What are the advantages and disadvantages of direct burning and alcohol production?

Answer 1

Direct burning of biomass is the most straightforward method of energy production. Mankind has burned wood and other forms of biomass for thousands of years, to keep warm, to cook food, and eventually to forge weapons and other tools.
The energy released by direct combustion takes the form of heat, and can be used to directly influence the temperature of a small environment or to power steam-driven turbines to produce electricity. Unfortunately, the burning of biomass is the cause of a great deal of pollution and has contributed to the so-called "greehouse effect" and global warming.
In alcohol fermentation, the starch in organic matter is converted to sugar by heating. This sugar is then fermented by yeast (as in the production of beer and wine). The resulting ethanol (also known as ethyl alcohol or grain alcohol) is distilled and then blended with another fuel. "Gasohol," the end product, has been used successfully in Brazil and the United States as an alternative to regular gasoline. The drawback to this method of biomass energy conversion is that the process itself requires the use of fossil fuels, and is therefore somewhat inefficient.