What is the easiest fuel a blockaded, sanctioned nation can procure/synthesize during a war?

Question

In my world, which is partially based on a WW2-style environment, there are two large countries, namely A and B, that are fighting each other.

A is a Nazi Germany-type country with fine revised tactics, like the blitzkrieg, i.e. entering territory so fast, that the enemy doesn't even have time to react. A also has superior technology, like long-range supersonic bombers and heavy-duty tanks that can ravage even through muddy terrain and all sorts of weather.

B, on the other hand, is a Soviet-style (remove the communism part) country, with a ton of personnel but, due to purges of military generals etc., the army is so badly led, that even with tons of soldiers they are agonizingly slow, such that even with good ammunitions and stuff, a smaller but better led army would be able to defeat them.

A and B are fighting each other in a bitter war to acquire control of uranium fields in the black-encircled region given in the map below (credits to Inkarnate):

This map is the entire map of the world, and, since my world is about as big as Earth, you can use a 1:100,000,000 scale.

However, we run into a problem.

A is blockaded and sanctioned from obtaining oil to fuel its war with B. Meaning that alongside B, there are other countries that are indirectly in the war, by blockading A from getting oil, such as C and D, on the western portion of the map. B, C and D form an alliance group that is analogous to what would be the Allied forces in WW2.

E, the island at the west of the map, was the area that A procured oil from. But as C and D have blockaded it, A has resorted to getting oil from within its territory only, which only meets about 15% of its fuel demand.

I see a congruity between the story in my setting, and World War 2. Just like the story in my setting, Nazi Germany could have theoretically defeated the Soviet Union during Operation Barbarossa due to better technology, aerial superiority, etc. However, Nazi Germany lost the war due to oil. Basically, most of the oil that Nazi Germany obtained was from Soviet Union (ignore that for now) and Mexico and the Caribbean (the analog for E in my setting). However, due to its close proximity to the USA (analog for C), Mexico had to stop its oil exports to Germany, which was disastrous for Operation Barbarossa, as the Wehrmacht and Luftwaffe were heavily reliant on petroleum to fuel their tanks, cars and fighter jets. This is an extremely massive reason why Germany lost the war (and Austrian Painter and his bois got rekt).

My world's setting also faces this problem. Due to the blockading of E by C, D and B to prevent A from getting oil, A's tanks and supersonic long-range bombers are practically useless due to lack of oil to fuel them, as I mentioned before. A's domestic oil production is barely 15% of their demands. There is no way to get oil from E without declaring war on all three countries at once. And although A has a massive army, that is nothing compared to the full might of all three countries C, D and B. Which means that A now has to look for an alternative source of fuel, something that it can manufacture easily using domestic resources.

I have been told that Nazi Germany was contemplating synthesizing oil from coal, but in my setting, A cannot do that, as the process is extremely inefficient and wasteful of energy. Furthermore, A doesn't have a plethora of coal deposits, which means that the coal-synthesized oil scenario is impossible. (However, if these assumptions are incorrect, feel free to point it out and I will gladly edit my question.)

What is the easiest fuel a blockaded, sanctioned nation can procure/synthesize during a war?

Criteria

• The fuel cannot be something whimsical or ridiculous. For example, something like "Antimatter Steam Engine" or "Muon Fusion Tanks" are totally out of the question.
• The fuel must be something that can be manufactured with 1980s technology.
• The fuel is something that is very easy and not very time-consuming to manufacture.
• No nuclear fusion/fission-based improbable tech. Uranium is terribly inefficient for vehicles, as most nuclear engines are basically steam engines, which means that a ton of water is required for powering, making a fission powered vehicle impossible—and don't get me started on fusion-powered vehicles.
• The fuel can either be synthetic or natural.

Some additional info:

• My world's technology is comparable to that of the 1980s.

• A has about 2.5 million troops, 4000 aircraft (mostly long-range supersonic bombers), 20,000 tanks and 15,000 submarines.

• B, on the other hand has 7 million troops, 5000 aircraft, 40,000 tanks, but zero navy. Despite the massiveness of B's army, it is so badly led, that it can in theory easily be defeated by A.

• C, D and E aren't directly involved in the war, except for the blockades and stuff, so the question of how much troops they have is irrelevant.

• If people want an analogy of what the blockade looks like, try to imagine something like the British blockade of Germany during WW1.

• Some clarification on the "uranium fields":

  Uranium and nuclear fission are prevalent. In fact, the reason A is invading B is to wrest control of the uranium fields on the map. A does have nuclear fission tech; however, there is an acute shortage of uranium ore in A's territory. That is why A is invading B to get uranium. Try to think Nazi Germany invading Kazakhstan for uranium, if you want a real world analogy (which neither was planned nor succeeded, but makes for a clear analogy).

  The "fuel", however, is not power generation or anything like that. The "fuel" that A needs is basically fuel to power vehicles, locomotives, tanks and planes. I am aware of the fact that uranium or anything remotely nuclear is a terrible choice for fuel as it is incredibly inefficient, and moreover, having a bunch of dirty bombs carrying radioactive fuel isn't particularly safe.

EDIT: I have often heard that the Fischer-Tropsch process was used by the Third Reich to synthesize fuel for its war machine during WW2. Although this scenario might seem plausible, it has been stressed in this question that Nation A does not possess a plethora of coal. And even with coal, the FT process is terribly inefficient, being at best, only meeting barely 10% of the war demand.

Answer 1

Biofuel.

With time to establish sufficient distributed infrastructure for the farming and manufacture of biofuels before the outbreak of war, it would be possible to break dependence upon fuels derived from mineral oil deposits.

While ethanol contains less energy per volume than an equivalent mineral fuel, methanol is also a potential biofuel with a higher energy density than ethanol but still lower than petrol/gasoline, as is butanol with a higher energy density than petrol/gasoline, which can supposedly be used as a direct replacement for petrol/gasoline in internal combustion engines.

Likewise, biodiesel fuels can largely or completely replace mineral diesel fuels without significant modification to diesel engines made to consume mineral fuel.

If the war and oil blockade was anticipated a number of years in advance of the war, it might be possible that A was able to establish sufficient biofuel production capacity and stockpile biofuel reserves sufficient to fight and win a war.

Answer 2

During WW2 the Germans created vast quantities of synthetic fuel using the Fischer Tropsch process: https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch_process

This helped them to avoid the blockade on oil as lignite coal can easily be used to generate the hydrogen and carbon monoxide required for the Fischer Tropsch process. Hundreds of thousands of tonnes of synthetic fuel were made during the war by these methods.

Answer 3

To me the obvious answer is electricity.

All you need to do turn a turbine, and charge batteries if you want to store it.

There are already bicycle powered turbines being used in the 3rd world.

Also, photo-electric solar is quite popular there, many remote villages have radio and satellite or even cell-phones powered by small 1-square foot solar panels, literally mounted on the roofs of grass huts and tents.

But there is also thermal-solar; which can be scaled to backyard sized up to acres. The idea here is to focus sunlight to create a heat source, very efficiently done with flat panel Fresnel lens, and apply the focused sunlight to a steam boiler (from tanker sized to palm held sized), that powers a steam engine to turn a turbine and generate electricity.

In 1980 we already had "closed cycle" steam engines; meaning the water never leaves the system as steam. Making the steam do work (turning the turbine) converts heat to work, cools the steam, it condenses and is returned to the boiler. This is actually more efficient, no residual heat energy is expended as spent steam in the air, it gets recycled as already hot water re-entering the boiler.

I am not sure but I think we already have lubricant-free steam engines in the 1980's, the pistons and cylinders are ultra-hard and ultra-polished and so finely fitted they need no oil or lubricant.

All of this stuff is 1980, or with the lubricant free steam engines, at least plausibly so. Fresnel lenses have been around forever. Although photoelectric panels are harder to make and require special materials; the thermal-solar and turbines are at least a century old and require no rare ingredients at all.

Iron, steel, copper, aluminum, and glass are extremely cheap and among the most plentiful ingredients on Earth. And for a bonus, this is non-polluting, no smoke or emissions.

You'd have to do some research on battery technology to store the electricity, but I doubt this is a show stopper in terms of fuel.

Many thermal solar farms in the world today use the heat during the day to melt down a form of salts, which is stored in a large underground tank, well insulated. The salts can remain molten for a week, and we loop pipes through it that carry the water we want to turn into steam, to extract that heat.

During the day, the thermal solar farm provides electricity to homes, and any excess is used to increase the heat of the salts in the tank. Any shortage due to overcasts, rain, night, etc, is made up for by the tanks.

The farms are designed large enough so that on sunny days, enough more than the expected 24 hour usage is generated while the sun is up, to more than cover the worst expected continuous shortages of sunlight.

P.S. In response to comments about slow charging or the limited capacity of batteries; I will also point out that electricity can be used to separate water (H2O) and compress it into tanks of liquid hydrogen and liquid oxygen; under pressure. This is literally rocket fuel. The energy loss in this conversion is significant (as opposed to just using the electricity directly), but the energy stored is actually over 3 times greater per kilogram stored, compared to gasoline. And don't forget, the electricity is free solar.

Gasoline has an energy density of about 45 megajoules per kilogram, while H + O, optimally combined, has an energy density of about 143 megajoules per kilogram. This would increase the range of tanks and aircraft for the same weight, and because the ignition thrust can be more powerful, it could increase the speed as well.

Answer 4

You specified 1980s which permits nuclear power to make synthetic fuel. While uranium is more common in some areas than others it's widely distributed, thus they can get it.

Fischer Tropsch is probably more efficient but even if they don't have coal they can make fuel.

Answer 5

If lacking in access to uranium, and we assume 1980s level of technology, then thorium as a fuel is possible. It's been tried with relative success. https://en.wikipedia.org/wiki/Thorium-based_nuclear_power#Germany,_1980s

Once a nation has access to nuclear power then synthesizing a number of fuels becomes possible. What may be obvious is synthesizing hydrocarbons using the Fischer Tropsch process. The preferred source of carbon in this case would be coal but anything relatively carbon rich should suffice. Wood and anything food related would likely be ruled out in war, they'd be far too valuable for making fuel. What might be suitable would be things like leaves fallen from trees, grass clippings, or any of a variety of plant matter that is largely considered a nuisance. Going overboard on this could be a problem long term, that plant matter is useful for building up soil suitable for growing food. The waste product from the fuel synthesis should be used as fertilizer, and perhaps some measures taken to control soil erosion that this plant matter would normally do.

Capture of CO2 from the air is possible for synthesizing hydrocarbons. This is an energy intensive process but if in a tight spot that is a compromise that might need to be made. Municipal sewage could be a place to source carbon for fuel synthesis, it would be a messy process but again this is war time.

A potential fuel to consider that doesn't require carbon is ammonia. https://en.wikipedia.org/wiki/Ammonia#Fuel

Fermenting plant matter into ethanol is an option. Again, I suspect food would be a valued resource so any traditional sources of ethanol (corn, grapes, etc.) is likely ruled out. Fermentation of cellulose rich matter like cornstalks, straw, grass clippings, sawdust, leaves, etc. is possible but not as easy as sugar rich matter that is typically used. This gets into my earlier concern of diverting plant matter from fertilizing and erosion control on crop lands. Ethanol as a fuel is not new, and has been used in wartime where petroleum is scarce many times through history. This is often a desperate move since it would impact food supplies in the short term (taking corn, grapes, or such) or long term (taking plant matter for fertilizer and erosion control). This could augment other fuel sources, and if done with care, the problems this creates could be minimal.

Don't rule out nuclear power for use in ships. If there is a navy involved then that is a huge consumer of fuel, and by building nuclear powered vessels that consumption goes away. Thorium might not be ideal but, again, this is war. The reactors would be larger and less efficient than those using highly enriched uranium as in naval reactors of the 1980s but not so much so that this is an impossibility. One possible type of reactor that might work is a fairly conventional heavy water reactor using solid fuel. There were molten salt reactor experiments in the 1960s and in wartime that technology might have been shoehorned into a ship for propulsion.

Thorium nuclear reactors need a "seed" fuel like enriched uranium-235 or plutonium to get the chain reaction going. The situation described tells me uranium and plutonium is rare, not nonexistent. Uranium exists as a salt in seawater so some can be produced by extraction from the sea, an energy intensive process but this is wartime. A nation seeking uranium mines for fuel will have nuclear reactors already and so should be able to breed plutonium from U-238 or breed U-233 from thorium. Thorium is a fairly common element in various sands and rock formations which means there should be some means to mine it. Mining for coal, iron, or most anything will have some thorium in the tails, and these tails could be processed for the thorium.

Answer 6

Maybe a boring answer, but the obvious answer is: Increase domestic oil production

A's domestic oil production is barely 15% of their demands.

They clearly have some known oil reserves, and more are likely to exist. They already have machinery for significant amount of oil production. They only need to replicate this equipment to use the known oil reserves faster, while also looking for new reserves.

Replicating existing, functional technology is bound to be easier and faster than transitioning to a new one.

Answer 7

Wood gas

https://en.wikipedia.org/wiki/Wood_gas

Wood gas vehicles were used during World War II as a consequence of the rationing of fossil fuels. In Germany alone, around 500,000 "producer gas" vehicles were in use at the end of the war. Trucks, buses, tractors, motorcycles, ships, and trains were equipped with a wood gasification unit. In 1942, when wood gas had not yet reached the height of its popularity, there were about 73,000 wood gas vehicles in Sweden,[3] 65,000 in France, 10,000 in Denmark, and almost 8,000 in Switzerland. In 1944, Finland had 43,000 "woodmobiles", of which 30,000 were buses and trucks, 7,000 private vehicles, 4,000 tractors and 600 boats.[4]

Wood gasifiers are still manufactured in China and Russia for automobiles and as power generators for industrial applications. Trucks retrofitted with wood gasifiers are used in North Korea[5] in rural areas, particularly on the roads of the east coast.

Answer 8

The easiest fuel to procure is the one you already own. So why not take a leaf out of the USA's book and have an equivalent of a Strategic Petroleum Reserve, but big enough to hold a year or two's worth of fuel, and then - and this is a crucial part - only go to war once you have filled it? ;)