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Comment by codeulike | Hacker News Reader

boils down to this quote: In a world without readily mined coal, would there ever be the opportunity to test profligate prototypes of steam engines, even if they could mature and become more efficient over time? How feasible is it that a society could attain a sufficient understanding of thermodynamics, metallurgy and mechanics to make the precisely interacting components of an internal combustion engine, without first cutting its teeth on much simpler external combustion engines – the separate boiler and cylinder-piston of steam engines?

Although there are other potential energy sources, without easily mined coal lying around, no-ones ever going to have the resources to do enough trial-and-error engineering to get anywhere.

tldr: Easily mined coal is vital, just like day 1 minecraft.

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There is a lot of coal left:

"America has plenty of coal. Its mines produced 1.2 billion tons in 2006, nearly all of it destined for electricity generation.31 That was a record year, but it barely scratched the surface of U.S. recoverable coal reserves, which are estimated at about 270 billion tons."

http://www.nap.edu/reports/energy/supply.html

Perhaps. Depends how you define 'recoverable'. Could it be recovered without machinery that runs on oil?

You might want to google 'coal steam shovel'

Right, but the point is, all the easy coal was mined first. To get those enormous stockpiles, you need advanced tools.

The article thus asks: if we lost those tools, and the knowledge/infra to make them, would we have enough readily available energy to practice and re-discover them, given that you need those tools to get to the remaining energy?

There is (at present) still plenty of easily mined coal in the Powder River Basin in Wyoming. Think of a few feet of overburden, then a hundred feet of coal. That could easily be mined by human muscle power.

It's also worth remembering that proven reserves are thought of in the context of current and projected global population and consumption. The thought experiment begins with a "post-global calamity/collapse" situation, in which the total population is much, much smaller.

So even what we currently think of as "small" or "negligible" deposits might be more than enough for productive use within the now-smaller population.

Yes. Humans were converting wood to coal 15 000 years ago, it doesn't require any infrastructure at all. We have large forests in Europe, Canada and Russia that can be used relatively sustainably to produce vast amounts of energy for bootstrapping us up. During WW2 they even had internal combustion engines running off wood chips.

I can ride a bicycle to a coal deposit in about an hour and pick coal off the ground with my bare hands. There are plenty of easily mined coal deposits that have not been exhausted.

What matters is volume and economics. The amount of man-hours per tonne of coal extracted by modern mines is far, far lower than during the early phases of industrialization. And that means that some coal mines, even ones that are easily mined, are just not economically competitive in modern times. But they're still there, the coal's still there, it's still easy to get at.

Cool, so at the current burn and growth rates of electricity demand, we have ~100-200 years left?

As technology improves, the extent of "recoverable" expands.

E.g. shale oil was unrecoverable oil during the industrial revolution and through the mid-20th century.

Further, efficiency of utilization increases with technological advancement. I don't know about coal at this point in time, but I can guarantee you the coal-burning plants of today are getting more electricity per ton(?) of coal than a plant in the early 1900s.

I got 155yrs w/ a 3% growth rate of consumption

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