Use of Biodiesel in a Transit Fleet (2007)

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This chapter provides additional detail regarding biodiesel use from the vehicle perspective in terms of emissions and engine characteristics and from the fuel management per- spective in terms of procurement specifications, blending, delivery, storage, and incentives. The reader with a more casual interest in biodiesel may want to pass over this chap- ter and return to it when more detail is required. EMISSIONS AND EPA COMPLIANCE Emissions Overview Biodiesel’s ability to reduce emissions ranks among its great- est attributes. Emissions, however, is a difficult subject to fully comprehend because of the chemical formulas and the way they are expressed. Of critical importance is that diesel emissions have been reduced drastically since they were first regulated in the 1980s, although to many the term “clean diesel” is still considered an oxymoron. A brief overview of emissions will illustrate the reductions achieved and the con- text in which biodiesel contributes to further reductions. Most emissions are generated from incomplete combus- tion of fuel within an engine. Despite significant steps taken to improve combustion efficiency, the stop-and-go nature of transit bus operations combined with other factors con- tinues to generate some diesel emissions that can not be fully eliminated. The four regulated emissions from a diesel engine are CO, HC, NOx, and PM. CO is a poisonous gas and HC is a green- house gas that contributes to smog. Diesel engines produce little CO or volatile HC, but NOx and PM emissions from diesel engines are targets of increasingly stringent regula- tions. NOx contributes to low-level ozone and photochemical smog, whereas PM, which is composed of very fine particles that settle in the lungs, is suspected of causing cancer. Trucks and buses are prime contributors to NOx and PM. Reducing both simultaneously presents a challenge because of their inverse relationship; that is, attempts to reduce PM causes NOx levels to rise and visa versa. Engine manufactur- ers typically control NOx through in-engine modifications such as higher fuel injection pressures, improved air intake control, exhaust gas recirculation, and the use of sophisticated electronic engine controls. Reducing PM is typically done with after treatment devices. Placed in the exhaust stream and 8 typically concealed inside the muffler, these devices “treat” the PM “after” exhaust gases leave the engine. 2007 Diesel Emissions-Reduction Technology EPA regulations for 2007 reduce PM and NOx to extremely low levels. The primary PM-reduction technology consists of a DPF (also called a PM filter) used in conjunction with ULSD fuel. Both are needed to meet PM levels for 2007. An after treatment device, the DPF is contained within the muf- fler along with a catalyst. Although each brand has different operating characteristics, DPFs that are passive in nature typ- ically work by trapping the solid PM contained in the exhaust. The increased backpressure resulting from the partial block- age of exhaust gases causes exhaust temperatures to rise. When temperatures reach a certain level the accumulated PM is burned off. The process of trapping the solid particulate and burning it off continues and is known as regeneration. In systems that use active regeneration, a small amount of diesel fuel is periodically introduced into the DPF to assist with burning off the PM. In both cases, the ash that builds up over time within the filter requires periodic cleaning. According to one DPF manufacturer, there is no effect on filter regeneration from testing done with biodiesel in concentrations up to B20. There is, however, a concern that if the biodiesel does not con- form to the ASTM specification, higher levels of potassium could cause catalyst contamination (M. Lassen, Johnson Matthey, personal communication, May 14, 2007). Although passive DPFs typically require no engine modi- fications or control systems, active DPFs do require systems to control the periodic injection of diesel fuel into the DPF to stimulate regeneration. To prevent clogging, all DPFs require ULSD with a sulfur content of no more than 15 parts per mil- lion (ppm). Most on-road diesel fuel sold is now ULSD, which can also be used in older engines without modifica- tions. The process of reducing sulfur, however, also reduces the fuel’s lubricating characteristics. Although fuel suppliers use additives to compensate for the lack of lubricity, the use of biodiesel further increases lubricity. 2010 Diesel Emissions-Reduction Technology The 2010 EPA requirements for NOx are even lower, although PM remains at 2007 levels. Before 2007, NOx emissions were CHAPTER THREE A CLOSER LOOK AT BIODIESEL

9typically reduced with in-engine modifications; however, the apparent technology to meet 2010 NOx requirements is an after treatment device called selective catalytic reduction, which is used in conjunction with the PM filter. Another tech- nology is NOx adsorbers, a type of catalytic converter coated with a precious metal called zeolite. Agencies are urged to follow these developments to determine which technology becomes the NOx solution to meet 2010 EPA requirements. Putting Emissions Reduction in Perspective Numbers alone make it difficult to appreciate the level of diesel emission reductions achieved by transit buses, which during the earlier years of diesel regulation had to conform to more strin- gent standards than trucks. Table 1 summarizes those reduc- tions in grams per brake horsepower-hour (g/bhp-hr), the unit of measurement used by EPA to denote emissions output. For every 100 lb of PM generated from a diesel engine in 1988, only 1.6 lb is emitted from a comparably sized 2007 engine. For every 100 lb of NOx emitted from a 1988 engine, only 11.2 lb are emitted from a 2007 engine. In 2010 when NOx requirements become more stringent, 2010 engines will emit only 1.8 lb of NOx compared with 100 lb from a 1988 engine. Figure 1 illustrates the steep reduction of PM and NOx generated from diesel bus engines from 1988 to 2007 as expressed in g/bhp-hr. These comparisons are important, because so much infor- mation on emissions refers to percentages of reductions with- out mentioning the level from which the reductions are taken. For example, a 25% reduction in PM from a 1988 diesel engine with a level of 0.60 g/bhp-hr is much more significant in terms of overall reduction than a 25% reduction from a 2007 engine where the level is already down to 0.01 g/bhp-hr. Indeed, a 25% reduction of PM from a 2007 engine would be extremely difficult to accurately measure. The intent here is not to downplay the importance of emis- sion reduction. Given the number of diesel vehicles on the road today, every reduction is significant. However, when emissions reductions are given in percentages, it is important to understand the level from which the reductions are applied regardless of the technology. Biodiesel and Emissions Reduction Atmospheric Carbon Dioxide Before addressing the regulated emissions of CO, HC, NOx, and PM discussed so far, it is important to note that biodiesel can also help meet national goals for reducing atmospheric carbon. As organic plant material, biodiesel naturally reduces the net amount of carbon CO2 gas, which contributes to global warming. Biodiesel, like other fuels, generates CO2 when burned in an engine. Unlike petroleum fuels, however, soybeans and other plants used to produce biodiesel actually consume CO2 during the plant’s growing process. According to a DOE study, the recycling of CO2 is not 100% because some fossil fuels are used in the production of biodiesel (4). The DOE study shows that substituting pure biodiesel (B100) for petroleum diesel reduces life-cycle CO2 emissions by 78%, whereas B20 reduces CO2 atmospheric emissions by approximately 16%. Exhaust Emissions Biodiesel is officially registered with the EPA and meets clean diesel standards established by the California Air Resources Board (CARB). Additionally, B100 has been des- ignated an alternative fuel by DOE and the U.S.DOT. Biodiesel is said to be the first and only alternative fuel to have a complete evaluation of emission results and potential Year PM (g/bhp-hr) NOx (g/bhp-hr) HC (g/bhp-hr) CO (g/bhp-hr) 1988 0.60 10.7 1.3 15.5 1991 0.25 5.0 1993 0.10 1995 0.05 1998 4.0 2004 2.5 0.5 (NMHC) (options) 2007 0.01 2.5–0.2 (phase in) Average of 1.2 0.5–0.14 (NMHC) (phase in) 2010 0.01 0.2 0.14 (NMHC) Unchanged NMHC = non-methane hydrocarbons. TABLE 1 TRANSIT BUS DIESEL EMISSIONS REDUCTION SINCE 1988

health effects submitted to the EPA under the Clean Air Act (5). Congress has also approved biodiesel as a strategy for complying with EPAct. Most research shows that biodiesel reduces emissions of PM, CO, and HC, primarily because B100 contains 11% oxygen by weight. The presence of oxygen in the fuel allows it to burn more completely, resulting in fewer unburned fuel emissions. Although reductions in PM, CO, and HC are generally accepted from biodiesel use, studies by the EPA, the National Renewable Energy Laboratory (NREL), and others show conflicting results for NOx emissions. The results of five biodiesel emissions studies follow. EPA Study The EPA conducted a comprehensive study of the impacts of biodiesel emissions on heavy-duty, on-highway engines (8). Although buses use heavy-duty engines and are considered on-highway vehicles, the stop-and-go nature of their opera- tion gives them a unique operating characteristic. Neverthe- less, EPA claims that its study depicts a statistically accurate relationship between biodiesel use and emissions for general highway applications. Figure 2 summarizes the findings of EPA’s study and shows that PM, CO, and HC emissions decrease as biodiesel 10 concentrations increase, whereas NOx emissions actually increase with higher biodiesel concentrations. For B20, a pop- ular biodiesel blend, the EPA reports that CO and PM emis- sions are reduced by approximately 12% each, HC emissions are reduced by approximately 20%, and NOx increases by approximately 2%. At full concentrations (B100), CO and PM emissions are reduced by approximately 48% each, HC emis- sions decrease by approximately 67%, and NOx increases by approximately 10%. The study also supports other findings that B20 biodiesel reduces fuel economy by 1%–2%. It should be noted that EPA’s testing included no engines equipped with exhaust gas recirculation, NOx adsorbers, or PM filters. In addition, approximately 98% of EPA’s data was collected on 1997 or earlier model year engines. The EPA also reported that biodiesel emissions depend on the type of biodiesel used (soybean, rapeseed, or animal fats) and the type of base diesel fuel used to make the biodiesel blend. The most prominent test cycle the EPA used was the Urban Driving Dynamometer Schedule, which forms the basis of the Federal Test Procedure used for engine certification. Houston Metro Study Houston Metro commissioned an emissions study that focused exclusively on hybrid and B10-fueled transit buses (10). The study, conducted by the University of Houston, documents emissions and fuel economy data from two 280 horsepower 0 0.1 0.2 0.3 0.4 0.5 0.6 PM 1988 (.6) 1991 (.25) 1993 (.10) 1995 (.05) 2007 (.01) 0 2 4 6 8 10 12 NOx 1988 (10.7) 1991 (5.0) 1993 (4.0) 2004 (2.5) 2007 (1.2) 2010 (0.2) FIGURE 1 Putting diesel emission reduction in perspective. Measurements expressed as g/bhp-hr.

11 40-ft buses, one with standard diesel propulsion and the other with diesel hybrid-electric. Testing took place in October 2006 using a heavy-duty chassis dynamometer and two drive cycles: Orange County, California, and Houston Metro. Buses were also tested with two different fuels: ULSD and B10 biodiesel. Testing results were measured with air conditioning on and off. The Houston Metro study found that B10: • Increased fuel consumption an average of 2.5%, • Increased NOx emissions by 2%, and • Reduced PM emissions by 11.5%. When compared with EPA’s study that was based on B20, Houston’s findings for B10, which has half as much biodiesel as B20, are interesting. Despite the differences in biodiesel concentrations, both studies have PM reductions in the 11% to 12% range and NOx increases of approximately 2%. How- ever, again using half as much biodiesel, the Houston study shows a fuel economy penalty of 2.5% for B10, in contrast to EPA’s findings that B20 reduces fuel economy by 1% to 2%. Differences between both studies could be the result of testing differences or differences between duty cycles. In presenting its findings, Houston Metro stated that additional testing is needed to validate the results (11). Naval Study An emissions study led by the Naval Facilities Engineering Service Center (NFESC) arrived at completely different find- ings (12). The report summarizes a three-year project to col- lect emissions data from ten Department of Defense (DoD) diesel engines, consisting primarily of buses and trucks, and portable generators. All testing was (1) performed with en- gines installed in the vehicles; (2) included the measurement of CO, HC, NOx, and PM; and (3) conducted in accordance with EPA testing standards and duty cycles. Biodiesel blends from B20 to B70 were tested along with B100. All biodiesel blends were mixed with ULSD as the base fuel. Although several blends were tested, the project focused on B20, the primary blend used in military vehicles. Testing performed on B20 fuels showed: 1. No consistent trends over all engines tested; 2. No statistically significant emissions differences found between biodiesel fuels manufactured from yellow grease or soybean oil feedstocks; and 3. No statistically significant differences in HC, CO, NOx, or PM emissions between B20 biodiesel and CARB ULSD petroleum diesel. NFESC’s results are in direct contrast to those of the EPA and Houston Metro studies. In its report, the naval agency expects that its findings will be incorporated with previous EPA datasets to provide a more detailed and comprehensive database. Despite its emissions findings, NFESC reported that use of B20, from a life-cycle cost perspective, is the most cost- effective method for DoD fleets to meet alternative vehicle requirements. Using B20 in place of petroleum diesel involved no new infrastructure requirements or additional environmen- tal compliance costs. The only cost reported was the $0.14 higher cost per gallon to purchase the B20. Denver RTD Study A study presented in an SAE paper by the NREL, Denver Regional Transportation District (RTD), and the Cummins FIGURE 2 Average emissions impacts of biodiesel.

Company evaluated nine identical 40-ft transit buses operat- ing on diesel and B20 biodiesel in transit service by the Denver RTD (13). Test buses consisted of Model 2000 Orion V buses powered by Cummins ISM engines. The study eval- uated the effects of biodiesel use on fuel economy, road calls, maintenance costs, and lubricants, the results of which are presented in chapter four. In addition to those tests, chassis dynamometer testing was also conducted on two of the test buses to evaluate exhaust emissions. The test driving cycle used was the City-Suburban Heavy-Vehicle Cycle. Emissions testing revealed that B20 reduced the emis- sions of all regulated pollutants, including NOx. On a gram- per-mile basis, NOx was reduced by approximately 5%, HC by approximately 34%, CO by approximately 24%, and PM by approximately 19%. NREL Study A study conducted by NREL published in October 2006, focused on biodiesel emissions with an emphasis on NOx (14). The report supports other findings that oxygen in bio- diesel reduces HC, CO, and PM. In particular, NREL wanted to take a closer look at EPA’s 2002 report (summarized ear- lier) that showed a 2% increase in NOx emissions for B20. NREL noted that this small increase in NOx as stated by EPA was causing some to consider banning biodiesel. NREL’s study consisted of testing eight heavy-duty diesel vehicles, including three transit buses, two school buses, two Class 8 trucks, and one motor coach. Four of the vehicles met the 1998 heavy-duty emissions requirement of 4 g/bhp-hr NOx and four met the 2004 limit of 2.5 g/bhp-hr NOx + HC. The three transit buses tested were all model year 2000. NREL used driving cycles that simulated both urban and freeway driving. Each vehicle was tested on soy-derived B20 mixed with petroleum diesel. Only one of the vehicles tested (a school bus) was equipped with a DPF. As mentioned earlier, DPFs are needed to meet 2007 EPA emissions standards for PM. NREL’s study found that on average B20 caused a reduc- tion in PM and CO emissions of 16% to 17% each, and a 12% 12 reduction of HC emissions when compared with diesel. Emis- sions of these three regulated pollutants nearly always went down with the exception of the school bus equipped with a DPF, which did not show significant changes in emissions. This last finding is interesting in that it suggests the impact of biodiesel on 2007 and newer engines may not be as significant because emissions are already at extremely low levels, and also supports the case that additional research is needed. When it came to NOx, the NREL study found the impact of B20 on emissions varied widely and depended on engine and vehicle technology and the driving cycle used. NOx emis- sions results ranged from a decrease of 5.8% to an increase of 6.2%. In summary, NREL concluded that the average NOx increase of 0.6% is statistically insignificant. When the results of NREL’s own testing are combined with the B20 results from other recently published studies, the average change in NOx is 0.9% (±1.5%), which again NREL claims is statisti- cally insignificant. NREL also found no discrepancy between engine and chassis testing studies regarding the effect of B20 on NOx emissions. Additional Emissions Research Required Variations on the effect biodiesel has on exhaust emissions, especially regarding NOx emissions, makes it clear that more definitive research is required in this important area. Table 2 summarizes the differences in average biodiesel emissions compared with diesel emissions for the five studies mentioned earlier. Another study, conducted by Pennsylvania State Univer- sity, found that biodiesel blends under low load conditions generally produced slightly less NOx compared with the baseline diesel fuel, whereas at high load conditions bio- diesel blends produced evidently more NOx emissions (15). The study also concluded that NOx emissions increased as injection timing was advanced under single injection condi- tions. The findings may help to explain why the various test- ing conducted to date using different duty cycles has pro- duced varying NOx emissions results for biodiesel, which strengthens the case for additional research. EPA Houston Naval Denver NREL Biodiesel (%) B20 B10 B20 B20 B20 NOx 2% increase 2% increase No difference 5% reduction 0.6% increase PM 12% reduction 11.5% reduction No difference 19% reduction 17% reduction HC 20% reduction N/A No difference 34% reduction 12% reduction CO 12% reduction N/A No difference 24% reduction 17% reduction Fuel economy 1%–2% reduction 2.5% reduction N/A 2% reduction N/A N/A = not available. TABLE 2 AVERAGE BIODIESEL EMISSIONS FINDINGS

13 In particular, additional emissions research is needed on engines equipped with DPFs installed to meet 2007 EPA standards, and NOx reduction technologies such as selective catalytic reduction, NOx adsorbers, and other such equip- ment needed to meet 2010 EPA standards. Additional testing with DPFs using standardized duty cycles may show less of an effect on PM emissions with biodiesel. Similar testing may also reveal that the NOx reduction equipment needed for 2010 is sufficient to neutralize any NOx increase resulting from biodiesel, even B100. This, however, could only be determined through additional testing. ENGINE AND FUEL SYSTEM DETAILS B20 Versus Higher Blends The beneficial attributes of biodiesel combined with lower costs have caused some to consider using concentrations higher than B20. Before using these higher concentrations, however, there is the need to become thoroughly aware of the potential issues involved and the steps needed to resolve them. As will be noted later in this chapter, the ASTM standard for biodiesel (D6751: Specification for Biodiesel Fuel Blend Stock) applies to B100 when used in blends of 20% by vol- ume (B20) or lower because of potential concerns when greater concentrations are used. ASTM D6751 was developed through a standards development process that included par- ticipation from many organizations including vehicle, engine, and fuel injection equipment companies and biodiesel pro- ducers. A recommendation contained in ASTM D6751 states: A considerable amount of experience exists in the U.S. with [B20] . . . Although B100 can be used, blends of over 20% biodiesel . . . should be evaluated on a case by case basis until further experience is available. According to guidance offered by the NBB, most engine and fuel injection equipment companies discourage the use of blends more than B20 owing to the impacts they may have on equipment and fuel systems (5). NBB also states that blends higher than B20 cannot be considered a direct replacement for petroleum diesel fuel and may require significant additional precautions, handling, and maintenance considerations, as well as potential fuel system and engine modifications. Fuel-related problems, whether caused by diesel or bio- diesel, are not considered manufacturing defects and generally are not covered by any engine or fuel injection equipment manufacturer’s warranty. The following section will discuss specific engine manufacturer’s positions regarding warranty and biodiesel use. Warranty All diesel engine manufacturers provide a warranty for their products. Although coverage varies, it typically includes defects related to materials and workmanship for a specified period of time. Each manufacturer recommends the types of fuels their engines were designed for, but do not warranty the fuel used in their engines whether that fuel is biodiesel or petroleum diesel. Therefore, the most important aspect regarding engine warranties and biodiesel is whether an engine manufacturer will void its parts and workmanship warranty when biodiesel is used, and whether the fuel producer or mar- keter will stand behind its fuels should problems occur (5). According to NBB, some engine companies specify that the B100 contained in the various biodiesel blends must meet the standards of ASTM D6751 to be used in their engines, whereas others are still in the process of adopting it (5). NBB also reports that most major engine companies have stated for- mally that blends of up to B20 will not void their parts and workmanship warranties. However, each engine manufacturer has its own guidelines for biodiesel use and sets specific limits on biodiesel concentrations for warranty coverage. Given the importance of warranty, it is strongly recommended that agen- cies become familiar with warranty coverage offered by engine manufacturers before using biodiesel. It is also recom- mended that agencies determine if specific biodiesel or any other alternative fuel is approved by the EPA. The EPA pro- vides alternative fuel information at http://www.epa.gov/ otaq/consumer/fuels/altfuels/altfuels.htm. Agencies are also advised to periodically check with engine manufacturers to determine if any of the positions presented herein have been revised. Cummins Engine Company The Cummins Engine Company recently changed its posi- tion regarding the use of biodiesel. Cummins now approves B20 blends for use in its 2002 and later emission-compliant ISB, ISC, ISL, ISM, and ISX engines, including recently released 2007 products (16). Cummins is able to upgrade its position on the use of biodiesel fuel from B5 to B20 for the following three key reasons: 1. ASTM D6751 now includes an important stability specification for B100 biodiesel; 2. The availability of quality fuels from BQ-9000 certi- fied marketers and accredited producers is growing rapidly; and 3. Cummins has completed the necessary testing and evaluations to ensure customers can reliably operate their equipment with confidence using B20 fuel. Concerning warranty, Cummins covers failures that are a result of defects in material or factory workmanship (17). Engine damage, service issues, and/or performance issues determined by Cummins to be caused by the use of biodiesel fuel not meeting the specifications outlined in its Fuels Service Bulletin (3379001-11) are not considered to be defects in material or workmanship, and are not covered under Cummins

engine warranty. This policy is no different from Cummins’ position with regard to regular diesel fuel. Cummins goes on to state that it is important to ensure when using diesel fuel or B20 with a Cummins engine that the fuel must meet industry acceptable quality standards. Cummins also emphasizes that its engines must operate on registered fuels prescribed by the EPA and other local reg- ulatory agencies such as CARB. Detroit Diesel Corporation The Detroit Diesel Corporation (DDC) recommends bio- diesel fuels made from soybean or rapeseed oil. Other feed- stock sources of biodiesel fuels such as animal fat and used cooking oils are not recommended by DDC. According to a 2005 DDC publication, biodiesel fuels meeting ASTM D6751 specifications before blending can be mixed up to 5% maximum by volume in petroleum diesel fuel (18). It is interesting to note that a previous publication issued in 2004 allowed 20% biodiesel (19). In all cases, however, DDC requires biodiesel to meet the fuel properties listed in a table provided on DDC’s website at http://www.detroitdiesel.com. DDC goes on to recommend that the cloud point (discussed later) of any diesel fuel should be 10°F (−12°C) below the low- est ambient temperature to prevent clogging of fuel filters. In addition, the filter plugging point temperature should be equal to or below the lowest expected fuel temperature. DDC notes that failures attributed to the use of biodiesel fuel will not be covered by DDC’s product warranty; any engine performance problem related to the use of biodiesel fuel would not be rec- ognized nor considered DDC’s responsibility. A May 2007 call to DDC revealed no change from the current biodiesel level of B5 maximum, and the company recommends that customers periodically check with DDC’s website or with their local DDC representative to determine if the company’s position on biodiesel has changed (Brent Calcut, DDC, personal communication, May 25, 2007). Caterpillar In its statement about biodiesel, Caterpillar, Inc., reminds customers that its engines are certified on only those fuels approved by EPA (20). As with other engine OEMs, Cater- pillar states that it does not approve nor disapprove of the use of biodiesel, and that it is not in a position to evaluate its many variations and long-term effects on engines or emis- sions compliance. For Caterpillar ACERT engine models that include C7, C9, C11, C13, and other models, the company’s position is that biodiesel may be blended up to a maximum of 30% (B30) if the ASTM D6751 specification and other Caterpil- lar requirements are met. For Caterpillar 3003 through 3004, 14 3054, and 3056 engines, the company allows up to a 5% biodiesel blend assuming that similar requirements are met. Failures resulting from not complying with these recommen- dations are not covered under Caterpillar’s warranty. Ford Motor Company The Ford Motor Company states that fuels containing no more than 5% biodiesel may be used in its diesel-powered vehicles as long as its definition for biodiesel is met, which includes compliance with ASTM D6751 (21). Ford’s position also includes a list of some unresolved technical concerns with the use of biodiesel, which can be reviewed at Ford’s website at http://www.fleet.ford.com. Cold Weather Operation As indicated in chapter two, biodiesel does have the potential to cause operational problems in cold weather, which can be avoided if the fuel is properly managed. Fuel Characteristics The characteristics of diesel fuel—even without biodiesel— are unlike gasoline in that diesel thickens or “gels” as tem- peratures get cooler. Those involved with diesel engines are already very familiar with this characteristic. It is not un- common for long-haul diesel truckers to let their engines idle throughout the night to prevent diesel from gelling in their tanks. Diesel fleets operating in cold environments also take other steps such as storing vehicles inside and adding fuel heaters and special fuel additives to prevent gelling. As with gasoline, diesel fuel is made through the refining and distillation of crude oil, the components of which range from lighter methane and propane to heavier components such as asphalt. Diesel fuels are on the heavy end of the pro- cessing, which provides higher energy content and power. The heaviness of diesel fuel, however, also causes it to gel at temperatures around 41°F (5°C). When fuel begins to gel the resulting solids get trapped in the fine mesh of fuel filters and causes them to clog. Whereas diesel fuel can start to gel at 41°F (5°C), B100 can gel at temperatures as high as 54°F (12°C), which exacerbates the gelling issue. Cloud Point The word gelling used so far technically refers to three terms that characterize the low temperature operability of diesel and biodiesel fuels. The least severe condition is cloud point, defined as the temperature where small solid crystals first form as the fuel cools and the fuel appears cloudy to the eye. Cloud point is a critical indicator for agencies to become aware of because it represents the first indication of more

15 serious conditions that will develop as temperatures fall. Concerning biodiesel use, it is essential to remember that the actual temperature of the fuel and the ambient air tempera- ture remain above the cloud point assigned to the fuel. Fail- ure to do so will cause the biodiesel to thicken or gel. The second term is cold filter plugging point, the temper- ature that causes a fuel filter to become plugged. At this stage engine performance is severely diminished or the engine may stop running. A third term is pour point, where the tempera- ture is so low the fuel essentially becomes a solid and will no longer flow. It is interesting to note that neither the ASTM specifica- tions for diesel (D975) or biodiesel (D6751) include a spe- cific requirement for the maximum cloud point. The reason being that the cold flow properties of diesel-based fuel not only depend on where in the country the fuel is being used, but also the time of year. For example, the cloud point requirement for Florida in summer months is much different than the cloud point requirement for Alaska during the same summer months. All transit operators should already be familiar with the cloud point requirements of their existing No. 1 or No. 2 diesel fuel. Given that biodiesel gels at temperatures higher than diesel, agencies using or planning to use biodiesel are strongly urged to obtain both cloud point and the cold filter plugging point information from their suppliers. Additives and Other Cold Weather Solutions Fuel additives are used to mitigate the effects of cold weather on diesel fuel. Doing the same for biodiesel can be more challenging. According to a DOE study, some additive man- ufacturers claim to reduce the pour point of a B100 by as much as 30°F, but the treat rate required is more than 10,000 ppm (4). This level of treatment can be expensive. In reality, B100 produced in the United States is extremely difficult to manage with current cold flow additives alone. Unlike rape- seed oil-based biodiesel produced in Europe, the saturated fat contained in U.S. B100 is too high for most cold weather ad- ditives to be effective. The use of cold flow additives is much more successful with biodiesel blends. According to NBB, blends of less than 20% biodiesel into existing diesel fuel have demonstrated little or no negative effect on the cold flow properties of the finished blend (5). The best way to minimize the effects of cold weather when using biodiesel blends is to follow the same general guidelines for using No. 2 diesel fuel: • Start with diesel fuel that possesses low cloud and cold filter plugging point values, • Use the appropriate ASTM and fuel quality specifica- tions, • Blend fuel with kerosene, • Use cold flow enhancing additives as appropriate, • Continually monitor and test fuel to ensure suitability for temperature, • Use fuel line heaters if necessary, and • Store vehicles inside or near a building. It is important to note that not all diesel fuel delivered to the engine is used by the engine. Unused fuel, which has been warmed by the engine as it travels through the pump, is returned back into the vehicle’s tank. This warming of the fuel that occurs, especially when combined with indoor vehicle storage, may lessen the amount of cold weather addi- tives required and may also allow the use of higher biodiesel concentrations. Material Compatibility Another potential concern is biodiesel’s incompatibility with certain materials, which can be eliminated through gaining an understanding of the materials involved and by taking appropriate steps to ensure compatibility. A materials compatibility study commissioned by the U.S. Army using ASTM test procedures revealed that B100 may degrade some hoses, gaskets, seal elastomers, glues, and plas- tics with prolonged exposure (22). Soft materials used for gas- kets and seals, such as natural or nitrile rubber compounds, polypropylene, polyvinyl, and Tygon materials, are particu- larly vulnerable to B100. Teflon, Viton, and Nylon, however, were found to have very little reaction to biodiesel. When it comes to the harder materials found in engines and fuel delivery systems, brass, bronze, copper, lead, tin, and zinc may accelerate oxidation of B100 biodiesel, creat- ing solids. Lead solders and zinc linings should be avoided, as should copper pipes, brass regulators, and copper fittings. Affected equipment such as lines and fittings should be replaced with stainless steel, carbon steel, or aluminum. Biodiesel blends of 20% have been shown to have a much smaller effect on these materials, although these effects are virtually nonexistent in low-level blends such as B2. Most engines made after 1994 have been constructed with gaskets and seals that are generally biodiesel resistant. Earlier engines or rebuilds that contain older gasket and seal materials may present a risk of swelling, leaking, or failure. Additionally, fuel pumps may contain rubber valves that may fail. Once again, agencies are strongly urged to contact their engine and bus representatives to determine specific policies regarding biodiesel and the effects the fuel may have on engine and other onboard fuel systems. Once these polices are understood, agencies can then revise their preventive mainte- nance inspection (PMI) program and fuel island procedures to address potential material compatibility concerns. If needed,

agencies could also establish campaigns to replace affected components. FUEL MANAGEMENT Introduction This section will address steps needed to ensure that the pro- curement, delivery, storage, and use of biodiesel are man- aged effectively to deliver optimum results. Biodiesel Costs As with petroleum diesel the cost of biodiesel is constantly changing, making it difficult to provide real-time compar- isons. Chapters four and five provide biodiesel costing infor- mation from the survey results and case studies. A good source for comparing biodiesel with traditional diesel (and other fuels) is the Clean Cities Alternative Fuel Price Report, which is published on a periodic basis by the DOE, Energy Efficiency and Renewable Energy (23). At the time of this writing, the most current issue was dated October 2006. The 2006 data show biodiesel prices for low-level blends (B2–B5) on an energy equivalent basis higher than regular diesel by approximately 14 cents per gallon, B20 higher by approximately 9 cents per gallon, and B100 higher by approximately $1.02 per gallon. Table 3 shows the average prices for B20 compared with regular diesel grouped by regions throughout the United States. Given the constantly changing landscape with regard to fuel pricing, agencies are urged to check with their local fuel suppliers and read the latest issue of DOE’s Clean Cities Alternative Fuel Price Report at http://www.eere.energy.gov/afdc/ resources/pricereport/price_report.html (24). Biodiesel Quality and Specifications Recognized standards (specifications) exist for most motor fuels to ensure an acceptable level of fuel performance. The specification for petroleum diesel fuel is ASTM D975, whereas ASTM D6751 serves as the standard for B100 biodiesel. As ASTM works to develop a separate specifica- 16 tion for biodiesel blends up to B20, the Engine Manufactur- ers Association (EMA) has offered one for consideration. Although essential in defining fuel performance characteris- tics, neither the ASTM nor EMA specifications address qual- ity control measures after the biodiesel has been blended with diesel. That task falls on the National Biodiesel Accreditation Program and its BQ-9000 specification. This section will describe the various fuel specifications in more detail. ASTM D6751 ASTM standards are universally recognized in the United States. The process to develop the ASTM D6751 specification for biodiesel included representation from engine and fuel injection equipment companies, fuel producers, and fuel users. ASTM D6751 applies to B100, which is then used as the source to produce other biodiesel blends. It does not, how- ever, apply to the finished blend. ASTM is working to develop specifications for finished biodiesel blends up to B20, but none have been finalized. Until these specifications are established, biodiesel procurements should contain language that the B100 used in the blending process to meet ASTM D6751, and the base diesel to meet ASTM D975. The ASTM D6751 specification is summarized in Table 4 (4). Whereas compliance to ASTM D975 can be confirmed through fuel testing, it is extremely difficult to determine the quality of B100 after it has been blended. In addition, ASTM D6751 does not address the specific raw materials or the man- ufacturing process used to produce the biodiesel. To remedy this, the following definition for biodiesel should also be in- cluded in biodiesel specifications: Biodiesel, a fuel composed of mono-alkyl esters of long-chain fatty acids derived from vegetable oils or animal fats, designated B100 (4). As with other fuels, ASTM’s biodiesel specification al- lows manufacturers to use several feedstocks and processes to produce the finished biodiesel product. Because biodiesel can be produced from several feedstocks, such as animal fats, vegetable oils, and recycled greases, the characteristics of the fuel, although meeting minimum ASTM requirements, will differ in properties according to the feedstock used. Proper- ties affected include the cetane number and cloud point. The Biodiesel (B20) Information Reported by Clean Cities ($ per gal) Diesel Information Reported by Clean Cities ($ per gal) Region Ave. Price/Standard Deviation of Price Approximate No. of Stations Ave. Price/Standard Deviation of Price Approximate No. of Stations New England $2.55/— 2 $2.67/0.07 18 Central Atlantic — — $2.67/0.13 30 Lower Atlantic $2.64/0.09 40 $2.58/0.08 46 Midwest $2.41/0.04 3 $2.57/0.10 95 Gulf Coast $2.60/0.27 3 $2.51/0.10 35 Rocky Mountain $2.71/0.16 4 $2.62/0.11 26 West Coast $2.78/0.25 13 $2.74/0.19 66 National Ave. $2.66/0.16 65 $2.62/0.15 316 TABLE 3 BIODIESEL (B20) AVERAGE PRICES BY REGION FROM CLEAN CITIES SOURCES

17 determining characteristic is the fatty acid chains contained in biodiesel feedstocks, which are saturated, monounsatu- rated, or polyunsaturated (4). Because of the effect feed- stocks have on biodiesel properties, agencies are urged to obtain from their fuel supplier specific information regarding the cloud point and cetane number before ordering a specific biodiesel product. This advice cannot be overstated. EMA Biodiesel Test Specification As ASTM works on a specification specifically for mixed blends of up to B20, EMA released its own test specification for B20 in June 2006, entitled Test Specification for Biodiesel Fuel (25). The specification is intended to jump start the test- ing and evaluation process. According to EMA, establishing a baseline B20 blend can be helpful for further testing and evaluation. A copy of the test specification is located at the EMA website at www.enginemanufacturers.org. Although EMA encourages vehicle owners to use the test specification along with BQ-9000, it is careful to note that the specification is not an approved national fuel standard. Comparison of Selected Fuel Properties Table 5 compares some properties of ASTM D6751 for B100, ASTM D975 for both No. 1 and No. 2 diesel, and the test specification being developed by EMA. BQ-9000 NBAP is a cooperative and voluntary program for the accred- itation of producers and marketers of biodiesel fuel (26). Defined as BQ-9000, the program combines the ASTM D6751 specification for biodiesel with a quality program that includes storage, sampling, testing, blending, shipping, distribution, and fuel management practices. The BQ-9000 program is available to any biodiesel manufacturer, marketer, or distribu- tor in the U.S. and Canada. The BQ-9000 program helps biodiesel companies reduce the likelihood of producing or distributing inadequate fuel. To receive accreditation companies must pass a rigorous review and inspection of their quality control processes by an inde- pendent auditor. Accreditation is available to both producers and marketers and is valid for only two years, at which time a company would need to recertify. The inclusion of a procure- ment requirement that biodiesel meet the BQ-9000 standard ensures that the finished fuel product as delivered to your agency conforms to nationally recognized quality standards regarding biodiesel production and distribution. Delivery The delivery of biodiesel is typically the responsibility of the fuel supplier. However, agencies may want to include lan- Property ASTM Method Limits Units Flash point D93 130.0 min. °C Water and sediment D2709 0.050 max. % vol. Kinematic viscosity, 40°C D445 1.9–6.0 mm2/s (centistokes) Sulfated ash D874 0.020 max. % mass Sulfur* D5453 0.0015 max. (S15) 0.05 max. (S500) % mass Copper strip corrosion D130 No. 3 max. Cetane number D613 47 min. Cloud point D2500 Report to customer °C Carbon residue† D4530 0.050 max. % mass Acid number D664 0.80 max. mg KOH/g Free glycerin D6584 0.020 max. % mass Total glycerin D6584 0.240 max. % mass Phosphorus content D4951 0.001 max. % max. Distillation temperature, 90% recovered (T90)‡ D1160 360 max. °C *Sulfur content of on-road diesel fuel to be lowered to 15 ppm in 2006. †Carbon residue shall be run on the 100% sample. ‡Atmospheric equivalent temperature. max. = maximum; min. = minimum. TABLE 4 REQUIREMENTS FOR BIODIESEL (B100) BLEND STOCK AS LISTED IN ASTM D6751-03

guage in their specifications to ensure that biodiesel be trans- ported in such a way that it does not present a problem to the end user. As with much of the material provided here on biodiesel, delivery of B100 is more critical than lower blends. The most critical aspect is that fuel and air tempera- tures be kept above biodiesel’s cloud point to prevent gelling during transportation. The other critical issue with the delivery of biodiesel is that it does not become contaminated during transportation. As with the transportation of diesel, suppliers are required to follow certain procedures that include: • Transport tanks be inspected and washed out as needed (obtain washout certificate); • Diesel fuel is generally the only acceptable residual; • No residual water is allowed; and • Hoses and seals must be clean and compatible with B100. 18 Blending Biodiesel must be thoroughly blended to maximize fuel per- formance and minimize problems. As noted in chapter two, splash blending occurs when B100 is poured atop the diesel and the heavier biodiesel mixes naturally with the existing diesel fuel in the tank as it falls downward. In-tank blending uses some form of agitation to facilitate the blending, and in-pipe blending mixes the two fuels simultaneously. A simple method is to have the supplier use a suitable blending method and deliver the fuel as a finished product. An increasing number of petroleum terminals are installing in- pipe equipment to thoroughly blend biodiesel at the rack and deliver it ready for use. There are also a growing number of public filling stations that carry premixed biodiesel. Some fuel suppliers will also fill individual vehicles at the agency’s site with premixed biodiesel from tanker trucks. The process is Property ASTM D6751 B-100 ASTM 975 No. 1 Diesel ASTM 975 No. 2 Diesel EMA Test Spec. B-20 Flash point 266ºF min. (ASTM D93) 100ºF min. (ASTM D93) 125ºF min. (ASTM D93) 100ºF min. No. 1 125ºF min. No. 2 (ASTM D93) Water and sediment Less than 0.05% by volume (ASTM D2709) Less than 0.05% by volume (ASTM D2709) Less than 0.05% by volume (ASTM D2709) Less than 0.05% by volume (ASTM D2709) Kinematic viscosity, 40º C 1.9–6.0 centistokes (ASTM D445) 1.3–2.4 centistokes (ASTM D445) 1.9–4.1 centistokes (ASTM D445) 1.3–4.1 centistokes (ASTM D445) Sulfur content Max. 15 ppm Max. 15 ppm Max. 15 ppm Max. 15 ppm Copper strip corrosion No. 3 rating (ASTM D130) No. 3 rating (ASTM D130) No. 3 rating (ASTM D130) No. 3 rating (ASTM D130) Cetane number 47 min. (ASTM D613) 40 min. (ASTM D613) 40 min. (ASTM D613) 43 min (ASTM D613) Cloud point Report to customer—seasonal (ASTM D2500) Report to customer—seasonal (ASTM D2500) Report to customer—seasonal (ASTM D2500) Report to customer— seasonal (ASTM D2500) Carbon residue Max 0.05% (ASTM D4530) Max. 0.15% (Ramsbottom ASTM D5240) Max 0.35% (Ramsbottom ASTM D5240) Max. 0.15%—No. 1 Max 0.35%—No. 2 (Ramsbottom ASTM D5240) Acid number Less than 0.80 mg KOH/g (ASTM D664) N/A N/A Max. 0.3 mg KOH/g (ASTM D664) Phosphorus content Less than 0.001 wt% mass (ASTM D4951) N/A N/A Less than 0.001 wt% mass (ASTM D4951) Lower heating value 118,170 BTU/gal (approx.) N/A 129,050 BTU/gal (approx.) N/A N/A = not available; Max. = maximum; min. = minimum. TABLE 5 COMPARISON OF SELECTED FUEL PROPERTIES

19 known as “wet hose” filling. The last two options can provide benefits to agencies wanting to test biodiesel in a select num- ber of buses before introducing it to their bulk storage tanks. Although buying premixed biodiesel provides an attrac- tive way to start using the fuel, lack of availability may force some to purchase B100 and do the blending themselves. Agencies may also prefer to do their own blending to ensure proper mixing and concentrations. The procedure is not dif- ficult if you remember (1) that the mixing must be thorough, and (2) biodiesel is slightly heavier than diesel (4). Because the specific gravity of B100 is heavier than diesel (0.88 for B100 compared with 0.85 for No. 2 diesel and 0.80 for No. 1), B100 should never be poured into an empty tank because the weight will keep it at the bottom. Problems may not occur in summer months when temperatures are above the fuel’s cloud point; however, colder weather will cause the heavier biodiesel to gel and clog filters. Because tanks typi- cally draw from the bottom, the more concentrated biodiesel could also create material compatibility problems with fuel dispensing seals and gaskets that would normally not occur if the fuel was blended at lesser levels. Highly concentrated biodiesel at the tank bottom may also start to dissolve sedi- ments, whereas lower levels would not. The best method for self-blending is to add B100 to a tank that already contains diesel. The B100 could be splash blended atop the diesel, allowing the added weight of the B100 to do the mixing as it works its way through the diesel. Some other means of mechanical agitation can also be used to facilitate the in-tank blending, such as immediately adding diesel after the biodiesel. Agencies could also purchase mechanical blending equipment, but this involves additional costs and can be complicated for smaller fleets. In all cases where the agency does its own blending, it needs to start by measuring the diesel content already con- tained in the tank and calculate the amount of B100 and petroleum diesel needed to achieve the desired blend (e.g., B5 and B20). A popular method for measuring fuel content is to “stick” the tank by inserting a long wooden rod into the tank to check the fuel level. If improper blending is suspected, there are tests that can be performed. One involves taking samples from the top, middle, and bottom portion of the stor- age tank using ASTM standard practice D4057 (Standard Practice for Manual Sampling of Petroleum and Petroleum Products). Each sample can then be tested for density or spe- cific gravity to determine the biodiesel percentage. There are also several relatively inexpensive and simple-to-use measur- ing devices available. Information on where to obtain this equipment is available from the NBB at www.biodiesel.org. Another testing method involves placing the three fuel sam- ples described earlier in a freezer and periodically noting when each batch begins to crystallize. If the samples are not within 5°F–6°F (3°C) of each other, the biodiesel blend will need further agitation. Regardless of where the blending takes place, colder win- ter temperatures present the biggest concern because of the biodiesel’s tendency to gel at higher temperatures than petroleum diesel. As noted throughout this study, agencies need to become familiar with the cloud point of the biodiesel they are using and must monitor air and existing fuel tem- peratures at time of delivery. To prevent cold weather gelling, some suppliers will also mix in a 50/50 ratio of kerosene with B100. Agencies will need to know this in advance to obtain the desired final biodiesel blend. For example, 60% diesel blended with 40% 50/50 mix- ture of biodiesel and kerosene will yield B20 (not B40). Fuel Storage Many of the same properties that affect engine and onboard bus fuel systems with biodiesel use also apply to facility stor- age. Some concerns may be amplified by facility storage because bulk fuel generally remains in tanks for longer peri- ods of time. Other concerns, such as cold weather operation, may be minimized by underground tank storage. According to the NBB, standard storage and handling pro- cedures used for petroleum diesel can also be used for biodiesel (5). NBB also states that existing storage tanks and dispensing equipment can be used for the most part. Fuel should be stored in a clean, dry, dark environment. Acceptable storage tank materials include aluminum, steel, fluorinated polyethylene, fluorinated polypropylene, and Teflon. Copper, brass, lead, tin, and zinc should be avoided. As discussed here, many of the issues related to biodiesel storage depend on the percentage of biodiesel contained in the fuel, temperature, fuel specification, and fuel quality. Fuel Stability and Storage Life Most transit agencies turn over their diesel fuel quickly, gen- erally in 2 to 4 months. Given this rapid use, the stability of biodiesel (whether B20 or B100) should not be problematic. ASTM standard D4625 (Standard Test Method for Distillate Fuel Storage) states that B100 could be stored for up to 8 months, with lower percentages lasting for a year or more. NBB recommends that B100 be stored no more than 6 months. Over time, biodiesel as with other liquid fuels will start to break down and deteriorate. The primary concern is oxi- dation, which over time can lead to high acid numbers, high viscosity, and the formation of gums and sediments that eventually clog filters. ASTM D6751 establishes lim- its for biodiesel stability. As with diesel fuel, periodic fuel monitoring and testing are highly recommended. The use of antioxidant additives can significantly improve the sta- bility and storage life of biodiesel. Before using any addi- tive, however, contact your fuel and engine supplier for recommendations.

Storage Temperatures The bigger concern with B100 storage is its tendency to gel more quickly relative to diesel and other biodiesel blends. Whether B100 or a blend, the temperature at which the fuel can be safely stored without gelling depends on the local climate. In general, any biodiesel blend should be stored in tanks where the fuel temperature will remain at least 5°F to 10°F above the cloud point of the fuel. A storage temperature of 40°F to 45°F should be adequate for just about all biodiesel blends. Although underground tank storage should not be a concern because temperatures are normally above 45°F, it is recommended that agencies monitor temperatures to make certain. For above- ground storage tanks, B20 is generally regarded as the limit, and temperature monitoring is again highly recommended. In some cases additional precautions may be needed to prevent gelling, such as extra tank insulation, equipment to agitate the fuel, and auxiliary heating systems. The same holds true for piping and dispensing equipment exposed to the elements. Glycerin Content A byproduct of manufacturing biodiesel is a form of sugar called glycerin. Makers of automotive coolant are testing glycerin as a substitute ingredient in the production of antifreeze. If successful, the new market created for glycerin may help reduce some of the costs associated with manufac- turing biodiesel. Although the vast majority of glycerin is removed from the biodiesel manufacturing process, levels that exceed those set by ASTM D6751 can cause filter plugging and other fuel related problems. As shown in Table 4, ASTM D6751 calls for a maximum of 0.020% free glycerin and a maximum of 0.240 total glycerin. Biological Contamination One area not yet addressed is the biological growth that occurs in biodiesel caused by the presence of water. Although some water is typically present in petroleum diesel, biodiesel is more susceptible to water contamination problems. As a result, biocide additives are generally needed to control the growth of bacteria, algae, and other microorganisms. These microorganisms usually grow at the fuel–water interface, and if left untreated can promote corrosion of fuel system compo- nents. The same products used to treat biological growth in petroleum diesel can also be used in biodiesel. The additives typically work by drying up water and killing the microor- ganisms. Fuel suppliers and engine OEMs should be con- sulted before using any fuel additive. In addition to additives, there are steps that agencies can take to reduce water levels in biodiesel (and other petroleum) fuels: 20 • Make sure the caps on all fuel tanks are in place and in working condition, especially gaskets. • Keep tanks full of fuel to minimize condensation buildup inside the tank caused by large temperature swings. • Insulate aboveground storage tanks (double wall) and provide shade if possible to moderate temperature swings and the formation of condensation. • Check for the presence of water and other signs of con- tamination when measuring tank levels. • Periodically drain a small amount of fuel from the bot- tom of storage tanks to remove any water accumulation. • Avoid prolonged exposure of fuel to light, which can induce bacterial growth (aboveground fiberglass tanks should be painted and/or placed in shaded areas). Cleansing Effect As discussed in chapter two, biodiesel has a cleansing effect on the components it comes in contact with. The same methyl esters found in biodiesel have been used for years as cleaners and solvents. As a result, biodiesel can dissolve and dislodge accumulated sediments that have formed over time in diesel tanks, fuel delivery systems, and other areas where fuel makes contact. Once dissolved, sediments can plug filters and create fuel injector and other fuel system-related prob- lems and failures. The level of biodiesel’s cleansing action depends on two factors: (1) the amount of sediment that has formed within the fuel system over time, and (2) the concentration of biodiesel used. The ideal scenario is one where both buses and storage tanks are new and therefore free of sediment, although this is rare. Anyone using B100 will need to have tanks and fuel systems cleaned (flushed) before using the fuel, although those using lesser concentrations should consider cleaning on a case-by-case basis. Although tank cleaning is generally not required for B20 and lower blends, a program to check and replace fuel filters (both vehicle and facility) is advisable when first using biodiesel. Filters used in fuel storage systems should be at least as fine as those on the vehicles. Informing bus operators of possible filter plugging caused by biodiesel will help them to better diagnose driv- ability problems. Any filter plugging problems that do occur should disappear after the first few tanks of fuel. Agencies should, however, be aware that moving from B20 to higher concentrations will dislodge sentiments that the weaker blend was not strong enough to remove. Any biodiesel splashed onto the vehicle or engine should imme- diately be wiped off. The cleansing effect of the fuel can damage paint and any decals or graphics. As with diesel, rags containing biodiesel need to be safely stored in a metal container and properly disposed of.

21 Material Compatibility The same material compatibility concerns discussed earlier for engines also apply to facility fuel storage and dispensing equipment. As with engines, most of the compatibility issues involve the use of B100; B20 and lower blends are not as serious. Most fuel storage tanks designed for diesel fuel should be adequate for storing up to and including B100. Acceptable materials used in storage tanks and fuel dispens- ing equipment include steel, aluminum, polyethylene, polypropylene, Teflon, and most fiberglass compounds. (See the previous section on material compatibility for engines and chapter two for a complete description of soft and hard materials affected by biodiesel.) Agencies need to monitor tanks, dispensing equipment, and fuel filters more closely when using biodiesel to ensure that there are no leaks, seepage, filter plugging, or seal dete- rioration caused by potential material incompatibility. Facility and Infrastructure Requirements One of the biggest advantages of biodiesel compared with other alternative fuels is that special facility and infrastruc- ture requirements are virtually nonexistent. Any equipment changes needed as a result of using biodiesel have already been addressed. Agencies may require equipment to blend and/or agitate the fuel if premixed is not available and splash blending proves insufficient. Modifications may also be needed to fuel dispensing and storage equipment if B100 is used, or material compatibility becomes an issue with lesser concentrations. Agencies will also need an extra supply of fuel filters (facility and vehicle) when first introducing biodiesel because of the fuel’s cleansing action. Most of the facility changes involve procedural steps to ensure a trouble-free transition. These steps are summarized in chapter six under Recommendations. INCENTIVES AND LOCAL REQUIREMENTS Tax Incentive In October 2004, Congress passed a biodiesel tax incentive as part of legislation known as the American Jobs Creation Act of 2004. The incentive is a federal excise tax credit given to the blender (petroleum distributor). Most of this blender’s tax credit is passed down to the end user as a way of reduc- ing biodiesel cost, although some may be applied to offset the supplier’s infrastructure costs. The credit equates to one penny per gallon for each percent of biodiesel content (e.g., a 20 cent per gallon credit for B20) for blends made from agricultural products like vegetable oils, and one-half penny per gallon for each percent of recycled oil content. Set to expire at the end of 2008, the biodiesel tax incentive is expected to be extended to 2017. Regardless of tax incentives, biodiesel is taxed at the same rate as diesel fuel unless the agency is exempt from paying fuel tax. Some states have also passed legislation that reduces fuel excise taxes or provides grants and other incentives. Agencies are urged to contact their local tax authorities for specific infor- mation regarding any fuel tax relief that may apply to their area. The DOE through its Clean Cities Program maintains a website that summarizes state and local laws and incentives related to all alternative fuels including biodiesel (www.eere.energy.gov/ cleancities/vbg/progs/laws.cgi). The site includes a map of the United States where users can “click” on their state for detailed information. The NBB also provides information on tax bene- fits and other incentives at www.biodiesel.org. Other Incentives One of the most significant benefits of biodiesel use is con- tained in the Biodiesel Fuel Use Credit Interim Final Rule that became effective in January 2001 (27). The ruling gives fleets that are otherwise required under EPAct to purchase AFVs the option of purchasing and using biodiesel. Credits for biodiesel use are given, which organizations can then use to offset 50% of their annual AFV acquisition requirements under EPAct. One biodiesel fuel use credit, which is counted as one AFV acquisition, is allocated to fleets for each purchase of 450 gallons of neat biodiesel fuel (B100). No credits are granted for the petroleum portion of biodiesel fuel blends, and biodiesel credits cannot be traded or banked. When it comes to biodiesel blends such as B20, a fleet may only count the biodiesel portion of the blend toward the allocation of a biodiesel fuel use credit. The rule applies to vehicles with a gross vehicle weight rating in excess of 8,500 lb. Credits offered under this program can only be claimed in the year in which the fuel is purchased. The ruling has created signifi- cant impetus for biodiesel use by those affected by EPAct. Users can find additional information from the EPAct web page at http://www.eere.energy.gov/vehiclesandfuels/ deployment/fcvt_epact.shtml. The Congressional Budget Office and the U.S. Depart- ment of Agriculture have confirmed that biodiesel is the least- cost alternative fuel option for meeting EPAct compliance requirements. Because it works with existing diesel engines, biodiesel offers an immediate and seamless way to transition existing diesel vehicles into a cleaner burning fleet (5). Local Requirements States and local governments have various requirements for using biodiesel and other alternative fuels. As mentioned, the DOE has a website that summarizes the various requirements and incentives pertaining to alternative fuels (www.eere. energy.gov/cleancities/vbg/progs/laws.cgi). The NBB also

provides information on tax benefits and other incentives at www.biodiesel.org. Although each state has various requirements, New York is used here as an example of how the use of biofuels is being encouraged. New York has issued two executive orders that promote AFVs and biofuels. Executive Order 111 involves both buildings and vehicles. Agencies are required to reduce energy consumption in buildings by 35% by 2010 relative to 1990 levels, must procure more AFVs, and must reduce petroleum consumption and emissions by using alternative fuels. 22 Executive Order 142 addresses the use of biofuels in state vehicles and buildings. Agencies are required to use E85 ethanol fuel when feasible. They are also required to use biodiesel at an increasing rate starting with B2 in 2007 and reaching B10 by 2012. New York State agencies that operate medium- and heavy-duty vehicles can also substitute biodiesel to offset the number of light-duty AFVs required. For example, the use of 450 gallons of B100, 2,250 gallons of B20 or 9,000 gallons of B5 can be used to substitute the purchase of one AFV.