Treethanol is an ethanol fuel (more precisely cellulosic ethanol) made from trees. [1]
The biofuel is a contender in the race to find an energy alternative to fossil fuels. Proponents of Treethanol claim that its energy yield is higher compared to the energy required for production when compared with more common sources of ethanol i.e. sugar cane and corn. [2]
Cellulosic ethanol is produced using the lignocellulose biomass that comprises much of the mass of plants. [3] Essentially at the core of the plant material is cellulose, which can be broken down into simple carbohydrate sugars. After these sugars have been extracted, they can be then be fermented into an alcohol, which is known as ethanol. [3] The most widely used and promising means of creating cellulosic ethanol is called the cellulolysis process. The process consists of hydrolysis on pretreated lignocellulosic materials. Then enzymes are used to break down cellulose into glucose. This glucose is then fermented and distilled. [2] The pretreatment step mentioned above is necessary when processing cellulosic ethanol because the glucose (sugars) are not readily accessible as they are with other ethanol sources such as corn or sugar cane. Rather, the cellulose in wood must be separated from the encapsulating hemicellulose and lignin.
There are three types of pretreatment: physical, chemical, and biological. Physical treatment involves physically reducing wood particle size. This can be accomplished through chipping, grinding, etc. Biological treatments involve the use of microorganisms to break down the wood. This type is considered favorable to physical pretreatments because it consumes far less energy in comparison, but the biological method has not proven to be scalable to an industrial level. The chemical method utilizes an alkaline or otherwise acidic medium to make the cellulose within wood fibers more accessible. This has shown to be the most efficient and has the lowest energy cost. [4]
Forest trees make up more than 90% of the total terrestrial biomass while performing functions such as carbon sequestration, producing oxygen, and promoting biodiversity. Trees are a promising source of ethanol because they grow all year round, require significantly less fertilizer and water and contain far more carbohydrates (the chemical precursors of ethanol) than food crops (like corn) do.[ citation needed ]
Poplar, Willow, and Eucalyptus tree are emerging as favorites in the process of creating Treethanol. [5] This is due to their ability to grow at a fast rate in many parts of the world. [6]
Treethanol is not an energy source that promises to power houses in the future, but rather it can be taken advantage of in applications where combustion engines are used. Approximately 85% of US energy consumption is produced from fossil fuels such as natural gas, coal, and oil. With China, India, and other rapidly developing nations increasing their demand for fossil fuels, the world’s total energy use is expected to grow by 57% over the next 20 years. [2] It is estimated that the U.S. alone uses 140 billion gallons of fuel per year for transportation alone. [7] Not only can Treethanol be mixed with ordinary fuels, it can also be burned directly in modified engines to greatly reduce greenhouse gas emissions. [2]
Cellulosic ethanol is an environmentally friendly and renewable transportation fuel that can be produced from forest biomass. Trees are a particularly promising feedstock because they grow all year round, require vastly less fertiliser and water and contain far more carbohydrates (the chemical precursors of ethanol) than food crops do. [8] Also, compared to corn ethanol, cellulosic biofuel does not require the same quantity of fertilizers, pesticides, energy, or water to grow. [9] The most important attribute of this type of ethanol is, like all types of ethanol, it is renewable. If you want or need to make more of it, you just grow more trees. [1]
The development of all types of biofuel, including Treethanol can be of importance for countries looking to decrease their dependence on petroleum, especially those countries that import most of their petroleum and also have plenty of crop/forest land such as New Zealand and Sweden. [1] [10]
An important issue is whether Treethanol is a superior alternative to more common forms of ethanol like corn based. The general consensus in an article by Hoover, F., & Abraham, J. (2009), is that most forms of cellulosic ethanol have the potential to yield higher energy outputs and be more sustainable than corn ethanol. They also note that while cellulosic ethanol does not necessarily yield more energy than say, corn based ethanol per unit of measurement, it requires far less energy inputs to produce which could give it a far higher net energy yield at the end of processing. The findings that lignocellulosic biomass has a far greater productivity yield than traditional biofuel sources is supported by Papini, A., & Simeone, M. (2010).
Responsible forestry practices do not contribute to greenhouse gases because the forest is allowed to regenerate following fiber harvesting. For this reason wood can be considered to be an essentially carbon-neutral source of energy.[ citation needed ]
While it seems reasonable that Treethanol could be an alternative to current ethanol types, it has one flaw, which is the extra processing needed to break down the tough cellulose and hemicellulose within the walls of the cell to isolate the sugars. [1] As discussed above in the production section, creating ethanol from the lignocellulose found in tree biomass requires the extra step of “pre-treatment”. It is this pre-treatment that still requires too much energy to make the Treethanol worth the effort.
That being said, many believe that the potential pros far out-weigh the short-term cons. [1] [2] The process of growing the tree biomass is energy efficient compared with growing corn or sugar cane for ethanol. However, it also takes longer to grow trees than to grow corn, and so any accurate research on sustainability and crop rotation (even for fast growing trees) requires a long time commitment, which up to now has been hard to find. It has been estimated that this process, including the building of processing plants and then refining of the growing and processing stage could take at least a decade. [11]
Another drawback to the processing of cellulosic ethanol is that there is little known about the waste/by products from the processing. Of particular concern to some is the biological method of pre-treatment. It is estimated that there is the possibility of producing almost as much (if not more) waste than usable ethanol, with waste products including mold, bacteria, yeast, biological toxins and allergens produced by these microorganisms, enzymes, and other chemicals. [12]
Biofuel 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. Biofuels are regarded as a renewable energy source.
Ethanol fuel is fuel containing ethyl alcohol, the same type of alcohol as found in alcoholic beverages. It is most often used as a motor fuel, mainly as a biofuel additive for gasoline.
Panicum virgatum, commonly known as switchgrass, is a perennial warm season bunchgrass native to North America, where it occurs naturally from 55°N latitude in Canada southwards into the United States and Mexico. Switchgrass is one of the dominant species of the central North American tallgrass prairie and can be found in remnant prairies, in native grass pastures, and naturalized along roadsides. It is used primarily for soil conservation, forage production, game cover, as an ornamental grass, in phytoremediation projects, fiber, electricity, heat production, for biosequestration of atmospheric carbon dioxide, and more recently as a biomass crop for ethanol and butanol.
Cellulosic ethanol is ethanol produced from cellulose 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.
A biorefinery is a refinery that converts biomass to energy and other beneficial byproducts. The International Energy Agency Bioenergy Task 42 defined biorefining as "the sustainable processing of biomass into a spectrum of bio-based products and bioenergy ". As refineries, biorefineries can provide multiple chemicals by fractioning an initial raw material (biomass) into multiple intermediates that can be further converted into value-added products. Each refining phase is also referred to as a "cascading phase". The use of biomass as feedstock can provide a benefit by reducing the impacts on the environment, as lower pollutants emissions and reduction in the emissions of hazard products. In addition, biorefineries are intended to achieve the following goals:
Bioenergy is energy made from biomass, which consists of recently living organisms, mainly plants. Types of biomass commonly used for bioenergy include wood, food crops such as corn, energy crops and waste from forests, yards, or farms. The IPCC defines bioenergy as a renewable form of energy. Bioenergy can either mitigate or increase greenhouse gas emissions. There is also agreement that local environmental impacts can be problematic.
Biomass to liquid is a multi-step process of producing synthetic hydrocarbon fuels made from biomass via a thermochemical route.
In order to create ethanol, all biomass needs to go through some of these steps: it needs to be grown, collected, dried, fermented, and burned. All of these steps require resources and an infrastructure. The ratio of the energy released by burning the resulting ethanol fuel to the energy used in the process, is known as the ethanol fuel energy balance and studied as part of the wider field of energy economics. Figures compiled in a 2007 National Geographic Magazine article point to modest results for corn ethanol produced in the US: 1 unit of energy input equals 1.3 energy units of corn ethanol energy. The energy balance for sugarcane ethanol produced in Brazil is much more favorable, 1 to 8. Over the years, however, many reports have been produced with contradicting energy balance estimates. A 2006 University of California Berkeley study, after analyzing six separate studies, concluded that producing ethanol from corn uses marginally less petroleum than producing gasoline.
The 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.
Lignocellulose 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. Being a composite of three very different components makes the processing of lignocellulose challenging. The evolved resistance to degradation or even separation is referred to as recalcitrance. Overcoming this recalcitrance to produce useful, high value products requires a combination of heat, chemicals, enzymes, and microorganisms. These carbohydrate-containing polymers contain different sugar monomers and they are covalently bound to lignin.
Energy crops are low-cost and low-maintenance crops grown solely for renewable bioenergy production. The crops are processed into solid, liquid or gaseous fuels, such as pellets, bioethanol or biogas. The fuels are burned to generate electrical power or heat.
The United States produces mainly biodiesel and ethanol fuel, which uses corn as the main feedstock. The US is the world's largest producer of ethanol, having produced nearly 16 billion gallons in 2017 alone. The United States, together with Brazil accounted for 85 percent of all ethanol production, with total world production of 27.05 billion gallons. Biodiesel is commercially available in most oilseed-producing states. As of 2005, it was somewhat more expensive than fossil diesel, though it is still commonly produced in relatively small quantities.
Renewable Fuels are fuels produced from renewable resources. Examples include: biofuels, Hydrogen fuel, and fully synthetic fuel produced from ambient carbon dioxide and water. This is in contrast to non-renewable fuels such as natural gas, LPG (propane), petroleum and other fossil fuels and nuclear energy. Renewable fuels can include fuels that are synthesized from renewable energy sources, such as wind and solar. Renewable fuels have gained in popularity due to their sustainability, low contributions to the carbon cycle, and in some cases lower amounts of greenhouse gases. The geo-political ramifications of these fuels are also of interest, particularly to industrialized economies which desire independence from Middle Eastern oil.
Corn ethanol is ethanol produced from corn biomass and is the main source of ethanol fuel in the United States, mandated to be blended with gasoline in the Renewable Fuel Standard. Corn ethanol is produced by ethanol fermentation and distillation. It is debatable whether the production and use of corn ethanol results in lower greenhouse gas emissions than gasoline. Approximately 45% of U.S. corn croplands are used for ethanol production.
Second-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.
China has set the goal of attaining one percent of its renewable energy generation through bioenergy in 2020.
Biogasoline or biopetrol is a type of gasoline produced from biomass such as algae. Like traditionally produced gasoline, it is made up of hydrocarbons with 6 (hexane) to 12 (dodecane) carbon atoms per molecule and can be used in internal combustion engines. Biogasoline is chemically different from biobutanol and bioethanol, as these are alcohols, not hydrocarbons.
Food versus fuel is the dilemma regarding the risk of diverting farmland or crops for biofuels production to the detriment of the food supply. The biofuel and food price debate involves wide-ranging views, and is a long-standing, controversial one in the literature. There is disagreement about the significance of the issue, what is causing it, and what can or should be done to remedy the situation. This complexity and uncertainty is due to the large number of impacts and feedback loops that can positively or negatively affect the price system. Moreover, the relative strengths of these positive and negative impacts vary in the short and long terms, and involve delayed effects. The academic side of the debate is also blurred by the use of different economic models and competing forms of statistical analysis.
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, 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. 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. In it, it 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 effect on climate, energy security and ecosystems, and suggested that environmental and social effects need to be assessed throughout the entire life-cycle.
Inbicon is a Danish company that produces cellulosic ethanol.
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