Bioenergy is energy derived from biofuels.
Biofuels are fuels produced directly or indirectly from organic material biomass
including plant materials and animal waste. Bioenergy covers approximately 10%
of the total world energy demand. More advanced and efficient conversion
technologies now allow the extraction of biofuels from materials such as wood,
crops and waste material. Biofuels can be solid, gaseous or liquid, liquid biofuels
use for transport. Bioethanol is an alcohol made by fermenting by sugar component
of plant material. Biodiesel are made from vegetable oil, animal fats.it can be used
as a fuel for vehicles. Most transportation fuels are liquid because vehicles usually
require high energy density. Fuel that are easiest to burn cleanly are typically
liquids and gases.
Biofuels that are made up of sugar, starch, vegetable oil or animal fats are first
generation of biofuel. The basic feedstocks for the production of first generation
biofuels are often seeds or grain such as wheat.
These feedstocks could instead enter the animal or human food chain, and as the
global population has risen their use in producing biofuel has been criticized for
diverting food away from the human food chain, leading to food storages and price
By action of microorganisms & enzymes through fermentation of sugars or
It is also called bio gasoline, less common. Direct replacement for gasoline & used
in gasoline engine. It is produced by ABE fermentation (acetone, butanol, and
ethanol). Used as high net energy gain. Less corrosive & less water soluble. E. coli
successfully engineered to producebutanol.
It is common worldwide
3. Its production methods are (a) Enzyme digestion, (b) fermentation of sugars,
(c) distillation and (d) drying.
It is replacement for gasoline in petrol engines.
It has high octane number than gasoline.
They are flueless.
It is obtained through natural gas.
It is alternative to hydrogen economically.
Produced from oils or fats by Trans esterification.
It is similar to fossil/mineral diesel.
Process:oils are mixed with sodium hydroxide & the chemical reaction
produces biodiesel & glycerol.
Source: animal fats, vegetable oils, mustard, sunflower etc.
Used in diesel engine when mixed with mineral diesel.
It is effective solvent & clean residues by mineral diesel.
It is safe to handle & transport as it is biodegradable.
Lower quality oil can be used as fuel
Process:(a) By cleaning water & particulates, (b) By heating to reduce its
Used in older diesel engines, as they have combustion chambers which
allow larger molecules more time to burn.
Hydrogenated oils blend with diesel
Bioethers are cost-effective and act as octane rating enhancers. Enhance
performance of engine and significantly reduce engine wear and toxic exhaust
emissions. Reduce amount of ground-level ozone and improve quality of air we
It is a Mixture of different gases produced by decomposition of matter in the
absence of oxygen. Decomposition of raw materials such as agricultural waste,
manure, municipal waste, plant materials, sewage or food waste. It can be used for
cooking, heating, electricity, vehicle fuel and hydrogen fuel cells. Microbes digest
4. coal in situ converting it directly to gases. Landfills gas is less clean form of biogas
which is produced through naturally occurring anaerobic reactions. If it escapes
into the atmosphere it is a potent greenhouse gas. Oil and gases can be produced
from various biological wastes. Thermal depolymerization of waste can extract
methane and other oils similar to petroleum. Green fuel technologies developed a
bioreactor system that use algae to take in smokestacks flue gases and produce
biofuels i.e. biodiesel, biogas etc. Farmers can producebiogas from manure from
their cows by getting anaerobic digesters
• A mixture of carbon monoxide and hydrogen, produced by partial
combustion of biomass.
• Combustion with an amount that is not sufficient to convert biomass
completely to carbondioxide and water.
• It produces synthetic natural gas, ammonia and methanol.
• It generates electricity by internal combustion.
• It includes wood, sawdust, grass cuttings, domestic refuse, charcoal,
agricultural waste, non-food energy crops and dried manure.
• When raw material is in an inconvenient form such as sawdustor grass dust
the typical process is to densify the biomass.
• The process includes grinding to an appropriate size 1 to 3cm.
• The current types of processesare pellet, cube or puck.
• It emits considerable amount of amount of pollutants such as polycyclic
• Even modern pellet boilers generate much more pollutants than oil or natural
• Pellets made from agricultural residues are usually worse than worse than
wood pellets, producemuch larger amount of dioxins and chlorophenols.
• Also producesignificant amount of CO2
5. Second generation biofuels are also known as advanced biofuels. What separates
them from first generation biofuels the fact that feedstockused in producing
second generation biofuels are generally not food crops. Theonly time the food
crops can act as second generation biofuels is if they have already fulfilled their
food purpose. Forinstance, waste vegetable oil is a second generation biofuels
because it has already been used and is no longer fit for human consumption.
Virgin vegetable oil, however, would be a first generation biofuel.
Because second generation biofuels are derived from different feed stock, Different
technology is often used to extract energy from them. This does not mean that
second generation biofuels cannot be burned directly as the biomass. In fact,
several second generation biofuels, like Switch grass, are cultivated specifically to
act as direct biomass
For the most part, second generation feedstock are processed differently than first
generation biofuels. This is particularly true of lignocellulose feedstock, which
tends to require several processing steps prior to being fermented (a first
generation technology) into ethanol. An outline of second generation processing
The first thermochemical route is known as gasification. Gasification is not a new
technology and has been used extensively on conventional fossil fuels for a
number of years. Second generation gasification technologies have been slightly
altered to accommodatethe differences in biomass stock. Through gasification,
carbon-based materials are converted to carbon monoxide, hydrogen, and carbon
dioxide. This process is different from combustion in that oxygen is limited. The
gas that result is referred to as synthesis gas or syngas. Syngas is then used to
produceenergy or heat. Wood, black liquor, brown liquor, and other feedstockare
used in this process.
The secondthermochemical route is known as pyrolysis. Pyrolysis also has a long
history of use with fossil fuels. Pyrolysis is carried out in the absence of oxygen
and often in the presence of an inert gas like halogen. The fuel is generally
converted into two products:tars and char. Wood and a number of other energy
crops can be used as feedstockto producebio-oil through pyrolysis.
6. A third thermochemical reaction, called torrefaction, is very similar to pyrolysis,
but is carried out at lower temperatures. The process tends to yield better fuels for
further use in gasification or combustion. Torrefaction is often used to convert
biomass feedstockinto a form that is more easily transported and stored.
A number of biological and chemical processes are being adapted for the
production of biofuel from second generation feedstock. Fermentation with unique
or genetically modified bacteria is particularly popular for second generation
feedstocklike landfill gas and municipal waste
Jatropha and other seed
Municipal solid waste
The term third generation biofuel has only recently entered the mainstream it refers
to biofuel derived from algae. Previously, algae were lumped in with second
generation biofuels. However, when it became apparent that algae are capable of
much higher yields with lower resource inputs than other feedstock, many
suggested that they be moved to their own category. As we will demonstrate, algae
provide a number of advantages, but at least one major shortcoming that has
prevented them from becoming a runaway success.
The list of fuels that can be derived from algae includes:
There are many environmental benefits to replacing oil with biofuels like ethanol
and biodiesel. For one, since such fuels are derived from agricultural crops, they
7. are inherently renewable—and our own farmers typically producethem
domestically, reducing our dependence on unstable foreign sources of oil.
Additionally, ethanol and biodiesel emit less particulate pollution than traditional
petroleum-based gasoline and diesel fuels. They also do not contribute significant
greenhouse gases to the global climate change problem, since they only emit back
to the environment the carbon dioxide that their sourceplants absorbed outof the
atmosphere in the first place. There are eco-benefits in replacing oil with ethanol
Biofuels are Easyto Use, but Not Always Easyto Find
They don’tneed special apparatus or a change in vehicle or home heating
infrastructure like hydrogen but those looking to replace gasoline with ethanol in
their car, however, must have a “flex-fuel” model that can run on either fuel.
Biofuels are far from a cure for our addiction to petroleum, A wholesale societal
shift from gasoline to biofuels, given the number of gas-only cars already on the
road and the lack of ethanol or biodiesel pumps at existing filling stations, would
take some time.
Are There Enough Farms and Crops to Support a Switch to Biofuels?
Growing enough crops to meet demand.
“Replacing only five percent of the nation’s diesel consumption with biodiesel
would require diverting approximately 60 percent of today’s soy crops to biodiesel
production,” says Matthew Brown, an energy consultant.
The intensive cultivation of crops forbiofuels is done with the help of large
amounts of pesticides, herbicides, and synthetic fertilizers.
Does Producing Biofuels Use More Energy than They CanGenerate?
Another dark cloud looming over biofuels is whether producing them actually
requires more energy than they can generate. The numbers just don’t add up. For
example: ‘producing ethanol from corn required 29 percent more energy than the
end productitself is capable of generating.’ Plus, there is just no energy benefit to
using plant biomass for liquid fuel.
POSITIVES OF BIOFUELS:biofuels are CostBenefit Renewable, are Easy
source, Reduces Greenhouse Gases, provides Economic Security, helps in lower
pollution, results in High-Quality Engine Performance and contribute in health
CostBenefit: biofuels costthe same in the market as gasoline does.
However, the overall costbenefit of using them is much higher. They are
8. cleaner fuels, which means they producefewer emissions on burning.
worldwide demand for oil increases, oil supplies dwindle, and more sources
of biofuels become apparent.
Source material: Whereas oil is a limited resource that comes from specific
materials, biofuels can be manufactured from a wide range of materials
including crop waste, manure, and other by products. This makes it an
efficient step in recycling.
Renewability: It takes a very long time for fossil fuels to be produced, but
biofuels are much more easily renewable as new crops are grown and waste
material is collected.
Security: Biofuels can be produced locally, which decreases the nation's
dependence upon foreign energy.so, countries can protectthe integrity of
their energy resources and make them safe from outside influences.
Lower carbonemissions: When biofuels are burned, they produce
significantly less carbonoutput and fewer toxins, making them a safer
alternative to preserve atmospheric quality and lower air pollution.
NEGATIVES OF BIOFUELS: Drawbacks include High Costof Production,
Monoculture, Use of Fertilizers, less Energy output, Shortage of Food, Water Use,
increase in Food prices and food shortage and its future Rise in Price.
Energy output: Biofuels have a lower energy output than traditional fuels
and therefore require greater quantities to be consumed in order to produce
the same energy level.
High cost:To refine biofuels to more efficient energy outputs, and to build
the necessary manufacturing plants to increase biofuel quantities, a high
initial investment is often required.
Foodprices: As demand for food crops suchas corngrows for biofuel
production, it could also raise prices for necessary staple food crops.
Wateruse: Massive quantities of water are required for properirrigation of
biofuel crops as well as to manufacture the fuel, which could strain local and
regional water resources.
Monoculture: Monoculture refers to practice of producing same crops year
after year, growing same crop every year may deprive the soil of nutrients
that are put back into the soil through crop rotation.