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 The Solar Car Book A complete kit for making a cool solar racecar. Everything is included: wheels, axles, motors, wires and a genuine one-volt solar cell. |
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Make Your Own Biodiesel
Biodiesel refers to a non-petroleum-based diesel fuel consisting of short chain alkyl (methyl or ethyl) esters, typically made by transesterification of vegetable oils or animal fats, which can be used (alone, or blended with conventional petrodiesel) in unmodified diesel-engine vehicles. Biodiesel is distinguished from the straight vegetable oil (SVO) (aka "waste vegetable oil", "WVO", "unwashed biodiesel", "pure plant oil", "PPO") used (alone, or blended) as fuels in some converted diesel vehicles. "Biodiesel" is standardized as methyl ester and other non-diesel fuels of biological origin are not included.[1] 
Biodiesel is biodegradable and non-toxic, and typically produces about 60% less net-lifecycle carbon dioxide emissions, as it is itself produced from atmospheric carbon dioxide via photosynthesis in plants. Its emissions of smog forming hydrocarbon are 67% less, although the Nitrogen Oxide emissions are about 10% greater than those from petroleum-based diesel.[2][3] Net-lifetime carbon dioxide emissions can actually differ widely between fuels depending upon production methods of the source vegetable oils and processing methods employed in their creation. It is therefore debatable as to the extent that biodiesel reduces total carbon dioxide emissions currently contributing to anthropogenic global warming compared to those from petroleum-based diesel. OriginOn August 31, 1937, G. Chavanne of the University of Brussels (Belgium) was granted a patent for a 'Procedure for the transformation of vegetable oils for their uses as fuels' (fr. 'Procédé de Transformation d’Huiles Végétales en Vue de Leur Utilisation comme Carburants') Belgian Patent 422,877. This patent described the alcoholysis (often referred to as transesterification) of vegetable oils using ethanol (and mentions methanol) in order to separate the fatty acids from the glycerol by replacing the glycerol with short linear alcohols. This appears to be the first account of the production of what is known as 'biodiesel' today.[4] Vehicular use and manufacturer acceptanceWhile some vehicle manufacturers are positive about the use of biodiesel, citing lower engine wear as one of the fuel's benefits, they rarely commit to the acceptability of biodiesel. Biodiesel is a better solvent than standard diesel, as it 'cleans' the engine, loosening petrodiesel deposits in the fuel lines, which can cause blockages downstream in engines that have previously run for some time on petroleum diesel. For this reason, car manufacturers recommend that the fuel filter be changed more frequently for a few months after switching to biodiesel. Most manufacturers release lists of the cars that will run on 100% biodiesel.[5] [5] Volkswagen, for example, may tell European customers that they have no problem with biodiesel, while dealers in the USA have posted notices that only blends above 95% petrodiesel are permitted. These concerns generally diminish in countries where biodiesel production becomes routine and conformant to standards. Warranty coverage is often cited as an issue with the adoption of biodiesel as a fuel, but in general warranties do not cover damage due to any kind of bad fuel, not specifically biodiesel. In the UK and the USA dealers may say there is no warranty coverage 5% biodiesel — blended in with 95% conventional diesel — although this position is generally considered to be overly cautious.[6] In these places customers often switch to petrodiesel temporarily before going for scheduled service, particularly those who have experienced "diagnosis by bumper sticker". Specific manufacturer policies include:
Railroad useThe British businessman Richard Branson's Virgin Voyager train, number 220007 Thames Voyager [9], billed as the world's first "biodiesel train" was converted to run on 80% petrodiesel and only 20% biodiesel, and is expected to save 14% on direct emissions. Aircraft useAircraft manufacturers are understandably even more cautious, but some test flights have been performed[10] and commercial passenger jet testing has been announced[11] by Virgin Atlantic's Richard Branson. The world's first biofuel-powered commercial aircraft took off from London's Heathrow Airport on February 24, 2008 on a demonstration flight hailed as a first step towards "cleaner" flying.[12] As a heating oilBiodiesel can also be used as a heating fuel in domestic and
commercial boilers. Older furnaces may contain rubber parts that would
be affected by biodiesel's solvent properties, but can otherwise burn
biodiesel without any conversion required. Care must be taken at first,
however, given that varnishes left behind by petrodiesel will be
released and can clog pipes- fuel filtering and prompt filter
replacement is required. Another approach is to start using biodiesel
as blend, and decreasing the petroleum proportion over time can allow
the varnishes to come off more gradually and be less likely to clog.
Thanks to its strong solvent properties, however, the furnace is
cleaned out and generally becomes more efficient. DistributionBiodiesel can be distributed using today's diesel infrastructure as long as minor adjustments are made, such as replacement of old solvent-prone fittings and hoses, filtering of loosened fossil fuel varnishes, and prevention of the growth of mold and care taken to prevent coagulation at colder temperatures. Its use and production are increasing rapidly. Fuel stations make biodiesel readily available to consumers across Europe, and increasingly in the USA and Canada, and a growing number of transport fleets use it as an additive in their fuel. Biodiesel is often more expensive to purchase than petroleum diesel but this is expected to diminish due to economies of scale and agricultural subsidies versus the rising cost of petroleum as reserves are depleted. DescriptionBiodiesel is a liquid which varies in color — between golden and dark brown — depending on the production feedstock. It is immiscible with water, has a high boiling point and low vapor pressure. Typical methyl ester biodiesel has a flash point of ~ 150 °C (300 °F). Biodiesel has a density of ~ 0.88 g/cm³, less than that of water. Biodiesel has a viscosity similar to petrodiesel, the current industry term for diesel produced from petroleum. Biodiesel has high lubricity and virtually no sulfur content, and it is often used as an additive to Ultra-Low Sulfur Diesel (ULSD) fuel. Much of the world uses a system known as the "B" factor to state the amount of biodiesel in any fuel mix: fuel containing 20% biodiesel is labeled B20, while pure biodiesel is referred to as B100. It is common to see B99, since 1% petrodiesel is sufficiently toxic to retard mold. Biodiesel is a renewable fuel that can be manufactured from vegetable oils, animal fats, recycled restaurant greases, and some types of algae; it can be produced locally in most countries. It is safe, biodegradable and reduces air pollutants, such as particulates, carbon monoxide and hydrocarbons. Blends of 20 percent biodiesel with 80 percent petroleum diesel (B20) can generally be used in unmodified diesel engines. Biodiesel can also be used in its pure form (B100), but may require certain engine modifications to avoid maintenance and performance problems. The volumetric energy density of biodiesel is about 33 MJ/l. This is 9 % lower than regular Number 2 petrodiesel. Variations in biodiesel energy density is more dependent on the feedstock used than the production process. Still these variations are less than for petrodiesel.[13] It has been claimed biodiesel gives better lubricity and more complete combustion thus increasing the engine energy output and partially compensating for the higher energy density of petrodiesel.[14] Historical backgroundTransesterification of a vegetable oil was conducted as early as 1853 by scientists E. Duffy and J. Patrick, many years before the first diesel engine became functional. Rudolf Diesel's prime model, a single 10 ft (3 m) iron cylinder with a flywheel at its base, ran on its own power for the first time in Augsburg, Germany, on August 10, 1893. In remembrance of this event, August 10 has been declared "International Biodiesel Day". Rudolf Diesel demonstrated a Diesel engine running on peanut oil (at the request of the French government) built by the French Otto Company at the World Fair in Paris, France in 1900, where it received the Grand Prix (highest prize). [15] This engine stood as an example of Diesel's vision because it was powered by peanut oil — a biofuel, though not biodiesel, since it was not transesterified. He believed that the utilization of biomass fuel was the real future of his engine. In a 1912 speech Diesel said, "the use of vegetable oils for engine fuels may seem insignificant today but such oils may become, in the course of time, as important as petroleum and the coal-tar products of the present time."[16] During the 1920s, diesel engine manufacturers altered their engines to utilize the lower viscosity of petrodiesel (a fossil fuel), rather than vegetable oil (a biomass fuel). The petroleum industries were able to make inroads in fuel markets because their fuel was much cheaper to produce than the biomass alternatives. The result, for many years, was a near elimination of the biomass fuel production infrastructure. Only recently, have environmental impact concerns and a decreasing price differential made biomass fuels such as biodiesel a growing alternative. Despite the widespread use of fossil petroleum-derived diesel fuels, interest in vegetable oils as fuels in internal combustion engines is reported in several countries during the 1920's and 1930's and later during World War II. Belgium, France, Italy, the United Kingdom, Portugal, Germany, Brazil, Argentina, Japan and China have been reported to have tested and used vegetable oils as diesel fuels during this time. Some operational problems were reported due to the high viscosity of vegetable oils compared to petroleum diesel fuel, which result in poor atomization of the fuel in the fuel spray and often leads to deposits and coking of the injectors, combustion chamber and valves. Attempts to overcome these problems included heating of the vegetable oil, blending it with petroleum-derived diesel fuel or ethanol, pyrolysis and cracking of the oils. On August 31, 1937, G. Chavanne of the University of Brussels (Belgium) was granted a patent for a "Procedure for the transformation of vegetable oils for their uses as fuels" (fr. 'Procédé de Transformation d’Huiles Végétales en Vue de Leur Utilisation comme Carburants') Belgian Patent 422,877. This patent described the alcoholysis (often referred to as transesterification) of vegetable oils using methanol and ethanol in order to separate the fatty acids from the glycerol by replacing the glycerol by short linear alcohols. This appears to be the first account of the production of what is known as "biodiesel" today. More recently, in 1977, Brazilian scientist Expedito Parente produced biodiesel using transesterification with ethanol, and again filed a patent for the same process. This process is classified as biodiesel by international norms, conferring a "standardized identity and quality. No other proposed biofuel has been validated by the motor industry."[17] Currently, Parente's company Tecbio is working with Boeing and NASA to certify bioquerosene (bio-kerosene), another product produced and patented by the Brazilian scientist.[18] Research into the use of transesterified sunflower oil, and refining it to diesel fuel standards, was initiated in South Africa in 1979. By 1983, the process for producing fuel-quality, engine-tested biodiesel was completed and published internationally.[19] An Austrian company, Gaskoks, obtained the technology from the South African Agricultural Engineers; the company erected the first biodiesel pilot plant in November 1987, and the first industrial-scale plant in April 1989 (with a capacity of 30,000 tons of rapeseed per annum). Throughout the 1990s, plants were opened in many European countries, including the Czech Republic, Germany and Sweden. France launched local production of biodiesel fuel (referred to as diester) from rapeseed oil, which is mixed into regular diesel fuel at a level of 5%, and into the diesel fuel used by some captive fleets (e.g. public transportation) at a level of 30%. Renault, Peugeot and other manufacturers have certified truck engines for use with up to that level of partial biodiesel; experiments with 50% biodiesel are underway. During the same period, nations in other parts of the world also saw local production of biodiesel starting up: by 1998, the Austrian Biofuels Institute had identified 21 countries with commercial biodiesel projects. 100% Biodiesel is now available at many normal service stations across Europe. In September 2005 Minnesota became the first U.S. state to mandate that all diesel fuel sold in the state contain part biodiesel, requiring a content of at least 2% biodiesel.[20] Technical standards
The common international standard for biodiesel is EN 14214. There are additional national specifications. ASTM D6751
is the most common standard referenced in the United States and Canada.
In Germany, the requirements for biodiesel are fixed in the DIN EN 14214 standard and in the UK the requirements for biodiesel is fixed in the BS EN 14214 standard, although these last two standards are essentially the same as EN 14214 and are just prefixed with the respective national standards institution codes.
The standards ensure that the following important factors in the fuel production process are satisfied:
Basic industrial tests to determine whether the products conform to the standards typically include gas chromatography, a test that verifies only the more important of the variables above. Tests that are more complete are more expensive. Fuel meeting the quality standards is very non-toxic, with a toxicity rating (LD50) of greater than 50 mL/kg. ApplicationsBiodiesel can be used in pure form (B100) or may be blended with petroleum diesel at any concentration in most modern diesel engines. Biodiesel will degrade natural rubber gaskets and hoses in vehicles (mostly found in vehicles manufactured before 1992), although these tend to wear out naturally and most likely will have already been replaced with FKM, which is nonreactive to biodiesel. Biodiesel has better lubricity than that of today's diesel fuels. During the manufacture of these, to comply with low SO2 engine emission limits set in modern standards, severe hydrotreatment is included. Biodiesel addition reduces wear[21] increasing the life of the fuel injection equipment that relies on the fuel for its lubrication, such as high pressure injection pumps, pump injectors (also called unit injectors) and fuel injectors. Use
Pure, non-blended biodiesel can be poured straight into the tank of any diesel vehicle. As with normal diesel, low-temperature biodiesel is sold during winter months to prevent viscosity problems. Some older diesel engines still have natural rubber parts which will be affected by biodiesel, but in practice these rubber parts should have been replaced long ago. Biodiesel is used by millions of car owners in Europe (particularly Germany). [22] Biodiesel is a better solvent than petrodiesel, and has been known to break down deposits of residue in the fuel lines of vehicles that have previously been run on petrodiesel.[23] As a result, fuel filters may become clogged with particulates if a quick transition to pure biodiesel is made, as biodiesel “cleans” the engine in the process. Therefore, it is recommended to change the fuel filter within 600–800 miles after first switching to a biodiesel blend. Research sponsored by petroleum producers has found petroleum diesel better for car engines than biodiesel, including for example the Volkswagen environmental awareness division, who note that biodiesel reduces engine wear. Pure biodiesel produced 'at home' is in use by thousands of drivers who have not experienced failure. In spite of the fact that biodiesel sold to the public is held to high standards set by national standards bodies, biodiesel has been widely available at fuel stations for less than a decade, and hence is reasonably perceived to carry more risk than older fuels. GellingThe cloud point, or temperature at which pure (B100) biodiesel starts to gel, varies significantly and depends upon the mix of esters and therefore the feedstock oil used to produce the biodiesel. For example, biodiesel produced from low erucic acid varieties of canola seed (RME) starts to gel at approximately −10 °C (14 °F). Biodiesel produced from tallow tends to gel at around +16 °C (68 °F). As of 2006, there are a very limited number of products that will significantly lower the gel point of straight biodiesel. A number of studies have shown that winter operation is possible with biodiesel blended with other fuel oils including #2 low sulfur diesel fuel and #1 diesel / kerosene. The exact blend depends on the operating environment: successful operations have run using a 65% LS #2, 30% K #1, and 5% bio blend. Other areas have run a 70% Low Sulfur #2, 20% Kerosene #1, and 10% bio blend or an 80% K#1, and 20% biodiesel blend. According to the National Biodiesel Board (NBB), B20 (20% biodiesel, 80% petrodiesel) does not need any treatment in addition to what is already taken with petrodiesel. Some people modify their vehicles to permit the use of biodiesel without mixing and without the possibility of gelling at low temperatures. This practice is similar to the one used for running straight vegetable oil. They install a second fuel tank (some models of trucks have two tanks already). This second fuel tank is insulated and a heating coil using engine coolant is run through the tank. There is then a temperature sensor installed to notify the driver when the fuel is warm enough to burn, the driver then switches which tank the engine is drawing from. Contamination by waterBiodiesel may contain small but problematic quantities of water. Although it is hydrophobic (non-miscible with water molecules), it is said to be, at the same time, hygroscopic to the point of attracting water molecules from atmospheric moisture[24]; one of the reasons biodiesel can absorb water is the persistence of mono and diglycerides left over from an incomplete reaction. These molecules can act as an emulsifier, allowing water to mix with the biodiesel. In addition, there may be water that is residual to processing or resulting from storage tank condensation. The presence of water is a problem because:
Previously, the amount of water contaminating biodiesel has been difficult to measure by taking samples, since water and oil separate. However, it is now possible to measure the water content using water in oil sensors. Heating applicationsBiodiesel can also be used as a heating fuel in domestic and commercial boilers. A technical research paper [25] describes laboratory research and field trials project using pure biodiesel and biodiesel blends as a heating fuel in oil fired boilers. During the Biodiesel Expo 2006 in the UK, Andrew J. Robertson presented his biodiesel heating oil research from his technical paper and suggested that B20 biodiesel could reduce UK household CO2 emissions by 1.5 million tonnes per year and would only require around 330,000 hectares of arable land for the required biodiesel for the UK heating oil sector. The paper also suggests that existing oil boilers can easily and cheaply be converted to biodiesel if B20 biodiesel is used. Availability and prices
Global biodiesel production reached 3.8 million tons in 2005. Approximately 85% of biodiesel production came from the European Union. In the United States, average retail (at the pump) prices, including Federal and state motor taxes, of B2/B5 are lower than petroleum diesel by about 12 cents, and B20 blends are the same as petrodiesel. [26] B99 and B100 generally cost more than petrodiesel except where local governments provide a subsidy. ProductionChemically, transesterified biodiesel comprises a mix of mono-alkyl esters of long chain fatty acids. The most common form uses methanol to produce methyl esters as it is the cheapest alcohol available, though ethanol can be used to produce an ethyl ester biodiesel and higher alcohols such as isopropanol and butanol have also been used. Using alcohols of higher molecular weights improves the cold flow properties of the resulting ester, at the cost of a less efficient transesterification reaction. A lipid transesterification production process is used to convert the base oil to the desired esters. Any Free fatty acids (FFAs) in the base oil are either converted to soap and removed from the process, or they are esterified (yielding more biodiesel) using an acidic catalyst. After this processing, unlike straight vegetable oil, biodiesel has combustion properties very similar to those of petroleum diesel, and can replace it in most current uses. A byproduct of the transesterification process is the production of glycerol. For every 1 tonne of biodiesel that is manufactured, 100 kg of glycerol are produced. Originally, there was a valuable market for the glycerol, which assisted the economics of the process as a whole. However, with the increase in global biodiesel production, the market price for this crude glycerol (containing 20% water and catalyst residues) has crashed. Research is being conducted globally to use this glycerol as a chemical building block. One initiative in the UK is The Glycerol Challenge. Usually this crude glycerol has to be purified, typically by performing vacuum distillation. This is rather energy intensive. The refined glycerol (98%+ purity) can then be utilised directly, or converted into other products. The following announcements were made in 2007: A joint venture of Ashland Inc. and Cargill announced plans to make propylene glycol in Europe from glycerol[27] and Dow Chemical announced similar plans for North America.[28] Dow also plans to build a plant in China to make epichlorhydrin from glycerol.[29] Epichlorhydrin is a raw material for epoxy resins. Biodiesel feedstocks
A variety of oils can be used to produce biodiesel. These include:
Worldwide production of vegetable oil and animal fat is not yet sufficient to replace liquid fossil fuel use. Furthermore, some environmental groups object to the vast amount of farming and the resulting over-fertilization, pesticide use, and land use conversion that they say would be needed to produce the additional vegetable oil. Many advocates suggest that waste vegetable oil is the best source of oil to produce biodiesel, but since the available supply is drastically less than the amount of petroleum-based fuel that is burned for transportation and home heating in the world, this local solution does not scale well. It is important to note that one unit of waste oil is not equivalent to one unit of biodiesel. Although it is economically profitable to use WVO to produce biodiesel, it is even more profitable to convert WVO into other products such as soap. Therefore, most WVO that is not dumped into landfills is used for these other purposes. Animal fats are similarly limited in supply, and it would not be efficient to raise animals simply for their fat. However, producing biodiesel with animal fat that would have otherwise been discarded could replace a small percentage of petroleum diesel usage. Currently, a 5-million dollar plant is being built in the USA, with the intent of producing 11.4 million litres (3 million gallons) biodiesel from some of the estimated 1 billion kg (2.3 billion pounds) of chicken fat[33] produced annually the local Tyson poultry plant. [30] The estimated transportation diesel fuel and home heating oil used in the United States is about 160 million tonnes (350 billion pounds) according to the Energy Information Administration, US Department of Energy - [34]. Waste vegetable oil and animal fats would not be enough to meet this demand. In the United States, estimated production of vegetable oil for all uses is about 11 million tonnes (24 billion pounds) and estimated production of animal fat is 5.3 million tonnes (12 billion pounds).[35] Biodiesel feedstock plants utilize photosynthesis to convert solar energy into chemical energy. The stored chemical energy is released when it is burned, therefore plants can offer a sustainable oil source for biodiesel production. Most of the carbon dioxide emitted when burning biodiesel is simply recycling that which was absorbed during plant growth, so the net production of greenhouse gases is small. YieldFeedstock yield efficiency per acre affects the feasibility of ramping up production to the huge industrial levels required to power a significant percentage of national or world vehicles. Some typical yields in US gallons of biodiesel per acre are:
Algae fuel yields have not yet been accurately determined, but DOE is reported as saying that algae yield 30 times more energy per acre than land crops such as soybeans.[39], and some estimate even higher yields up to 15000 gpa .[40] The Jatropha plant has been cited as a high-yield source of biodiesel but such claims have also been exaggerated.[41] The more realistic estimates put the yield at about 200 gpa [42] (1.5-2 tonnes per hectare). It is grown in the Philippines, Mali and India, is drought-resistant, and can can share space with other cash crops such as coffee, sugar, fruits and vegetables.[43] Efficiency and economic argumentsAccording to a study written by Drs. Van Dyne and Raymer for the Tennessee Valley Authority, the average US farm consumes fuel at the rate of 82 litres per hectare (8.75 US gallons per acre) of land to produce one crop. However, average crops of rapeseed produce oil at an average rate of 1,029 L/ha (110 US gal/acre), and high-yield rapeseed fields produce about 1,356 L/ha (145 US gal/acre). The ratio of input to output in these cases is roughly 1:12.5 and 1:16.5. Photosynthesis is known to have an efficiency rate of about 3-6% of total solar radiation[44] and if the entire mass of a crop is utilized for energy production, the overall efficiency of this chain is currently about 1%. While this may compare favorably to solar cells combined with an electric drive train, biodiesel is less costly to deploy (solar cells cost approximately US$1,000 per square meter) and transportation (electric vehicles require batteries which currently have a much lower energy density than liguid fuels). However, these statistics by themselves are not enough to show whether such a change makes economic sense. Additional factors must be taken into account, such as: the fuel equivalent of the energy required for processing, the yield of fuel from raw oil, the return on cultivating food, the effect biodiesel will have of food prices and the relative cost of biodiesel versus petrodiesel. A 1998 joint study by the U.S. Department of Energy (DOE) and the U.S. Department of Agriculture (USDA) traced many of the various costs involved in the production of biodiesel and found that overall, it yields an average 3.2 units of fuel product energy, depending on the feedstock and production methods, for every unit of fossil fuel energy consumed.[45] That measure is referred to as the energy yield. A comparison to petroleum diesel, petroleum gasoline and bioethanol using the USDA numbers can be found at the Minnesota Department of Agriculture website[46]. In the comparison petroleum diesel fuel is found to have a 0.843 energy yield, along with 0.805 for petroleum gasoline, and 1.34 for bioethanol. The 1998 study used soybean oil primarily as the base oil to calculate the energy yields. Furthermore, due to the higher energy density of biodiesel, combined with the higher efficiency of the diesel engine, a unit of biodiesel produces the effective energy of 2.25 units of ethanol.[47] Also, higher oil yielding crops could increase the energy yield of biodiesel. The debate over the energy balance of biodiesel is ongoing. Transitioning fully to biofuels could require immense tracts of land if traditional food crops are used (although non food crops can be utilized). The problem would be especially severe for nations with large economies, since energy consumption scales with economic output.[48] If using only traditional food plants, most such nations do not have sufficient arable land to produce biofuel for the nation's vehicles. Nations with smaller economies (hence less energy consumption) and more arable land may be in better situations, although many regions cannot afford to divert land away from food production. For third world countries, biodiesel sources that use marginal land could make more sense, e.g. honge oil nuts[49] grown along roads or jatropha grown along rail lines. More recent studies using a species of algae with up to 50% oil content have concluded that only 28,000 km² or 0.3% of the land area of the US could be utilized to produce enough biodiesel to replace all transportation fuel the country currently utilizes. Furthermore, otherwise unused desert land (which receives high solar radiation) could be most effective for growing the algae, and the algae could utilize farm waste and excess CO2 from factories to help speed the growth of the algae.[50] In tropical regions, such as Malaysia and Indonesia, oil palm is being planted at a rapid pace to supply growing biodiesel demand in Europe and other markets. It has been estimated in Germany that palm oil biodiesel has less than 1/3 the production costs of rapeseed biodiesel.[51] The direct source of the energy content of biodiesel is solar energy captured by plants during photosynthesis. The website biodiesel.co.uk[52] discusses the positive energy balance of biodiesel:
Biodiesel is becoming of interest to companies interested in commercial scale production as well as the more usual home brew biodiesel user and the user of straight vegetable oil or waste vegetable oil in diesel engines. Homemade biodiesel processors are many and varied. Environmental effects
Environmental benefits in comparison to petroleum based fuels include: Carbon intensity aka carbon footprint
Pollution
Biodegradable
Nontoxic to humans
Flammability
Environmental concernsThe locations where oil-producing plants are grown is of increasing concern. Mono-culture plantations clear cut large areas of tropical forest in order to grow such oil rich crops such as oil palm. In the Philippines and Indonesia such forest clearing is already underway for the production of palm oil. In Indonesia, for example, deforestation has caused displacement of indigenous peoples. Also, in some areas use of pesticides for biofuel crops are disrupting clean water supplies.[56] Loss of habitat on such a scale could endanger numerous species of plants and animals. A particular concern which has received considerable attention is the threat to the already-shrinking populations of orangutans on the Indonesian islands of Borneo and Sumatra, which face possible extinction.[57] Third world productionBiodiesel and feedstock oils produced in Asia, South America and Africa are currently less expensive than those produced in Europe and North America suggesting that imports to these wealthier nations are likely to increase in future. Like all petroleum based fuels, biodiesel also requires a significant investment of energy before it arrives at petrol pumps, thus fair comparisons among fuels require full lifecycle analyses for each fuel type. The US EPA currently estimates that the use of biodiesel represents a 67% reduction in greenhouse gas emissions in comparison with petroleum based fuels. If deforestation, and monoculture farming techniques were used to grow biofuel crops, biodiesel is predicted to become a serious threat to the environment. These problems could be exacerbated as biodiesel becomes more popular unless stringent laws are introduced and enforced to control biodiesel production. Non-food energy crops and lipid rich algaes with vastly greater oil yields may also replace low-yield annual food crops such as soybeans, skirting the deforestation risk associated with widespread uptake of biodiesel.GuJi As non-food crops also facilitate the use of degraded lands, wastewater, processed sewage, and other waste streams, the benefits of such crops go well beyond their greater yields. Moreover, select non-food crops such as jatropha and castorbean can be grown in polycultures, in non-till agricultural applications, and they scale well from the standpoint of production, storage, and processing. As such, these crops might benefit small-scale farmers throughout tropical and temperate latitudes, providing a cash crop option which can also displace local demand for imported petroleum. NOx emissionsIf burned without additives, Biodiesel (B100) is estimated to produce about 10% more nitrogen oxide NOx tailpipe-emissions than petrodiesel. As biodiesel has a low sulfur content, NOx emissions can be reduced through the use of catalytic converters to less than the NOx emissions from conventional diesel engines. Moreover, as a transportation fuel, biodiesel is in its infancy in terms of additives which are capable of improving energy density, resistance to gelling, and NOx emissions. Debate continues over NOx, particulates, smog, and greenhouse gas emissions from biodiesel and all other new transportation fuels, biofuels in particular. Ultimately, greater clarity on the fundamental distinctions between smog and other local pollution issues vs. greenhouse gas emissions will be essential for both well founded public policy as well as well informed consumer choices. In February 2006 a Navy biodiesel expert claimed NOx emissions in practice were actually lower than baseline. Further research is needed. Recent advances in the use of cerium oxide help eliminate NOx emissions from both petrodiesel and biodiesel,[58] and diesel fuel additives based on cerium oxide can improve fuel consumption by 11% in unmodified diesel engines. Current researchThere is ongoing research into finding more suitable crops and improving oil yield. Using the current yields, vast amounts of land and fresh water would be needed to produce enough oil to completely replace fossil fuel usage. It would require twice the land area of the US to be devoted to soybean production, or two-thirds to be devoted to rapeseed production, to meet current US heating and transportation needs. Specially bred mustard varieties can produce reasonably high oil yields, and have the added benefit that the meal leftover after the oil has been pressed out can act as an effective and biodegradable pesticide. AlgacultureFrom 1978 to 1996, the U.S. National Renewable Energy Laboratory experimented with using algae as a biodiesel source in the "Aquatic Species Program".[59] A self-published article by Michael Briggs, at the UNH Biodiesel Group, offers estimates for the realistic replacement of all vehicular fuel with biodiesel by utilizing algae that have a natural oil content greater than 50%, which Briggs suggests can be grown on algae ponds at wastewater treatment plants.[50] This oil-rich algae can then be extracted from the system and processed into biodiesel, with the dried remainder further reprocessed to create ethanol. The production of algae to harvest oil for biodiesel 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. Some companies[5][6] are pursuing algae bio-reactors for various purposes, including biodiesel production. On May 11, 2006 the Aquaflow Bionomic Corporation in Marlborough, New Zealand announced that it had produced its first sample of bio-diesel fuel made from algae found in sewage ponds.[31] Unlike previous attempts, the algae was naturally grown in pond discharge from the Marlborough District Council's sewage treatment works. See also
ReferencesFootnotes
Other references
External links
This article is licensed under the GNU Free Documentation License. It uses material from Wikipedia Encyclopedia article "Biodiesel" |
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