A biofuel is a fuel that is produced through
contemporary processes from biomass, rather
than a fuel produced by the very long-winded
geological processes involved in the formation
of fossil fuels, such as oil.
Since biomass technically can be used as a
fuel directly (e.g. wood logs), some people
use the terms «biomass» and «biofuel»
interchangeably.
More often than not however, the word «biomass»
simply denotes the biological raw material
the fuel is made of, or some form of thermally/chemically
altered solid end product, like torrefied
pellets or briquettes.
The word «biofuel» is usually reserved for
liquid or gaseous fuels, used for transportation.
The EIA (U.S. Energy Information Administration)
follow this naming practice.
If the biomass used in the production of biofuel
can regrow quickly, the fuel is generally
considered to be a form of renewable energy.
Biofuels can be produced from plants (i.e.
energy crops), or from agricultural, commercial,
domestic, and/or industrial wastes (if the
waste has a biological origin).
Renewable biofuels generally involve contemporary
carbon fixation, such as those that occur
in plants or microalgae through the process
of photosynthesis.
Some argue that biofuel can be carbon-neutral
because all biomass crops sequester carbon
to a certain extent.
For Miscanthus x giganteus, McCalmont et al.
found carbon accumulation rates ranging from
0.42 to 3.8 tonnes per hectare per year,
with a mean accumulation rate of 1.84 tonne
(0.74 tonnes per acre per year),
or 20% of total harvested carbon per year.
The grass sequesters carbon in its continually
increasing root biomass, together with carbon
input from fallen leaves.
However, the simple proposal that biofuel
is carbon-neutral put forward in the early
1990s has been superseded by the more nuanced
proposal that for a particular biofuel project
to be carbon neutral, the total carbon sequestered
by the crop's root system must compensate
for all the emissions from the related, aboveground
biofuel project.
This includes any emissions caused by direct
or indirect land use change.
Many first generation biofuel projects are
not carbon neutral given these demands.
Some have even higher total GHG emissions
than some fossil based alternatives.Some are
carbon neutral or even negative, though, especially
perennial crops.
The amount of carbon sequestrated and the
amount of GHG (greenhouse gases) emitted will
determine if the total GHG life cycle cost
of a biofuel project is positive, neutral
or negative.
Whitaker et al. estimates that for Miscanthus
x giganteus, GHG neutrality and even negativity
is within reach.
A carbon negative life cycle is possible if
the total below-ground carbon accumulation
more than compensates for the above-ground
total life-cycle GHG emissions.
The graphic on the right displays two CO2
negative Miscanthus x giganteus production
pathways, represented in gram CO2-equivalents
per megajoule.
The yellow diamonds represent mean values.
Successful sequestration is dependent on planting
sites, as the best soils for sequestration
are those that are currently low in carbon.
The varied results displayed in the graph
highlights this fact.
For the UK, successful sequestration is expected
for arable land over most of England and Wales,
with unsuccessful sequestration expected in
parts of Scotland, due to already carbon rich
soils (existing woodland) plus lower yields.
Soils already rich in carbon includes peatland
and mature forest.
Grassland can also be carbon rich, however
Milner et al. argues that the most successful
carbon sequestration in the UK takes place
below improved grasslands.
The bottom graphic displays the estimated
yield necessary to compensate for the disturbance
caused by planting plus lifecycle GHG-emissions
for the related above-ground operation.
The two most common types of biofuel are bioethanol
and biodiesel.
Bioethanol is an alcohol made by fermentation,
mostly from carbohydrates produced in sugar
or starch crops such as corn, sugarcane, or
sweet sorghum.
Cellulosic biomass, derived from non-food
sources, such as trees and grasses, is also
being developed as a feedstock for ethanol
production.
Ethanol can be used as a fuel for vehicles
in its pure form (E100), but it is usually
used as a gasoline additive to increase octane
and improve vehicle emissions.
Bioethanol is widely used in the United States
and in Brazil.
Biodiesel is produced from oils or fats using
transesterification and is the most common
biofuel in Europe.
It can be used as a fuel for vehicles in its
pure form (B100), but it is usually used as
a diesel additive to reduce levels of particulates,
carbon monoxide, and hydrocarbons from diesel-powered
vehicles.
In 2018, worldwide biofuel production reached
152 billion liters (40 billion gallons US),
up 7% from 2017, and biofuels provided 3%
of the world's fuels for road transport.
The International Energy Agency want biofuels
to meet more than a quarter of world demand
for transportation fuels by 2050, in order
to reduce dependency on petroleum.
However, the production and consumption of
biofuels are not on track to meet the IEA's
sustainable development scenario.
From 2020 to 2030 global biofuel output has
to increase by 10% each year to reach IEA's
goal.
Only 3% growth annually is expected.There
are various social, economic, environmental
and technical issues relating to biofuels
production and use, which have been debated
in the popular media and scientific journals.
== Generations ==
=== First-generation biofuels ===
"First-generation" or conventional biofuels
are biofuels made from food crops grown on
arable land.
With this biofuel production generation, food
crops are thus explicitly grown for fuel production,
and not anything else.
The sugar, starch, or vegetable oil obtained
from the crops is converted into biodiesel
or ethanol, using transesterification, or
yeast fermentation.
=== Second-generation biofuels ===
Second generation biofuels are fuels manufactured
from various types of 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 derived from plant materials, but
can also include animal materials.
Whereas first generation biofuels are made
from the sugars and vegetable oils found in
arable crops, second generation biofuels are
made from lignocellulosic biomass or woody
crops, agricultural residues or waste plant
material (from food crops that have already
fulfilled their food purpose).
The feedstock used to generate second-generation
biofuels thus either grows on arable lands,
but are just byproducts of the actual harvest
(main crop) or they are grown on lands which
cannot be used to effectively grow food crops
and in some cases neither extra water or fertilizer
is applied to them.
Non-human food second generation feedstock
sources include grasses, jatropha and other
seed crops, waste vegetable oil, municipal
solid waste and so forth.This has both advantages
and disadvantages.
The advantage is that, unlike with regular
food crops, no arable land is used solely
for the production of fuel.
The disadvantage is that unlike with regular
food crops, it may be rather difficult to
extract the fuel.
For instance, a series of physical and chemical
treatments might be required to convert lignocellulosic
biomass to liquid fuels suitable for transportation.
=== Third-generation biofuels ===
From 1978 to 1996, the US NREL experimented
with using algae as a biofuels source in the
Aquatic Species Program.
A self-published article by Michael Briggs,
at the UNH Biofuels Group, offers estimates
for the realistic replacement of all vehicular
fuel with biofuels by using algae that have
a natural oil content greater than 50%, which
Briggs suggests can be grown on algae ponds
at wastewater treatment plants.
This oil-rich algae can then be extracted
from the system and processed into biofuels,
with the dried remainder further reprocessed
to create ethanol.
The production of algae to harvest oil for
biofuels has not yet been undertaken on a
commercial scale, but feasibility studies
have been conducted to arrive at the above
yield estimate.
In addition to its projected high yield, algaculture
– unlike crop-based biofuels – does not
entail a decrease in food production, since
it requires neither farmland nor fresh water.
Many companies are pursuing algae bioreactors
for various purposes, including scaling up
biofuels production to commercial levels.
Prof. Rodrigo E. Teixeira from the University
of Alabama in Huntsville demonstrated the
extraction of biofuels lipids from wet algae
using a simple and economical reaction in
ionic liquids.
=== Fourth-generation biofuels ===
Similarly to third-generation biofuels, fourth-generation
biofuels are made using non-arable land.
However, unlike third-generation biofuels,
they do not require the destruction of biomass.
This class of biofuels includes electrofuels
and photobiological solar fuels.
Some of these fuels are carbon-neutral.
== Types ==
The following fuels can be produced using
first, second, third or fourth-generation
biofuel production procedures.
Most of these can even be produced using two
or three of the different biofuel generation
procedures.
=== Biogas ===
Biogas is methane produced by the process
of anaerobic digestion of organic material
by anaerobes.
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.
Biogas can be recovered from mechanical biological
treatment waste processing systems.
Landfill gas, a less clean form of biogas,
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 cattle by using anaerobic digesters.
=== Syngas ===
Syngas, a mixture of carbon monoxide, hydrogen
and other hydrocarbons, 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.
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, turbines or high-temperature
fuel cells.
The wood gas generator, a wood-fueled gasification
reactor, can be connected to an internal combustion
engine.
Syngas can be used to produce methanol, DME
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
greater than 700 °C.
Lower-temperature gasification is desirable
when co-producing biochar, but results in
syngas polluted with tar.
=== Ethanol ===
Biologically 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.
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 from which alcoholic beverages such
as whiskey, can be made (such as 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 (sometimes unsustainable
natural gas fossil fuel, but cellulosic biomass
such as bagasse, the waste left after sugar
cane is pressed to extract its juice, is the
most common fuel in Brazil, while pellets,
wood chips and also waste heat are more common
in Europe) Waste steam fuels ethanol factory
– where waste heat from the factories also
is used in the district heating grid.
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
that of gasoline; this 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",
bioethanol fires are extremely useful for
newly built homes and apartments without a
flue.
The downsides to these fireplaces is that
their heat output is slightly less than electric
heat or gas fires, and precautions must be
taken to avoid carbon monoxide poisoning.
Corn-to-ethanol and other food stocks has
led to the development of cellulosic ethanol.
According to a joint research agenda conducted
through the US Department of Energy, the fossil
energy ratios (FER) for cellulosic ethanol,
corn ethanol, and gasoline are 10.3, 1.36,
and 0.81, respectively.Ethanol has roughly
one-third lower energy content per unit of
volume compared to gasoline.
This is partly counteracted by the better
efficiency when using ethanol (in a long-term
test of more than 2.1 million km, the BEST
project found FFV vehicles to be 1–26% more
energy efficient than petrol cars, but the
volumetric consumption increases by approximately
30%, so more fuel stops are required).
With current subsidies, ethanol fuel is slightly
cheaper per distance traveled in the United
States.
=== Other bioalcohols ===
Methanol is currently produced from natural
gas, a non-renewable fossil fuel.
In the future it is hoped to be produced from
biomass as biomethanol.
This is technically feasible, but the production
is currently being postponed for concerns
that the economic viability is still pending.
The methanol economy is an alternative to
the hydrogen economy, compared to today's
hydrogen production from natural gas.
Butanol (C4H9OH) 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), 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.
Escherichia coli strains have also been successfully
engineered to produce butanol by modifying
their amino acid metabolism.
One drawback to butanol production in E. coli
remains the high cost of nutrient rich media,
however, recent work has demonstrated E. coli
can produce butanol with minimal nutritional
supplementation.
=== Biodiesel ===
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, also known as "neat"
biodiesel) currently reduces emissions with
up to 60% compared to diesel Second generation
B100.
Biodiesel can be used in any diesel engine
when mixed with mineral diesel.
It can also be used in its pure form (B100)
in diesel engines, but some maintenance and
performance problems may then occur during
wintertime utilization, since the fuel becomes
somewhat more viscous at lower temperatures,
depending on the feedstock used.
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.
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.
Note however, that no vehicles are certified
for using pure biodiesel before 2014, as there
was no emission control protocol available
for biodiesel before this date.
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
multiple-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.
Biodiesel is also an oxygenated fuel, meaning
it contains a reduced amount of carbon and
higher hydrogen and oxygen content than fossil
diesel.
This improves the combustion of biodiesel
and reduces the particulate emissions from
unburnt carbon.
However, using pure biodiesel may increase
NOx-emissionsBiodiesel is also safe to handle
and transport because it is non-toxic and
biodegradable, 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).In the US, 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 US gallons (3,800,000
m3).In France, biodiesel is incorporated at
a rate of 8% in the fuel used by all French
diesel vehicles.
Avril Group produces under the brand Diester,
a fifth of 11 million tons of biodiesel consumed
annually by the European Union.
It is the leading European producer of biodiesel.
=== Green diesel ===
Green diesel is produced through hydrocracking
biological oil feedstocks, such as vegetable
oils and animal fats.
Hydrocracking is a refinery method that uses
elevated temperatures and pressure in the
presence of a catalyst to break down larger
molecules, such as those found in vegetable
oils, into shorter hydrocarbon chains used
in diesel engines.
It may also be called renewable diesel, hydrotreated
vegetable oil or hydrogen-derived renewable
diesel.
Unlike biodiesel, green diesel has exactly
the same chemical properties as petroleum-based
diesel.
It does not require new engines, pipelines
or infrastructure to distribute and use, but
has not been produced at a cost that is competitive
with petroleum.
Gasoline versions are also being developed.
Green diesel is being developed in Louisiana
and Singapore by ConocoPhillips, Neste Oil,
Valero, Dynamic Fuels, and Honeywell UOP as
well as Preem in Gothenburg, Sweden, creating
what is known as Evolution Diesel.
=== Straight vegetable oil ===
Straight unmodified edible vegetable oil is
generally not used as fuel, but lower-quality
oil has been used for this purpose.
Used vegetable oil is increasingly being processed
into biodiesel, or (more rarely) cleaned of
water and particulates and then used as a
fuel.
As with 100% biodiesel (B100), to ensure the
fuel injectors atomize the vegetable 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.
MAN B&W Diesel, Wärtsilä, 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, such as 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 with a high cetane number, low
in aromatics and sulfur and does not contain
oxygen.
Hydrogenated oils can be blended with diesel
in all proportions.
They have several advantages over biodiesel,
including good performance at low temperatures,
no storage stability problems and no susceptibility
to microbial attack.
=== Bioethers ===
Bioethers (also referred to as fuel ethers
or oxygenated fuels) are cost-effective compounds
that act as octane rating enhancers."Bioethers
are produced by the reaction of reactive iso-olefins,
such as iso-butylene, with bioethanol."
Bioethers are created from wheat or sugar
beets.
They also enhance engine performance, while
significantly reducing engine wear and toxic
exhaust emissions.
Although bioethers are likely to replace petroethers
in the UK, it is highly unlikely they will
become a fuel in and of itself due to the
low energy density.
By greatly reducing the amount of ground-level
ozone emissions, they contribute to air quality.When
it comes to transportation fuel there are
six ether additives: dimethyl ether (DME),
diethyl ether (DEE), methyl tert-butyl ether
(MTBE), ethyl tert-butyl ether (ETBE), tert-amyl
methyl ether (TAME), and tert-amyl ethyl ether
(TAEE).The European Fuel Oxygenates Association
(EFOA) identifies methyl tert-butyl ether
(MTBE) and ethyl tert-butyl ether (ETBE) as
the most commonly used ethers in fuel to replace
lead.
Ethers were introduced in Europe in the 1970s
to replace the highly toxic compound.
Although Europeans still use bioether additives,
the US no longer has an oxygenate requirement
therefore bioethers are no longer used as
the main fuel additive.
== By region ==
There are international organizations such
as IEA Bioenergy, 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 UN International Biofuels Forum is formed
by Brazil, China, India, Pakistan, South Africa,
the United States and the European Commission.
The world leaders in biofuel development and
use are Brazil, the United States, France,
Sweden and Germany.
Russia also has 22% of world's forest, and
is a big biomass (solid biofuels) supplier.
In 2010, Russian pulp and paper maker, Vyborgskaya
Cellulose, said they would be producing pellets
that can be used in heat and electricity generation
from its plant in Vyborg by the end of the
year.
The plant will eventually produce about 900,000
tons of pellets per year, making it the largest
in the world once operational.
Biofuels currently make up 3.1% of the total
road transport fuel in the UK or 1,440 million
litres.
By 2020, 10% of the energy used in UK road
and rail transport must come from renewable
sources – this is the equivalent of replacing
4.3 million tonnes of fossil oil each year.
Conventional biofuels are likely to produce
between 3.7 and 6.6% of the energy needed
in road and rail transport, while advanced
biofuels could meet up to 4.3% of the UK's
renewable transport fuel target by 2020.
== Air pollution ==
Biofuels are similar to fossil fuels in that
biofuels contribute to air pollution.
Burning produces carbon dioxide, airborne
carbon particulates, carbon monoxide and nitrous
oxides.
The WHO estimates 3.7 million premature deaths
worldwide in 2012 due to air pollution.
Brazil burns significant amounts of ethanol
biofuel.
Gas chromatograph studies were performed of
ambient air in São Paulo, Brazil, and compared
to Osaka, Japan, which does not burn ethanol
fuel.
Atmospheric Formaldehyde was 160% higher in
Brazil, and Acetaldehyde was 260% higher.The
Environmental Protection Agency acknowledged
in April 2007 that the increased use of bioethanol
will lead to worse air quality.
The total emissions of air pollutants such
as nitrogen oxides will rise due the growing
use of bioethanol.
There is an increase in carbon dioxide from
the burning of fossil fuels to produce the
biofuels as well as nitrous oxide from the
soil, which has most likely been treated with
nitrogen fertilizer.
Nitrous oxide is known to have a greater impact
on the atmosphere in relation to global warming,
as it is also an ozone destroyer.
== Debates regarding the production and use
of biofuel ==
There are various social, economic, environmental
and technical issues with biofuel production
and use, which have been discussed in the
popular media and scientific journals.
These include: the effect of moderating oil
prices, the "food vs fuel" debate, food prices,
poverty reduction potential, energy ratio,
energy requirements, carbon emissions levels,
sustainable biofuel production, deforestation
and soil erosion, loss of biodiversity, impact
on water resources, the possible modifications
necessary to run the engine on biofuel, as
well as energy balance and efficiency.
The International Resource Panel, which provides
independent scientific assessments and expert
advice on a variety of resource-related themes,
assessed the issues relating to biofuel use
in its first report Towards sustainable production
and use of resources: Assessing Biofuels.
"Assessing Biofuels" outlined the wider and
interrelated factors that need to be considered
when deciding on the relative merits of pursuing
one biofuel over another.
It concluded that not all biofuels perform
equally in terms of their impact on climate,
energy security and ecosystems, and suggested
that environmental and social impacts need
to be assessed throughout the entire life-cycle.
Another issue with biofuel use and production
is the US has changed mandates many times
because the production has been taking longer
than expected.
The Renewable Fuel Standard (RFS) set by congress
for 2010 was pushed back to at best 2012 to
produce 100 million gallons of pure ethanol
(not blended with a fossil fuel).
=== Banning of first-generation biofuels ===
In the EU, the revised renewable energy directive
calls for a complete ban on first-generation
biofuels by 2030.
Particularly fuels made from such oils such
as palm oil and soy oil are being targeted.
=== Sustainable biofuels ===
Many of the biofuels that were being supplied
in 2008 (using the first-generation biofuel
production procedure) have been criticised
for their adverse impacts on the natural environment,
food security, and land use.
In 2008, the Nobel-prize winning chemist Paul
J. Crutzen published findings that the release
of nitrous oxide (N2O) emissions in the production
of biofuels means that overall they contribute
more to global warming than the fossil fuels
they replace.
In 2008, the challenge was to support biofuel
development, including the development of
new cellulosic technologies, with responsible
policies and economic instruments to help
ensure that biofuel commercialization is sustainable.
Responsible commercialization of biofuels
represented an opportunity to enhance sustainable
economic prospects in Africa, Latin America
and Asia.
Biofuels in the form of liquid fuels derived
from plant materials have entered the market,
driven by the perception that they reduce
climate gas emissions, and also by factors
such as oil price spikes and the need for
increased energy security.
According to the Rocky Mountain Institute,
sound biofuel production practices would not
hamper food and fibre production, nor cause
water or environmental problems, and would
enhance soil fertility.
The selection of land on which to grow the
feedstocks is a critical component of the
ability of biofuels to deliver sustainable
solutions.
A key consideration is the minimisation of
biofuel competition for prime cropland.
=== Greenhouse gas emissions ===
Some scientists have expressed concerns about
land-use change in response to greater demand
for crops to use for biofuel and the subsequent
carbon emissions.
The payback period, that is, the time it will
take biofuels to pay back the carbon debt
they acquire due to land-use change, has been
estimated to be between 100 and 1000 years,
depending on the specific instance and location
of land-use change.
However, no-till practices combined with cover-crop
practices can reduce the payback period to
three years for grassland conversion and 14
years for forest conversion.A study conducted
in the Tocantis State, in northern Brazil,
found that many families were cutting down
forests in order to produce two conglomerates
of oilseed plants, the J. curcas (JC group)
and the R. communis (RC group).
This region is composed of 15% Amazonian rainforest
with high biodiversity, and 80% Cerrado forest
with lower biodiversity.
During the study, the farmers that planted
the JC group released over 2193 Mg CO2, while
losing 53-105 Mg CO2 sequestration from deforestation;
and the RC group farmers released 562 Mg CO2,
while losing 48-90 Mg CO2 to be sequestered
from forest depletion.
The production of these types of biofuels
not only led into an increased emission of
carbon dioxide, but also to lower efficiency
of forests to absorb the gases that these
farms were emitting.
This has to do with the amount of fossil fuel
the production of fuel crops involves.
In addition, the intensive use of monocropping
agriculture requires large amounts of water
irrigation, as well as of fertilizers, herbicides
and pesticides.
This does not only lead to poisonous chemicals
to disperse on water runoff, but also to the
emission of nitrous oxide (NO2) as a fertilizer
byproduct, which is three hundred times more
efficient in producing a greenhouse effect
than carbon dioxide (CO2).Converting rainforests,
peatlands, savannas, or grasslands to produce
food crop–based biofuels in Brazil, Southeast
Asia, and the United States creates a “biofuel
carbon debt” by releasing 17 to 420 times
more CO2 than the annual greenhouse gas (GHG)
reductions that these biofuels would provide
by displacing fossil fuels.
Biofuels made from waste biomass or from biomass
grown on abandoned agricultural lands incur
little to no carbon debt.In addition to crop
growth requiring water, biofuel facilities
require significant process water.
== Current research ==
Specially bred mustard varieties can produce
reasonably high oil yields and are very useful
in crop rotation with cereals, and have the
added benefit that the meal left over after
the oil has been pressed out can act as an
effective and biodegradable pesticide.The
NFESC, with Santa Barbara-based Biodiesel
Industries, is working to develop biofuels
technologies for the US navy and military,
one of the largest diesel fuel users in the
world.
A group of Spanish developers working for
a company called Ecofasa announced a new biofuel
made from trash.
The fuel is created from general urban waste
which is treated by bacteria to produce fatty
acids, which can be used to make biofuels.
Before its shutdown, Joule Unlimited was attempting
to make cheap ethanol and biodiesel from a
genetically modified photosynthetic bacterium.
=== Ethanol biofuels (bioethanol) ===
As the primary source of biofuels in North
America, many organizations are conducting
research in the area of ethanol production.
The National Corn-to-Ethanol Research Center
(NCERC) is a research division of Southern
Illinois University Edwardsville dedicated
solely to ethanol-based biofuel research projects.
On the federal level, the USDA conducts a
large amount of research regarding ethanol
production in the United States.
Much of this research is targeted toward the
effect of ethanol production on domestic food
markets.
A division of the US Department of Energy,
the National Renewable Energy Laboratory (NREL),
has also conducted various ethanol research
projects, mainly in the area of cellulosic
ethanol.Cellulosic ethanol commercialization
is the process of building an industry out
of methods of turning cellulose-containing
organic matter into fuel.
Companies, such as Iogen, POET, and Abengoa,
are building refineries that can process biomass
and turn it into bioethanol.
Companies, such as Diversa, Novozymes, and
Dyadic, are producing enzymes that could enable
a cellulosic ethanol future.
The shift from food crop feedstocks to waste
residues and native grasses offers significant
opportunities for a range of players, from
farmers to biotechnology firms, and from project
developers to investors.As of 2013, the first
commercial-scale plants to produce cellulosic
biofuels have begun operating.
Multiple pathways for the conversion of different
biofuel feedstocks are being used.
In the next few years, the cost data of these
technologies operating at commercial scale,
and their relative performance, will become
available.
Lessons learnt will lower the costs of the
industrial processes involved.In parts of
Asia and Africa where drylands prevail, sweet
sorghum is being investigated as a potential
source of food, feed and fuel combined.
The crop is particularly suitable for growing
in arid conditions, as it only extracts one
seventh of the water used by sugarcane.
In India, and other places, sweet sorghum
stalks are used to produce biofuel by squeezing
the juice and then fermenting into ethanol.A
study by researchers at the International
Crops Research Institute for the Semi-Arid
Tropics (ICRISAT) found that growing sweet
sorghum instead of grain sorghum could increase
farmers incomes by US$40 per hectare per crop
because it can provide fuel in addition to
food and animal feed.
With grain sorghum currently grown on over
11 million hectares (ha) in Asia and on 23.4
million ha in Africa, a switch to sweet sorghum
could have a considerable economic impact.
=== Jatropha ===
Several groups in various sectors are conducting
research on Jatropha curcas, a poisonous shrub-like
tree that produces seeds considered by many
to be a viable source of biofuels feedstock
oil.
Much of this research focuses on improving
the overall per acre oil yield of Jatropha
through advancements in genetics, soil science,
and horticultural practices.
SG Biofuels, a San Diego-based jatropha developer,
has used molecular breeding and biotechnology
to produce elite hybrid seeds that show significant
yield improvements over first-generation varieties.
SG Biofuels also claims additional benefits
have arisen from such strains, including improved
flowering synchronicity, higher resistance
to pests and diseases, and increased cold-weather
tolerance.Plant Research International, a
department of the Wageningen University and
Research Centre in the Netherlands, maintains
an ongoing Jatropha Evaluation Project that
examines the feasibility of large-scale jatropha
cultivation through field and laboratory experiments.
The Center for Sustainable Energy Farming
(CfSEF) is a Los Angeles-based nonprofit research
organization dedicated to jatropha research
in the areas of plant science, agronomy, and
horticulture.
Successful exploration of these disciplines
is projected to increase jatropha farm production
yields by 200-300% in the next 10 years.
=== Fungi ===
A group at the Russian Academy of Sciences
in Moscow, in a 2008 paper, stated they had
isolated large amounts of lipids from single-celled
fungi and turned it into biofuels in an economically
efficient manner.
More research on this fungal species, Cunninghamella
japonica, and others, is likely to appear
in the near future.
The recent discovery of a variant of the fungus
Gliocladium roseum (later renamed Ascocoryne
sarcoides) 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.
Many other fungi that can degrade cellulose
and other polymers have been observed to produce
molecules that are currently being engineered
using organisms from other kingdoms, suggesting
that fungi may play a large role in the bioproduction
of fuels in the future.
=== Animal gut bacteria ===
Microbial gastrointestinal flora in a variety
of animals have shown potential for the production
of biofuels.
Recent research has shown that TU-103, a strain
of Clostridium bacteria found in Zebra feces,
can convert nearly any form of cellulose into
butanol fuel.
Microbes in panda waste are being investigated
for their use in creating biofuels from bamboo
and other plant materials.
There has also been substantial research into
the technology of using the gut microbiomes
of wood-feeding insects for the conversion
of lignocellulotic material into biofuel.
== See also
