Biofuel
From Wikipedia, the free encyclopedia
Biofuels are a wide range of fuels which are in some way derived from
biomass. The term covers
solid biomass,
liquid fuels and various
biogases.
[1] Biofuels are gaining increased public and scientific attention, driven by factors such as
oil price spikes, the need for increased
energy security, and concern over
greenhouse gas emissions from
fossil fuels.
Bioethanol is an
alcohol made by
fermenting the sugar components of plant materials and it is made mostly from
sugar and
starch crops. With advanced technology being developed,
cellulosic biomass, such as trees and grasses, are also used as
feedstocks for ethanol production. Ethanol can be used as a fuel for vehicles in its pure form, but it is usually used as a
gasoline additive to increase octane and improve vehicle emissions. Bioethanol is widely used in the
USA and in
Brazil.
Biodiesel is made from
vegetable oils,
animal fats or recycled greases. Biodiesel can be used as a fuel for vehicles in its pure form, but it is usually used as a
diesel additive to reduce levels of particulates,
carbon monoxide, and
hydrocarbons from diesel-powered vehicles. Biodiesel is produced from oils or fats using
transesterification and is the most common biofuel in Europe.
Biofuels provided 1.8% of the world's transport
fuel in 2008. Investment into biofuels production capacity exceeded $4 billion worldwide in 2007 and is growing.
[2]
[edit] Liquid fuels for transportation
Most transportation fuels are liquids, because vehicles usually require high
energy density, as occurs in liquids and solids. High
power density can be provided most inexpensively by an
internal combustion engine; these engines require clean burning fuels, to keep the engine clean and minimize
air pollution.
The fuels that are easiest to burn cleanly are typically liquids and gases. Thus liquids (and gases that can be stored in liquid form) meet the requirements of being both portable and clean burning. Also, liquids and gases can be pumped, which means handling is easily mechanized, and thus less laborious.
[edit] First generation biofuels
'First-generation biofuels' are biofuels made from sugar, starch, vegetable oil or animal fats using conventional technology.
[3] The basic feedstocks for the production of first generation biofuels are often seeds or
grains such as
sunflower seeds, which are pressed to yield vegetable oil that can be used in biodiesel, or
wheat, which yields starch that is fermented into bioethanol. These feedstocks could instead enter the animal or human food chain, and as the global population has risen their use in producing biofuels has been criticised for diverting food away from the human food chain, leading to food shortages and price rises.
The most common biofuels are listed below.
[edit] Bioalcohols
Main article:
Alcohol fuelBiologically produced
alcohols, most commonly
ethanol, and less commonly
propanol and
butanol, are produced by the action of
microorganisms and
enzymes through the fermentation of sugars or starches (easiest), or cellulose (which is more difficult).
Biobutanol (also called biogasoline) is often claimed to provide a direct replacement for gasoline, because it can be used directly in a gasoline engine (in a similar way to biodiesel in diesel engines).
Ethanol fuel is the most common biofuel worldwide, particularly
in Brazil.
Alcohol fuels are produced by fermentation of sugars derived from
wheat,
corn,
sugar beets,
sugar cane,
molasses and any sugar or starch that
alcoholic beverages can be made from (like
potato and
fruit waste, etc.). The ethanol production methods used are
enzyme digestion (to release sugars from stored starches), fermentation of the sugars,
distillation and drying. The distillation process requires significant energy input for heat (often unsustainable
natural gas fossil fuel, but cellulosic biomass such as
bagasse, the waste left after sugar cane is pressed to extract its juice, can also be used more sustainably).
Ethanol can be used in petrol engines as a replacement for gasoline; it can be mixed with gasoline to any percentage. Most existing car petrol engines can run on blends of up to 15% bioethanol with petroleum/gasoline. Ethanol has a smaller energy density than gasoline, which means it takes more fuel (volume and mass) to produce the same amount of work. An advantage of ethanol (CH3CH2OH) is that it has a higher
octane rating than ethanol-free gasoline available at roadside gas stations which allows an increase of an engine's compression ratio for increased
thermal efficiency. In high altitude (thin air) locations, some states mandate a mix of gasoline and ethanol as a winter
oxidizer to reduce atmospheric pollution emissions.
Ethanol is also used to fuel bioethanol
fireplaces. As they do not require a chimney and are "flueless", bio ethanol fires
[4] are extremely useful for new build homes and apartments without a flue. The downside to these fireplaces, is that the heat output is slightly less than electric and gas fires.
In the current alcohol-from-corn production model in the United States, considering the total energy consumed by
farm equipment, cultivation, planting,
fertilizers,
pesticides,
herbicides, and
fungicides made from petroleum,
irrigation systems, harvesting, transport of feedstock to processing plants, fermentation, distillation, drying, transport to fuel terminals and retail pumps, and lower ethanol fuel energy content, the net energy content value added and delivered to consumers is very small. And, the net benefit (all things considered) does little to reduce un-
sustainable imported
oil and fossil fuels required to produce the ethanol.
[5]
Although ethanol-from-corn and other food stocks has implications both in terms of world food prices and limited, yet positive energy yield (in terms of energy delivered to customer/fossil fuels used), the technology has led to the development of cellulosic ethanol. According to a joint research agenda conducted through the U.S. Department of Energy,
[6] the fossil energy ratios (
FER) for cellulosic ethanol, corn ethanol, and gasoline are 10.3, 1.36, and 0.81, respectively.
[7][8][9]
Many car manufacturers are now producing
flexible-fuel vehicles (FFV's), which can safely run on any combination of bioethanol and petrol, up to 100% bioethanol. They dynamically sense exhaust oxygen content, and adjust the engine's computer systems, spark, and fuel injection accordingly. This adds initial cost and ongoing increased vehicle maintenance.
[citation needed] As with all vehicles, efficiency falls and pollution emissions increase when FFV system maintenance is needed (regardless of the fuel mix being used), but is not performed. FFV
internal combustion engines are becoming increasingly complex, as are multiple-
propulsion-system FFV
hybrid vehicles, which impacts cost, maintenance,
reliability, and useful lifetime
longevity.
[citation needed]
Even dry ethanol has roughly one-third lower energy content per unit of volume compared to gasoline, so larger / heavier fuel tanks are required to travel the same distance, or more fuel stops are required. With large current unsustainable, non-
scalable subsidies, ethanol fuel still costs much more per distance traveled than current high gasoline prices in the United States.
[10]
Methanol is currently produced from
natural gas, a non-
renewable fossil fuel. It can also be produced from biomass as
biomethanol. The
methanol economy is an interesting alternative to get to the
hydrogen economy, compared to today's
hydrogen production from natural gas. But this process is not the
state-of-the-art clean
solar thermal energy process, where
hydrogen production is directly produced from water.
[11]
Butanol is formed by
ABE fermentation (acetone, butanol, ethanol) and experimental modifications of the process show potentially high net energy gains with butanol as the only liquid product. Butanol will produce more energy and allegedly can be burned "straight" in existing gasoline engines (without modification to the engine or car),
[12] and is less corrosive and less water soluble than ethanol, and could be distributed via existing infrastructures.
DuPont and
BP are working together to help develop Butanol.
E. coli have also been successfully engineered to produce Butanol by hijacking their
amino acid metabolism.
[13]
[edit] Green diesel
Main article:
Green dieselGreen diesel, also known as
renewable diesel, is a form of diesel fuel which is derived from renewable feedstock rather than the fossil feedstock used in most
diesel fuels. Green diesel feedstock can be sourced from a variety
oils including
canola,
algae,
jatropha and
salicornia in addition to
tallow. Green diesel uses tradional
fractional distillation to process the oils, not to be confused with biodiesel which is chemically quite different and processed using transesterification.
“Green Diesel” as commonly known in
Ireland should not be confused with dyed green diesel sold at a lower tax rate for agriculture purposes, using the dye allows custom officers to determine if a person is using the cheaper diesel in higher taxed applications such as commercial haulage or cars.
[14]
[edit] Biodiesel
In some countries biodiesel is less expensive than conventional diesel.
Biodiesel is the most common biofuel in Europe. It is produced from oils or fats using
transesterification and is a liquid similar in composition to fossil/mineral diesel. Chemically, it consists mostly of fatty acid methyl (or ethyl) esters (
FAMEs). Feedstocks for biodiesel include animal fats, vegetable oils,
soy,
rapeseed,
jatropha,
mahua,
mustard,
flax,
sunflower,
palm oil,
hemp,
field pennycress,
pongamia pinnata and
algae. Pure biodiesel (B100) is the lowest emission diesel fuel. Although
liquefied petroleum gas and hydrogen have cleaner combustion, they are used to fuel much less efficient petrol engines and are not as widely available.
Biodiesel can be used in any
diesel engine when mixed with mineral diesel. In some countries manufacturers cover their diesel engines under warranty for B100 use, although
Volkswagen of
Germany, for example, asks drivers to check by telephone with the VW environmental services department before switching to B100. B100 may become more
viscous at lower temperatures, depending on the feedstock used. In most cases, biodiesel is compatible with diesel engines from 1994 onwards, which use '
Viton' (by
DuPont) synthetic rubber in their mechanical
fuel injection systems.
Electronically controlled '
common rail' and '
unit injector' type systems from the late 1990s onwards may only use biodiesel blended with conventional diesel fuel. These engines have finely metered and atomized multi-stage injection systems that are very sensitive to the viscosity of the fuel. Many current generation diesel engines are made so that they can run on B100 without altering the engine itself, although this depends on the
fuel rail design. Since biodiesel is an effective
solvent and cleans residues deposited by mineral diesel,
engine filters may need to be replaced more often, as the biofuel dissolves old deposits in the fuel tank and pipes. It also effectively cleans the engine
combustion chamber of carbon deposits, helping to maintain efficiency. In many European countries, a 5% biodiesel blend is widely used and is available at thousands of gas stations.
[15][16] Biodiesel is also an
oxygenated fuel, meaning that it contains a reduced amount of carbon and higher hydrogen and oxygen content than fossil diesel. This improves the
combustion of fossil diesel and reduces the particulate emissions from un-burnt carbon.
Biodiesel is also safe to handle and transport because it is as
biodegradable as sugar, 10 times less toxic than table salt, and has a high
flash point of about 300 F (148 C) compared to petroleum diesel fuel, which has a flash point of 125 F (52 C).
[17]
In the USA, more than 80% of commercial trucks and city buses run on diesel. The emerging US biodiesel market is estimated to have grown 200% from 2004 to 2005. "By the end of 2006 biodiesel production was estimated to increase fourfold [from 2004] to more than 1 billion gallons".
[18]
[edit] Vegetable oil
Straight unmodified
edible vegetable oil is generally not used as fuel, but lower quality oil can be used for this purpose. Used vegetable oil is increasingly being processed into biodiesel, or (more rarely) cleaned of water and particulates and used as a fuel.
Also here, as with 100% biodiesel (B100), to ensure that the
fuel injectors atomize the vegatable oil in the correct pattern for efficient combustion, vegetable oil fuel must be heated to reduce its
viscosity to that of diesel, either by electric coils or heat exchangers. This is easier in warm or temperate climates. Big corporations like
MAN B&W Diesel,
Wartsila and
Deutz AG as well as a number of smaller companies such as
Elsbett offer engines that are compatible with straight vegetable oil, without the need for after-market modifications.
Vegetable oil can also be used in many older diesel engines that do not use
common rail or
unit injection electronic diesel injection systems. Due to the design of the combustion chambers in
indirect injection engines, these are the best engines for use with vegetable oil. This system allows the relatively larger oil molecules more time to burn. Some older engines, especially Mercedes are driven experimentally by enthusiasts without any conversion, a handful of drivers have experienced limited success with earlier pre-"Pumpe Duse"
VW TDI engines and other similar engines with
direct injection. Several companies like
Elsbett or
Wolf have developed professional conversion kits and successfully installed hundreds of them over the last decades.
Oils and fats can be
hydrogenated to give a diesel substitute. The resulting product is a straight chain hydrocarbon, high in
cetane, low in
aromatics and
sulfur and does not contain oxygen.
Hydrogenated oils can be blended with diesel in all proportions Hydrogenated oils have several advantages over biodiesel, including good performance at low temperatures, no storage stability problems and no susceptibility to microbial attack.
[19]
[edit] Bioethers
Bio
ethers (also referred to as fuel ethers or
oxygenated fuels) are cost-effective
compounds that act as
octane rating enhancers. They also enhance
engine performance, whilst significantly reducing engine wear and
toxic exhaust emissions. Greatly reducing the amount of ground-level
ozone, they contribute to the quality of the air we breathe.
[20][21]
[edit] Biogas
Biogas is
methane produced by the process of
anaerobic digestion of
organic material by
anaerobes.
[22] It can be produced either from
biodegradable waste materials or by the use of
energy crops fed into
anaerobic digesters to supplement gas yields. The solid byproduct,
digestate, can be used as a biofuel or a fertilizer.
- Note:Landfill gas is a less clean form of biogas which is produced in landfills through naturally occurring anaerobic digestion. If it escapes into the atmosphere it is a potential greenhouse gas.
- Farmers can produce biogas from manure from their cows by getting a anaerobic digester (AD).[23]
[edit] Syngas
Main article:
Gasification, a mixture of
carbon monoxide and
hydrogen, is produced by partial combustion of biomass, that is, combustion with an amount of
oxygen that is not sufficient to convert the biomass completely to carbon dioxide and water.
[19] Before partial combustion the biomass is dried, and sometimes
pyrolysed. The resulting gas mixture, syngas, is more efficient than direct combustion of the original biofuel; more of the energy contained in the fuel is extracted.
- Syngas may be burned directly in internal combustion engines or turbines. The wood gas generator is a wood-fueled gasification reactor mounted on an internal combustion engine.
- Syngas can be used to produce methanol and hydrogen, or converted via the Fischer-Tropsch process to produce a diesel substitute, or a mixture of alcohols that can be blended into gasoline. Gasification normally relies on temperatures >700°C.
- Lower temperature gasification is desirable when co-producing biochar but results in a Syngas polluted with tar.
[edit] Solid biofuels
Examples include
wood,
sawdust,
grass cuttings,
domestic refuse,
charcoal,
agricultural waste, non-food
energy crops (see picture), and dried
manure.
When raw biomass is already in a suitable form (such as
firewood), it can burn directly in a stove or furnace to provide heat or raise steam. When raw biomass is in an inconvenient form (such as sawdust, wood chips, grass, urban waste wood, agricultural residues), the typical process is to densify the biomass. This process includes grinding the raw biomass to an appropriate particulate size (known as hogfuel), which depending on the densification type can be from 1 to 3 cm (1 in), which is then concentrated into a fuel product. The current types of processes are
wood pellet, cube, or puck. The pellet process is most common in Europe and is typically a pure wood product. The other types of densification are larger in size compared to a pellet and are compatible with a broadrange of input feedstocks. The resulting densified fuel is easier to transport and feed into thermal generation systems such as boilers.
A problem with the combustion of raw biomass is that it emits considerable amounts of
pollutants such as
particulates and PAHs (
polycyclic aromatic hydrocarbons). Even modern pellet boilers generate much more pollutants than oil or natural gas boilers. Pellets made from agricultural residues are usually worse than wood pellets, producing much larger emissions of
dioxins and
chlorophenols.
[24]
Notwithstanding the above noted study, numerous studies have shown that biomass fuels have significantly less impact on the environment than fossil based fuels. Of note is the U.S. Department of Energy Laboratory, Operated by Midwest Research Institute Biomass Power and Conventional Fossil Systems with and without CO2}} Sequestration – Comparing the
Energy Balance,
Greenhouse Gas Emissions and Economics Study. Power generation emits significant amounts of greenhouse gases (GHGs), mainly
carbon dioxide (CO
2).
{{Sequestering CO2 from the power plant flue gas can significantly reduce the GHGs from the power plant itself, but this is not the total picture. CO
2 capture and sequestration consumes additional energy, thus lowering the plant's
fuel-to-electricity efficiency. To compensate for this, more fossil fuel must be procured and consumed to make up for lost capacity.
Taking this into consideration, the
global warming potential (GWP), which is a combination of CO
2, methane (CH
4), and
nitrous oxide (N
2O) emissions, and energy balance of the system need to be examined using a
life cycle assessment. This takes into account the upstream processes which remain constant after CO
2 sequestration as well as the steps required for additional power generation. firing biomass instead of coal led to a 148% reduction in GWP.
A derivative of solid biofuel is
biochar, which is produced by biomass
pyrolysis. Bio-char made from agricultural waste can substitute for wood charcoal. As wood stock becomes scarce this alternative is gaining ground. In eastern
Democratic Republic of Congo, for example, biomass
briquettes are being marketed as an alternative to charcoal in order to protect
Virunga National Park from
deforestation associated with
charcoal production.
[25]
[edit] Second generation biofuels
Supporters of biofuels claim that a more viable solution is to increase political and industrial support for, and rapidity of, second-generation biofuel implementation from
non-food crops. These include
waste biomass, the stalks of wheat, corn, wood, and
special-energy-or-biomass crops (e.g.
Miscanthus). Second generation (2G) biofuels use
biomass to liquid technology,
[26] including
cellulosic biofuels.
[27] Many second generation biofuels are under development such as
biohydrogen,
biomethanol,
DMF, Bio-DME,
Fischer-Tropsch diesel, biohydrogen diesel, mixed alcohols and wood diesel.
Cellulosic ethanol production uses non-food crops or inedible waste products and does not divert food away from the animal or human food chain.
Lignocellulose is the "woody" structural material of plants. This feedstock is abundant and diverse, and in some cases (like citrus peels or sawdust) it is in itself a significant disposal problem.
Producing ethanol from
cellulose is a difficult technical problem to solve. In nature,
ruminant livestock (like
cattle) eat grass and then use slow enzymatic digestive processes to break it into
glucose (sugar). In
cellulosic ethanol laboratories, various
experimental processes are being developed to do the same thing, and then the sugars released can be fermented to make ethanol fuel. In 2009 scientists reported developing, using "synthetic biology", "15 new highly stable fungal
enzyme catalysts that efficiently break down cellulose into sugars at high temperatures", adding to the 10 previously known.
[28] The use of high temperatures, has been identified as an important factor in improving the overall economic feasibility of the biofuel industry and the identification of enzymes that are stable and can operate efficiently at extreme temperatures is an area of active research.
[29] In addition, research conducted at
TU Delft by Jack Pronk has shown that
elephant yeast, when slightly modified can also create ethanol from non-edible ground sources (e.g. straw).
[30][31]
The recent discovery of the fungus
Gliocladium roseum points toward the production of so-called
myco-diesel from cellulose. This organism was recently discovered in the rainforests of northern
Patagonia and has the unique capability of converting cellulose into medium length hydrocarbons typically found in diesel fuel.
[32] Scientists also work on experimental
recombinant DNA genetic engineering organisms that could increase biofuel potential.
Scientists working in New Zealand have developed a technology to use industrial waste gases from
steel mills as a feedstock for a microbial fermentation process to produce ethanol.
[33][34]
Second, third, and fourth generation biofuels are also called advanced biofuels.
[edit] Third generation biofuels
Algae fuel, also called oilgae or third generation biofuel, is a biofuel from
algae. Algae are low-input, high-yield
feedstocks to produce biofuels. Based on laboratory experiments, it is claimed that algae can produce up to 30 times more energy per acre than land crops such as
soybeans,
[35] but these yields have yet to be produced commercially. With the higher prices of fossil fuels (
petroleum), there is much interest in
algaculture (farming algae). One advantage of many biofuels over most other fuel types is that they are
biodegradable, and so relatively harmless to the environment if spilled.
[36][37][38] Algae fuel still has its difficulties though, for instance to produce algae fuels it must be mixed uniformly, which, if done by agitation, could affect biomass growth.
[39]
The
United States Department of Energy estimates that if algae fuel replaced all the petroleum fuel in the United States, it would require only 15,000 square miles (38,849
square kilometers), which is roughly the size of
Maryland,
[35] or less than one seventh the amount of land devoted to corn in 2000.
[40]
Algae, such as
Botryococcus braunii and
Chlorella vulgaris are relatively easy to grow,
[41] but the
algal oil is hard to extract. There are several approaches, some of which work better than others.
[42] Macroalgae (seaweed) also have a great potential for bioethanol and biogas production.
[43]
[edit] Ethanol from living algae
Most biofuel production comes from harvesting organic matter and then converting it to fuel but an alternative approach relies on the fact that some algae naturally produce ethanol and this can be collected without killing the algae. The ethanol evaporates and then can be condensed and collected. The company
Algenol is trying to commercialize this process.
[edit] Fourth generation biofuels
A number of companies are pursuing advanced "bio-chemical" and "thermo-chemical" processes that produce "drop in" fuels like "green gasoline," "green diesel," and "green aviation fuel." While there is no one established definition of "fourth-generation biofuels," some have referred to it as the biofuels created from processes other than first generation ethanol and biodiesel, second generation cellulosic ethanol, and third generation algae biofuel. Some fourth generation technology pathways include:
pyrolysis,
gasification, upgrading,
solar-to-fuel, and genetic manipulation of organisms to
secrete hydrocarbons.
[44]
- GreenFuel Technologies Corporation developed a patented bioreactor system that uses nontoxic photosynthetic algae to take in smokestacks flue gases and produce biofuels such as biodiesel, biogas and a dry fuel comparable to coal.[45]
- With thermal depolymerization of biological waste one can extract methane and other oils similar to petroleum.
Hydrocarbon plants or petroleum plants are plants which produce
terpenoids as
secondary metabolites that can be converted to
gasoline-like fuels.
Latex producing members of the
Euphorbiaceae such as
Euphorbia lathyris and
E. tirucalli and members of
Apocynaceae have been studied for their potential energy uses.
[46][47]
[edit] Green fuels
However, if
biocatalytic cracking and traditional
fractional distillation used to process properly prepared algal biomass i.e. biocrude,
[48] then as a result we receive the following distillates:
jet fuel, gasoline, diesel, etc.. Hence, we may call them third generation or green fuels.
[edit] Biofuels by region
Recognizing the importance of implementing bioenergy, there are international organizations such as IEA Bioenergy,
[49] established in 1978 by the
OECD International Energy Agency (IEA), with the aim of improving cooperation and information exchange between countries that have national programs in bioenergy research, development and deployment. The
U.N. International Biofuels Forum is formed by
Brazil,
China,
India,
South Africa, the
United States and the
European Commission.
[50] The world leaders in biofuel development and use are Brazil, United States, France, Sweden and Germany.
[edit] Issues with biofuel production and use
There are various current issues with biofuel production and use, which are presently being discussed in the popular media and scientific journals. These include: the effect of moderating
oil prices, the "
food vs fuel" debate,
[51] carbon emissions levels,
sustainable biofuel production,
deforestation and
soil erosion, impact on
water resources,
human rights issues,
poverty reduction potential, biofuel prices, energy balance and efficiency, and centralised versus decentralised production models.
[edit] First generation biofuel controversies
There is controversy and political speculation surrounding first-generation biofuels due to the agricultural, economic, and social implications associated with the potential expansion of biofuel production.
- Research has been done in China that indicates that the demand for bio-fuel feedstock such as maize, sugarcane, and cassava will significantly increase due to the expansion of biofuel production; the increased demand for feedstock will lead prices for such grain to significantly increase.[52]
- A similar study done examining a potential increase in ethanol production capacity in the United States also predicts an upward trend in agricultural prices as a direct effect of expanding domestic biofuel production.[53]
- Expanding biofuel production is also projected to have an effect on livestock prices. A study done in China predicted that increased maize prices, due to biofuel expansion, will indirectly cause the prices of livestock production to increase due to the heavy reliance on maize for animal feed.[54] The increase in input prices would also lead to a decrease in livestock production and ultimately decrease in the income of livestock producers, affecting families globally.
Increased agricultural prices will also provide incentives for farmers to stray away from producing other less profitable grains, causing a shift in the
crop production structure, leading to a decrease in agricultural diversity subsequently diverting food away from the
human food chain. In order for the United States to meet the biofuel target introduced in the
Energy Independence and Security Act:
- 40% of the land that is currently devoted to corn production would have to be converted to biofuel feedstock production.[55]
- Shifts in crop production and the changes in world price of agricultural commodities due to the expansion of the biofuel market are expected to have global impacts on consumers.
Individuals who are food insecure will be more heavily impacted by the increase in world prices; food price volatility has the largest impact on the extremely poor, those who spend 55-75% of their income on food.
[56]
[edit] See also
[edit] References
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- ^ "Towards Sustainable Production and Use of Resources: Assessing Biofuels". United Nations Environment Programme. 2009-10-16. http://www.unep.fr/scp/rpanel/pdf/Assessing_Biofuels_Full_Report.pdf. Retrieved 2009-10-24.
- ^ "BioEnergyBroch_FINAL05.indd" (PDF). http://esa.un.org/un-energy/pdf/susdev.Biofuels.FAO.pdf. Retrieved 2010-07-14.
- ^ Bio ethanol fires information bio ethanol fireplace. (2009)
- ^ Andrew Bounds (2007-09-10). "OECD warns against biofuels subsidies". Financial Times. http://www.ft.com/cms/s/0/e780d216-5fd5-11dc-b0fe-0000779fd2ac.html. Retrieved 2008-03-07.
- ^ see "Breaking the Biological Barriers to Cellulosic Ethanol"
- ^ Brinkman, N. et al., "Well-to-Wheels Analysis of Advanced/Vehicle Systems", 2005.
- ^ Farrell, A.E. et al. (2006) "Ethanol can Contribute to Energy and Environmental Goals", Science, 311, 506-8.
- ^ Hammerschlag, R. 2006. "Ethanol's Energy Return on Investment: A Survey of the Literature 1999-Present", Environ. Sci. Technol., 40, 1744-50.
- ^ "With only 2/3 the energy of gasoline, ethanol costs more per mile". zFacts.com. 2007-04-27. http://zfacts.com/p/436.html. Retrieved 2008-03-07.
- ^ "Hydrogen Solar home". Hydrogensolar.com. http://www.hydrogensolar.com/. Retrieved 2010-07-14.
- ^ "ButylFuel, LLC Main Page". Butanol.com. 2005-08-15. http://www.butanol.com/. Retrieved 2010-07-14.
- ^ Evans, Jon (14 January 2008). "Biofuels aim higher". Biofuels, Bioproducts and Biorefining (BioFPR). http://www.biofpr.com/details/feature/102347/Biofuels_aim_higher.html. Retrieved 2008-12-03.
- ^ "Customs seize illegal fuel". BBC News. 2004. http://news.bbc.co.uk/2/hi/uk_news/northern_ireland/4083017.stm. Retrieved 2010-07-25.
- ^ "ADM Biodiesel: Hamburg, Leer, Mainz". Biodiesel.de. http://www.biodiesel.de/. Retrieved 2010-07-14.
- ^ RRI Limited for Biodiesel Filling Stations. "Welcome to Biodiesel Filling Stations". Biodieselfillingstations.co.uk. http://www.biodieselfillingstations.co.uk. Retrieved 2010-07-14.
- ^ "Biofuels Facts". Hempcar.org. http://www.hempcar.org/biofacts.shtml. Retrieved 2010-07-14.
- ^ THE FUTURIST, Will Thurmond. July–August 2007
- ^ a b Evans, G. "Liquid Transport Biofuels - Technology Status Report", National Non-Food Crops Centre, 2008-04-14. Retrieved on 2009-05-11.
- ^ "Council Directive 85/536/EEC of 5 December 1985 on crude-oil savings through the use of substitute fuel components in petrol". Eur-lex.europa.eu. http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=CELEX:31985L0536:EN:HTML. Retrieved 2010-07-14.
- ^ "Microsoft Word - IA 55 EN.doc" (PDF). http://www.europarl.europa.eu/registre/docs_autres_institutions/commission_europeenne/sec/2007/0055/COM_SEC(2007)0055_EN.pdf. Retrieved 2010-07-14.
- ^ Redman, G., The Andersons Centre. "Assessment of on-farm AD in the UK", National Non-Food Crops Centre, 2008-06-09. Retrieved on 2009-05-11.
- ^ "BIOGAS: No bull, manure can power your farm." Farmers Guardian (September 25, 2009): 12. General OneFile. Gale.
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[edit] Further reading
[edit] External links
Source:
http://en.wikipedia.org/wiki/Biofuel
All of FreshDirect’s trucks will be using B5 by the end of February. It began filling 30 of its trucks with B5 in early January and has been gradually phasing the fuel into the rest of the fleet. Tri-State, which purchases finished biodiesel from the same local producers it sends feedstock to, predicts that FreshDirect’s fleet will use 10 to 15 gallons of biodiesel-blended fuel per truck per day, resulting in approximately 600,000 gallons of biodiesel-blended fuel per year. Tri-State's own trucks run on B20, Baker said, and the company may increase the blend ratio if manufacturer warranties allow it.
