Ask Joe Mechanic - CNG/LNG/LPG Vehicles

            Compressed natural gas and Propane gas are two technologies that have been well tested and with the reduction of cost of natural gas, seems to be a great alternative fuel source. A natural gas vehicle is an alternative fuel vehicle that uses compressed natural gas (CNG) or liquefied natural gas (LNG) as a cleaner alternative to other fossil fuels. Natural gas vehicles should not be confused with vehicles powered by propane (LPG), which is a fuel with a fundamentally different composition.

            As of 2009, the U.S. had a fleet of 114,270 compressed natural gas (CNG) vehicles, mostly buses; 147,030 vehicles running on liquefied petroleum gas (LPG); and 3,176 vehicles liquefied natural gas (LNG). Worldwide, there were 14.8 million natural gas vehicles by 2011.

            Existing gasoline-powered vehicles may be converted to run on CNG or LNG, and can be dedicated (running only on natural gas) or bi-fuel (running on either gasoline or natural gas. Diesel engines for heavy trucks and busses can also be converted and can be dedicated with the addition of new heads containing spark ignition systems, or can be run on a blend of diesel and natural gas, with the primary fuel being natural gas and a small amount of diesel fuel being used as an ignition source. An increasing number of vehicles worldwide are being manufactured to run on CNG. Until recently, the Honda Civic GX was the only NGV commercially available in the US market., however now Ford, GM and Ram have bi-fuel offerings in their vehicle lineup. Fords approach is to offer a bi-fuel prep kit as a factory option, and then have the customer choose an authorized partner to install the natural gas equipment.

Choosing GM's bi-fuel option sends the HD pickups with the 6.0L gasoline engine to IMPCO in Indiana to upfit the vehicle to run on CNG. Ram currently is the only pickup truck manufacturer with a truly factory-installed bi-fuel system available in the U.S. market. Outside the U.S. GM do Brazil introduced the MultiPower engine in August 2004 which was capable of using CNG, alcohol and gasoline (E20-E25 blend) as fuel, and it was used in the Chevrolet Astra 2.0 model 2005, aimed at the taxi market. In 2006 the Brazilian subsidiary of FIAT introduced the Fiat Siena Tetra fuel, a four-fuel car developed under Magneti Marelli of Fiat Brazil. This automobile can run on natural gas (CNG); 100 percent ethanol (E100); E20 to E25 gasoline blend, Brazil's mandatory gasoline; and pure gasoline, though no longer available in Brazil it is used in neighboring countries.

             NGV filling stations can be located anywhere that natural gas lines exist. Compressors (CNG) or liquifaction plants (LNG) are usually built on large scale but with CNG small home refueling stations are possible. A company called FuelMaker pioneered such a system called Phill Home Refueling Appliance (known as "Phill"), which they developed in partnership with Honda for the American GX model. Phill is now manufactured and sold by BRC FuelMaker, a division of Fuel Systems Solutions, Inc.

           

 CNG may also be mixed with biogas, produced from landfills or wastewater, which doesn't increase the concentration of carbon in the atmosphere.

            Despite its advantages, the use of natural gas vehicles faces several limitations, including fuel storage and infrastructure available for delivery and distribution at fueling stations. CNG must be stored in high-pressure cylinders (3000psi to 3600psi operation pressure), and LNG must be stored in cryogenic cylinders (-260F to -200F). These cylinders take up more space than gasoline or diesel tanks that can be molded in intricate shapes to store more fuel and use less on-vehicle space. CNG tanks are usually located in the vehicle's trunk or pickup bed, reducing the space available for other cargo. This problem can be solved by installing the tanks under the body of the vehicle, or on the roof (typical for busses), leaving cargo areas free. As with other alternative fuels, other barriers for widespread use of NGVs are natural gas distribution to and at fueling stations as well as the low number of CNG and LNG stations.

             Though LNG and CNG are both considered NGVs, the technologies are vastly different. Refueling equipment, fuel cost, pumps, tanks, hazards, capital costs are all different. One thing they share is that due to engines made for gasoline, computer controlled valves to control fuel mixtures are required for both of them, often being proprietary and specific to the manufacturer. The on-engine technology for fuel metering is the same for LNG and CNG.

            CNG, or compressed natural gas, is stored at high pressure, 3,000 to 3,600 pounds per square inch (21 to 25 MPa). The required tank is more massive and costly than a conventional fuel tank. Refueling stations are more expensive to operate than LNG stations because of the energy required for compression. Time to fill a CNG tank varies greatly depending on the station. Home refuelers typically fill at about 0.4 GGE/hr. "Fast-fill" stations may be able to refill a 10 GGE tank in 5–10 minutes. Also, because of the lower energy density, the range on CNG is limited by comparison to LNG.

            LNG, or liquified natural gas, is natural gas that has been cooled to a point that it is a cryogenic liquid. In its liquid state, it is still more than 2 times as dense as CNG. LNG is dispensed from bulk storage tanks at LNG fuel stations at rates exceeding 20 GGE/min. Because of its cryogenic nature, it is stored in specially designed insulated tanks. Generally speaking, these tanks operate at fairly low pressures (about 70-150 psi) when compared to CNG. A vaporizer is mounted in the fuel system that turns the LNG into a gas (which may simply be considered low pressure CNG).

            LNG – and especially CNG – tends to corrode and wear the parts of an engine less rapidly than gasoline. Thus it's quite common to find diesel engine NGVs with high mileages (over 500,000 miles). Emissions are cleaner, with lower emissions of carbon and lower particulate emissions per equivalent distance traveled. There is generally less wasted fuel. CNG-powered vehicles are considered to be safer than gasoline-powered vehicles.

            Autogas, also known as LPG, has different chemical composition, but still petroleum based gas, has a number of inherent advantages and disadvantages, as well as noninherent ones. The inherent advantage of autogas over CNG is that it requires far less compression (20% of CNG cost), is denser as its a liquid at room temperature, and thus far cheaper tanks (consumer) and fuel compressors (provider) than CNG. As compared to LNG, it requires no chilling (and thus less energy), or problems associated with extreme cold such as frostbite. Like NGV, it also has advantages over gasoline and diesel in cleaner emissions, along with less wear on engines over gasoline. The major drawback of LPG is its safety, the fuel is heavier than air, which causes it to collect in a low spot in the event of a leak, making it far more hazardous to use, as more care is needed.

            Varieties of LPG bought and sold include mixes that are primarily propane (C3H8), primarily butane (C4H10) and, most commonly, mixes including both propane and butane, depending on the season — in winter more propane, in summer more butane In the United States, primarily only two grades of LPG are sold, commercial propane and HD-5. The Gas Processors Association (GPA) and the American Society of Testing and Materials (ASTM) publish these specifications. Propane/butane blends are also listed in these specifications. Propylene, butylenes and various other hydrocarbons are usually also present in small concentrations. HD-5 limits the amount of propylene that can be placed in LPG, and is utilized as an autogas specification. A powerful odorant, ethanethiol, is added so that leaks can be detected easily. The international standard is EN 589. In the United States, tetrahydrothiophene (thiophane) or amyl mercaptan are also approved odorants, although neither is currently being utilized.

           

LPG is prepared by refining petroleum or "wet" natural gas, and is almost entirely derived from fossil fuel sources, being manufactured during the refining of petroleum (crude oil), or extracted from petroleum or natural gas streams as they emerge from the ground. Dr. Walter Snelling first produced it in 1910, and the first commercial products appeared in 1912. It currently provides about 3% of all energy consumed, and burns relatively cleanly with no soot and very few sulfur emissions. As it is a gas, it does not pose ground or water pollution hazards, but it can cause air pollution. LPG has a typical specific calorific value of 46.1 MJ/kg compared with 42.5 MJ/kg for fuel oil and 43.5 MJ/kg for premium grade petrol (gasoline). However, its energy density per volume unit of 26 MJ/L is lower than either that of petrol or fuel oil, as its relative density is lower (about 0.5—0.58, compared to 0.71—0.77 for gasoline).

           

In places like the US, Thailand, and India, there are five to ten times more stations thus making the fuel more accessible than NGV stations. Other countries like Poland, South Korea, and Turkey, LPG stations and autos are widespread while NGVs are not. In addition, in some countries such as Thailand, the retail LPG fuel is considerably cheaper in cost.        Though ANG (adsorbed natural gas) has not yet been used in either providing neither stations nor consumer storage tanks, its low compression (500psi vs 3600 psi) has the potential to drive down costs of NGV infrastructure and vehicle tanks.

 

The primary component of natural gas is methane (CH₄), the shortest and lightest hydrocarbon molecule. It may also contain heavier gaseous hydrocarbons such as ethane (C₂H₆), propane (C₃H₈) and butane (C₄H₁₀), as well as other gases, in varying amounts. Hydrogen sulfide (H₂S) is a common contaminant, which must be removed prior to most uses. Combustion of one cubic meter yields 38 MJ (10.6 kWh). Natural gas has the highest energy/carbon ratio of any fossil fuel, and thus produces less carbon dioxide per unit of energy.

            The major difficulty in the use of natural gas is transportation. Natural gas pipelines are economical and common on land and across medium-length stretches of water (like Langeled, Interconnector and Trans-Mediterranean Pipeline), but are impractical across large oceans. Liquefied natural gas (LNG) tanker ships, railway tankers, and tank trucks are also used.

            CNG is typically stored in steel or composite containers at high pressure (3000 to 4000 psi, or 205 to 275 bar). These containers are not typically temperature controlled, but are allowed to stay at local ambient temperature. There are many standards for CNG cylinders; the most popular one is ISO 11439. For North America the standard is ANSI NGV-2.

           

LNG storage pressures are typically around 50-150 psi, or 3 to 10 bar. At atmospheric pressure, LNG is at a temperature of -260°F (-162°C), however, in a vehicle tank under pressure the temperature is slightly higher (see saturated fluid). Storage temperatures may vary due to varying composition and storage pressure. LNG is far denser than even the highly compressed state of CNG. As a consequence of the low temperatures, vacuum insulated storage tanks typically made of stainless steel are used to hold LNG.

           

CNG can be stored at lower pressure in a form known as an ANG (Adsorbed Natural Gas) tank at 35 bar (500 psi, the pressure of gas in natural gas pipelines) in various sponge like materials, such as activated carbon and metal-organic frameworks (MOFs). The fuel is stored at similar or greater energy density than CNG. This means that vehicles can be refueled from the natural gas network without extra gas compression; the fuel tanks can be slimmed down and made of lighter, less strong materials.

           

As its boiling point is below room temperature, LPG will evaporate quickly at normal temperatures and pressures and is usually supplied in pressurized steel vessels. They are typically filled to between 80 percent and 85 percent of their capacity to allow for thermal expansion of the contained liquid. The ratio between the volumes of the vaporized gas and the liquefied gas varies depending on composition, pressure, and temperature, but is typically around 250:1. The pressure at which LPG becomes liquid, called its vapor pressure, likewise varies depending on composition and temperature; for example, it is approximately 220 kilopascals (32 psi) for pure butane at 20 °C (68 °F), and approximately 2.2 megapascals (320 psi) for pure propane at 55 °C (131 °F). LPG is heavier than air, unlike natural gas, and thus will flow along floors and tend to settle in low spots, such as basements. There are two main dangers from this. The first is a possible explosion if the mixture of LPG and air is within the explosive limits and there is an ignition source. The second is suffocation due to LPG displacing air, causing a decrease in oxygen concentration. In addition, an odorant is mixed with LPG used for fuel purposes so that leaks can be detected more easily.

           

Conversion kits for gasoline or diesel to LNG/CNG are available in many countries, along with the labor to install them. However, the range of prices and quality of conversion vary enormously. Recently, regulations involving certification of installations in USA has been loosened to include certified private companies, those same kit installations for CNG have fallen to the $6,000+ range (depending on type of vehicle).

           

With the recent increase in natural gas production due to widespread use of fracking technology, many countries, including the United States and Canada, now can be self-sufficient. Canada is a substantial net exporter of natural gas, though the United States still has a net import of natural gas. Natural gas prices have decreased dramatically in the past few years and are likely to decrease further as additional production comes on line. However, the EIA predicts that natural gas prices will start increasing in a few years as the most profitable natural gas reserves are used up. Natural gas prices have decreased from $13 per mmbtu (USD) in 2008 to $3 per mmbtu (USD) in 2012. It is likely therefore that natural gas-powered vehicles will be increasingly cheaper to run relative to gasoline-powered vehicles. The issue is how to finance the purchase and installation of conversion kits. Some support may be available through the Department of Energy. Private initiatives, which essentially lease the conversion equipment in exchange for slightly higher natural gas refueling, can be self-financing and offer considerable advantages to liquidity strapped consumers.

           

Natural Gas has been used as a motor fuel in Canada for over 20 years.^{http://en.wikipedia.org/wiki/Natural_gas_vehicle - cite_note-36} With assistance from federal and provincial research programs, demonstration projects, and NGV market deployment programs during the 1980s and 1990s, the population of light-duty NGVs grew to over 35,000 by the early 1990s. This assistance resulted in a significant adoption of natural gas transit buses as well. The NGV market started to decline after 1995, eventually reaching today’s vehicle population of about 12,000.

            This figure includes 150 urban transit buses, 45 school buses, 9,450 light-duty cars and trucks, and 2,400 forklifts and ice-resurfacers. The total fuel use in all NGV markets in Canada was 1.9 petajoules (PJs) in 2007 (or 54.6 million litres of gasoline litres equivalent), down from 2.6 PJs in 1997. Public CNG refueling stations have declined in quantity from 134 in 1997 to 72 today. There are 22 in British Columbia, 12 in Alberta, 10 in Saskatchewan, 27 in Ontario, and 1 in Québec. There are only 12 private fleet stations.

            As of December 2009, the U.S. had a fleet of 114,270 compressed natural gas (CNG) vehicles, 147,030 vehicles running on liquefied petroleum gas (LPG), and 3,176 vehicles running on liquefied natural gas (LNG). The NGV fleet is made up mostly of transit buses but there are also some government fleet cars and vans, as well as increasing number of corporate trucks replacing diesel versions, most notably Waste Management, Inc and UPS trucks. As of 12-Dec-2013 Waste Management has a fleet of 2000 CNG Collection trucks; as of 12-Dec-2013 UPS has 2700 alternative fuel vehicles. As of February 2011, there were 873 CNG refueling sites, 2,589 LPG sites, and 40 LNG sites, led by California with 215 CNG refueling stations in operation, 228 LPG sites and 32 LNG sites. The number of refueling stations includes both public and private sites, and not all are available to the public. As of December 2010, the U.S. ranked 6th in the world in terms of number of NGV stations.

            When LPG is used to fuel internal combustion engines, it is often referred to as autogas or auto propane. In some countries, it has been used since the 1940s as a petrol alternative for spark ignition engines. In some countries, there are additives in the liquid that extend engine life and the ratio of butane to propane is kept quite precise in fuel LPG. Two recent studies have examined LPG-fuel-oil fuel mixes and found that smoke emissions and fuel consumption are reduced but hydrocarbon emissions are increased. The studies were split on CO emissions, with one finding significant increases, and the other finding slight increases at low engine load but a considerable decrease at high engine load. Its advantage is that it is non-toxic, non-corrosive and free of tetraethyllead or any additives, and has a high octane rating (102-108 RON depending on local specifications). It burns cleanlier than petrol or fuel oil and is especially free of the particulates from the latter.

           

            LPG has a lower energy density than either petrol or fuel oil, so the equivalent fuel consumption is higher. Many governments impose less tax on LPG than on petrol or fuel oil, which helps offset the greater consumption of LPG than of petrol or fuel oil. However, in many European countries this tax break is often compensated by a much higher annual road tax on cars using LPG than on cars using petrol or fuel oil. Propane is the third most widely used motor fuel in the world. 2008 estimates are that over 13 million vehicles are fueled by propane gas worldwide. Over 20 million tons (over 7 billion US gallons) are used annually as a vehicle fuel.

            Not all automobile engines are suitable for use with LPG as a fuel. LPG provides less upper cylinder lubrication than petrol or diesel, so LPG-fueled engines are more prone to valve wear if they are not suitably modified. Many modern common rail diesel engines respond well to LPG use as a supplementary fuel. This is where LPG is used as fuel as well as diesel. Systems are now available that integrate with OEM engine management systems.

            The recent increases in natural gas production in the United States, now number one in the world in CNG production, makes looking at this technology extremely attractive. Commercial fleets are increasingly looking at conversion to natural gas, with the biggest movement now being explored is in the commercial trucking industry. With tighter regulations on commercial diesel emissions, CNG appears to be the answer being explored the most and expect to see major changes over the next few years. If this conversion is successful, which appears highly likely, heavy truck emissions would be cut significantly.

            Next week we will wrap up the discussion on alternative fuels. Some information for this article obtained from Wikipedia.org.

This week’s recalls:

1,176,407 008-2013 Buick Enclave and GMC Acadia and 2009-2013 Chevrolet Traverse and 2008-2010 Saturn Outlook vehicles.
In the affected vehicles, increased resistance in the driver and passenger seat mounted side impact air bag (SIAB) wiring harnesses may result in the SIAB and seat belt pretensioners not deploying in the event of a crash. Failure of the side impact air bags and seat belt pretensioners to deploy in a crash increases the risk of injury to the driver and front seat occupant.

303,013 009-2014 Chevrolet Express and GMC Savana vans manufactured January 27, 2009, through March 7, 2014.
With a gross vehicle weight rating of 10,000 pounds and less and equipped with front passenger air bags. In the affected vehicles, during a frontal impact below the air bag deployment threshold, if an unbelted front passenger's head hits the instrument panel above where the passenger air bag is located, the panel may not sufficiently absorb the impact. As such, these vehicles fail to meet the requirements of Federal Motor Vehicle Safety Standard number 201, "Occupant Protection in Interior Impact." In the event of a crash below the air bag deployment threshold, an unbelted front passenger seat occupant has an increased risk of injury.

63,903 2013-2014 Cadillac XTS vehicles manufactured February 14, 2012, through March 7, 2014.
In the affected vehicles, a cavity plug on the brake booster pump connector may dislodge allowing corrosion of the brake booster pump relay connector. The corrosion of the brake booster pump relay connector may cause a resistive short and melt the connector, increasing the risk of a fire.

886,815 Honda is recalling certain 2005-2010 Honda Odyssey vehicles manufactured June 23, 2004, through September 4, 2010.
In the affected vehicles, the fuel pump strainer cover may deteriorate allowing fuel to leak out. A fuel leak increases the risk of a fire.

18,092 2014 Fiat 500L vehicles manufactured April 5, 2013, through January 22, 2014.

In certain temperatures, moving the transmission shift lever may have a delayed effect or no effect on selecting a transmission gear. If there is no effect, the vehicle might not shift out of the Park position. If there is a delayed effect, the vehicle may move in an unintended or unexpected direction, increasing the risk of a crash.

18,690 2012-2013 Dodge Durango and Jeep Grand Cherokee vehicles manufactured October 11, 2011, through October 1, 2012.
Under certain braking events, the Ready Alert Braking System (RAB) may result in the driver experiencing a hard brake pedal feel. If the driver experiences a hard brake pedal, the driver may not push the pedal as intended, lengthening the distance needed to stop the vehicle and increasing the risk of a crash.

If you own one of these affected vehicles, contact your dealer or the manufacturer for further instructions.

                                   

Ask Joe Mechanic - Flex Fuel Vehicles (Part 2)

The E85 blend is used in gasoline engines modified to accept such higher concentrations of ethanol, and the fuel injection is regulated through a dedicated sensor, which automatically detects the amount of ethanol in the fuel, allowing to adjust both fuel injection and spark timing accordingly to the actual blend available in the vehicle's tank. Because ethanol contains close to 34% less energy per unit volume than gasoline, E85 FFVs have a lower mileage per gallon than gasoline. Based on EPA tests for all 2006 E85 models, the average fuel economy for E85 vehicles was 25.56% lower than unleaded gasoline.

             The American E85 flex-fuel vehicle was developed to run on any mixture of unleaded gasoline and ethanol, anywhere from 0% to 85% ethanol by volume. Both fuels are mixed in the same tank, and E85 is sold already blended. In order to reduce ethanol evaporative emissions and to avoid problems starting the engine during cold weather, the maximum blend of ethanol was set to 85%. There is also a seasonal reduction of the ethanol content to E70 (called winter E85 blend) in very cold regions, where temperatures fall below 0 °C (32 °F) during the winter. In Wyoming for example, E70 is sold as E85 from October to May.

             E85 flex-fuel vehicles are becoming increasingly common in the Midwest, where corn is a major crop and is the primary feedstock for ethanol fuel production. Regional retail E85 prices vary widely across the US, with more favorable prices in the Midwest region, where most corn is grown and ethanol produced. Depending of the vehicle capabilities, the break-even price of E85 has to be between 25 and 30% lower than gasoline.

            As ethanol FFVs became commercially available during the late 1990s, the common use of the term "flexible-fuel vehicle" became synonymous with ethanol FFVs. In the United States flex-fuel vehicles are also known as "E85 vehicles". In Brazil, the FFVs are popularly known as "total flex" or simply "flex" cars. In Europe, FFVs are also known as "flexifuel" vehicles. Automakers, particularly in Brazil and the European market, use badging in their FFV models with the some variant of the word "flex", such as Volvo Flexifuel, or Volkswagen Total Flex, or Chevrolet FlexPower or Renault Hi-Flex, and Ford sells its Focus model in Europe as Flexifuel and as Flex in Brazil. In the US, only since 2008 FFV models feature a yellow gas cap with the label "E85/Gasoline" written on the top of the cap to differentiate E85s from gasoline only models.

             Flexible-fuel vehicles (FFVs) are based on dual-fuel systems that supply both fuels into the combustion chamber at the same time in various calibrated proportions. The most common fuels used by FFVs today are unleaded gasoline and ethanol fuel. Ethanol FFVs can run on pure gasoline, pure ethanol (E100) or any combination of both. Methanol has also been blended with gasoline in flex-fuel vehicles known as M85 FFVs, but their use has been limited mainly to demonstration projects and small government fleets, particularly in California.

             The term flexible-fuel vehicle is sometimes used to include other alternative fuel vehicles that can run with compressed natural gas (CNG), liquefied petroleum gas (LPG; also known as autogas), or hydrogen. However, all these vehicles actually are bi-fuel and not flexible-fuel vehicles, because they have engines that store the other fuel in a separate tank, and the engine runs on one fuel at a time. Bi-fuel vehicles have the capability to switch back and forth from gasoline to the other fuel, manually or automatically. The most common available fuel in the market for bi-fuel cars is natural gas (CNG), and by 2008 there were 9,6 million natural gas vehicles, led by Pakistan (2.0 million), Argentina (1.7 million), and Brazil (1.6 million). Natural gas vehicles are a popular choice as taxicabs in the main cities of Argentina and Brazil. Normally, standard gasoline vehicles are retrofitted in specialized shops, which involve installing the gas cylinder in the trunk and the CNG injection system and electronics.

            Multifuel vehicles are capable of operating with more than two fuels. In 2004 GM do Brasil introduced the Chevrolet Astra 2.0 with a "MultiPower" engine built on flex fuel technology developed by Bosch of Brazil, and capable of using CNG, ethanol and gasoline (E20-E25 blend) as fuel. This automobile was aimed at the taxicab market and the switch among fuels is done manually. In 2006 Fiat introduced the Fiat Siena Tetra fuel, a four-fuel car developed under Magneti Marelli of Fiat Brazil. This automobile can run as a flex-fuel on 100% ethanol (E100); or on E-20 to E25, Brazil's normal ethanol gasoline blend; on pure gasoline (though no longer available in Brazil since 1993, it is still used in neighboring countries); or just on natural gas. The Siena Tetrafuel was engineered to switch from any gasoline-ethanol blend to CNG automatically, depending on the power required by road conditions. Another existing option is to retrofit an ethanol flexible-fuel vehicle to add a natural gas tank and the corresponding injection system. This option is popular among taxicab owners in São Paulo and Rio de Janeiro, Brazil, allowing users to choose among three fuels (E25, E100 and CNG) according to current market prices at the pump. Vehicles with this adaptation are known in Brazil as "tri-fuel" cars.

            Flex-fuel hybrid electric and flex-fuel plug-in hybrid are two types of hybrid vehicles built with a combustion engine capable of running on gasoline, E-85, or E-100 to help drive the wheels in conjunction with the electric engine or to recharge the battery pack that powers the electric engine. In 2007 Ford produced 20 demonstration Escape Hybrid E85s for real-world testing in fleets in the U.S. Also as a demonstration project, Ford delivered in 2008 the first flexible-fuel plug-in hybrid SUV to the U.S. Department of Energy (DOE), a Ford Escape Plug-in Hybrid, which runs on gasoline or E85. GM announced that the Chevrolet Volt plug-in hybrid, launched in the U.S. in late 2010, would be the first commercially available flex-fuel plug-in capable of adapting the propulsion to several world markets such as the U.S., Brazil or Sweden, as the combustion engine can be adapted to run on E85, E100 or diesel respectively. The Volt was initially expected to be flex-fuel-capable in 2013.^] Lotus Engineering unveiled the Lotus CityCar at the 2010 Paris Motor Show. The CityCar is a plug-in hybrid concept car designed for flex-fuel operation on ethanol, or methanol as well as regular gasoline.

            A 2005 survey found that 68 percent of American flex-fuel car owners were not aware they owned an E85 flex. This was because the exteriors of flex and non-flex vehicles look exactly the same; there is no sale price difference between them; the lack of consumers' awareness about E85s; and also the initial decision of American automakers of not putting any kind of exterior labeling, so buyers could be aware they are purchasing an E85 vehicle. Since 2008, all new FFV models in the US feature a bright yellow gas cap to remind drivers of the E85 capabilities and proper flex-fuel badging.

            Some critics have argued that American automakers have been producing E85 flex models motivated by a loophole in the Corporate Average Fuel Economy (CAFE) requirements, that allows for a fuel economy credit for every flex-fuel vehicle sold, whether or not in practice these vehicles are fueled with E85. This loophole might allow the car industry to meet the CAFE targets in fuel economy just by spending between US$100 and US$200 that it cost to turn a conventional vehicle into a flex-fuel, without investing in new technology to improve fuel economy, and saving them the potential fines for not achieving that standard in a given model year. The CAFE standards proposed in 2011 for the period 2017-2025 will allow flexible-fuel vehicles to receive extra credit but only when the carmakers present data proving how much E85 such vehicles have actually consumed.

            A major restriction hampering sales of E85 flex vehicles, or fueling with E85, is the limited infrastructure available to sell E85 to the public. As of May 2011, there were only 2,749 gasoline fueling stations selling E85 to the public in the entire US, with a great concentration of E85 stations in the Corn Belt states. The main constraint for a more rapid expansion of E85 availability is that it requires dedicated storage tanks at filling stations, at an estimated cost of US$60,000 for each dedicated ethanol tank. The Obama Administration set the goal of installing 10,000 blender pumps nationwide until 2015, and to support this target the US Department of Agriculture (USDA) issued a rule in May 2011 to include flexible fuel pumps in the Rural Energy for America Program (REAP). This ruling will provide financial assistance to fuel station owners to install E85 and blender pumps.

            General Motors announced that the new Chevrolet Volt plug-in hybrid, launched in the United States market in December 2010, will be flex-fuel-capable in 2013. General Motors do Brasil announced that it will import from five to ten Volts to Brazil during the first semester of 2011 as part of a demonstration and also to lobby the federal government to enact financial incentives for green cars. If successful, GM would adapt the Volt to operate on ethanol fuel, as most new cars sold in Brazil are flex-fuel.

             In 2008, Chrysler, General Motors, and Ford pledged to manufacture 50 percent of their entire vehicle line as flexible fuel in model year 2012, if enough fueling infrastructure develops. The Open Fuel Standard Act (OFS), introduced to Congress in May 2011, is intended to promote a massive adoption of flex-fuel vehicles capable of running on ethanol or methanol. The bill requires that 50 percent of automobiles made in 2014, 80 percent in 2016, and 95 percent in 2017, would be manufactured and warranted to operate on non-petroleum-based fuels, which includes existing technologies such as flex-fuel, natural gas, hydrogen, biodiesel, plug-in electric and fuel cell.

             

Comparison of key characteristics among the leading ethanol flexible-fuel vehicle markets
Characteristic	Brazil	Sweden	U.S.	Units/comments
Type of flexible-fuel vehicle (fuel used)[12][15]	E20 to E100	E85	E85	Brazil's mandatory blend is E20-E25. Winter E85 is actually E70 in the US and E75 in Sweden.
Main feedstock used for ethanol consumption[12][105]	Sugar cane	80% imported	Maize	In 2007, most Swedish ethanol was imported, with a high share from Brazil.[105][109]
Total flex-fuel vehicles produced/sold[2][3][4][6]	23.0 million	229,400	10 million(1)	Brazil as of October 2013, Sweden sales as of September 2013 and .U.S. fleet on the road as of December 2011. The Brazilian fleet includes 3.0 million flex fuel motorcycles.[3] USDOE estimates that in 2009 only 504,297 flex-fuel vehicles were regularly fueled with E85 in the US.[141]
Share of flex-fuel vehicles as % of total registered	22.0%	4.7%	4.0%	Brazil's fleet is 64.8 mi (2010),[183] Sweden fleet is 4.8 mi (2008),[184] and US fleet is 248.5 mi (2009).[141]
Ethanol fueling stations in the country[114][185][186]	35,017	1,723	2,757	Brazil for December 2007, the US and Sweden as of August 2011.
Ethanol filling stations as % of total[95][105][110][141][186]	100%	30%	1.7%	As % of total fueling gas stations in the country.
Ethanol fueling stations per million inhabitants	184.2	130.4	6.5	See List of countries by population. Brazil and US as of 2008-09-12, and Sweden as of 2008-06-30.
Retail price of E85 or E100 (local currency/unit)	R$ 1.259/L	SEK 8.79/L	US$ 2.60/gal	Selected regions:(2)São Paulo, June 2008,[187] Sweden, January 2008,[124] and Minnesota, August 2008.[188]
Retail price of gasoline or E25. (local currency/unit)	R$ 2.385/L	SEK 11.99/L	US$ 3.70/gal	Prices in São Paulo (E25), June 2008,[187] Sweden, January 2008,[124] and Minnesota, August 2008.[188]
Price economy ethanol/gasoline price as %	47.2%(2)(3)	26.7%(3)	29.7%(2)(3)	São Paulo, June 2008, Sweden January 2008, and Minnesota, August 2008.
Notes: (1)The effective number of E85 flex vehicles in US roads actually using ethanol fuel is lower than shown, as a survey have shown than 68% of E85 owners are not aware they own a flex-fuel vehicle.[12] A 2007 national survey found that only 5% of drivers actually use biofuels.[189] (2) Regional prices vary widely in Brazil and the US. The states chosen reflect some of the lowest retail prices for ethanol, as both São Paulo and Minnesota are main growers of feedstock and producers of ethanol, hence, the comparison presented is one of the most favorable for ethanol/gasoline price ratios. For example, US average spread was 16.9% in August 2008, and it varied from 35% in Indiana to 3% in Utah.[188] See more US price comparisons for most states at e85prices.com, and annual fuel costs for 2008 FFV US models at www.fueleconomy.gov. (3) Brazilian gasoline is heavily taxed (~54%),[190] US ethanol production was subsidized (a US$ 0.51/gal federal tax credit) until December 2011,[95] and Swedish E85 is exempt of CO2 and energy taxes until 2009 (~30% price reduction).[109][124]

Certain information for this article was sourced from Wikipedia.org

Ask Joe Mechanic - Flex Fuel Vehicles (Part 1)

A flexible-fuel vehicle (FFV) or dual-fuel vehicle (colloquially called a flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank. Modern flex-fuel engines are capable of burning any proportion of the resulting blend in the combustion chamber as fuel injection and spark timing are adjusted automatically according to the actual blend detected by a fuel composition sensor. Flex-fuel vehicles are distinguished from bi-fuel vehicles, where two fuels are stored in separate tanks and the engine runs on one fuel at a time, for example, compressed natural gas (CNG), liquefied petroleum gas (LPG), or hydrogen.

           

The most common commercially available FFV in the world market is the ethanol flexible-fuel vehicle, with about 39 million automobiles, motorcycles and light duty trucks manufactured and sold worldwide through October 2013, and concentrated in four markets, Brazil (23.0 million), the United States (15 million), Canada (more than 600,000), and Europe, led by Sweden (229,400).  The Brazilian flex fuel fleet includes over 3 million flexible-fuel motorcycles produced since 2009 through October 2013. In addition to flex-fuel vehicles running with ethanol, in Europe and the US, mainly in California, there have been successful test programs with methanol flex-fuel vehicles, known as M85 flex-fuel vehicles. There have been also successful tests using P-series fuels with E85 flex fuel vehicles, but as of June 2008, this fuel is not yet available to the general public. These successful tests with P-series fuels were conducted on Ford Taurus and Dodge Caravan flexible-fuel vehicles.

             Though technology exists to allow ethanol FFVs to run on any mixture of gasoline and ethanol, from pure gasoline up to 100% ethanol (E100), North American and European flex-fuel vehicles are optimized to run on a maximum blend of 15% gasoline with 85% anhydrous ethanol (called E85 fuel). This limit in the ethanol content is set to reduce ethanol emissions at low temperatures and to avoid cold starting problems during cold weather, at temperatures lower than 11 °C (52 °F). The alcohol content is reduced during the winter in regions where temperatures fall below 0 °C (32 °F)^] to a winter blend of E70 in the U.S. or to E75 in Sweden from November until March. Brazilian flex fuel vehicles are optimized to run on any mix of E20-E25 gasoline and up to 100% hydrous ethanol fuel (E100). The Brazilian flex vehicles are built-in with a small gasoline reservoir for cold starting the engine when temperatures drop below 15 °C (59 °F). An improved flex motor generation was launched in 2009, which eliminated the need for the secondary gas tank

            Most people think that flex fuel vehicles are a fairly new technology, as in the last ten years. Actually, the first commercial flexible fuel vehicle was the Ford Model T, produced from 1908 through 1927. It was fitted with a carburetor with adjustable jetting, allowing use of gasoline or ethanol, or a combination of both. Other car manufactures also provided engines for ethanol fuel use. Henry Ford continued to advocate for ethanol as fuel even during the prohibition. However, cheaper oil caused gasoline to prevail, until the 1973 oil crisis resulted in gasoline shortages and awareness on the dangers of oil dependence. This crisis opened a new opportunity for ethanol and other alternative fuels, such as methanol, gaseous fuels such as CNG and LPG, and also hydrogen. Ethanol, methanol and natural gas CNG were the three alternative fuels that received more attention for research and development, and government support.

            Since 1975, and as a response to the shock caused by the first oil crisis, the Brazilian government implemented the National Alcohol Program -Pró-Álcool- (Portuguese: Programa Nacional do Álcool), a nationwide program financed by the government to phase out automotive fuels derived from fossil fuels in favor of ethanol made from sugar cane. It began with a low blend of anhydrous alcohol with regular gasoline in 1976, and since July 2007 the mandatory blend is 25% of alcohol or gasohol E25. In 1979, and as a response to the second oil crisis, the first vehicle capable of running with pure hydrous ethanol (E100) was launched to the market, the Fiat 147, after testing with several prototypes developed by Fiat, Volkswagen, GM and Ford The Brazilian government provided three important initial drivers for the ethanol industry: guaranteed purchases by the state-owned oil company Petrobras, low-interest loans for agro-industrial ethanol firms, and fixed gasoline and ethanol prices. After reaching more than 4 million cars and light trucks running on pure ethanol by the late 1980s, the use of E100-only vehicles sharply declined after increases in sugar prices produced shortages of ethanol fuel.

            After extensive research that began in the 90s, a second push took place in March 2003, when the Brazilian subsidiary of Volkswagen launched to the market the first full flexible-fuel car, the Gol 1.6 Total Flex. Several months later was followed by other Brazilian automakers, and by 2010 General Motors, Fiat, Ford, Peugeot, Renault, Volkswagen, Honda, Mitsubishi, Toyota, Citroën, Nissan and Kia Motors were producing popular models of flex cars and light trucks. The adoption of ethanol flex fuel vehicles was so successful, that production of flex cars went from almost 40 thousand in 2003 to 1.7 million in 2007. This rapid adoption of the flex technology was facilitated by the fuel distribution infrastructure already in place, as around 27,000 filling stations countrywide were available by 1997 with at least one ethanol pump, a heritage of the Pró-Álcool program.

             In the United States, initial support to develop alternative fuels by the government was also a response to the first oil crisis, and some time later, as a goal to improve air quality. Also, liquid fuels were preferred over gaseous fuels not only because they have a better volumetric energy density but also because they were the most compatible fuels with existing distribution systems and engines, thus avoiding a big departure from the existing technologies and taking advantage of the vehicle and the refueling infrastructure. California led the search of sustainable alternatives with interest focused in methanol.

Ford Motor Company and other automakers responded to California's request for vehicles that run on methanol. In 1981, Ford delivered 40 dedicated methanol fuel (M100) Escorts to Los Angeles County, but only four refueling stations were installed. The biggest challenge in the development of alcohol vehicle technology was getting all of the fuel system materials compatible with the higher chemical reactivity of the fuel. Methanol was even more of a challenge than ethanol but much of the early experience gained with neat ethanol vehicle production in Brazil was transferable to methanol. The success of this small experimental fleet of M100s led California to request more of these vehicles, mainly for government fleets. In 1983, Ford built 582 M100 vehicles; 501 went to California, and the remaining to New Zealand, Sweden, Norway, United Kingdom, and Canada.

             As an answer to the lack of refueling infrastructure, Ford began development of a flexible-fuel vehicle in 1982, and between 1985 and 1992, 705 experimental FFVs were built and delivered to California and Canada, including the 1.6L Ford Escort, the 3.0L Taurus, and the 5.0L LTD Crown Victoria. These vehicles could operate on either gasoline or methanol with only one fuel system. Legislation was passed to encourage the US auto industry to begin production, which started in 1993 for the M85 FFVs at Ford. In 1996, a new FFV Ford Taurus was developed, with models fully capable of running on either methanol or ethanol blended with gasoline. This ethanol version of the Taurus became the first commercial production of an E85 FFV. The momentum of the FFV production programs at the American car companies continued, although by the end of the 1990s, the emphasis shifted to the FFV E85 version, as it is today.

Ethanol was preferred over methanol because there is a large support from the farming community, and thanks to the government's incentive programs and corn-based ethanol subsidies available at the time. Sweden also tested both the M85 and the E85 flexifuel vehicles, but due to agriculture policy, in the end emphasis was given to the ethanol flexifuel vehicles. Support for ethanol also comes from the fact that it is a biomass fuel, which addresses climate change concerns and greenhouse gas emissions, though nowadays these benefits are questioned and depend on the feedstock used for ethanol production and their indirect land use change impacts.

            The demand for ethanol fuel produced from field corn in the United States was stimulated by the discovery in the late 90s that methyl tertiary butyl ether (MTBE), an oxygenate additive in gasoline, was contaminating groundwater. Due to the risks of widespread and costly litigation, and because MTBE use in gasoline was banned in almost 20 states by 2006, the substitution of MTBE opened a new market for ethanol fuel. This demand shift for ethanol as an oxygenate additive took place at a time when oil prices were already significantly rising. By 2006, about 50 percent of the gasoline used in the U.S. contained ethanol at different proportions, and ethanol production grew so fast that the US became the world's top ethanol producer, overtaking Brazil in 2005. This shift also contributed to a sharp increase in the production and sale of E85 flex vehicles since 2002.

             Since 1998 a total of 15.1 million E85 flex-fuel vehicles had been sold or lease in the United States through December 2012. Of these, about 11 million flex-fuel cars and light trucks were still in operation as of early 2013, up from 7.3 million in 2008, 4.1 million in 2005, and 1.4 million on U.S roads in 2001. For the 2011 model year there are about 70 vehicles E85 capable, including sedans, vans, SUVs and pick-up trucks. Many of the models available in the market are trucks and sport-utility vehicles getting less than 20 mpg_-US (12 L/100 km; 24 mpg_-imp) when filled with gasoline. Actual consumption of E85 among flex-fuel vehicle owners is limited. Nevertheless, the U.S. Department of Energy estimated that in 2009 only 504,297 flex-fuel vehicles were regularly fueled with E85, and these were primarily fleet-operated vehicles. As a result, from all the ethanol fuel consumed in the country in 2009, only 1% was E85 consumed by flex-fuel vehicles.

Certain information for this article was sourced from Wikipedia.org.

Ask Joe Mechanic - Biofuels and Biofuel Vehicles (Part 1)

            Biofuels are one area of alternative fuels that holds a lot of promise, but there are still significant drawbacks and limitations to their effective use. It will never be able to completely replace fossil fuels because not enough land can be devoted to raising the crops needed to produce it. It has also had an effect on food prices as the demand for corn and soybeans increases.

            A biofuel is a fuel that contains energy from geologically recent carbon fixation. These fuels are produced from living organisms. Examples of this carbon fixation occur in plants and microalgae. These fuels are made by a biomass conversion (biomass refers to recently living organisms, most often referring to plants or plant-derived materials). This biomass can be converted to convenient energy containing substances in three different ways: thermal conversion, chemical conversion, and biochemical conversion. This biomass conversion can result in fuel in solid, liquid, or gas form. This new biomass can be used for biofuels. Biofuels have increased in popularity because of rising oil prices and the need for energy security.

            In 2010, worldwide biofuel production reached 105 billion liters (28 billion gallons US), up 17 percent from 2009, and biofuels provided 2.7 percent of the world's fuels for road transport, a contribution largely made up of ethanol and biodiesel. Global ethanol fuel production reached 86 billion liters (23 billion gallons US) in 2010, with the United States and Brazil as the world's top producers, accounting together for 90 percent of global production. The world's largest biodiesel producer is the European Union, accounting for 53 percent of all biodiesel production in 2010. As of 2011, mandates for blending biofuels exist in 31 countries at the national level and in 29 states or provinces. The International Energy Agency has a goal for biofuels to meet more than a quarter of world demand for transportation fuels by 2050 to reduce dependence on petroleum and coal.

             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 Union. The world leaders in biofuel development and use are Brazil, the United States, France, Sweden and Germany. Russia also has 22 percent 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 percent of the total road transport fuel in the UK or 1,440 million litres. By 2020, 10 percent of the energy used in UK road and rail transport must come from renewable sources – this is the equivalent of replacing 4.3 million ton of fossil oil each year. Conventional biofuels are likely to produce between 3.7 and 6.6 percent of the energy needed in road and rail transport, while advanced biofuels could meet up to 4.3 percent of the UK’s renewable transport fuel target by 2020.

            Most transportation fuels are liquids, because vehicles usually require high energy density, as occurs in liquids and solids. An internal combustion engine can provide high power density most inexpensively; these engines require clean-burning fuels, to keep the engine clean and minimize air pollution.  The fuels that are easiest to burn cleanly are typically liquids and gases. Thus, liquids (and gases that can be stored in liquid form) meet the requirements of being both portable and clean burning. Also, liquids and gases can be pumped, which means handling is easily mechanized, and thus less laborious.

            There are two basic classifications of biofuels, first-generation or conventional biofuels are made from sugar, starch, or vegetable oil, and second generation or advanced biofuels. First generation biofuels are made from the sugars and vegetable oils found in arable crops, which can be easily extracted using conventional technology. In comparison, second generation biofuels are made from lignocellulosic biomass or woody crops, agricultural residues or waste, which makes it harder to extract the required fuel.

Most first generation biofuels fall into two categories, they are either designed or formulated to be used in either a gasoline or a diesel engine. We will cover the internal combustion or gasoline alternatives first, with the best known being 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 (in a similar way to biodiesel in diesel engines).

            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 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 (often unsustainable natural gas fossil fuel, but cellulosic biomass such as bagasse, the waste left after sugar cane is pressed to extract its juice, can also be used more sustainably).

            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 percent 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.

            In the current corn-to-ethanol production model in the United States, considering the total energy consumed by farm equipment, cultivation, planting, fertilizers, pesticides, herbicides, and fungicides made from petroleum, irrigation systems, harvesting, transport of feedstock to processing plants, fermentation, distillation, drying, transport to fuel terminals and retail pumps, and lower ethanol fuel energy content, the net energy content value added and delivered to consumers is very small. And, the net benefit (all things considered) does little to reduce imported oil and fossil fuels required to produce the ethanol.

             Although corn-to-ethanol and other food stocks have implications both in terms of world food prices and limited, yet positive, energy yield (in terms of energy delivered to customer/fossil fuels used), the technology 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.  Even dry ethanol has roughly one-third lower energy content per unit of volume compared to gasoline, so larger (therefore heavier) fuel tanks are required to travel the same distance, or more fuel stops are required. With large current unsustainable, unscalable subsidies, ethanol fuel still costs more per distance traveled than current high gasoline prices in the United States.

                  Methanol is currently produced from natural gas, a nonrenewable fossil fuel. It can also be produced from biomass as biomethanol. 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. E. Coli strains have also been successfully engineered to produce butanol by hijacking their amino acid metabolism.

In 2013 UK researchers developed a genetically modified strain of Escherichia coli, which could transform glucose into biofuel gasoline that does not need to be blended. Later in 2013, UCLA researchers engineered a new metabolic pathway to bypass glycolysis and increase the rate of conversion of sugars into biofuel, while KAIST researchers developed a strain capable of producing short-chain alkanes, free fatty acids, fatty esters and fatty alcohols through the fatty acyl (acyl carrier protein (ACP)) to fatty acid to fatty acyl-CoA pathway in vivo. It is believed that in the future it will be possible to "tweak" the genes to make gasoline from straw or animal manure.

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." They also enhance engine performance, whilst significantly reducing engine wear and toxic exhaust emissions. 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- 1. Dimethyl Ehters (DME) 2. Diethyl Ether (DEE) 3. Methyl Teritiary-Butyl Ether (MTBE) 4. Ethyl ter-butyl ether (ETBE) 5. Ter-amyl methyl ether (TAME) 6. Ter-amyl ethyl Ether (TAEE).

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. It should be noted that 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, 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.

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) is the lowest-emission diesel fuel. Although liquefied petroleum gas and hydrogen have cleaner combustion, they are used to fuel much less efficient petrol engines and are not as widely available.

Biodiesel can be used in any diesel engine when mixed with mineral diesel. In some countries, manufacturers cover their diesel engines under warranty for B100 use. Volkswagen of Germany, for example, asks drivers to check by telephone with the VW environmental services department before switching to B100.  B100 may become more viscous at lower temperatures, depending on the feedstock used. 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.

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 percent 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 unburned carbon.

Biodiesel is also safe to handle and transport because it is as biodegradable as sugar, one-tenth as toxic as table salt, 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 USA, more than 80 percent of commercial trucks and city buses run on diesel. The emerging US biodiesel market is estimated to have grown 200 percent 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).

Green diesel is produced through hydrocracking biological oil feed stocks, 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, hydro treated vegetable oil or hydrogen-derived renewable diesel. Green diesel has 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. ConocoPhillips, Neste Oil, Valero, Dynamic Fuels, and Honeywell UOP are developing green diesel in Louisiana and Singapore.

Straight unmodified edible vegetable oil is generally not used as fuel, but lower-quality oil can and has been used for this purpose. Used vegetable oil is increasingly being processed into biodiesel, or (more rarely) cleaned of water and particulates and used as a fuel.  Also here, as with 100 percent 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. Big corporations like 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. Enthusiasts without any conversion drive some older engines, especially Mercedes, experimentally, 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.

There is one other small sub-group of first generation biofuels, and they are actually solids. Examples include wood, sawdust; grass trimmings, domestic refuse, charcoal, agricultural waste, nonfood energy crops, and dried manure. There is also a plant to be built in nearby Schuylkill County, which will actually convert coal and coal waste into a clean biodiesel.

When raw biomass is already in a suitable form (such as firewood), it can burn directly in a stove or furnace to provide heat or raise steam. When raw biomass is in an inconvenient form (such as sawdust, wood chips, grass, urban waste wood, agricultural residues), the typical process is to densify the biomass. This process includes grinding the raw biomass to an appropriate particulate size (known as hogfuel), which, depending on the densification type can be from 1 to 3 cm (0 to 1 in), which is then concentrated into a fuel product. The current processes produce wood pellets, cubes, or pucks. The pellet process is most common in Europe, and is typically a pure wood product. The other types of densification are larger in size compared to a pellet, and are compatible with a broad range of input feed stocks. The resulting densified fuel is easier to transport and feed into thermal generation systems, such as boilers.

Industry has used sawdust, bark and chips for fuel for decades, primary in the pulp and paper industry, and also bagasse (spent sugar cane) fueled boilers in the sugar cane industry. Boilers in the range of 500,000 lb/hr of steam, and larger, are in routine operation, using grate, spreader stoker, suspension burning and fluid bed combustion. Utilities generate power, typically in the range of 5 to 50 MW, using locally available fuel. Other industries have also installed wood waste fueled boilers and dryers in areas with low cost fuel.

 One of the advantages of solid biomass fuel is that it is often a byproduct, residue or waste product of other processes, such as farming, animal husbandry and forestry. In theory, this means fuel and food production do not compete for resources, although this is not always the case.  A problem with the combustion of raw biomass is that it emits considerable amounts of pollutants, such as particulates and polycyclic aromatic hydrocarbons. Even modern pellet boilers generate much more pollutants than oil or natural gas boilers. Pellets made from agricultural residues are usually worse than wood pellets, producing much larger emissions of dioxins and chlorophenols.

In spite of the above noted study, numerous studies have shown biomass fuels have significantly less impact on the environment than fossil-based fuels. Of note is the US Department of Energy Laboratory, operated by Midwest Research Institute Biomass Power and Conventional Fossil Systems with and without CO2 Sequestration – Comparing the Energy Balance, Greenhouse Gas Emissions and Economics Study. Power generation emits significant amounts of greenhouse gases (GHGs), mainly carbon dioxide (CO₂). Sequestering CO₂ from the power plant flue gas can significantly reduce the GHGs from the power plant itself, but this is not the total picture. CO₂ capture and sequestration consumes additional energy, thus lowering the plant's fuel-to-electricity efficiency. To compensate for this, more fossil fuel must be procured and consumed to make up for lost capacity.

Taking this into consideration, the global warming potential (GWP), which is a combination of CO₂, methane (CH₄), and nitrous oxide (N₂O) emissions, and energy balance of the system needs to be examined using a life cycle assessment. This takes into account the upstream processes, which remain constant after CO2 sequestration, as well as the steps, required for additional power generation. Firing biomass instead of coal led to a 148 percent reduction in GWP.

A derivative of solid biofuel is biochar, which is produced by biomass pyrolysis. Biochar made from agricultural waste can substitute for wood charcoal. As wood stock becomes scarce, this alternative is gaining ground. In eastern Democratic Republic of Congo, for example, biomass briquettes are being marketed as an alternative to charcoal to protect Virunga National Park from deforestation associated with charcoal production.

             
Next week, we will continue this discussion by exposing some of the drawbacks and criticisms of the development of biofuels. We will also look at ongoing research into better, more efficient production of biofuels.  And, with some new areas being researched to develop new biofuels, which would have less economic and environmental impacts than existing sources. We will also examine related fuels such as flex fuels, dimethyl ether and ammonia-based fuels.

Some information for this article was obtained from Wikipedia.org.