Biomass

By: Cem Ozcan

Biomass is a very important renewable energy source for the United States in the future. Since 2000, biomass has been the largest source of renewable energy for the United States, making up 47% of the renewable total and 4% of all energy sources. Biomass is also the only viable renewable alternative to oil as a liquid transportation fuel. Starting this year, ethanol (biomass in its fuel state) will be produced at a rate of about 4.4 billion gallons annually. Biomass will be very important as a renewable energy source.

What is it?

Biomass is a plant-derived material converted into fuels, chemicals and power. Some materials that are often used for biomass production are:

Agricultural residues such as bagasse, corn fiber, rice straws, hulls, and nut shells
Municipal waste, which is primarily paper products
Wood waste: sawdust, timber slash, and mill scrap
Energy crops like poplar and willow trees, switchgrass, elephant grass, and prairie bluestem corn husks and stalks used for biomass

Energy production via biomass produces no net greenhouse gases, and therefore does not add to global warming. Since plants "breathe" carbon dioxide, the carbon dioxide that is released is the same that would be released if the material was not being burned for fuel.

Ethanol and Biodiesel

Ethanol and biodiesel are two fuels combined with a small amount of petroleum to create a fuel that can be used in transportation vehicles. Ethanol is biodegradable, produces less pollutants and has a lower heating value (about 80,000 BTUs) than gasoline. The infrastructure for ethanol's widespread use is in place; all that is needed are several minor changes to engine designs, mainly the need to redesign oxygen sensors and have different seals in the fuel system. Today, about 1 in every 8 gallons of gasoline sold in America has 10% ethanol content. If implemented widely, this could drastically reduce the amount of greenhouse gases emitted every day by automobiles.

Ethanol is also known as ethyl alcohol, and its more prominent use is for the purpose of getting intoxicated. However, it can also be used as a fuel alternative to petroleum. Already, it is widely in use in the South American country of Brazil. In the United States 3.4 billion gallons of ethanol were used as fuel in 2004. This amount should only increase in the coming years with the sharp decline in amount of petroleum available. Also many states are beginning to ban the use of Methyl Tertiary Butyl Ether (MTBE), a very toxic gasoline additive, which will force increased use of ethyl fuels. There are currently 81 ethanol plants in the U.S. with another 16 planned for construction. To produce ethanol, these four steps must be followed:

1.Producing biomass results in the fixing of atmospheric carbon dioxide into organic carbon.
2.Converting this biomass to a useable fermentation feedstock (typically some form of sugar) can be achieved using a variety of different process technologies. These processes for fermentation feedstock production constitute the critical differences among all of the bioethanol technology options.
3.Fermenting the biomass intermediates using biocatalysts (microorganisms including yeast and bacteria) to produce ethanol in a relatively dilute aqueous solution is probably the oldest form of biotechnology developed by humankind.
4.Processing the fermentation product yields fuel-grade ethanol and byproducts that can be used to produce other fuels, chemicals, heat and/or electricity.
With new technologies, many more biomass products can be used to produce ethanol. Among them are industrial waste, municipal waste, trees, and grasses. A possible problem with the use of ethanol fuel is that it is essentially the same alcohol that many use to get drunk. People worried that gas stations would become a place to fill one's belly instead of one's gas tank. The clever solution to this problem was to insert a small amount of petroleum into the ethanol, making the mixture unfit to drink.

Diesel fuel is widely in use in large automobiles: tractor trailers, 18-wheelers, and the like. It is also a large pollutant that emits large amounts of toxic and greenhouse gases. Biodiesel is an intriguing prospect that greatly reduces upon the emissions of standard diesel. Biodiesel is produced by transforming animal fat or vegetable oil with alcohol. Not only can it be used as a straight alternative for standard diesel fuel, but biodiesel can also be used as an additive. The additive is an oxygenate and usually around 20% biodiesel. It is currently the only alternative fuel that does not require the purchase of a new vehicle designed specifically for its consumption. Biodiesel is mainly made from canola oil, soybean oil, or grease recycled from restaurants.

Due to the fact that biodiesel is oxygenated, the prevalence of air toxins, carbon monoxide, soot, small particles, and hydrocarbons will essentially be halved if pure biodiesel were to replace standard diesel. If this pure biodiesel were to be used, several modifications will be needed in car engines. Extra care would be needed in colder climates, and many materials produced pre-1994 would need replaced.

There have also been experiments into blending ethanol and diesel. This blend contains anywhere from 8 to 15% ethanol and 5% special additives that prevent the ethanol and diesel from separating at low temperatures, eliminating the problem stated above, or in the case of water contamination. The slight loss in miles per gallon is negated by the drastic decline of toxic emissions of particulate matter, carbon monoxide, and nitrogen oxides. Some believe that the rise of this E-Diesel, as it is called, will force engine manufacturers to quickly redesign their engines. Currently they are able to drag their feet and the redesigning process could take up to ten years.

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