Ethanol Production

Ethanol

Typically, sugars are extracted from the biomass crop by crushing. This biomass is mixed with water and yeast and then kept warm in large tanks called fermenters. The yeast breaks down the sugar and converts it to ethanol. A distillation process is required to remove the water and other impurities from the dilute alcohol product, which is generally about 10%-15% ethanol. The concentrated ethanol (95% by volume with a single step distillation process) is drawn off and condensed back to a liquid form, which can be used as a supplement or substitute for petrol in spark ignition engines. Brazil has a successful, industrial-scale ethanol project, which produces ethanol from sugar cane for blending with petrol. In the USA, maize is used for ethanol production and then blended with gasoline to produce "gasohol”, which is usually E10 (10% ethanol and 90% petrol). Current internal combustion engines in cars require some engine modifications to run with a total petrol substitute.

Fluctuations in petroleum prices, coupled with the uncertainty in agricultural prices, make forecasting the relative production costs of fermented compared to petrochemical derived ethanol difficult. In general, the production of fuel alcohols from petroleum is cheaper than fermentation and extraction from biomass, but this is expected to change as fermentation and extraction processes become more efficient while petroleum becomes more expensive (Wikipedia, 2006).

Ethanol Production, Economics, Policy, Markets & Laws

Ethanol can be produced from certain biomass materials that contain sugars, starch or cellulose (see Table 1). The best-known feedstock for ethanol production is sugar cane, but other materials can be used, including sugar beet, Jerusalem artichokes, wood, wheat and other cereals. The choice of biomass is important, as feedstock costs typically make up 55 - 80% of the final alcohol selling price (World Energy Council, 1994). Starch-based biomass is usually cheaper than sugar-based materials, but requires additional processing. Similarly, cellulose materials, such as wood and straw, are readily available, but require expensive preparation. The lignin by-product, which is around 50% of the material, can be combusted to provide the energy to drive the process.

In ethanol production, there is a significant energy loss in the distillation stage, particularly the complex secondary distillation process required to achieve ethanol concentrations of 99% or better. This may be acceptable, however, due to the convenience of a liquid fuel, and the relatively low cost and maturity of the technology. The final cost of ethanol produced is currently being pushed below $1 per litre (some researchers are achieving small scale levels of $0.45 per litre Chandra M.J.) at present to assist ethanol competitiveness at the bowser.

Through the Information Portal, RISE provides networking services to assist people researching various renewable energy applications. There are many excellent decision-making and capacity building resources freely available for people to download provided by other quality institutions. Duplication of this information is unnecessary. In this This Information Portal, RISE has provided an excellent collection of resources that are directly applicable for your own sustainable solution to your fuel needs. Below is a list of excellent online ethanol resources, and a short description of each to assist in your search :

Australian Friends of Ethanol. This is a very good resource that includes such topics as greenhouse gases, oil imports, carbon monoxide, ozone, Kyoto targets, regional stimulation, emissions, sustainable agriculture, national security, fuel economy, car warranties, employment, etc. It looks at the ethanol industry with a wide scope of view and also includes news, information and FAQ's for ethanol blended automotive fuels.

The Queensland Government has provided the 2005 International Ethanol Conference Presentations in pdf format. This is an excellent resource and the topics include the current global situation, policies, economics, markets, fuel diversification, technology developments and production facilities, etc.

Journey to Forever – Make Your Own Ethanol. This is resource covers a large variety of introductory issues concerning ethanol's history, production and energy balance. In addition there are more links to alternative internet resources concerning small scale ethanol distillation, feedstock, effects on vehicles etc.

Wikipedia - Ethanol & Ethanol Fuel. The ethanol page contains comprehensive resources on the history, production and chemistry of ethanol. The ethanol fuel page covers the global fuel production, economics, energy balance, sources, fuel mixtures and environmental topics regarding ethanol fuels for vehicles.

US Department of Energy – Alternative Fuels - Ethanol. A good American resource. Includes such topics as ethanol markets, benefits, research, infrastructure, ethanol incentives, laws, publications, ethanol industry contacts etc.

Energy Information Administration – Ethanol. This resource includes papers that cover topics such as background, data, analysis and forecasts for ethanol use, production, performance and emissions characteristics and costs from a US perspective.

American Coalition for Ethanol (ACE). This website contains significant details on production, policy, research, marketing, technology relating to the American use of ethanol. A very well rounded resource.

Renewable Fuels Association - Ethanol (US). This is another great resource about ethanol and energy security, economics, production, policy, industry, etc.

Conclusion

There is a large potential for the application of ethanol to provide sustainable fuel supplies for distributed generation and regional energy security. Sustainably produced local crops converted for use as a renewable fuel to be used in existing engines, while utilising cyclical carbon from plants are all attractive benefits of ethanol use. However to compete economically there must be similar assistance and subsidies for ethanol that were offered to other industries in their development phase, such as LPG and other conventional fossil fuels.

Further Information

World Fuel Ethanol Analysis and Outlook, By Dr. Christoph Berg, April 2004. This is a very good article with excellent data sets for world production and trade. This article includes many details on national outputs, imports and exports relating to ethanol.

For further information on Biomass Technologies (Ethanol Production), see the RISE Information Portal Technologies Biomass File .

For further information on Waste to Energy Technologies (Fermentation), see the RISE Information Portal Technologies Waste to Energy File.

References

Wikipedia, 2006. "Ethanol" (Online, Accessed 13 July 2006).

World Energy Council, 1994. New renewable energy resources, Kogan Page, London.