Steampunk Tech Without Fossil Fuels

[AlexanderHowl]

A good rule of thumb is that a society as advanced as the early 1800s (mid-TL5) needs 20 acres of forested woodlands or 5 acres of coppiced woodlands per household (translating to 4 acres of forested woodlands or 1 acre of coppiced woodlands per person). The difference between the two is that forested woodlands required around 1/20 the labor of arable land under cultivation while coppiced woodlands required around 1/4 the labor of arable land under cultivation. The advantage that coal provided was that you could use much less land and much less labor to produce energy, meaning that you could use the land and labor for food production instead of energy production (watermills and windmills are useful for energy production, but they are power plants, not portable fuel).

Without coal, steam with not replace sail, as the endurance and speed of steam ships will be inferior. There is also less need for early steam, as the first steam engines powered pumps that kept coal mines dry, so steam is unlikely to develop beyond the most primitive of engines. Instead of a steampunk world, you end up with a world that does not really progress beyond TL5 in the material sciences, though it could develop a divergent technology based around advanced biological sciences, advanced ceramics, advanced glasses, etc.

[mlangsdorf]

Some rough numbers for comparison:
A TL6 tank with DR 180 front armor, DR 90 on the sides, and DR 40 on all other faces, a 4 person crew, a light 75mm howitzer, 4 hours of fuel, and a 200 kW diesel engine weighs roughly 24 tons with a max speed of 31 mph.

Replacing the diesel engine with a triple expansion steam engine burning diesel increases the weight to 41 tons and reduces the speed to 24 mph. The weight increase is split evenly among doubling the hull volume to fit in the larger engine, heavier armor to cover the increased surface area, and a much heavier engine.

Burning coal instead of diesel increases the weight to 44 tons and reduces speed to 23 mph.

Burning charcoal instead of coal increases the weight to 51 tons and reduces speed to 21 mph.

Burning charcoal briquettes instead reduces the weight to 49 tons and improves speed to 21.6 mph.

Burning a mix of charcoal and charcoal briquettes reduces weight to 44 tons and improves speed to 23 mph - the difference between the mix and coal doesn't really show up.

So performance wise, a society that went for steam engines using intelligently designed charcoal systems shouldn't see too much of a performance difference between the same society using coal. But as AlexanderHowl points out, it's going to have to devote a huge amount of land and labor to making charcoal.

Steam powered ships don't have to deal with the wind, and that's such a large advantage that I suspect any navy is going to want that, even if the charcoal steamers are slower than the sailships under good wind conditions.

* Per my Vehicles 2e spreadsheet.

[AlexanderHowl]

I think that math is off for the briquettes. Briquettes are bricks of fuel made from coal ash, bio waste, wood scrap, etc, and have 50% to energy content of charcoal per mass (15 MJ/kg versus 30 MJ/kg if you are not including oxygen mass). Vehicles using any amount of briquettes should have worse performance than charcoal (charcoal possesses around the same energy per mass as coal, it just is much less dense). The advantage of briquettes is that they are made from waste, so they are cheap and plentiful.

[Not]

Unlimited slave labor and superscience frictionless flywheels or hyperefficient wind-ups.

[whswhs]

Originally Posted by Not

Unlimited slave labor and superscience frictionless flywheels or hyperefficient wind-ups.

This is why one of the timelines in GURPS Steampunk had an "industrial revolution" based on the large-scale creation of golems.

[PTTG]

You could do some interesting stuff with solar concentration, or have enchantments that produce heat. Maybe you can convince the Sun God to provide intense lasers directly onto your boilers.

Other magical solutions include a tree with magically combustive wood, a single small hunk of firewood burning for days, or such.

I wouldn't say it's impossible to get past TL4 without fossil fuels. Longer, yes, but you don't REALLY need oil to make ICs or even photovoltaics.

[tshiggins]

I'd go with the biofuels option, myself. Maybe some version of hyper-cannibinoids that produce highly volatile oils?

[Varyon]

Originally Posted by AlexanderHowl

I think that math is off for the briquettes. Briquettes are bricks of fuel made from coal ash, bio waste, wood scrap, etc, and have 50% to energy content of charcoal per mass (15 MJ/kg versus 30 MJ/kg if you are not including oxygen mass). Vehicles using any amount of briquettes should have worse performance than charcoal (charcoal possesses around the same energy per mass as coal, it just is much less dense). The advantage of briquettes is that they are made from waste, so they are cheap and plentiful.

Fuel on board a vehicle doesn't just take up mass, it takes up volume. The more volume something takes up, the more surface area it is going to have, and thus the heavier its armor is going to be. In the case of mlangsdorf's steamtank, the added volume of using raw charcoal makes the armor heavy enough to more than negate the mass advantage raw charcoal has over briquettes.


As for steampunk without fossil fuels, you may want to fall back on superscience or magic*. It's simply too labor-intensive to produce enough portable fuel otherwise. Something like clockpunk would be doable, of course, with your gears and springs being wound by water/windmills, animal (including human) power, and so forth. There may be some stationary steam facilities, tapping into geothermal/volcanic power, or even just using less mass/volume efficient fuel, but steamtanks don't seem likely.

*It occurs to me that RTG's might be an option, but I'm not certain those really produce enough heat to be usable with a steam mechanism, and they seem too advanced for a steam era society to produce (or even conceive of). You might be able to justify some sort of "hot rocks" - naturally occurring bundles of radioactive material that can be used as the basis for RTG's - but that strikes me as highly improbable, and to your players (and, arguably, the characters) will probably just look like magic. I mean, really, there's not much difference between "There are magical but poisonous rocks that boil water" and "There are rocks with an improbable quantity of (say) uranium that boil water," particularly when the characters are going to have no idea what it is that makes the rocks special, only that a) they boil water and b) spending too much time around them makes you really sick.

[warellis]

I imagine such a setting would not be able to advance to space due to lack of fossil fuels?

[Anthony]

Originally Posted by warellis

I imagine such a setting would not be able to advance to space due to lack of fossil fuels?

Same as everything else -- alternatives exist, they're just more expensive.