Energy Production from Waste

[IvanZhidlovsky]

South America, with its agrarian societies, surprisingly consumes very few wastes for the production of steam or electricity. Brazil is the largest country in South America and is also the largest energy consumer, consuming about 8.5 quads of energy each year as compared to 6.1 quads for Mexico, 12.5 quads for Canada, and 97.0 quads for the United States. Due to the large size of Brazil's agricultural sector, biomass is seen as the best future alternative energy source. Currently, Brazil produces about 4,000 gigawatt (1 × 109) hours annually (i.e., 0.1 quads equivalent) in the sugar industry to run its own refineries and distilleries. At the same time, Brazil produces up to 3.9 billion gallons of ethanol (i.e., 0.5 quads equivalent) for automobiles each year, although it is manufactured from sugar and not waste materials. No other South American countries produce significant quantities of energy from waste; however, Argentina's biomass energy use, like Brazil's, is expected to grow in the coming years.

In the United States, corn is the primary feedstock along with barley and wheat that is currently being used to produce ethanol, although neither corn or grains are considered wastes. Considerable ongoing research is exploring the use of true waste treatment into wood pellets such as corn stover or wood chips and sawdust for ethanol production. One project at the U.S. Department of Energy involves the cofiring of sawdust and tires with coal in utility boilers.


I am wondering how vital is it for USA?

 

[dalcazar]

Brazil is pretty much the only country making good sense of renewable fuel production, they have completely mastered the art of fermenting molasses and other sugar byproducts into ethanol, which requires very little energy investment. This feedstock IS already waste. And the depeleted sugar cane from which the sugar has already been extracted is burned in boilers and power generating systems.

Turning wood and sawdust and corn stover into alcohol is a complete waste of time, you have to beat the celulose to a pulp and then digest it into sugars and then ferment it to ethanol, lots of chemicals and energy would go into that process.

Despite needing energy to start the process, all the solid waste you mentioned could be gasified into syngas in a wood gas generator, which can then be either burned straight or converted to liquid fuel thru a Fischer-Tropsch process. The technology is well known and mature and is much smarter than taking perfectly good FOOD and turning into a corrosive fuel additive that makes cars get worse gas mileage than they already do.

 

[bimr]

The feedstock that Brazil is using is not waste. In fact, Brazil is using a valuble commondity, the organic material in farmland to make ethanol. Once the soil's organic material is depleted through land farming, the soil's value for farming will be lost.

Use of waste material for energy is not vital at all in the US. Most waste materials have finite quantities and in an efficient market will find a suitable use. These materials are not currently being stockpiled.

The use of corn for ethanol is a good example of this. Demand for energy has driven up the cost of the finite supply of corn and the previous consumers of corn (syrup producers, feedlots, etc.) are now paying more for corn.