Cellulosic ethanolCellulosic ethanol is ethanol (ethyl alcohol) produced from cellulose (the stringy fiber of a plant) rather than from the plant's seeds or fruit. It can be produced from grasses, wood, algae, or other plants. It is generally discussed for use as a biofuel. The carbon dioxide that plants absorb as they grow offsets some of the carbon dioxide emitted when ethanol made from them is burned, so cellulosic ethanol fuel has the potential to have a lower carbon footprint than fossil fuels.
Lignocellulosic biomassLignocellulose refers to plant dry matter (biomass), so called lignocellulosic biomass. It is the most abundantly available raw material on the Earth for the production of biofuels. It is composed of two kinds of carbohydrate polymers, cellulose and hemicellulose, and an aromatic-rich polymer called lignin. Any biomass rich in cellulose, hemicelluloses, and lignin are commonly referred to as lignocellulosic biomass. Each component has a distinct chemical behavior.
BiofuelBiofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. Biofuel can be produced from plants or from agricultural, domestic or industrial biowaste. The climate change mitigation potential of biofuel varies considerably, from emission levels comparable to fossil fuels in some scenarios to negative emissions in others. Biofuels are mostly used for transportation, but can also be used for heating and electricity.
BiorefineryA biorefinery is a refinery that converts biomass to energy and other beneficial byproducts (such as chemicals). The International Energy Agency Bioenergy Task 42 defined biorefining as "the sustainable processing of biomass into a spectrum of bio-based products (food, feed, chemicals, materials) and bioenergy (biofuels, power and/or heat)". As refineries, biorefineries can provide multiple chemicals by fractioning an initial raw material (biomass) into multiple intermediates (carbohydrates, proteins, triglycerides) that can be further converted into value-added products.
Second-generation biofuelsSecond-generation biofuels, also known as advanced biofuels, are fuels that can be manufactured from various types of non-food biomass. Biomass in this context means plant materials and animal waste used especially as a source of fuel. First-generation biofuels are made from sugar-starch feedstocks (e.g., sugarcane and corn) and edible oil feedstocks (e.g., rapeseed and soybean oil), which are generally converted into bioethanol and biodiesel, respectively.
Biomass (energy)Biomass, in the context of energy production, is matter from recently living (but now dead) organisms which is used for bioenergy production. Examples include wood, wood residues, energy crops, agricultural residues including straw, and organic waste from industry and households. Wood and wood residues is the largest biomass energy source today. Wood can be used as a fuel directly or processed into pellet fuel or other forms of fuels. Other plants can also be used as fuel, for instance maize, switchgrass, miscanthus and bamboo.
Algae fuelAlgae fuel, algal biofuel, or algal oil is an alternative to liquid fossil fuels that uses algae as its source of energy-rich oils. Also, algae fuels are an alternative to commonly known biofuel sources, such as corn and sugarcane. When made from seaweed (macroalgae) it can be known as seaweed fuel or seaweed oil. In December 2022, ExxonMobil, the last large oil company to invest in algae biofuels, ended its research funding. In 1942 Harder and Von Witsch were the first to propose that microalgae be grown as a source of lipids for food or fuel.
Bioconversion of biomass to mixed alcohol fuelsThe bioconversion of biomass to mixed alcohol fuels can be accomplished using the MixAlco process. Through bioconversion of biomass to a mixed alcohol fuel, more energy from the biomass will end up as liquid fuels than in converting biomass to ethanol by yeast fermentation. The process involves a biological/chemical method for converting any biodegradable material (e.g., urban wastes, such as municipal solid waste, biodegradable waste, and sewage sludge, agricultural residues such as corn stover, sugarcane bagasse, cotton gin trash, manure) into useful chemicals, such as carboxylic acids (e.
Alcohol fuelVarious alcohols are used as fuel for internal combustion engines. The first four aliphatic alcohols (methanol, ethanol, propanol, and butanol) are of interest as fuels because they can be synthesized chemically or biologically, and they have characteristics which allow them to be used in internal combustion engines. The general chemical formula for alcohol fuel is CnH2n+1OH. Most methanol is produced from natural gas, although it can be produced from biomass using very similar chemical processes.
FuelA fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but has since also been applied to other sources of heat energy, such as nuclear energy (via nuclear fission and nuclear fusion). The heat energy released by reactions of fuels can be converted into mechanical energy via a heat engine.
Inverted sugar syrupInverted sugar syrup, also called invert syrup, invert sugar, simple syrup, sugar syrup, sugar water, bar syrup, syrup USP, or sucrose inversion, is a syrup mixture of the monosaccharides glucose and fructose, that is made by hydrolytic saccharification of the disaccharide sucrose. This mixture's optical rotation is opposite to that of the original sugar, which is why it is called an invert sugar. It is 1.3x sweeter than table sugar, and foods that contain invert sugar retain moisture better and crystallize less easily than do those that use table sugar instead.
Pyrolysis oilPyrolysis oil, sometimes also known as bio-crude or bio-oil, is a synthetic fuel under investigation as substitute for petroleum. It is obtained by heating dried biomass without oxygen in a reactor at a temperature of about with subsequent cooling. Pyrolysis oil is a kind of tar and normally contains levels of oxygen too high to be considered a pure hydrocarbon. This high oxygen content results in non-volatility, corrosiveness, immiscibility with fossil fuels, thermal instability, and a tendency to polymerize when exposed to air.
Renewable energyRenewable energy is energy from renewable resources that are naturally replenished on a human timescale. Renewable resources include sunlight, wind, the movement of water, and geothermal heat. Although most renewable energy sources are sustainable, some are not. For example, some biomass sources are considered unsustainable at current rates of exploitation. Renewable energy is often used for electricity generation, heating and cooling.
Ethanol fuel in BrazilBrazil is the world's second largest producer of ethanol fuel. Brazil and the United States have led the industrial production of ethanol fuel for several years, together accounting for 85 percent of the world's production in 2017. Brazil produced 26.72 billion liters (7.06 billion U.S. liquid gallons), representing 26.1 percent of the world's total ethanol used as fuel in 2017. Between 2006 and 2008, Brazil was considered to have the world's first "sustainable" biofuels economy and the biofuel industry leader, a policy model for other countries; and its sugarcane ethanol "the most successful alternative fuel to date.
Sustainable biofuelSustainable biofuel is biofuel produced in a sustainable manner. It is not based on petroleum or other fossil fuels. It includes not using plants that are used for food stuff to produce the fuel thus disrupting the world's food supply. Low-carbon fuel standard In 2008, the Roundtable for Sustainable Biofuels released its proposed standards for sustainable biofuels. This includes 12 principles: "Biofuel production shall follow international treaties and national laws regarding such things as air quality, water resources, agricultural practices, labor conditions, and more.
SugarSugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double sugars, are molecules made of two bonded monosaccharides; common examples are sucrose (glucose + fructose), lactose (glucose + galactose), and maltose (two molecules of glucose). White sugar is a refined form of sucrose. In the body, compound sugars are hydrolysed into simple sugars.
LigninLignin is a class of complex organic polymers that form key structural materials in the support tissues of most plants. Lignins are particularly important in the formation of cell walls, especially in wood and bark, because they lend rigidity and do not rot easily. Chemically, lignins are polymers made by cross-linking phenolic precursors. Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid.
Issues relating to biofuelsThere 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, poverty reduction potential, carbon emissions levels, sustainable biofuel production, deforestation and soil erosion, loss of biodiversity, effect on water resources, the possible modifications necessary to run the engine on biofuel, as well as energy balance and efficiency.
Bioenergy with carbon capture and storageBioenergy with carbon capture and storage (BECCS) is the process of extracting bioenergy from biomass and capturing and storing the carbon, thereby removing it from the atmosphere. BECCS can be a "negative emissions technology" (NET). The carbon in the biomass comes from the greenhouse gas carbon dioxide (CO2) which is extracted from the atmosphere by the biomass when it grows. Energy ("bioenergy") is extracted in useful forms (electricity, heat, biofuels, etc.
Butanol fuelButanol may be used as a fuel in an internal combustion engine. It is more similar to gasoline than it is to ethanol. A C4-hydrocarbon, butanol is a drop-in fuel and thus works in vehicles designed for use with gasoline without modification. Both n-butanol and isobutanol have been studied as possible fuels. Both can be produced from biomass (as "biobutanol" ) as well as from fossil fuels (as "petrobutanol"). The chemical properties depend on the isomer (n-butanol or isobutanol), not on the production method.
