Looking to the Future: Cellulosic Ethanol

While there are clear benefits in alternative sources of energy such as ethanol, its future as a viable competitor to oil remains uncertain due to number of concerns that range from environmental trade-offs, economic competitiveness, sustainability, etc. One major stumbling block for the ethanol industry is the extent to which the land intensity of current biofuel production can be reduced. While to be competitive with oil, current rates of production need to increase significantly, such a huge increase is not viable due to present intensity of land use. The good news is that cellulosic ethanol is an alternative energy resource that can potentially resolve this issue, and significantly reduce world’s dependence on oil with less negative consequences for the environment than other sources of energy.

What is Cellulosic Ethanol?

Cellulosic Ethanol is alcohol made from tough plant stems, leaves and trunks instead of supple starch. Unlike corn and sugar – the plants now used to make most ethanol – cellulose is not used for food, and it can be grown in all parts of the world. Cellulosic ethanol is expected to be less expensive and more energy-efficient than today’s ethanol because it can be made from low-cost feedstocks, including sawdust, forest thinnings, waste paper, grasses, and farm residues (e.g., corn stalks, wheat straw, and rice straw). The main advantage of cellulose is its abundance. In fact, it is estimated that cellulose makes up half of all the organic carbon on earth. Research shows that cellulosic ethanol could raise per acre ethanol yields to more than 1,000 gallons, significantly reducing land requirements. In the U.S., ethanol production from corn is expected to hit a limit of 15 to 20 billion gallons per year. Additional feedstocks are required to replace a larger share of gasoline demand, which is currently running at 140 billion gallons per year.

One of those feedstocks – Georgia’s pine forests – provides a prolific source for the production of cellulosic ethanol. For Range Fuels, Inc., a cellulosic ethanol company funded by Khosla Ventures, LLC, forestry waste or unmerchantable timber left behind by the forest industry will become the feedstock for cellulosic ethanol.


Advantages and Disadvantages of Cellulosic Ethanol

One major advantage of cellulosic ethanol is that it does no require fossil fuels for production, which makes for less greenhouse gas emissions. Moreover, cellulotic ethanol has low energy input to produce and a high energy output; the waste generated from production can be recycled; and it has the potential to cost dramatically less than corn-based ethanol. As an additional benefit, many of the crops used in the production of cellulosic ethanol are perennial crops. This means that they do not have to be replanted every year, and they use fewer fertilizers and pesticides than corn, which run off in to rivers and lakes, causing less water pollution.

One major disadvantage of cellulosic ethanol production is prohibitively high cost, which is now higher than both the cost of producing corn ethanol and oil. For example, U.S. cellulosic fuel production costs are now estimated at more than $2.50 per gallon, compared with $1.65 per gallon for corn ethanol. Because of the perceived potential benefits, venture capital and government subsidies are currently supporting companies interested in making cellulosic ethanol commercially viable. Research and improvement of the efficiency of cellulotic ethanol production is currently being funded in the United States, Canada, Brazil, China, Japan, and Spain.

Other Considerations

In the meantime, other costs of cellulosic ethanol production need to be fully assessed, such as the impact of harvesting grasses, trees, and crop residues on the erodibility and fertility of land resources. There are also questions regarding the upfront and environmental costs of harvesting, transporting, and storing large volumes of bulky feed-stock used in processing. Overall, while there are many clear benefits that cellulosic ethanol can offer, the budding industry has to clear many technical and economic hurdles before we will see it at the gas pump.

About Author: This article was written by Yelena G – Follow Yelena on Google+

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