H LV <[email protected]> wrote: I have heard the first synthetic fuel was made in 1925. Germany synthesized > fuel in WWII. >
The Germans converted coal to gasoline. That would not be a good idea today, but it might be good to use thermal depolymerization to convert sewage, garbage and plastic to liquid or gas fuel. You kill two bird with one stone, producing fuel and reducing waste at the same time. The fuel may not be cost effective but you save money on garbage disposal. The problem with this is that there isn't much garbage per capita. Take waste food, for example. Let us assume that people waste as much as they eat. That's unrealistically high, even when you include inedible parts of food such as banana peels. But anyway, suppose there is that much organic garbage. People consume 12,301 kJ of food per day (2940 kcal, http://large.stanford.edu/courses/2013/ph240/bechstein2/). That is 4,489 MJ per year. Convert all of that to gasoline and you get 100 kg, or 34 gallons. That is not enough for one person per year. In 2013, the average American consumed 392 gallons of gasoline. So that wouldn't even supply 10% of gasoline, and it would supply no electricity or heating. http://www.autonews.com/article/20150325/OEM06/150329911/average-u.s.-gasoline-usage-lowest-in-3-decades-study-says I expect the total caloric content of organic garbage is much lower than the caloric content of food, and I doubt the conversion to gasoline is 100% effective, so total production would be much less than 34 gallons per capita per year, even with a massive infrastructure devoted to that purpose. Still, it would produce a lot of energy in absolute terms. In the third world, it could have a large impact, as you see in this graph: https://www.globalpetrolprices.com/articles/52/ If you want a large amount of pollution-free synthetic fuel with today's technology, I think the best method would be to convert North American wind energy to hydrogen gas, or synthetic hydrocarbon gas, and send it by pipeline to population centers. I suppose the wind energy would be converted to electricity which might be sent to the population centers, and the fuel might be produced locally. I do not know which would be more cost effective. Wind power varies throughout the day, and it is sometimes quite low. This would not matter much, because over a large area, such as most of North Dakota, there is always some wind. Also because if the production of fuel fluctuated, it would not matter much. It would not add much to the cost. When the wind is low you might supplement it with nuclear power or some other cheap source. If you were to burn the hydrogen fuel to generate electricity, or use it in fuel cells, this would be a method of storing wind energy. It might be inefficient compared to batteries. It might be less cost effective. I wouldn't know. I think you would have to build up a fairly large infrastructure and see how prices fall before you would know. - Jed
