- Second generation biofuels
Biofuel technologies are able to manufacture
biofuels from biomass. Biomass is a wide-ranging term meaning any source of organic carbon that is renewed rapidly as part of the carbon cycle. Biomass is all derived from plant materials but can include animal materials.
Second generation biofuel technologies have been developed because
first generation biofuelsmanufacture has important limitations. First generation biofuel processes are useful, but limited: there is a threshold above which they cannot produce enough biofuel without threatening food supplies and biodiversity. They are not cost competitive with existing fossil fuels such as oil, and some of them produce only limited greenhouse gasemissions savings. When taking emissions from production and transport into account, life-cycle emissions from first-generation biofuels frequently exceed those of traditional fossil fuels.
Second generation biofuels can help solve these problems and can supply a larger proportion of our fuel supply sustainably, affordably, and with greater environmental benefits.
bioethanolis produced by fermenting plant-derived sugars to ethanol, using a similar process to that used in beerand wine-making. This requires the use of 'food' crops such as sugar cane, corn, wheat, and sugar beet. These crops are required for food, so if too much biofuel is made from them, food prices could rise and shortages might be experienced in some countries. Corn, wheat and sugar beet also require high agricultural inputsin the form of fertilizers, which limit the greenhouse gasreductions that can be achieved.
The goal of second generation biofuel processes is to extend the amount of biofuel that can be produced
sustainablyby using biomass comprised of the residual non-foodparts of current crops, such as stems, leavesand husks that are left behind once the food crop has been extracted, as well as other crops that are not used for food purposes ( non food crops), such as switch grass, jatrophaand cereals that bear little grain, and also industry waste such as wood chips, skins and pulpfrom fruit pressing, etc.
The problem that second generation biofuel processes are addressing is to extract useful feedstocks from this woody or fibrous biomass, where the useful sugars are locked in by lignin and cellulose. All plants contain
celluloseand lignin. These are complex carbohydrates (molecules based on sugar). Lignocellulosic ethanolis made by freeing the sugar molecules from cellulose using enzymes, steam heating, or other pre-treatments. These sugars can then be fermented to produce ethanol in the same way as first generation bioethanolproduction. The by-product of this process is lignin. Lignin can be burned as a carbon neutralfuel to produce heat and power for the processing plant and possibly for surrounding homes and businesses.
The greenhouse gas emissions savings for lignocellulosic ethanol are greater than those obtained by first generaiton biofuels. Lignocellulosic ethanol can reduce greenhouse gas emissions by around 90% when compared with fossil petroleum [http://ies.jrc.ec.europa.eu/wtw.html Concawe Well to Wheels LCA.]
An operating lignocellulosic ethanol production plant is located in Canada, run by IOGEN Corporation [http://www.iogen.ca/ IOGEN] . The demonstration-scale plant produces around 700,000 litres of bioethanol each year. A commercial plant is under construction. Many further lignocellulosic ethanol plants have been proposed in North America and around the world.
In the future, there might be bio-synthetic liquid fuel available. It can be produced by the
Fischer-Tropsch process, also called Biomass-To-Liquids (BTL). [ [http://www.senternovem.nl/mmfiles/Status_perspectives_biofuels_EU_2005_tcm24-152475.pdf Status And Perspectives of Biomass-To-Liquid Fuels in the European Union] (PDF).]
The following second generation biofuels are under development:
Biohydrogen. Biohydrogen is the same as hydrogenexcept it is produced from a biomass feedstock. This is done using gasification of the biomass and then reforming the methane produced, or alternatively, this might be accomplished with some organisms that produce hydrogen directly under certain conditions. BioHydrogen can be used in fuel cellsto produce electricity.
BioDME. Bio-DME, Fischer-Tropsch, BioHydrogen diesel, Biomethanol and Mixed Alcohols all use syngasfor production. This syngas is produced by gasificationof biomass, however, it can be produced much easier from coal or natural gas, which is done on very large scales in power plants and in gas-to-liquid processes.Fact|date=December 2007 HTU (High Temperature Upgrading) diesel is produced from particularly wet biomass stocks using high temperature and pressure to produce an oil.is the same as DME but is produced from a bio-sources. Bio-DME can be produced from Biomethanol using catalytic dehydration or it can be produced from syngas using DME synthesis. DME can be used in the compression ignition engine.
Biomethanol. Biomethanol is the same as methanolbut it is produced from biomass. Biomethanol can be blended with petrol up to 10-20% without any infrastructure changes. [ [http://www.refuel.eu/biofuels/biomethanol/ Refuel.com biomethanol] ]
* DMF. Recent advances in producing DMF from
fructoseand glucoseusing catalytic biomass-to-liquidprocess have increased its attractiveness.
* HTU diesel. HTU diesel is produced from wet biomass. It can be mixed with fossil diesel in any percentage without need for infrastructure. [ [http://www.refuel.eu/biofuels/htu-diesel/ Refuel.com HTU diesel] ]
Fischer-Tropsch(FT) fuels. FT diesel is produced using the Fischer-Tropsch gas-to-liquids technology. FT diesel can be mixed with fossil dieselat any percentage without need for infrastructure change.
* Mixed Alcohols (i.e., mixture of mostly ethanol, propanol and butanol, with some pentanol, hexanol, heptanol and octanol). Mixed alcohols are produced from
syngaswith catalysts similar to those used for methanol. Most R&D in this area is concentrated in producing mostly ethanol. However, some fuels are marketed as mixed alcohols (see Ecalene). [http://www.powerenergy.com/] [ [http://www.standardalcohol.com/biofuel.htm Biodegradable Fuel for a cleaner Earth ] ] Mixed alcohols are superior to pure methanol or ethanol, in that the higher alcohols have higher energy content. Also, when blending, the higher alcohols increase compatibility of gasoline and ethanol, which increases water tolerance and decreases evaporative emissions. In addition, higher alcohols have also lower heat of vaporization than ethanol, which is important for cold starts. (For another method for producing mixed alcohols from biomass see bioconversion of biomass to mixed alcohol fuels)
* Wood diesel A new biofuel was developed by the
University of Georgiafrom woodchips. The oil is extracted and then added to unmodified diesel engines. Either new plants are used or planted to replace the old plants. The charcoal byproduct is put back into the soil as a fertilizer. According to the director Tom Adams since carbon is put back into the soil, this biofuel can actually be carbon negative not just carbon neutral. Carbon negative decreases carbon dioxide in the air reversing the greenhouse effect not just reducing it.
On the other hand, Biofuels from non-food energy crops that can be grown on marginal land (as
Jatropha) and use salt waterare considered second generation biofuels and are nowadays available in mass production.
USDOEhas announced [http://www.energy.gov/news/6525.htm] that it has selected six university-led advanced biofuels projects to receive up to $4.4 million, subject to annual appropriations. The awardees— Georgia Tech Research Corporation, the University of Georgia, the University of Maine, Montana State University, Steven's Institute of Technologyin New Jersey, and the University of Toledoin Ohio—will all receive funding to conduct research and development of cost-effective, environmentally friendly biomass conversion technologies for turning non-food feedstocks into advanced biofuels. Combined with a university cost share of 20%, more than $5.7 million is slated for investment in these projects.
Most of the projects will involve
microbiology, including the University of Georgia and Montana State University projects, which are both focused on producing oils from algae. The University of Georgia will investigate the use of poultry litter to produce low-cost nutrients for algae, while Montana State, in partnership with Utah State University, will research the oil content, growth, and oil production of algae cultures in open ponds. Applying microbiology to biomass conversion, the University of Maine will study the use of bacteria to create biofuels from regionally available feedstocks, such as seaweed sludge and paper mill waste streams, while the University of Toledo will attempt to use pellets containing enzymes to efficiently convert cellulosic biomass into ethanol.
In contrast, Georgia Tech Research Corporation and Steven's Institute of Technology are both investigating the
gasification of biomass. Georgia Tech will evaluate two experimental gasifiers run on forest residues, while Steven's Institute will test a novel microchannelreactor that gasifies pyrolysis oil, a petroleum-like oilproduced by exposing biomass sources such as wood chips to high temperatures in the absence of oxygen. Gasified biomasscan be used as a gaseous fuel or passed through a catalystto produce a wide range of liquid fuels and chemicals.
Algae fuel, described as the third generation biofuels.
Cellulosic ethanol commercialization
Food vs fuel
* [http://www.nnfcc.co.uk The National Non-Food Crops Centre]
Wikimedia Foundation. 2010.
Look at other dictionaries:
Biofuels-The Next Great Source of Energy? — ▪ 2008 by Clarence Lehman A boom in the production of biofuel was under way in 2007, especially in the United States, where in January about 75 refineries for producing the biofuel ethanol from corn (maize) were being built or expanded. This… … Universalium
Issues relating to biofuels — There are a number of issues relating to biofuels.Biofuels are proposed as having such benefits as: reduction of greenhouse gas emissions, reduction of fossil fuel use, increased national energy security, increased rural development and a… … Wikipedia
Carburants verts de deuxième génération — Biocarburant La canne à sucre peut être utilisée pour produire des agrocarburants. Un biocarburant ou agrocarburant est un carburant produit à partir de matériaux organiques non fossiles, provenant de la biomasse. Il existe actuellement deux… … Wikipédia en Français
Biofuel — Information on pump regarding ethanol fuel blend up to 10%, California … Wikipedia
Food vs fuel — is the dilemma regarding the risk of diverting farmland or crops for biofuels production in detriment of the food supply on a global scale. The food vs. fuel or food or fuel debate is internationally controversial, with good and valid arguments… … Wikipedia
Chemrec — AB Type Venture backed private Industry Black liquor gasification and biofuels Genre … Wikipedia
Cellulosic ethanol commercialization — can contribute to a successful renewable fuels future. Companies such as Iogen, Broin, and Abengoa are all building refineries that can process biomass and turn it into ethanol, while companies such as Diversa, Novozymes, and Dyadic are producing … Wikipedia
Cumberland School of Law's Center for Biotechnology, Law, and Ethics — The Center for Biotechnology, Law, and Ethics … Wikipedia
David King (scientist) — For other people named David King, see David King (disambiguation). Sir David King Born August 12, 1939 (1939 … Wikipedia
Corn ethanol — Corn is the main feedstock for the production of ethanol fuel in the U.S. See also: Ethanol fuel in the United States Corn ethanol is ethanol produced from corn as a biomass through industrial fermentation, chemical processing and distillation.… … Wikipedia