Michael Foster writes:
"One other thing. I seem to remember Jed saying that burning all the biomass on earth wouldn't feed our present energy consumption . . ."
I was quoting Pimentel & Pimentel (P&P), "Food, Energy and Society." The statement applies to the United States. I do not know about other countries. Some have much lower energy consumption so perhaps they supply their needs with biomass.
P&P, Fig. 3.1 shows that all agricultural crops and forests in the US could supply roughly 20 percent of the energy we now derive from fossil fuels, and all plant growth in the U.S. could supply around 55 percent. In other words, if we stop eating and building houses, and burn every scrap of farm and forestry products, it will supply one-fifth of the energy we get from coal and oil.
". . . and that it takes more petroleum product to make energy from agriculturally produced fuels than from the petrolem directly; i.e., it takes two gallons of petroleum product to make the biomass energy equivalent of one gallon of petroleum."
It is about 1.2 to 1.5 gallons. See P&P, p. 263: "Even when the energy in byproducts is included, the energy output from ethanol production ranges from 8,700 BTU to 108,000 BTU per gallon, compared with more than 131,000 BTU required for production." There are other, equally serious problems with this. The mechanized agricultural production used to grow corn in the U.S. is destroying the water table, and eroding the land at a rate 18 times faster than it can be reformed. In other words, corn -- as it is grown in the U.S. -- is not a renewable resource. Once we run out of land and destroy the aquifers, we will not be able to grow more corn -- or anything else.
Despite all that, the proposals by Sparber and others to convert organic waste into fuel oil have great merit. They kill two birds with one stone: they reduce noxious, dangerous waste, and they produce a significant amount of fuel. They are like geothermal energy: they can only supply a tiny fraction of the total energy we consume, but it would still be enough to meet the needs of millions of people.
As far as I know, the only alternative energy sources large enough to meet present US consumption would be wind and solar energy (which are actually the same thing), and nuclear fission. US per capita consumption could be reduced by something on the order of 50% to 80% without impoverishing or seriously inconveniencing anyone. On the contrary, this reduction would actually make life much more convenient, and it would save thousands of dollars per person. But even if consumption were reduced by 80%, I doubt that other alternative energy sources such as biomass, geothermal, or Ocean Thermal Energy Conversion (OTEC) could meet more than a few percent of U.S. demand.
Futuristic energy sources large enough to meet all demand include space-based solar energy, plasma fusion, advanced fission (such as the Beene Gaia reactor), and cold fusion. There may be others such as the Mills effect or ZPE, but there is no widespread agreement among experts that these even exist.
- Jed
