Comment by hermitShell
6 days ago
In N Stephensons “Anathem” there are “fuel trees” and a couple paragraphs describing how they are ‘cooked’ for hydrocarbon fuels. I like trees and his vision of a future where genetically modified trees are the best way to collect solar energy and then harvest and store it. Solar panels are cool but one of the themes of the book is civilization over many millennia, and I can see how he arrived at his conclusion that most tech doesn’t work as well as trees.
Sounds like that isn't far from the truth. Cooking wood in an anoxic environment creates wood gas and charcoal. Wood gas can be burned as it comes out of the retort or can be refined into methanol and other hydrocarbon fuels. The charcoal product is a high quality activated charcoal. That can also be burned as fuel or charged and put back in the ground as biochar.
Indeed charcoal fueled the early stages of the industrial revolution, and its massive production was one of the primary reasons Western Europe lost most of its forest cover. As wood became scarce, charcoal was replaced by the more difficult to extract coal and lignite.
One can get about twice the liquid fuel from wood by reacting it with hydrogen than one can get from the wood itself. Wood is (simplistically) carbohydrates. So, C(H2O) + H2 --> CH2 + H2O. This treats wood more as a carbon carrier than an energy carrier.
There aren't enough trees to support industrial civilization. Britain was burning coal before the Industrial Revolution and would have quickly exhausted all land for wood. Wood is useful for other things, buildings and paper would compete with fuel. It is the same problem with turning food crops into fuel.
Solar doesn't require high tech. We use solar panels cause we are good at making circuits. But solar thermal with mirrors should work for lower technology. They wouldn't have the chips for controlling mirrors, but could have some system of central control or just have people move them.
There aren’t enough trees in Britain, that’s for sure! In places with lots of trees and not a lot of people, wildfires burn off a considerable amount of energy stored in dead wood. Canada, for example.
It does work, but the problem is gasoline has distorted our view on how much energy we are actually using. Most people would shrug at using a single gallon of gas to drive to the store. But telling them they gotta cut down an entire tree just to drive to the corner store doesn't fly as well. Of course if we used all the energy in the tree instead of just what can be distilled off it would reduce the amount used quite a lot, but nobody is going to switch to steam boiler powered cars that they gotta fire up 45 minutes before hand.