“The use of plant oil as fuel may seem insignificant today. But such products can in time become just as important as kerosene and the coal-tar-products of today.”
- Rudolf Diesel, 1912
Chapter 6. Biodiesel
Biodiesel is a petroleum diesel alternative made from a base of virgin or used vegetable oils or animal fats, blended with methanol and lye in a transesterification process. Using vegetable oil for automotive fuel is not new; Rudolf Diesel demonstrated his first working engine using peanut oil as the medium of combustion. Be that as it may, biodiesel is the new kid on the block in the world of modern alternative fuels. Only making the Department of Energy’s list in the last seven years, it has since become the fastest growing alternative fuel in terms of production and use and it is a promising fuel for the future of the United States.
Whether it is used in a blend with regular diesel, most commonly B20, 20 percent biodiesel and 80 percent petrol-diesel, or in pure form, B100, biodiesel has many advantages for the user and the nation as a whole. As with all things “alternative fuels,” disadvantages are inherent, not the least of which is competing with a 100 year old oil industry. This chapter will run biodiesel through the Fuel-o-Tron to assess its general advantages and disadvantages, its emissions, its ability to support national security, sustainability factors, its economic impact, and future potential.
General Advantages
Unlike ethanol, which needs specially modified vehicles for blends higher than 10 percent, biodiesel can be used in any percentage blend in any vehicle with a diesel engine assembled after 1992 without modification. This quality allows the fuel to be used “neat” as well as in blends from 1 percent to 99 percent. Of course, burning biodiesel at the 100 percent level, or B100, means there is no petroleum burned in the fuel cycle, making vehicles mostly independent from oil (considering life-cycle). Combine this with the amount of light and heavy-duty on-road diesel engines, some 5 million by 1997, transit and school buses, off-road diesel engines used for power generation, marine vessels, and rail engines and it is apparent biodiesel has the ability to displace a significant percentage of imported oil.
Along with its ready usability in engines, it also needs no changes to infrastructure; whether transportation, fueling, or storage. Fuel pump hoses are designed to withstand biodiesel’s solvent nature and it is safe to hold in common storage tanks. It can also be “splash blended” on site at a fueling station or it can be shipped pre-blended, and then pumped into a holding tank. This increases biodiesel’s usability because there is no special equipment needed and no extra costs involved to start using biodiesel, a hurdle many alternative fuels find difficult to pass.
Addressing biodiesel’s solvent nature, it could be considered a disadvantage by some, but for the purposes of this paper it won’t be. Because it cleans the containers it is put in, when a fuel provider begins offering the fuel to the public, it will clean out the deposits left behind by the petroleum diesel that was previously stored in the tanks. The same is true for a vehicle’s gas tank and fuel lines. A vehicle that has been running on petrol-diesel will have to change fuel filters a few times after starting biodiesel use. This shouldn’t be considered a negative, however, because the cleansing affect makes the engine run more efficiently, prolonging its life. This benefit is available even with low percentage blends.
Like ethanol’s higher octane content, biodiesel has higher cetane content than petrol-diesel. Cetane is a molecule that is easily combustible when compressed and that adds lubricity to a fuel. Biodiesel’s higher cetane content means that it burns more efficiently than regular diesel thus improving the performance and life-span of diesel engines. A specific use for this quality could be in ultra-low sulfur diesel (15 ppm) that is mandated for use in all diesel engines by 2007. Just as ethanol became a useful additive when lead was banned from gasoline, biodiesel would be able to maintain the lubricity in diesel fuel that is lost when sulfur is removed without adding any extra. It remains to be seen whether this will happen, but even a low percentage blend, such as B2-B5, would be sufficient to compensate for lost sulfur, is or can be available, and would also reduce emissions and petroleum use.
A final advantage of biodiesel is that it is safer to handle than other fuels. Biodiesel has a higher flash-point and lower volatility than diesel. A higher flash-point means it combusts at higher temperatures and lower volatility reduces evaporation, reducing fumes. This makes it safer for handling, especially in the case of a spill, because it reduces the chances for ignition and reduces health risks from inhaling fumes. The fuel is also safer for the environment, and thus humans; it biodegrades four times faster than petroleum diesel (and is more biodegradable than sugar) and is 10 times less toxic than table salt. This trait can be especially useful for marine applications but you still wouldn’t want to put it on your Wheaties.
Next, some disadvantages of biodiesel will be discussed.
General Disadvantages
Perhaps not a disadvantage, but a prominent hurdle biodiesel faces is its relative youth in the alternative fuels arena. As of 1996, there were only two commercial producers of biodiesel in the country and a number of homebrew cooperatives. Compare this to other fuels like ethanol, which started major production in the 1970s or electricity, which had mandated use in California as of 1992. The newness factor plays out in two major ways. First, there is less research and data available about biodiesel than other fuels. While seven years may seem like a long time, remember that for research to be thorough every model engine, light and heavy-duty, generator, etc., must be tested. Thus, there hasn’t been time to observe long-term effects on the fuel systems of vehicles and the best processes and feedstock for production are still being debated and/or discovered. This translates into reluctance by vehicle and motor manufactures to promote biodiesel use in their products.
In fact, most auto manufacturers will only warrantee their engines for use with blends up to B20, and some will only allow the use of B5. Here is an example from US manufacturers:
Biodiesel fuels may be produced from a wide variety of sources and maybe used in all DDC engines provided they are derived from soy methyl ester and rape methyl ester (canola) and are blended to a maximum of 20% by volume in diesel fuel. The resulting blend must meet DDC specified fuel properties. These blends have not been fully evaluated relative to diesel fuel system durability or engine oil effects.
Blends higher than B20 void the warrantee, making fuel retailers less likely to carry them. This is why more research is needed. Manufacturers were equally reluctant with ethanol, even in low percentage blends like gasohol, when it was being introduced and today, after much research has been done, they are all fully behind it and provide flexible fuel vehicles that can use high percentage blends. With more research, biodiesel could receive the same backing which could greatly increase its use.
The second factor is cost. The youth of the industry makes the costs of production high because economies of scale and advances in technology have not developed to the point of noticeable decreases in cost at the pump. As of September, 2005, a gallon of B20 cost about $0.10 more than petrol-diesel and a gallon of B100 was $0.60 more. Lower blends of B2-B5 were priced equally but if the fuel is going to provide the advantages desired, higher blends will need to be used. People who are environmentally conscious or are “Made in America” backers would most likely pay the extra cost for the B20 blend. This would increase petroleum displacement greatly if all diesel fuel were B20 but to maximize alternative fuel benefits, offering B100 (as an option, not a replacement) would be best. Most consumers, however conscious they may be, would still balk at paying an extra $0.60 per gallon to fuel their car.
Like all alternative fuels, even if consumers were willing to pay the premium to use B100 or a blend, availability is a problem. The Energy Efficiency and Renewable Energy office of the Department of Energy lists 334 biodiesel retail sites but the National Biodiesel Board website shows slightly more than this in just the six most densely populated states (in terms of biodiesel sites) clustered around Illinois. If consumers can’t purchase the fuel, they aren’t going to use it but as the number of production plants is going to double in the next couple years, availability should increase.
But how much petroleum can be displaced, i.e. not imported, by switching to biodiesel from petrol-diesel? Currently, there are a great deal of tractor-trailers and buses operating on the roads. Compared to light-duty passenger vehicles, however, they are only a small percentage of total vehicles and fuel consumption. In the year 2003, there were over 228 million passenger vehicles in the US compared to around 8.7 million heavy-duty vehicles. There are many heavy-duty vehicles that use gasoline, like the delivery trucks that operate in a city, but according to the NBB only one third of 1 percent of light duty vehicles operate on diesel. In fact, only 10 models are offered in the 2006 model year, mostly from Volkswagen. There are many diesel pick-ups and SUVs but they too are a relatively small portion of the total.
Fuel consumption is a different story with around 132 billion gallons of gasoline consumed and 38.5 billion gallons of diesel. Here, diesel is a higher percentage of the total but if biodiesel were used in low percentage blends, it ability to displace total petroleum usage would be relatively low.
Also, like ethanol, biodiesel produces less power per gallon compared to its petroleum alternative. One gallon of petrol-diesel contains 130,000 btu of energy compared to 120,000 btu for biodiesel. This translates to about 5 percent less engine power (torque) and about 15 percent increase in fuel consumption when using B100. A B20 blend, however, shows a proportional change in these figures with fuel use increasing 2-3 percent and engine power roughly equal to petrol-diesel. This factor must be taken into consideration when calculating costs of the fuel and when considering it as a replacement fuel as more will be needed to displace a quantity of diesel.
A final disadvantage that is specific to biodiesel is that it has lower resistance to cold weather than other fuels. Biodiesel blends, like B20, freeze at temperatures 2 to 3 degrees higher than petrol diesel which begins to cloud at 15° F. B100, however, starts to freeze at temperatures of 25° F, making it unsuitable for use in winter months in most of the country without a preheating mechanism. Blending the fuels together does increase usability in the winter and B20 has been used at temperatures of -25° F without difficulties.
Grade for Advantages and Disadvantages: B-
Emissions
Unfortunately, the GREET Model that was used to assess ethanol’s life-cycle emissions hasn’t yet been developed to include biodiesel. This hampers direct comparisons between all alternative fuels considered in this paper because base conditions are guaranteed to be different between studies. There are, however, general trends in the literature that point to all emissions for biodiesel being lower except for nitrous oxides, which are roughly 20 percent higher for B100
In 1998 the National Renewable Energy Laboratories conducted a study for the Departments of Agriculture and Energy and used the TEAM™ model for life-cycle analysis of biodiesel. The study found a significant reduction in CO2, a major contributor to global warming. Pure biodiesel showed a 78.5 percent life-cycle reduction in CO2 emissions with B20 offering a 15.7 percent reduction. Remember, any blend of biodiesel will have higher emissions levels because of the inclusion of petrol-diesel. There was also observed a modest reduction in methane emission (this most likely means very low as another study sited equal emissions) which is also a prime contributor to global warming.
B100 also reduces other emissions that are targeted under the EPA’s National Ambient Air Quality Standards. Carbon monoxide (CO) emission drops 35 percent overall and drops 46 percent in tailpipe only emissions. Total particulate matter (PM) drops 38 percent over the life-cycle and 62 percent for matter 10 microns and under which is specifically targeted by the EPA. Recent studies have connected PM emissions with global warming and it also contributes to smog in urban centers, making biodiesel use doubly important for this emission. In an EPA study it was shown that both PM and CO show proportional reductions in tailpipe emissions when blended with petrol-diesel. Finally, sulfur oxide (SOx) emissions are decreased by 8 percent over the life-cycle but biodiesel actually contributes nothing to these emissions, having none from the tailpipe. SOx emissions come from other sources such as the fuel and fertilizer used during the agricultural process and from the electricity used to operate the biodiesel production facility.
The NREL study shows that nitrous oxide (NOx) emissions are higher on a life-cycle basis for B100. This is not news; NOx is sited in every study and FAQ sheet available as being higher for biodiesel, usually about 35 percent higher than regular diesel. NOx contributes to smog formation and respiratory problems like asthma. With the large amount of diesel engines driving through, in, and around city centers, higher emissions of this gas can be detrimental. The effects can be mitigated by blending. B20 shows only a 9 percent increase but then there is a trade-off of increased emissions of other pollutants. Reasearch into the means of overcoming NOx increases is ongoing and will most likely produce results in the next few years. Ideas being considered are cetane improving additives, diesel catalytic converters, and feedstock manipulation.
Finally, total hydrocarbon (THC) emissions, including methane, benzene, formaldehyde, and non-methane hydrocarbons, are also higher for B100. The NREL study sites a 35 percent life-cycle increase over petrol-diesel. THCs contribute to ground level ozone formation, health problems, and smog. Tailpipe emissions, however, are 35 percent lower. The discrepancy is likely due to large emissions during the soybean crushing phase which account for half the total. There is no comparably high factor for petrol-diesel production.
Grade for Emissions: B
National Security
National security is based on reducing US dependence on foreign sources of oil, especially from volatile regions. In order for an alternative fuel to be effective at increasing our national security by decreasing our energy dependence, it will have to fit into the established networks that keep our transportation system running. Biodiesel has the ability to contribute significantly to national security because it requires little to no infrastructure improvement and can be produced from start to finish on domestic soil.
Perhaps more so than any other alternative fuel, biodiesel can fit into the existing network of gasoline/diesel transport and distribution because there is no need to modify existing infrastructure; it is just a matter of putting in the tank and pumping it out. It isn’t quite that simple, however, because before it can be put in a tank, it has to be made. Currently, very little biodiesel is produced compared to the amount of diesel that is consumed. In 2005, production is expected to meet 25 million gallons which is six ten-thousandths of total consumption (based on the above figure of 39 billion gallons).
Clearly, it isn’t a significant contribution to reducing petroleum use but a report by the NBB states that government fleet vehicles operating on B20 blends have much greater potential to displace petroleum, the focus of EPAct regulations, than other light-duty vehicle use. Table 6.1 is a reproduction of the NBB’s work and is included here because of its clarity on this subject.
The table shows that B20 has greater potential to displace petroleum than light-duty vehicles that operate on alternative fuels 85 percent of the time. Of course, most non-dedicated vehicles in government fleets don’t use their particular alternative fuel nearly as often as 85 percent but this is a measure of potential, not what’s so. The reason that biodiesel has the greater potential to displace petroleum even though it is used in a lower percentage blend is based on a combination of vehicle miles traveled (VMT) and miles per gallon. VMT tends to be two to three times greater for vehicles that operate diesel engines and those vehicle’s average mileage is between half and one-sixth that of the light duty passenger vehicles. The two in combination show roughly 1.5 to 5.5 times more petroleum displaced for medium and heavy-duty trucks and transit busses. Multiplying these results to cover all vehicles in the nation means a large portion of petroleum could be displaced by B20 fuel, on the order of 7 to 8 billion gallons a year (based on the above figure of 39 billion gallons of diesel consumed).
Table 6.1
Estimated Petroleum Displacement from Alternative Fuel Use
Vehicle / Fleet Type VMTs MPG Fuel %petrol Total(g)
Use Displaced Displaced
Light duty Passenger
E85, CNG, Propane 8000 24 334 85 283
Light duty Truck B20 16400 16 1025 20 205
Medium Duty Truck B20 16400 8 2050 20 410
Heavy Duty Truck B20 16400 6 2734 20 547
School Bus B20 8000 8 1000 20 200
Transit Bus B20 33200 4 8300 20 1660
Source: National Biodiesel Board, B20 Vehicles: EPAct. Online. Available: http://www.biodiesel.org /resources/reportsdatabase/reports/gen/19980701_gen-055.pdf. Accessed: December 3, 2005.
Thus, biodiesel has great potential to provide for national security. As time passes and more research is conducted, automobile manufacturers will most likely accept higher percentage blends of fuel for use with their vehicles, adding to the fuel’s potential to displace petroleum. For now, however, only a miniscule fraction of petroleum is being displaced by biodiesel. This is likely to change significantly by the end of the decade. More and more biodiesel production facilities are coming on line every year and the most recent Energy Policy Act, signed in June 2005, has provisions that promote the use of biodiesel and provide tax credits for manufacturers and distributors. The provisions call for an engine testing program to be conducted by the EPA, testing of biodiesel for electricity generation at universities, and exemption from excise taxes for vendors and a income tax credit for producers.
Grade for National Security: C
Sustainability
Biodiesel has an excellent sustainability factor when comparing fossil fuel production inputs. Every unit of fossil fuel energy used in the production of biodiesel creates 3.2 units of usable energy. This is a life-cycle analysis so it includes the fuel used to grow the feedstock (usually soybeans in the US) as well as the fossil fuels used in fertilizer and the electricity that runs the production plant. Thus, “the biodiesel life cycle produces more than three times as much energy in its final fuel product as it uses in fossil energy.” This is excellent news both in terms of sustainability and national security as a small amount of fossil fuels can create a larger amount of green energy that can be used in transportation and electricity generation. In comparison, ethanol has an average net energy balance of about 1.14 and petroleum diesel has a negative net energy balance of about .83 (this is a ratio with a value of 1 being one unit in = one unit out).
A further study will show that biodiesel, when taking into consideration all energy inputs, has a negative net balance of .80, which is very similar to petrol-diesel. This figure, however, takes into consideration the solar energy used in photosynthesis, an energy input that doesn’t seem like it should be included as it isn’t being generated by human technological means. Solar energy is considered in petrol-diesel production as well, but for petroleum, the energy rate is a geologic scale and for soybean production it is yearly. Also, biodiesel production is likely to become more efficient as economies of scale are reached and production processes and technologies are fine tuned. Petrol-diesel, however, is likely to become less efficient as energy costs of transporting oil to the US are likely to increase and domestic drilling becomes less efficient due to depletion.
Thus, biodiesel is very energy efficient in terms of fossil fuel inputs to total energy output. As with ethanol, however, the same question must be asked of biodiesel, “Can enough feedstock be produced to meet energy demands?” In the case of ethanol, all the land outside of urban centers would have needed to be converted to corn production to meet demand. This amount could be lower once cellulosic ethanol is perfected but for now, it is an impossibility. The story for soybean production is the same but worse.
In “A Life Cycle Comparison of Alternative Automobile Fuels,” Heather MacLean, et. al., describe a scenario for short-term production of soy based biodiesel and long-term, sustainable production (all inputs are renewables). Based on production of 36 bushels per acre per year and a fuel yield of 1.4 gallons per bushel, MacLean estimates that short-term production using fossil fuel inputs would require 1.5 billion acres to replace all diesel fuel. For sustainable production, the figure rises to 2.6 billion acres. To keep things in context, the US only has 1.9 billion acres of surface land, and another 4 billion acres or so that is underwater. Therefore, for sustainable production, the US would have to become share croppers to the Canadian and Mexican governments.
That is a bit of tongue in cheek humor but it does demonstrate current technical limitations on the ability of biodiesel to completely replace diesel fuels. Some of this can be mitigated by using feedstock that is not commonly used in the US, namely rapeseed oil, which has about 2 times the oil production of a similar quantity of soybeans. In either case, it is obvious that more than one solution to the problem of petroleum use needs to be considered if the US is going to increase national security and promote sustainability.
Grade for Sustainability: C-
Economic Impact
In the mid-1990s, Jian Ma, James Scott, and Thomas Johnson conducted an economic impact analysis of building and operating a 5 million gallon capacity soy biodiesel plant in northwestern Missouri. The findings of the study were significant. There was an expected increase of 81 jobs directly related to the plant with an additional 162 jobs resulting from increased economic activity in the neighboring area. There would be an increase of $50 million in commercial and industrial sales and area income would raise $14 million per year. The construction phase of the plant would also increase spending and jobs in the area for two to three years, but this was not quantified. Finally, government revenues could be expected to raise 3.5 percent throughout the time interval of the study, 1997-2006, to $12 million annually.
Other impacts of building the plant include an increase in population of 500 people as employees move into the area. It would also create a slight decrease in unemployment levels, because the area has a relatively high level of in-commuting, and would increase property values and retail sales. On the negative side, county government expenditures are expected to increase faster than new revenues causing deficit spending if not countered by other measures such as increasing taxes.
These projections are based on a production facility of about 5 million gallons in size. Modern biodiesel plants are being built at the 30 million gallon size and could be expected to have a greater impact on the local economy, though not proportionately as capital would maximize labor production. There is a caveat that goes with this information as well, “Not all locations are created equal.”
Northwest Missouri has many accommodations that make building a biodiesel plant in the area economically feasible. The study sites plentiful ground, rail, and water connections, proximity to soybean agricultural production and livestock yards for the soymeal byproduct, and a history of public-private partnership to promote the economy of the region. Other areas of the country that don’t have these particular assets may find building a biodiesel plant unfeasible or not as economically enriching. Higher costs of transportation, difficulty in securing cooperation, and lack of markets for byproducts could all increase costs associated with production that would supersede the ability to make profits and thus improve an areas economy.
Another study by D.L. Van Dyne, et. al., based in another Missouri county finds similar results to the Ma, et. al., study. One result this study finds is that for a small size production facility, about 500,000 gallon capacity, net job creation is only one employee. The study states, “New jobs created through the operation of the biodiesel plant are expected to be partially offset by a decrease in jobs in the fuel, high protein meal and the grain handling industries within the county.” Larger scale facilities would have a higher net impact; a 6.5 million gallon plant would produce 13 net jobs (and 112 for the construction phase) and a 15 million gallon plant would create 31 jobs (with 281 in the construction phase).
Most plants currently being built are slated to produce upwards of 30 million gallons of biodiesel because demand for the product is much higher in 2005 than in the mid-1990s. A 30 million gallon plant would increase net employment even more and have greater impact on the local economy. Thus, overall, the economic impact of biodiesel is likely to be excellent.
Grade for Economic Impact: B+
Future Potential
Future potential of this alternative fuel is great, mostly because there isn’t much actual (kinetic) happening but also because of government incentives and increased visibility. The National Biodiesel Board estimates a doubling of production facilities in the next few years. Tax incentives will keep the cost of biodiesel competitive with petrol-diesel, especially in blends which show promise in displacing oil usage. High profile celebrities like Willie Nelson and Emmylou Harris are promoting the fuel, using it to power their tour busses. Finally, increased research as the industry matures will lead to decreased costs and increased efficiencies which will make the fuel even more viable.
Grade for Future Potential: B+
Final Grade for Biodiesel: B-
