add ethanol (made from sugar cane) to diesel to make bio-diesel.

Actually, no. Ethanol (whatever the source) is mixed with gasoline (it has the same type of combustion). To make bio-diesel you need to use fuels processed from vegetable oils (sunflower, soy, etc.)

Quoting Pyrex (Reply 20): Boy, you know something is expensive when even the United States Air Force is looking for ways not to pay for it...

Not exactly. They are looking at ways to guarantee availability.

Quoting Ikramerica (Reply 19): The oil companies don't want to invest in the infrastructure to get to it, because the return would not be worth it (getting oil from the mid-east is WAY cheaper). And the Arabs know this too, so whenever the oil price reaches a point that the investment WOULD be worth it, the price of oil magically drops to below the point where it makes sense to use something besides crude.

I would argue a bigger problem is the end users of more expensive fuel products than oil would be put out of business if their competitors, foreign or domestic, use significantly cheaper energy sources and gain an advantage from it. So you can't mandate the use of some more expensive synthetic fuel throughout the economy without experiencing users experiencing consequences.

But the Air Force can use synthetic fuel as they don't compete for business since the US government pays their bills. And the expense of using some syn fuel will only have a marginal impact on the USAF operating budget, so the cost to the tax payers won't be that much. But whatever they do, they should make sure that the systems they use are compatible with fuel derived from "natural" fuels for maxium flexibility.

Quoting Ikramerica (Reply 19): The record oil company profits shown recently should be used to invest in non-mid-east based sources of fuel around the world, in stable places, but it won't be unless they feel assurances that the new world order is constant, that oil will remain at $70 or higher for the foreseeable future.

The only stable places are in and around the US, Canada, UK, Norway and Australia.

Please all forgive me, but I want to derail this thread for a moment regarding a trend I have noticed in the Mil Av & Space forum lately.

Quoting ZE701 (Reply 9): That doesn't take into account accessability. Most of the coal deposits in the U.S are not yet accessable

Quoting Lumberton (Reply 11): Not to belabor this, but strip mining, i.e., surface mining, is a huge industry in the U.S. I grew up in western Pennsylvanis (eastern U.S.) and strip mining was quite common, as well as deep coal mining. Much, and I mean quite a bit, of the U.S. coal is accessable by either surface or deep mining. And most of it is bituminous coal.

Lumberton, thank you for pointing this out, you beat me to it. I would like additionally point out though that this is a perfect example for everyone to please take a moment and check your facts before posting. I've noticed lately in some of the other threads that fact checking before posting is at an all time low. Even worse, to me it sees that opinions lately are being passed as fact. While there is nothing wrong with posting your opinion, it is just that, YOUR opinion. PLEASE do not try to pass it off as a hard fact.

Now not to pick on him, and I'm not saying what ZE701 posted was an opinion, but less than five minutes of his time on google.com or any other search engine would've shown him the error.

Thanks for your time; I'm off my soap box and back to lurking

Truck

Quoting PSA727 (Reply 3): I know the Allies did bombing raids in central Germany on synthetic fuel factories in 1944 I think. Do you know from what materials these fuels were being processed; and more importantly, what happened to this technology?

Like everything else on this planet. If you don't need it right now, you don't spend money developing it until you need it and the development costs have gone through the roof. Time to start thinking about a future, not the now. Perhaps the next generation of politicians won't have their heads up their asses and we can make some leaps in this area rather than bitch back and forth about it.

Quoting Boeing7E7 (Reply 23): Like everything else on this planet. If you don't need it right now, you don't spend money developing it until you need it and the development costs have gone through the roof. Time to start thinking about a future, not the now. Perhaps the next generation of politicians won't have their heads up their asses and we can make some leaps in this area rather than bitch back and forth about it.

This technology was further developed by South-Africa (SASOL), and is available to the market. China is building at least one CtL plant (coal-to-liquid), IIRC two or three. The technology is there, applications are running, biggest issues are how to reduce costs.

Quoting Sjoerd (Reply 5): It is also possible to make fuel out of organic material (waste, crops).

various experiments have been carried out in India, particularly by the railways to use Bio-Diesel. Its still pretty long before something like this can be used as aviation fuel. Here is a quote

Quote: With the shortage of Petrodiesel and soaring prices, the world is going the BIO-DIESEL way and INDIA is no exception. Biodiesel is basically a TBO ( Tree borne Oil) and the best source of producing biodiesel is JATROPHA CURCUS, a plant that grows well mainly in tropical climate...... Indian Railways have already completed a trial run on AMRITSAR-SHATABDI EXPRESS. The Chief Minister of CHATTISGARH runs his official vehicle on Biodiesel, HARYANA State Transport buses have been run by using Biodiesel. A train from KHARAGPUR to Howrah in West Bengal had been given a trial run by using Biodiesel. All lands by the side of Railway tracks in India will be planted with JATROPHA and INDIAN OIL and other agencies in possession of a Biodiesel Processing units will eventually process the Jatropha oil into Biodiesel for Indian Railways and for the national needs.

BioDiesel Technologies

if somebody is interested, then here is a research paper.
Properties and use of jatropha curcas oil and diesel fuel blends in compression ignition engine


rgds
VT-ASJ

[Edited 2006-05-23 05:46:49]

Quoting Boeing7E7 (Reply 23): Like everything else on this planet. If you don't need it right now, you don't spend money developing it until you need it and the development costs have gone through the roof. Time to start thinking about a future, not the now.

a good example would be the timely development of Alberta oil sands in Canada. Till a decade ago, the process was not considered feasible, but skyrocketing oil prices and development of technology made it possible.
rgds
VT-ASJ

I've read that the problem isn't that there aren't physically enough oil or oil-convertible deposits on Earth to last us for another hundred years, but rather that they would be uneconomical to develop using present technology at present prices -- emphasis on the word "present" in both cases.

I think growing oil-laden algae on a huge scale could solve the USAF's problems.

Since the primary oil extracted from these algae is biodiesel fuel and the closely-related heating oil, given today's catalytic "cracker" systems at most oil refineries the biodiesel fuel could be a base to make synthetic kerosene fuel needed for gas turbine engines.

What we have is a failure of government to force oil companies to diversify into non-oil-based technologies.

BP is running a public campaign touting its effort to reduce the "carbon footprint" of American citizens. If BP can do this, then why couldn't government do it years ago?

The fact is that there is some truth to the fact that background determines action. Background often means tradition. Convention is the hallmark of tradition. And, the thinking of the Bush Administration is nothing if not conventional -- and not in a good way. It was years into this Administration before the President stated that America was "addicted" to oil. Well, then, setting aside the fact that you've never made this claim before, what is the excuse of the federal government for taking a laissez-faire approach while the oil companies did what was best for -- the oil companies?

And keep in mind -- I'm not accusing the oil companies of being "big bad meanies". They are what they are -- companies. They exist to generate profits.

But there is little excuse for government, which exists to address long-term and other needs that private capital cannot, or will not, not to have institute major initiatives to solve America's energy needs.

I'm tired of defending the government on this score, and I no longer believe that the Administration was in any way on top of the energy agenda. Far from it; even private enterprise is further along, with the initiatives of BP (a foreign company) and others.

The Air Force should not have to go begging to protect its future need for fuel.

Once again, the Administration has proved incompetent on a matter of national security. For shame!

[Edited 2006-05-24 17:01:24]

Quoting AerospaceFan (Reply 29): The fact is that there is some truth to the fact that background determines action. Background often means tradition. Convention is the hallmark of tradition. And, the thinking of the Bush Administration is nothing if not conventional -- and not in a good way. It was years into this Administration before the President stated that America was "addicted" to oil. Well, then, setting aside the fact that you've never made this claim before, what is the excuse of the federal government for taking a laissez-faire approach while the oil companies did what was best for -- the oil companies?

Because for transportation and many industrial purposes, there is no good substitute. And unless your international competitors switch as well, you will be put at a disadvantage by using a more expensive energy source, which is what any alternative to oil will be. And that will lead to a further decline in the manufacturing base in this country.

Quoting AerospaceFan (Reply 29): But there is little excuse for government, which exists to address long-term and other needs that private capital cannot, or will not, not to have institute major initiatives to solve America's energy needs.

The only long term solution to energy needs is nuclear, one which the body politic has a hard time accepting. Renewable sources won't support current energy requirements, and anyway even renewable energy projects are rejected out of hand by NIMBYs (the Cape wind generation project rejected by Mass Democrats as an example) or by special interests (reduction on tariffs on Brazillian ethanol).

Solutions will come on the consumption side slowly, at least for non-transportation related sectors.

Brazilian manufacturer Embraer released the World's first all ethanol powered aircraft, a lightweight crop duster, last year. They say they have plans to eventually release heavier models. It's a a long way from the needs of the USAF but it's a start. I imagine if the USAF pumped a few billion into research advances could be made fairly quickly.

Quoting Lenbrazil (Reply 31): Brazilian manufacturer Embraer released the World's first all ethanol powered aircraft, a lightweight crop duster, last year. They say they have plans to eventually release heavier models. It's a a long way from the needs of the USAF but it's a start. I imagine if the USAF pumped a few billion into research advances could be made fairly quickly.

I suspect that it is a decent choice for a crop duster simply because the crop duster is being used close to the fuel source, and crop dusters can always come back and refuel. However, ethanol will never be the fuel of choice when range and endurance are critical performance parameters. The energy density is far lower than conventional jet fuel, so for a given TOW the plane would have have much less range.

Quoting many of the previous contributors and giving some supplementary information.

Germany used two main processes in WWII, the Fischer Tropsch (F-T) process as mentioned, and the Bergius process. The two processes are very different apart from both using coal. In the F-T, the coal is gasified to end up with the working gases carbon monoxide, methane and hydrogen. These are then synthesised in the presence of a complex and highly secret set of catalysts to a range of product hydrocarbons. The Bergius process adds hydrogen to the structures within coal, a suite of reactions usually termed hydrogenation.

Germany has virtually no minable reserves of oil shale and did not use it in WWII. UK torpedoes in WWII (Astuteman please correct me if I am wrong) tended to use shale oil, presumably because the SG is slightly higher than that for equivalent crude oil based kerosenes. This is because most of the kerosenes in shale oil have at least one double bond - similar to those in unsaturated fats!

The F-T process in simple in theory but expensive in energy. It is a problem of entropy, and you cannot get much better than about 30% energy efficiency - input to product. Well that is unless you become the first person to run rings around the laws of Thermodynamics. As two UK songwriters (Flanders and Swann) in the 50s had it, "Its all a question of Entropy Man!"

After WWII, large parts of the plants ended up in the US and were the basis for an extensive program lasting through to about 1980 on oil-related products from coal. The US concentrated mainly on derivatives of the Bergius process. The most elegant of these would be (if it were ever achieved) the hydrogen shuffle. In this the dominantly aromatic hydrogen atoms in coal (atomic H/C ratio of about 0.8) are rearranged and supplemented to form benzene (H/C ratio of 1). Great idea, impossible to do.

In the context of the US program, you need to use the qualifier oil-related products because the main target was a heavy oil substitute to allow the high sulphur coals to be used for domestic heating without killing the neighbours with sulphur dioxide. Probably the most sophisticated effort was the Exxon Donor Solvent process.

Meanwhile, various countries slapped boycotts on South Africa, which responded by developing the SASOL process from the F-T method. In part this was chosen because it is more suitable for the subhydrous S African coals, and partly because the products can be designed over a greater range.

Input costs of the SASOL feed coals are very low, but they have very low quality. In 2002, realised petrol prices were close to world parity, SASOL made a profit, but interestingly most of its profit was attributed to the less common byproduct, sometimes called the aspirin suite of chemical, but in practice mostly chemicals such as aniline dyes.

Yes, SASOL will licence its process but, no, you will under no circumstances get to know the composition of, or the way to make, the catalysts.

Now that natural gas is available to SASOL from neighbouring Mozambique, at least one of SASOL plants is/has switching/switched to natural gas as the feedstock. Which brings us back to US oil companies. A number of them have been developing liquids from natural gas processes. Some of these have used silicate minerals as catalysts - the German F-T and presumably SASOL used a range of platinum metals and nickel as catalysts as best we can guess.

The liquids from natural gas processes are not as thermally inefficient as F-T but are nevertheless wasteful as they commonly use oxidation to methanol (methyl alcohol, the stuff you should NOT drink) as an intermediate step. As methane has a H:C ratio of 4 and octane for example is marginally over 2, it is also wasteful of hydrogen.

Coal reserves, the references cited are fine. Probably the most exhaustive and up to date stats covering the world are issued each year by BP - you can download them at: http://www.bp.com/genericsection.do?categoryId=92&contentId=7005893
Just be careful about units in there. Coal is expressed on two bases, oil equivalent and tonnes of black coal. Neither is the necessarily the same as a tonne of coal you might go and buy from your friendly W Virginia coal mine. They are methods of trying to get the data to a common base. You can also go to WEA, but I find their stuff political in that it may be done to please governments. BP pleases itself.

One problem with reserves is that they are not always what they seem. Back in 1976, the US State coal geologists recognised this and started a project to work out what was really recoverable as coal that could be sold in terms of the reserves data. Alas and alack, that turned out usually to be less than about 20 to 25% of the numbers previously considered to be reserves. These calculations have been published in specialist journals, but for the most part have not filtered through to generalist publication such as the BP stats or the that cited by Lumberton:

Quoting Lumberton (Reply 11): Here is another link that addresses accessability: http://www.eia.doe.gov/kids/energyfa....html

Once those corrections flow through to reserves to production ratios, instead of having about 200 years of coal reserves, we may well have about 50 to 60 years, much more like oil and gas R/P figures.

It is true, however, that the US will have much more recoverable reserves of coal than it will ever have of either oil or gas. The Green River (GRF) oil shale is the largest resource of oil shale known. The difference between a reserve and a resource is that a reserve can be recovered economically and a resource may or may not be economically recoverable. It is probable that the recoverable reserves of shale oil from the GRF are quite low - cost and sheer difficulty of extraction.

The best way for the US to ensure oil products for aviation would be to conserve its own oil reserves. Second, it could try to produce oil substitutes from a range of things, one of which would be coal. But remember, when someone tells you the process will be economical if oil reaches, say, USD70 a barrel, by the time it gets there, coal for instance will cost more, and so will all the equipment, not to mentions the labour and capital. When oil was $25 a barrel, coking coal was about $48 a tonne, now it is $115 a tonne.

Quoting Ikramerica (Reply 19): Which is why OPEC won't let it happen, or at least hasn't let it happen in the past.

OPEC certainly was a problem in the past, but it has largely lost that power while we keep up the demand in the brave way we are managing to do!!

It certainly would be expensive to develop oil from coal plants for a some millions barrels of oil products a day – you would need to substitute for about 5 million barrels to make a difference. Old figures were about $40,000 per daily barrel. So if you wanted 4 million, just multiply the two numbers together. So try $400 billion for capex, or about one Iraq war!! But I think a figure of closer to $100,000 per daily barrel might be more realistic now. For comparison, Gulf of Mexico oil will be about $20,000 per daily barrel and historical costs of Middle East oil were less then $1000 per daily barrel. North Slope oil was very expensive at about $15,000. That is the capital cost, then you have to pay more to run the thing, be it an Gulf oil well, or an oil-from-coal-plant. You also need rather a lot of water!!

Accessibility of coal. Well it varies. It is true, large amounts of coal occur in the Appalachian coalfields at shallow depth and apart from the sulphur contents it is of high quality. However, the best seams are largely worked out and production is moving to deeper underground mines, with higher costs, gas and all that. The centre of production in the US is steadily moving to the west where the coals are mostly of poorer quality.

Europe had some good coals, and large reserves, but as production costs rose, these turned into resources when mines were shut for cost reasons and for the most part flooded. This is a consequence the economic rationalists will have to answer for one day – alas not soon enough!

The main coalfields left in the UK are in the southern North Sea, the Irish Sea and the Bristol Channel. These are a bit difficult to get to as well as being rather deep. There is the Oxford coalfield too, but not much coal there. Australia does have a huge deep coalfield in the middle of nowhere, and two out at sea, but has coalfields stretching from S of Sydney to just S of Townsville - roughly 2000 km and for the most part within 200 km of the coast. I know that would be the middle of nowhere to any self respecting Brit, but we and the UK steel companies will just have to make do with this sad situation!

The real puzzle with coal is China. It claims huge reserves and produced close to 2 billion tonnes of coal last year, about twice the US total. No idea how long it can keep that up. New mines in the north are probably a major factor in a doubling of Chinese coal production in about 4 or 5 years.

Here is an offer. I will guarantee to buy for Lumberton and Ikramerica each a gallon of the first commercially available gasoline made from coal that is sold in the US other than byproducts from a coke oven. In the days of petrol strikes, these held no fears for cities with steel mills having byproduct coke ovens, you just went down and filled up with benzene. So it would be back to the future.

Quoting Baroque (Reply 33): I will guarantee to buy for Lumberton and Ikramerica each a gallon of the first commercially available gasoline made from coal that is sold in the US other than byproducts from a coke oven.

Can I pass on the gas, and substitute 3.8 liters of wine from Adelaide?

Quoting Baroque (Reply 33): Once those corrections flow through to reserves to production ratios, instead of having about 200 years of coal reserves, we may well have about 50 to 60 years, much more like oil and gas R/P figures.

First I heard of this. I certainly have no reason to doubt you on this. BTW, have you read Dr. Alex Kuhlman's article on "Peak Oil" here.? Now I have something else to worry about. Thanks.

Quoting Baroque (Reply 33): Yes, SASOL will licence its process but, no, you will under no circumstances get to know the composition of, or the way to make, the catalysts.

Couldn't one determine the composition through laboratory analysis?

Baroque, I must say that you seem to have written the definitive a.net post on this subject. Every now and then, we get posts (like Lightsaber's on engines, and Widebodyphotog's on operations) that should be relegated to a reference archive. (Perhaps and A.net "Hall of Fame"?) This is one of them. Thank you for the info. Welcome to my RU list.

BTW, I grew up in Western Pennsylvania when they had those nasty coke ovens...and nasty steel mills...and dangerous deep mines. For better or for worse, they are gone, and the jobs with them.  

Quoting Atmx2000 (Reply 32): Quoting Lenbrazil (Reply 31): "Brazilian manufacturer Embraer released the World's first all ethanol powered aircraft, a lightweight crop duster, last year. They say they have plans to eventually release heavier models. It's a a long way from the needs of the USAF but it's a start. I imagine if the USAF pumped a few billion into research advances could be made fairly quickly." "I suspect that it is a decent choice for a crop duster simply because the crop duster is being used close to the fuel source, and crop dusters can always come back and refuel. However, ethanol will never be the fuel of choice when range and endurance are critical performance parameters. The energy density is far lower than conventional jet fuel, so for a given TOW the plane would have have much less range".

I'm not sure but I think the energy density of jet fuel is only about 10% more than aviation gasoline. The difference between normal gasoline and ethanol is not huge. Over 90 % of new Brazilian cars use "flex" technology that allows them to use any combination of gas and ethanol. It is estimated that a car will consume 20 - 30 % more ethanol than gas for the same trip. (I assume) Much less money has been invested in gasoline and jet fuel research than in ethanol.

Atmx2000 (or anybody else who wants to answer)- You obviously know much more about this than I do.

1) Do you think with research the "octane rating" of ethanol could be improved?

2) Can ethanol be mixed with jet fuel or aviation gasoline like it is with automotive gasoline?

3) Could ethanol or some combination of it and aviation gasoline or jet fuel be used for transport and cargo planes?

“I suspect that it is a decent choice for a crop duster simply because the crop duster is being used close to the fuel source, and crop dusters can always come back and refuel.”

Ethanol is sold in every Brazilian gas station so it is more widely available than jet fuel in isolated farm (or just about anywhere other than an airport) and it's true that crop dusters don't need much range. My impression was that they started with a light weight plane because it was sort of a working prototype. IIRC they said they plan on introducing general avaiation models soon.

Len

PS- Off topic but Brazil doesn’t have any national automobile manufactures. The big four here are (in order of market share Fiat, VW, GM and Ford, 90 – 100% of the cars they have sold the last year or two are “flex” models, Peugeot also makes cars that can use ethanol. Obviously they could experiment introducing these cars in the US. This could break the vicious circle against ethanol; people don’t but ethanol cars because so few gas stations sell the fuel, gas stations are reluctant to invest in ethanol pumps because so demand is so low.

Quoting Lumberton (Reply 34): Couldn't one determine the composition through laboratory analysis?

Thank you for your kind words. Asking me about coal and oil is a bit like asking Lightsaber if he has ever heard of a GTF!

On the catalysts, you could indeed analyse them IF you could get hold of any. The security at SASOL is out of this world. The whole plant is behind a ?20' high wall - mainly to stop the ANC being able to figure out what they would target with home made mortars. The wall is still there - even with an ANC derived Government in power. And if some catalyst was smuggled out, you still have the problem of knowing how to fabricate it so that is equivalent to the material coating parts of the huge reactors. A large part of the effectiveness of the catalysts almost certainly lies in their structure and in particular their surface area - that is, the internal surface areas as well as what is obvious as surface area. Substances such as coal (and catalysts) with a complex microstructure have surface areas of acres per cubic inch.

Quoting Lumberton (Reply 34): Can I pass on the gas, and substitute 3.8 liters of wine from Adelaide?

Do be careful how you �pass on the gas�, but yes, 3.8l from Adelaide can be substituted - by the time the event occurs, I do suspect we will all be better off on the wine. You could, of course, have asked for an Imp gallon! Nice that the US still holds by true British standards - that is pre-1776 standards. I was once foolish enough to ask an American why they had a different gallon and was told why. For those who dont know, the Brits revalued the gallon as a method of reducing the excise on grog but they did this after the War of Independence. So the US stuck with the original gallon � as in a pint is a pound, all the world round and not a pint of pure water weighs a pound and a quarter.

Quoting Lumberton (Reply 34): First I heard of this. I

The two big sleepers in energy are the extraordinary tales the Middle East governments spin about their reserves and coal reserves.

Basically Iran, Iraq, Kuwait and Saudi multiplied their reserves by 2 to 3 overnight in the 80s to support higher production quotas, and since then, these reserves have not decreased by a single barrel in spite of billions of barrels of production. If the US did invade Iraq for its oil, it probably did for the false numbers, and NOT those up on the Amer Ass Petroleum Geologists (AAPG) website at the time of the invasion. AAPG had the 2003 reserves at about 49 billion, not the 100 or 200 billion that was waved around, especially in the press.

The other sleeper one is the overstating of coal reserves. In the 60s, US coal reserves were calculated down to (this from memory) 5400' and a thickness of 9 inches. Well nobody has mined coal anywhere near 5400' deep. It is true that some coals down to 9 inches have been mined underground, but they were restricted to unusual labor (note spelling) conditions - the only mines I know underground at that thickness were at Fort Leavenworth, yes that Ft Leavenworth and near Topeka. Current underground limits are about 1400' and a thicknesses greater than about a metre. And you can guess who did the mining at the Fort! In open pit mines, UK practice is to take coals down to about 4" if they occur in the section between more major seams. By the 70s, assumptions in the US were much more realistic, so the revisions when they came were a bit of a shock.

When we will get �clean� reserves data on oil or coal is a great question. All the fuss about Shell overstating reserves by, what 30%, when the Middle East countries may be overstating by more than 50%. The US data were published about 2003, but the revisions have been studiously ignored. However, the USGS knows all about them.

No, I had not seen that particular piece on peak oil, but its premises are very similar to many others and, equally, they are difficult to fault. Apart from the original material by King Hubbert in the 50s, Hubberts Peak by Ken Deffeyes, Princeton UP, 2001, pp208 is an excellent source with an account of the conclusions from taking Hubberts principles into this century. It is worth recording (again) that in the mid-50s, Hubbert predicted peak oil for the US for early 1970s - it was 1970.

I found this section in the article cited by Lumberton especially useful.
https://www.airliners.net/articles/read.main?id=81
"The traditional view of economists that the ever-insightful market will solve all problems is a fallacy. The supreme goal in all countries to raise incomes, living standards, and the GDP as much as possible, constantly and without any notion of a limit, is unattainable. On current trends, a country like China will be requiring 99 million barrels of oil per day by 2031, while total world production today is only 84 million barrels. Even present levels of production and consumption are grossly unsustainable with a shrinking energy base. The theory that economic stimulus will spur discoveries, and the market will maintain equilibrium, ignores the serious technical limitations of various replacement technologies. Furthermore, it assumes that the supply side can respond quickly in the short term, ignoring the long lead times required for any new oil projects and alternative energy projects to go online (up to 10 years) while disregarding the huge cost involved in modifying the trillion-dollar global infrastructure that was predicated on consistently low oil prices (aviation included). Finally, fundamental economic theory fails to address the laws of physics and thermodynamics. For example, looking at energy equations, to extract oil from the highly glorified tar sands takes two units of energy to produce three units and its net energy value is therefore marginal. In the early days of oil discovery, this ratio used to be 1:20. There will always be large deposits of oil left in the earth that would simply require more energy to extract than they yield regardless of the market price."

Once peak oil is reached, oil will not disappear overnight, but it will become extremely expensive - unlike now! The critical sentence is the one that suggests the paradigm that the rational market will solve all our problems is wrong. At best the market solves problems where there is gradual change not a quantum movement. I think peak oil will produce quantum changes. That is pretty much what I wrote recently in a column in another place. And to see why, read the last two sentences about the energy (not $) costs of access to more difficult fuel substitutes.

A simple example is recovery of oil from oil shales. The measure of grade for oil shales is oil recovery in litres per tonne at zero moisture (the zero moisture is just a trick to get a common base). I thought I had a number for the lowest grade at which recovered oil has a higher energy content than the energy input, but I don�t. However, this will provides similar information. For an oil shale giving 100 litres of oil per tonne, energy input at the retorts, is about 600-830 Megajoules to give products with an energy content of 2500 to 4200 Megajoules. So energy consumption can be nearly 33% for restoring and that does not include mining, refining and transport. When you add those, it can be difficult to come out energy positive. The Green River shales do reach about 200 litre/tonne, but most are down close to that 100 l/t figure which is why we used it in a publication in 1980.

In situ retorting is a possible method. You drill holes into the shale and basically set a controlled fire. The problem is to control heat within the range at which oil is produced. Below about 430 degrees C, nothing happens. Above about 600 degrees C, you break down the liquids to gas. This process is difficult enough to control at the surface in specially designed retorts. What are the chances of controlling it a kilometre down a narrow borehole? Well you do the maths. Apart from anything else, efficiencies would be just awful.

Back in 1980, I calculated that the 50 staff on the Halibut oil platform in Bass Strait oversaw energy production of 291.4 x10 to the power 18 joules, while at the Morwell coal mine about 100 kms to the north, 800 staff produced 163.3x10 to the power 18 joules. Coal may be cheaper than oil, but the production is inherently more expensive by about an order of magnitude. Adapting out of an oil economy would not be a simple matter. This is why it would be much easier to prolong oil by conservation than to swap to systems based on other energy sources.

I might add for the biofuels enthusiasts, it can be very difficult to come out on the positive side for them too after you include tractor fuel, energy for fertilisers and all the other parts of the chain.

It is not difficult to see why flow oil has been such an attractive source of energy. Failing to recognise its unusual features, will make a transition from the oil age doubly difficult.

And one last killer for the optimists. If you continue exponential growth, delaying peak oil by even a few years, requires huge additions to known oil reserves. The only departure (minor) from the curves that lead the followers of Hubbert to their conclusions was the fall in oil consumption after 1980 when the Ayatollahs efforts resulted in oil prices higher than they are now. Hence the conclusion that conservation is likely better than just about any technical advance around.

Quoting Lenbrazil (Reply 35): Do you think with research the "octane rating" of ethanol could be improved?

The RON (Research Octane Number) for ethanol is fixed by its chemistry. The scale is based on the straight chain heptane (7 carbon atoms n-paraffinic molecule) being zero and iso-octane (the most branched 8 carbon atoms iso-paraffin) being 100. You might change the RON with additives, not sure how ethanol reacts to additives.

Quoting Lenbrazil (Reply 35): It is estimated that a car will consume 20 - 30 % more ethanol than gas for the same trip.

Yes, and it will cause a plane to consume a great deal more than that because it would have to carry a greater weight of ethanol compared with jet fuel. Ethanol has an SG of 0.789 and jet kerosene is about 0.78-0.82 so you could have a slight volume problem too. It is likely that air transport will be pushed towards longer distances, and here high energy density is critical. As Atmx2000 writes powering a crop duster is a far different problem from an efficient long distance transport solution.

Gas turbines will run on almost anything, so that is not the issue. They had turbines running on brown coal in Victoria in the late 50s - ran quite well, until the ash wore the blades out after a very short time. But even those guys never thought of using the brown coal turbines to power an aeroplane. So ethanol turbines might find a place for fixed power, especially if they are developed to a combined cycle system. But much better for cars.

Quoting Baroque (Reply 36): Adapting out of an oil economy would not be a simple matter. This is why it would be much easier to prolong oil by conservation than to swap to systems based on other energy sources. I might add for the biofuels enthusiasts, it can be very difficult to come out on the positive side for them too after you include tractor fuel, energy for fertilisers and all the other parts of the chain.

And for a totally uninformed question, would these alternative fuels help mitigate/defuse charges that aircraft emissions are contributing greatly to global warming?

Hmmm. Shell and Anglo American just signed an agreement to examine production of synthetic diesel and electricity from brown coal in Victoria, Australia. I might have to take a trip to Adelaide on behalf of Lumberton and Ikramerica (see post 34) but I won�t buy the ticket just yet!
http://www.smh.com.au/news/business/...ject/2006/05/29/1148754938793.html

"If the process proves viable, a $5 billion energy complex could be built within a decade. Its diesel and other liquids production of more than 60,000 barrels a day would be bigger than the fast-falling liquids production from the ExxonMobil/BHP Billiton Bass Strait oil and gasfields of 50,000 barrels a day."

Currently they will (yet again) build a pilot plant. The main project at $Aus5 billion comes to $US3.778 or about $75,000 per daily barrel. Presumably that includes the cost of the electricity part of the system, but it may not. Whatever, it is not that far from the $100,000 I suggested and this is before they find the problems!

Other parts of the proposal include carbon dioxide sequestration in depleted gas fields in nearby Bass Strait.

It all sounds great. But then again, similar things sounded great in the late '70s. Interesting change of emphasis however. The last time around, the emphasis was on hydrogenation and production of a substitute for coking coal, with the Japanese company Mitsui being the lead proponent.

The article does not say what process they are going to use, but it looks like gasification followed by a version of F-T synthesis.

IF it is all commercially viable, you would have a system that produced about 8% of Australia�s current crude oil demand. The carbon sequestration would remove what you might term the by-product carbon dioxide - that associated with the process - but would have no effect on carbon dioxide resulting from combustion of the product. Still it would be a start. I am not at all clear how the production of electricity fits in with production of synthesis gas.

Last time around, the Mitsui study produced a pitch (type of bitumen, similar in some properties to asphalt) that was indeed a good substitute for coking coal but not at an economic cost. The main spin-off has been a process for drying low rank coals (developed initially at Monash University) which some Indonesians are now trying to commercialise.

What will we get this time? Will we get commercial production of diesel and other liquids or another interesting spin off? The carbon sequestration aspect will ensure (Australian) Federal Government support, but it only deals with a part of the carbon dioxide problem. At least it would put liquids from coal on a constant basis with conventional oil in terms of carbon dioxide, but there is the cost and virtually no advance in emissions compared with conventional oil.

Quoting DEVILFISH (Reply 38): And for a totally uninformed question, would these alternative fuels help mitigate/defuse charges that aircraft emissions are contributing greatly to global warming?

This proposal includes a partial answer. Most of the alternatives have a heavier carbon dioxide footprint. The Shell proposal includes an attempt to bring the "competing" process back to current practices. Most of the alternatives have potential to increase the footprint rather than decrease it.

If we were really keen on decreasing aircraft input to gases, we would go to lighter hydrocarbons as they have a higher hydrogen to carbon ratio. This has three effects; the energy released by combustion of hydrogen to water is greater than that for carbon to carbon dioxide, there is a weight advantage and water is not considered a problem. (I don�t know why water is not considered a problem as it absorbs infra-red just as well or better than carbon dioxide.) Alas and alack, lighter hydrocarbons are more volatile with methane having a boiling point of −161.6�C (111.55 K) or damned cold in Fahrenheit! And of course hydrogen boils at nearly 100 degrees lower. If you settle for these fuels as gases, you could decrease the carbon dioxide footprint but at the cost of carrying around monster storage vessels. There is also a bit of a problem if the monster gas carrier crashes, explosion rather than fire would be the risk/certainty.

Quoting Lenbrazil (Reply 35): This could break the vicious circle against ethanol; people don’t but ethanol cars because so few gas stations sell the fuel, gas stations are reluctant to invest in ethanol pumps because so demand is so low.

A lot of the world (and the US) is out of range of easy transport for domestic ethanol, due to its corrosive nature making it unsuitable for conventional pipelines. Of course Brazillian ethanol could solve part of the distribution problem here in the US along the coasts.

Quoting Baroque (Reply 36): It is not difficult to see why flow oil has been such an attractive source of energy. Failing to recognise its unusual features, will make a transition from the oil age doubly difficult.

Which is why people who theorize that oil companies or governments are holding back alternative energy sources are idiots.

Quoting Baroque (Reply 36): I might add for the biofuels enthusiasts, it can be very difficult to come out on the positive side for them too after you include tractor fuel, energy for fertilisers and all the other parts of the chain.

Biodiesels seem the most attractive as its energy density is higher. The downstream processing appears less energy and labor intensive. And plants should be able to store more energy in it for a given amount of weight support.

If cellulosic ethanol ever becomes economical, then we will be able to make energy with the structural support for that weight as well.

We can probably genetically engineer plants with better energy yield. Of course that would cause a lot of enviros to flip out. Ideally, a plant or tree that you could tap to extract oil.

Quoting Baroque (Reply 39): If we were really keen on decreasing aircraft input to gases, we would go to lighter hydrocarbons as they have a higher hydrogen to carbon ratio. This has three effects; the energy released by combustion of hydrogen to water is greater than that for carbon to carbon dioxide, there is a weight advantage and water is not considered a problem. (I don�t know why water is not considered a problem as it absorbs infra-red just as well or better than carbon dioxide.)

People claim that water is a problem, they just don't hype it, probably because more people would be skeptical about such claims.

A spot of furious agreement with Atmx2000.

Quoting Atmx2000 (Reply 40): Ideally, a plant or tree that you could tap to extract oil.

The main compounds in natural rubber are not that far away from oil and palm oil is close too. The problem is that without remarkable increases in yields, this type of industry would still not match the energy input from fossil fuels. If the high yields require fertilisers, you are almost certainly trying to lift yourself up by tugging on your shoelaces. Use of the cellulosic parts of plants is more promising in volume terms, but the chemistry is not so nice because cellulose has a high oxygen content.

As Ken Deffeyes writes in his book (op cit), to the effect that he expects his grandchildren will write to him in astonished terms - you guys actually burned this stuff.

It is important that oil use be restricted to operations where its properties are critical - basically transport and petrochemicals (plus the other things I have forgotten). Even these uses are going to be too heavy a drain. For cars and trucks, use of ethanol is feasible. For most commercial airplanes, use of fuels such as ethanol would impose heavy cost penalties. Suitable biodiesel could be used for turbines, but availability is a problem.

We will need major changes in our patterns of oil use, to prolong the benefits we obtain from commercial aircraft. I imagine that the military will claim priority, but it will be an interesting day when the military have to submit and energy budget as well as a dollar budget.

These would need dramatic changes in our habits and, presumably, a number of laws that might not be popular in the short term. The penalty for not doing this, is a shorter, albeit merry, rush into the decline of the oil age. Once you hit that decline, change will be forced but will be more painful.

Unhappily, governments get elected for five of fewer years and they have little incentive to look beyond that period.

Quoting Atmx2000 (Reply 40): People claim that water is a problem

The observations made in the central west of the US in the days after S11 have brought forward an appreciation of what water does. A major problem in evaluating it significance is that there is so much water up there from natural evaporation. And cloudiness affects albedo markedly. But in SE Australia we have been sitting here for about five years wondering why the moisture up there never falls down while up in Jawa, they are wondering if the wet season will ever end!

Highly interesting to read what you wrote. Brought you on me RU list...

One question:

Quoting Baroque (Reply 36): I might add for the biofuels enthusiasts, it can be very difficult to come out on the positive side for them too after you include tractor fuel, energy for fertilisers and all the other parts of the chain.

On what generation of biofuel is this based? The first one where only the fruit i.e. just the seeds are used, or already the second one where the whole plant is used?

Is it known how China stands with its coal? We all know that they produce a very big amount of it, and that many or their coal fields are actually burning underground. How much is this influencing their actual reserves?

Quoting Flying-Tiger (Reply 42): The first one where only the fruit i.e. just the seeds are used, or already the second one where the whole plant is used?

Thank you for the kind comments.

You are correct in identifying this as a major problem for biofuels. The fruiting body (palm nuts, or corn seed) is a small proportion of the biomass for all plants. So producing biofuels from that part means that the fuel yield from a crop is low. Rubber is bit different in that it is the sap, but there are limits to how much sap you can draw before you kill the plant.

Hence the reference to the use of the cellulosic part of plants. This is the bulk of all non-woody plants. If you can get useful fuel products out of the cellulosic part, at an economic cost in energy terms, biofuels look a whole lot more attractive. Making ethanol from materials such as corn is (chemically) easy. Just hook on to a few yeasts and they will do the chemistry for you. Cellulose has been used as a basis for a range of products for a long time, ranging from explosives to clothing (both natural and synthetic).

For woody plants, you would have to tackle lignin as well. Lignin can be reacted but lignins (each plant group has a slightly different lignin) are a very complex set of compounds. The core of lignin molecules is set of linked naphthenic rings. Heat treatment of lignin tends to convert these to benzene rings - the simplest example being the production of charcoal from wood.

So it is difficult chemistry to treat cellulosic components, and even more difficult chemistry to get useful products from lignins - apart from charcoal!

It is probably most sensible if a biofuels looks at it from a segmented point of view. Bio diesel might suit the US Military and civil aircraft. Ethanol can be used in surface transport. The products from cellulose might be more suited to a range of other uses. But you can bet it will all cost a lot more than conventional oil even at $70 a barrel.

Quoting Flying-Tiger (Reply 42): We all know that they produce a very big amount of it, and that many or their coal fields are actually burning underground. How much is this influencing their actual reserves?

It is known it is a huge problem, and suspected that it must be having a huge influence on reserves. The official Chinese view seems to be that while regrettable, it is not a (reserves) problem. Underground fires also release large amounts of carbon dioxide, not to mention a fair bit of carbon monoxide and sulphur oxides. So it is not nice to be around a burning coal mine.

Just ask the folks at Centralia in PA. That is also a case study in how not to fight an underground fire. I think there have been three main attempts to extinguish this fire which started when a burning garbage heap fell down into underground workings in an old anthracite mine. First it would have been a good idea not to have a burning garbage heap, especially on top of old mine workings. Then a series of attempts was made to extinguish it. The hindsight view of these is that the second try would have worked if it had been tried first and so on. The fire is in an anthracite (difficult to ignite) and may continue to burn for about 250 years. I started that from memory but refreshed it from:
http://en.wikipedia.org/wiki/Centralia,_Pennsylvania

The Chinese coal industry has seen closures of large numbers of small mines in the past 5 or so years. This probably increases the underground fires problem. How many of the mines remain closed is also a question. It appears that the locals go back in as soon as the officials depart the scene.