Biodiesel: Fuel of the Present

By Bill Creasy

Four years after 9/11/01, we are as dependent on foreign oil as we were then. The U.S. is also at war in Iraq, in part because that region is important due to our reliance on oil from the Middle East. Little has been done to decrease our dependence on the Middle East for energy supplies. Hurricanes Katrina and Rita have shown that price increases can result from natural disasters that interrupt production and supply of fuel. In addition, evidence for global climate change is indicating that fossil fuel use may cause serious environmental problems, sooner rather than later.

It is becoming critically important to look at U.S. dependence on energy. We may no longer have decades of time to find alternatives. What can we do now to reduce dependence on foreign oil and nonrenewable fossil fuels?

A major use of oil is for transportation. About 40% of oil consumption is for cars and trucks. Biodiesel is one alternative energy source that can be used for transportation. It is beginning to get attention, even though few people know much about it. How can there be a fuel that is a renewable energy source and that can be used for transportation but that hardly anyone has heard of?

Not only is biodiesel renewable, it is also compatible with existing fuel distribution systems, so it can be shipped in existing trucks and sold in existing gas stations. Not only that, it can be used as fuel in existing diesel cars and trucks. Not only that, it can be produced in the U.S.

I didn't believe that biodiesel could have this many advantages and still be so obscure. So last year (2004) in the interests of scientific inquiry, I bought a diesel Mercedes and got some biodiesel fuel to run it. I can report that biodiesel really has those advantages. It is a renewable fuel produced in this country, compatible with existing infrastructure, and you can buy a car now that runs on it.

That is the main point of this article. However, there are some additional details that you may need to know about it, since it is not identical to petroleum diesel that we are used to.

There are two types of fuel that are commonly called biodiesel. Biodiesel originates from any vegetable oil, most commonly soybean oil. Commercial biodiesel, certified by government standards, is a methyl ester made from chemically modifying the vegetable oil. This is a simple procedure that reduces the viscosity of the oil, so it performs better in engines. The commercial biodiesel can be put in the fuel tank of a diesel car or truck with no noticable effect on performance, except in cold (below freezing) weather. The fuel can be blended in any proportion with petroleum diesel. It is commonly sold as B3 (3% biodiesel in diesel), B20 (20%), or B100 (100% biodiesel). (Blends work better at low temperatures.)

NOTE 1: Methanol is used in the production of biodiesel. Methanol is commonly made from natural gas, a fossil fuel. So technically, biodiesel is not totally renewable, but the methanol only contributes a few percent of the energy value. It is possible to use renewable ethanol instead of methanol. Processing the oil is done by adding methanol and caustic, and some waste is generated. Processing removes little of the energy from the fuel.

NOTE 2: Pure biodiesel begins to solidify, or "cloud," at 32 F, and it solidifies at 20-25 F. As a result, it can't be used in pure form at these temperatures. A simple solution to the problem is to mix it with diesel or kerosene to lower the freezing point when it is cold.

NOTE 3: Most auto manufacturers will agree that B20 performs in a way that is indistinguishable from petroleum diesel, except it is superior in being a better lubricant. Even so, many new cars have warranties that only include B3. Some manufacturers are especially hesitant about B100 use, because it may degrade plastics and rubber tubing in the engine. (Check your warranty if you have a new car, because use of more than B3 may void the warranty.) There is plenty of anecdotal evidence that even B100 can be used in diesel cars and truck with minimal if any repair problems. There doesn't seem to be any systematic study showing biodiesel is harmful to long-term engine performance or lifetime.

The other type of biodiesel fuel is the original unmodified oil. The oil can be used in modified vehicles. It often receives more publicity in the media as a "green" fuel. Some users obtain discarded cooking oil and use it directly in the vehicle as a "free" fuel source. It is not a good idea to use unmodified vegetable oil in an unmodified diesel car, though. Some users also react the oil to make the methyl ester, and instructions can be found on the internet.

Personally, I think it is more important (as well as safer for the engine and easier) to buy commercial biodiesel and increase the demand, rather than try to get free oil for fuel.

NOTE 4: Cars can be modified to run on unmodified oil. A company called Greasel sells kits to modify diesel cars. (See www.greasel.com). Kits sell for about $1000. Most of their customers get used restaurant oil. Apparently they get good results. But it does depend on the quality of the oil. You have to find a restaurant that has good oil, filter out the food and junk, and be careful of the water. Oil from fast food restaurants is often over used and contains solid animal fats and fatty acids that can cause problems. It's not as easy as it sounds.

NOTE 5: The main practical differences between vegetable oil and commercial biodiesel is the viscocity and the temperature that it solidifies. The oil is so viscous that it has to be heated up before it can be pumped well by the engine fuel pump. The auto modification by Greasel is to use heat from the engine to heat the fuel and decrease the viscosity. The engine has to be started and warmed up on regular diesel so the oil can be heated. It has the advantage that vegetable oil can be used directly as fuel.

There are environmental and national security implications of biodiesel. With regard to the global climate change, biodiesel fuel comes from plants, most commonly soybeans. All the carbon in the fuel comes from the atmosphere, not from nonrenewable fossil fuel. There is no net contribution to carbon dioxide in the atmosphere from burning the oil. In other words, biodiesel is a medium for indirectly using solar power for transportation, since the plants grow on solar power.

The crops are grown in the U.S., so there is no dependence on foreign energy or need for foreign wars to defend our supply of fuel. Instead, it supports American farmers.

NOTE 6: Biodiesel has some advantages for reducing pollution. All diesel engines contribute to acid rain by producing oxides of nitrogen and sulfur. These oxides are difficult to scrub from the exhaust of a vehicle. Biodiesel contains essentially no sulfur, so sulfur oxides are not produced, but there are more nitrogen oxides in the exhaust. (New federal regulations to reduce sulfur oxides in exhaust, which go into effect in 2006, may increase demand for biodiesel.) Biodiesel produces fewer particulates or aromatic hydrocarbons which may contribute to asthma. Finally, biodiesel is biodegradable, so a fuel spill of biodiesel causes much less long-term environmental damage compared to crude oil or petroleum diesel.

Of course, biodiesel has some disadvantages. The biggest current problem with biodiesel is how few places sell it. It usually takes a significant drive for me to get some. Hopefully, demand will increase so there will be more retailers who sell it. It should be sold everywhere that diesel is sold.

Biodiesel is also more expensive than petroleum diesel, so it isn't currently cost effective to use biodiesel, if price at the pump is the major consideration. However, more production plants are being built. Production tripled in 2005. Biodiesel may soon be competitive, although the economics of biodiesel are completely different from crude oil.

Diesel engines in cars tend to have poorer performance in terms of acceleration than gasoline cars, although newer engines are improving. The performance is probably a main reason gasoline cars are more popular. It seems unlikely that diesel cars will replace gasoline cars unless there is a significant cost advantage, as there is in some European countries due to fuel taxes.

It is likely that renewable ethanol fuel will be more important than biodiesel as a renewable fuel. There was 3.4 billion gal. of ethanol produced in the U.S. last year for fuel, over 30 times as much as biodiesel. Ethanol is used mostly as an additive to gasoline, but it does reduce the amount of fossil fuel that is consumed. Brazil is the current world leader in ethanol production at 4 billion gallons a year, and it already uses ethanol as a major transportation fuel. Cars may need some modification to run on ethanol fuel, though.

The difference in price and performance is not large between renewable fuels and fossil fuels. The price can be tolerated because it is guilt-free, if you are concerned about foreign wars or climate change. Biodiesel is a renewable fuel that is available now to replace petroleum.

A controversial issue is the question of the efficiency for producing biodiesel. A reasonable question is whether more energy is derived from biodiesel fuel than the fuel it takes to make it. Fuel is needed to grow the crops, including fuel for tractors as well as energy to make fertilizers and pesticides. The crops must be made into the liquid fuel and transported to the user.

The most detailed study of this issue is by the U.S. DOE National Renewable Energy Laboratory, which concludes that biodiesel returns 3.2 times as much energy as is used to produce it. In other words, only 25% of the energy value of the fuel is used to produce it. This is an excellent efficiency.

For comparison, petroleum diesel only returns 0.83 units of energy compared to the energy value in the crude oil consumed to make it, since the oil must be refined and transported. This comparison is debatable since biodiesel and diesel are made in such different ways. But it illustrates that converting a raw material to a final, useful product always consumes some energy.

There was a recent study by David Pimentel, a professor from Cornell University, that found that biodiesel returns less energy than is put into it. The implication is that producing biodiesel (as well as ethanol) is an inefficient use of fossil fuel, because fossil fuel, that could be used directly, is being used to produce renewable fuel with less energy content. The National Biodiesel Board responded to the study to say it was done with incorrect assumptions and outdated data.

The most significant point of contention seems to be following. Only 20% of soybeans is oil, and the other 80% is protein that can be fed to animals. But when calculating the efficiency for producing oil, do you count the energy to produce all the soybeans, as if the remaining 80% is waste? Or do you count only 20% of the energy used to produce the soybeans, since the other 80% was used to produce animal feed, which is the main reason for growing the beans? Obviously, this makes a factor of 5 difference in the calculation. It seems legitimate to do the calculation based on the fraction of the soybeans used for oil, which Pimentel did not appear to do.

Biodiesel is often compared to ethanol as a renewable fuel. Ethanol production may consume more energy than biodiesel. Ethanol must be fermented and distilled, and then dried to remove water that remains after distillation. Efficiency of alcohol production from fermentation is low. But on the other hand, all types of grains and some waste materials can be used as feedstock. The NREL report calculates that ethanol contains 30% more energy than is consumed to make it from corn, so it is fuel efficient but not as good as biodiesel. An important question is still the use of the waste. It has been reported that the waste can be used as feed, which improves the economic return for the producer.

In terms of overall usefulness, how does biodiesel compare to other renewable fuels?

Ethanol may be less energy efficient to produce than biodiesel. It also contains less energy as a fuel, so the milage per gallon is lower. Currently, it is usually used as a gasoline additive. Some existing cars can burn 85% ethanol, but the computers in the cars have to be programmed to adjust the timing. As a result, ethanol can be another fuel, in addition to biodiesel, that is available now for transportation. There seem to be even fewer retail outlets for pure ethanol than biodiesel, though. As an additive, ethanol is now produced in quantities 10 times greater than biodiesel, so it's impact as a renewable fuel is correspondongly greater.

Natural gas, or methane, is usually a fossil fuel. It produces less carbon dioxide per unit energy than petroleum or coal. It can be produced renewably from decomposing plant material or sewage, but not efficiently. A sewage plant in Los Angeles creates methane for its own use. Methane is a potent greenhouse gas, so it is better to burn it than release it in the atmosphere, but that isn't always cost effective.

Hydrogen is getting publicity and research funding, but it is a medium for transporting energy, not an energy source itself, since it must be produced from another energy source. There are serious problems in transporting and storing hydrogen because it is hard to liquify. Research is underway, but hydrogen is not expected to significantly contribute to energy consumption for at least 10 years.

To use a completely renewable fuel system, the most efficient, in theory, may be a combination of solar power/ hydrogen/ fuel cells. The solar panels are used to produce energy to make hydrogen, and the hydrogen is reacted in fuel cells to power transportation. This is probably the most efficient way to convert solar energy for transportation. Solar cells and fuel cells can be much more efficient than plants for making fuel and internal combusion engines for burning it. But a lot of research is still needed.

Besides, efficiency is not the only consideration. Lots of expenses and infrastructure changes are needed to manufacture and install solar panels, produce and ship hydrogen, and produce fuel-cell powered cars.

The alternative that is close to being available today is plug-in electric or hybrid cars. Current hybrid cars can be designed to charge by being plugged in, and preferentially run on the batteries. These cars aren't for sale in the U.S., but they are apparently for sale in Europe. Technically, electricity from the power grid isn't renewable, and in fact it is currently 50% from coal power in the U.S., which is the fossil fuel that produces the most carbon dioxide. But power plants can be converted gradually to renewable sources such as solar and wind. It is much easier to control emissions from fixed power plants than mobile automobiles.

In theory, one could install solar panels at home and use them to charge the car, and do most of the driving on the batteries. Of course, all this equipment is going to cost more than a used Mercedes or VW diesel that uses biodiesel.

In conclusion, biodiesel can be an important fuel that is renewable, doesn't produce net greenhouse gases, doesn't depend on foreign supplies, and can be used now. Why isn't it a major emphasis of energy policy? I'll leave this question open, because I really don't understand why it isn't.

Resources:

Information on biodiesel: www.biodiesel.org

Information on greasel: www.greasel.com

Forum on biodiesel: forums.biodieselnow.com. This forum has information on stations that sell Biodiesel. There are stations in Taylorsville, on Liberty Road west of Baltimore, and Taylor Fuels in Baltimore. There are also stations on the eastern shore, near Berlin, MD.

Information and recipes for biodiesel and ethanol: www.journeytoforever.org

 

Other information:

Diesel cars and trucks annually consume 40 billion gal. of diesel fuel on the U.S. highways, according to Bruce Calvert, senior technical advisor for Uniqema.... Capacity to produce biodiesel is now about 100 million gal. and may increase another 100 million gal. by next year, according to the National Biodiesel Board. Calvert says the amount of available vegetable oil and animal fat is too small to supply biodiesel as a 2% additive to regular diesel. (Chemical & Engineering News, Sept. 5, 2005, 20-21.) This implies that biodiesel could have a shortage in 2006 when new regulations take effect to lower sulfur in diesel fuel.

World production of soybeans is 100 million tons, and U.S. production is about 50 million tons (1987). Soybeans are 20% oil. (Z. Berk, Technology of Production of Edible Flours and Protein Products from Soybeans, FAO Agricultural Services Bulletin No. 97, United Nations, 1992.)

World production of corn is 600 million metric tons, with 235 million in the U.S. Corn has 18/48 as much oil as soybeans. A rough calculation confirms that all the oil from corn and soybeans that are grown in the U.S. could only supply a few percent of the U.S. demand for gasoline and diesel.

There was 3.4 billion gal. of ethanol produced in the U.S. last year. It is scheduled to increase to 7.5 billion gal. by 2012 by federal regulation. The demand for gasoline is 140 billion gal./year. Tad W. Patzek, prof. of civil and environmental engineering at UC Berkeley, and David Pimentel, prof. emeritus of ecology at Cornell U., argue that ethanol consumes more energy than it provides. Their study in Natural Resourcs Research (2005, 14, 65) reported that making a gallon of ethanol from corn requires about 29% more energy from fossil fuels than a gallon of ethanol can provide. This includes production of pesticides and fertilizer, operation of farm machinery and irrigation, fermentation and distillation of ethanol, and transportation to users. Pimentel says the government spends more than $3 billion a year in subsidies to make ethanol production profitable. (The direct ethanol subsidy is $0.50/gal., or 5 cents/gal. for 10% ethanol blend). Ethanol advocates say the study is flawed because it uses obsolete farming and production practices from data from the 1970's. Pimentel and Patzek are the only researchers since 1995 who say ethanol has a negative energy balance. Every other study found an energy gain of at least 25%. A U. S. Department of Energy has an energy balance of 67%. A study by the Department of Energy Argonne National Lab concluded that ethanol generates 35% more energy than it takes to produce. By comparison, gasoline contains 20% less usable energy than is consumed in the process of making it. Pimentel claims that this study neglects energy used to maintain farm machinery and irrigate fields. (ref. "Ethanol Wins Big in Energy Policy" Chemical & Engineering News Sept. 12, 2005, 28-30.)

On the other hand, Bruce E. Dale points out in the same article and in a subseqent letter that "the net energy argument is irrelevant." He argues that all types of energy are not created equal. We pay ten times as much per unit energy for electricity than for coal because electricity is more convenient and easier to apply. But electricity has a net energy loss of 235% to be produced. (Chemical & Engineering News October 10, 2005, p. 6.). The net energy argument may be valid if petroleum fuel is consumed to produce less ethanol of equivalent utility to the petroleum. If the ethanol has advantages, or if useful byproducts are produced with the ethanol, then there is a net benefit from using petroleum to produce ethanol, even if some energy content may be lost.

Hydrogen as a transportation fuel is acknowledged to be potentially a very efficient method to transmit energy in fuel cells. However, it is also accepted that hydrogen won't have any significant impact on the economy until 2020 at the earliest, and perhaps not until 2035. This is too late to begin to address the dependence on petroleum. In particular, the following problems will have to be addressed by years of research:

1) An energy-efficient method to produce hydrogen must be found. Currently most hydrogen is made from methane, a fossil fuel that can be burned directly.

2) A technology for storing hydrogen with a high density to carry safely in vehicles is needed.

3) A method and infrastructure to transport hydrogen from producers to consumers, including filling stations, is needed.

4) An increase in efficiency and lifetime of fuel cells, and decrease in cost, are needed to make hydrogen competitive.

Without improvements in all these areas, hydrogen will be too expensive to compete with electric/gasoline hybrid cars. In fact, hybrid cars that can charge their batteries by plugging into the electric grid already have many of the advantages that are sought in hydrogen fuel cell cars, and the distribution system already exists. ("Competing Visions of a Hydrogen Economy" Chemical & Engineering News, August 22. 2005, 30-35.)