by Subjectivist » Tue 25 Mar 2014, 08:22:19
$this->bbcode_second_pass_quote('pea-jay', 'I') keep thinking that coal, as currently utilized will not be the fallback energy source that everyone thinks it will be, especially in places that have long extracted and utilized the substance. Why? Because we already use a crap load of oil to get at the coal seam. Look at modern coal operations in many countries. Huge equipment is required. In Appalachia they bulldoze entire mountains to get at the seam. From an energy stand point, thats a huge expenditure to move a lot of rock to get at a relatively small resource. For deep operations, great big lifts are required to bring the coal to the surface. Again, thats a lot of energy is expenditure.
Now fast forward to an energy poor future. Where will all of that energy needed to extract the coal come from? Continued reliance on oil (diesel) will force the cost of the coal upwards like the cost of the fuel the equipment requires. Plus eventually, the decision will eventually have to be made what other use will have to go without (when continuing declines) leave less fuel supplied than can be produced. Plus for oil importing nations with coal deposits, where will the funds come from to pay for the oil to get the coal.
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Coal certainly can't be extracted by coal derived synthetic oil. The process usually consumes more energy than it produces and even if it is positive, it is barely so. Now taking that syncrude, converting it to diesel to put into the equipment to run...well that sounds like an energy black hole.
Now, if the coal is extracted by human power and then burnt, maybe. From what I have read, alot of Chinese mines are largely human powered (which also explains their high fatality rate, too). But that's just one country. We already mined the most easily accessed coal supplies by human power more than a hundred years ago. Heck, even the number of machine driven (but people run) deep coal operations in this country have dwindled in favor of the large surface mining pits. If we have to go back to human powered operations of the mid 1900s or late 1800s how in the world are we going to produce at the current level of production, let alone increase to meet this anticipated increase in demand for coal.
Maybe I am missing something. But I don't think conventional coal production is going to cut it, post peak.
What about non conventional? This I am not so sure about. If scientists are sucessful enough, perhaps they could figure out how to get at the coal unconventionally. I certainly hope not. From what I have read though, so far no efforts have been successful (commercially) to date. Specifically I am refering to Underground Coal Gassification, but it could be anyother mean of accessing coal without conventionally mining it.
I think the jury is still out on that one.
ROCKMAN, there used to be a lot of talk about coal seam gassification underground. Basically as I understand it they would take played out coal bed methane wells and inject a mixture of oxygen and high temperature steam. The oxygen would burn the coal and the heat would break down the steam into hydrogen gas and oxygen that would also burn coal. Out the other end a recovery well would extract hydrogen and carbon monoxide with some carbon dioxide and water vapor. This mix would feed into a synfuel plant to be converted into methane or liquid fuels.
There was a proposal for one of those up in mid Michigan in the Aughts, aparently the coal there is in thin layers so it is more expensive to mine than it is worth when competing with really thick coal beds in the western states, but when th 2008 crash happenned everything went quiet.
Are these just pie in the sky ideas or is there a real possibillity these things could be money makers and get built?