Two main types of biofuels are currently in use: bioethanol, sourced mainly from corn and sugarcane; and biodiesel, sourced mainly from soybean and oilseed rape.
To be viable alternatives, biofuels should provide a high net energy gain, have high environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies. In line with this, Jason Hill and colleagues of St. Olaf College, Minnesota, USA, examine the “Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels.” Their work appears in the latest issue of the Proceedings of the National Academy of Sciences.
By using current data on farm yields, commodity and fuel prices, farm energy and agrichemical inputs, production plant efficiencies, co-product production, greenhouse gas (GHG) emissions, and other environmental effects brought about by the use of corn grain ethanol and soybean biodiesel, researchers concluded that biodiesel is the more viable fuel alternative, at least in the US. In particular, they found that:
1) Bioethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more;
2) GHG emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel;
3) Biodiesel releases less air pollutants per net energy gain than ethanol;
4) Biodiesel has minimal impact on human and environmental health through nitrogen, phosphorous, and pesticide release; and
5) Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels.
"Source":[ http://www.checkbiotech.org/root/index.cfm?fuseaction=news&doc_id=13223&start=11&control=181&page_start=1&page_nr=101&pg=1]
The Long-Run Impact of Corn-Based Ethanol on the Grain, Oilseed, and Livestock Sectors with Implications for Biotech Crops -
The ongoing growth of corn–based ethanol production raises some fundamental questions about what impact continued growth will have on US and world agriculture (22.5.2007)
UN warns on impacts of biofuels -
A UN report warns that a hasty switch to biofuels could have major impacts on livelihoods and the environment (10.5.2007)
New variety of corn makes ethanol production for cars more cost effective -
Michigan State University researchers claim to have developed a new variety of corn that promises to make ethanol production for running cars, more cost-effective and efficient (9.5.2007)
New generation biofuels coming soon -
The credentials of biofuels might have been dented by claims that current production methods are inefficient, lead to deforestation and drive up food prices, but a German firm hopes to change all this with new technology (24.4.2007)
A new biofuel: propane -
While much of the attention on biofuels has focused on ethanol, the process developed by the MIT researchers produces propane, says Andrew Peterson, one of the graduate students who demonstrated the reactions (20.4.2007)
