Post 3: Chapter 4, Part I

“Advanced technology vehicles, such as hybrids, plug-in hybrids, and clean diesels, and alternative fuels like cellulosic ethanol and biodiesel…offer the uncompromised features of conventional vehicles while improving dramatically automobile fuel economy and reducing our dependence on oil. It should be national policy to foster early introduction on a significant scale of these vehicle technologies and non-petroleum transportation fuels…”
- R. James Woolsey, former Director, Central Intelligence,


Chapter 1. Costs, Benefits

Beneficial, or not so?

In the 1970s, oil policy shifted from supply-side measures to consumption based measures. After the oil shocks of the 1970s, the 1980s saw a shift in to an expansionist policy, whereby the military was seen as a primary measure for securing US oil interests in foreign nations. It wasn’t until the 1990s that this came to fruition, perhaps due to the end of the Cold War. It was also at this time that policies promoting the use of alternative fuels came about. The basis of these policies was to promote air quality, national security, and the sustainability of the resources that are the basis of the national economy and way of life, or in other terms three pillars of alternative fuels. But the question must be asked, “Are alternative fuels all that they are promoted to be?” This chapter will be a point-counterpoint discussion of the many aspects of alternative fuels and alternative fuel policies.

Low emissions

Tailpipe emissions from alternative fuels are almost across the board lower than those for petroleum fuels. Some fuels, such as electricity and the much touted hydrogen fuel cell, have no tailpipe emissions at all. This is why agencies like the EPA are promoting alternative fuel technologies, especially in urban areas where air pollution tends to be the worst. Other alternative fuels, like ethanol and biodiesel that are derived from plant sources, tend to have higher emissions relative to electricity but that are still lower than gasoline or diesel. In pure form or in blends, these two fuels offer lowered emissions with little or no difference in engine performance.
There is an inherent difficulty in comparing emissions tests across all the alternative fuels this paper wishes to cover. The first difficulty is with biodiesel. It is a relatively new phenomenon compared to other fuels, only making the EPAct list in 1998, and it doesn’t need a specialty engine, it can be used in a regular diesel. Another difficulty, there isn’t one study that has covered all six fuels this paper is most interested in, thus making comparisons obvious and easy.
Next, any combination of studies will focus on different emissions or give the results in different measurements, making comparison of the various fuel’s emissions difficult. There is also the problem of vehicles used to perform the study. If one researcher is using a Ford flexible fuel vehicle (it can use pure gasoline and/or a blend of gasoline and ethanol) and another is using a Honda dedicated vehicle, the results are highly likely to be different. To counter this problem, the focus of this section will be on percentage decrease or increase of emissions from alternative fuels versus conventional gasoline, or in the case of biodiesel, conventional diesel. Those results that are not able to be compared will be marked “not available.”
Table 4.1 shows alternative fuel tailpipe emissions as a percentage of gasoline tailpipe emissions with gasoline equaling 100. (For a brief explanation of the method used, we see that ethanol produces 96 percent the emissions of carbon dioxide (CO2) as gasoline and 150 percent the emissions of methane (CH4)) It can be seen from the data in the table that on average, tailpipe emissions of various pollutants are lower by 10 to 100 percent than those for gasoline, depending on the type of fuel. In some cases, however, emissions can be somewhat higher, as is the case with NOx emissions from biodiesel, or radically higher, as in the case with CH4 emissions from CNG (although it must be said that CNG is composed of 90 to 98 percent CH4, so having higher emissions in this category is not surprising).
Table 4.1
Comparison of Tailpipe Emissions: of Alternative Fuels to Gasoline by Percentage (Gasoline = 100)
Emission by
Fuel Type Oil
Use CO2 CH4 N2O GHGs VOC CO NOx PM10 SOx
Ethanol a 20.2 96 150 100 96.3 85 75 90 78.2 4.1
CNG a 0 83.7 1000 80 87.7 21.6 80 90 65.5 4.5
Electricity a 0 0 0 0 0 0 0 0 63.6 0
Biodiesel b 0 22 na na na 84.6 52 110 53 0
Propane c 0 na 20 na na 10.7 68 64.7 60 na
Hydrogen d 0 0 0 0 0 0 0 0 0 0
Sources: a GREET 1.6 Beta software from Argonne National Laboratory (see Appendix B). b NBB, Biodiesel as a Greenhouse Gas Reduction Option, and EPA, Comprehensive Analysis of Biodiesel Impacts on Exhaust Emissions. c Society of Automotive Engineers, Reactivity Comparison of Exhaust Emission from Heavy-Duty Engines Operation on Gasoline, Diesel and Alternative Fuels. d Maclean and Lave, Evaluating Fuel/Propulsion System Technologies for H2

These findings reinforce what advocates say about alternative fuels being good for the environment. This, however, is just tailpipe emissions. What most concerns policy analysts when quantifying emissions is the life-cycle or “well-to-wheel” aspect of alternatives. This approach involves looking at the whole cycle of production for alternative fuels, not just what comes out of the tailpipe. General Motors, in its well-to-wheel analysis report for North America, uses a three stage life-cycle that is fitting for the purposes of this paper:
1. The feedstock stage: involving recovery, processing, storage, and transportation,
2. The fuel-related stage: involving production, storage, transportation, and delivery
3. The vehicle stage: involving refueling and driving.
The life-cycle process therefore looks at all stages of a fuel’s life. In the life-cycle of biodiesel, one must consider the amount of land that goes to grow the feedstock, say soybeans, and the emissions from the tractors used to grow and harvest the soybeans, plus the fertilizer used, then the transport of the soybeans to the processing plant, each stage within the plant until the soybeans become biodiesel, then shipping to the retailer, filling emissions, and final use.
In the case of electric vehicles that have almost no tailpipe emissions, one needs consider where the electric is coming from. The essential question is, “What is the mix of sources that the electric is made from?” If the electric mix is produced mostly by coal, then the life-cycle of electricity will be much closer to gasoline than if the mix comes mostly from natural gas. If the electricity can be made 100 percent by renewable sources (a goal of some electric proponents) then the life-cycle will be very low, but not zero as one must consider the production inputs for wind turbines or solar panels. Table 4.2 shows a life-cycle comparison of emissions for the same fuels as Table 4.1.
Table 4.2
Life-Cycle Emissions Comparison: Alternative Fuels to Gasoline by Percentage (Gasoline = 100)
Emission by
Fuel Type Oil
Use CO2 CH4 N2O GHG VOC CO NOx PM10 SOx
Ethanol a 25.9 34.9 98.2 312 37.6 94.7 55.9 37.1 141 41.9
CNG a .6 17.5 345 38.6 19.6 10.2 46.2 7.8 10.3 4.3
Electric a 1.8 17.7 74.9 8.7 18 5.6 1.4 7.1 26.1 37.9
Biodiesel b na 21.5 100 na na na 65 135 62 92
Propane c na na na na 85.5 33 50 na na na
Hydrogen c na na na na 15.7 5 10 na na na
Source: a, GREET 1.6 Beta software from Argonne National Laboratory (see Appendix A), and b, USDA and DOE, Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus, NREL/SR-580-24089 (Washington DC: 1998) and; C Laurie Michaelis, “The Abatement of Air Pollution from Motor Vehicles: the Role of Alternative Fuels,” Journal of Transportation Economics and Policy (January 1995), pp. 73,75.
(Ethanol, CNG, and electricity are going to give the most accurate comparisons because the results are from Argonne National Laboratory’s GREET modeling software and used the same input assumptions for electric and petroleum production [see Appendix A for a detailed table of the assumptions]. The other three fuels were assembled from different reports and are certain to use differing methods, testing equipment, and reporting measures. For the purposes of this paper, emissions from these three will be assumed to have been evaluated equally.)

What the results of the comparison show is that life-cycle analyses can have a marked difference on the amount of emissions produced compare to what come out at the tailpipe. Emissions for electricity are up across the range due to the average mix of energy production sources in the US relying heavily on coal. Even though emission are higher (meaning there are some), they are still significantly lower than emissions for gasoline, ranging from 1.4 percent the emissions of carbon monoxide (CO) to 75 percent the emissions of CH4. This makes electricity the clear winner in terms of emissions for use as an alternative fuel.
CNG also fared very well with no emissions rating above 50 percent those for gasoline except CH4 and less petroleum use than electricity. Looking at CH4 though, there is a 65 percent reduction in this emission over the life-cycle compared to tail pipe emission comparisons. This is likely due to an increase in CH4 release during the life-cycle of gasoline.
Ethanol showed mixed results in the life-cycle analysis. Around half the emissions tested showed an increase in the percentage comparison of this fuel to gasoline with one emission, nitrous oxide (N20), tripling and another, SOx, increasing tenfold. Other emissions have been decreased significantly, however, and it is unknowable with these results if the amount of emissions that are offset by the use of ethanol is larger than the increase. Petroleum usage for ethanol is much higher than the other fuels because the majority of its usage is in blends with gasoline, either at 85 percent ethanol to 15 percent gasoline (E85), or at 10 percent ethanol to 90 percent gasoline (gasohol).
As for the other fuels, there is too little data in the tables to make any justified comparisons. Therefore, discussion of these fuels will use life-cycle analysis, which is the true measure of any fuel’s environmental impact, and information from the literature.
Hydrogen, used in a fuel cell, is the second cleanest fuel as seen from the little available in the tables. This may, however, be based on what technologies will be available in the future. For now, the fuel cell is a very efficient means of using hydrogen as an alternative fuel and is currently in an “advanced development stage,” but the process for extracting hydrogen is very dirty. The process is energy intensive using current technologies and most of the energy comes from fossil fuels. If hydrogen were to be made from renewable sources only, like hydropower or wind, the life-cycle of hydrogen would be much cleaner; however, there isn’t the capacity in the US for to accomplish at this time. Thus, at current levels of technology the promise of reduced emissions from hydrogen is not a reality.
Finding propane emissions studies for anything other than buses and forklifts has proven difficult and these two vehicles don’t translate into the more prolific types of vehicles that might use this fuel source. A 1994 report by the Energy Information Administration compared life-cycle emissions among four common alternative fuels, one being propane. The study found propane to have 2 to 24 percent lower emissions for all five emissions studied, CO, NOx, N20, CH4, and CO2. It was also found to be the second best alternative among the fuels for emissions quality, CNG being the best with ethanol and methanol taking third and fourth.
Biodiesel is a newcomer in the world of alternative fuels and therefore hasn’t been studied as often in comparison to other fuels. The Energy Information Agency (EIA) didn’t start tracking its yearly consumption until 2000, when it made its debut at roughly 6.7 million gallons. Like all other alternative fuels, the verdict is still out on biodiesel’s potential to save the world. Most life-cycle studies of the fuel, however, take a favorable light, stating significant decreases in emissions like VOCs, CO2, and PM. The one exception is NOx, which has a ten percent increase over gasoline in when used in pure form, B100, lessening as the fuel is blended with conventional or low-sulfur diesel, a process that also reduces the benefits of the fuel for other emissions.
Thus, even when comparing alternative fuels to gasoline in a life-cycle approach, the fuels show a positive potential for reducing overall emissions. Some of the fuels perform better than others however, with the performance of certain fuels like ethanol questionable. Also, the fuels that perform best, like hydrogen and electricity, are the fuels that are least likely to be used in a significant amount in the near or even mid-term due to technological barriers.
Thus, in the short term, one can expect a moderate amount of air quality benefit from the use of alternative fuels with increasing benefits as time progresses. But how much benefit is received if alternative fuels are consumed in only minute proportions? The next section will look at this question.

National Security

The benefits of alternative fuels in terms of security are based on a simple equation. Given that improving national security requires reducing the amount of oil that is imported into our nation from foreign sources, there is a direct, negative, one-to-one, relationship of alternative fuels to petroleum. That is, for every gallon of an alternative fuel that is burned in a vehicle’s gas tank, there is one less gallon of imported petroleum. In its most simplistic terms, this equation is true; however, not all fuels are created equal.
Taking the energy production of one gallon of gasoline and one gallon of diesel as a baseline number for comparison (117,000 and 129,000 btu average respectively), most alternative fuels are found to have a deficiency of power. Compared to diesel, biodiesel has roughly 90 percent the amount of power in one gallon (118,500 btu). Compared to gasoline, ethanol has about 70 percent the power (80,000 btu), CNG holds only 25 percent the power (35,000 btu in gge), and propane holds about 75 percent the power (84,000 btu). What this means is that more alternative fuel will be needed to make up the imbalance of energy output per gallon.
At present rates, alternative fuels make up only three percent of transportation consumption. In a study for the Oak Ridge National Laboratory conducted in 2000, Paul Leiby and Jonathan Rubin have projected several scenarios of alternative fuel growth based on different factors. Their best case projection is for 25 percent replacement of petroleum by 2010, based on three assumptions: no transitional barriers, gasoline prices remaining high, and low prices for propane. Everyone is aware, at this moment, that the second assumption is true, with the average price for gasoline at about $2.60 per gallon , and it seems it will stay that way for some time.
The National Propane Gas Association expects average propane prices for 2005 to rise by 29 percent over 2004 to $1.80 per gallon nationwide with regional prices as high as $2.27 per gallon. Another rise is expected in the average price to $2.07 per gallon in the year 2006. In the year 2000, the time of the study, average prices were around $1.10 per gallon. Therefore, it appears that assumption number three is fallacious.
As for the first assumption, there would be no transitional barriers, “if [alternative] vehicles and fuels were produced at large scale costs, all motor fuels were widely available at retail locations, and the limited diversity of AFV models were not an issue.” Now, five years after the report and five years from the end of their projections, this isn’t anywhere near a reality and it’s not certain that the author’s believed it would be. This is merely a best case scenario that hasn’t happened. Had it occurred, however, it would most likely be enough to displace all the oil we import from Saudi Arabia and perhaps Venezuela , which would increase our national security and decrease Saudi Arabia’s economic and political pull in the US.
Leiby and Rubin’s worst case scenario shows usage of alternative fuels at .5 percent total fuel consumption and only one percent market penetration for AFVs in 2010 due to transitional barriers, regardless of the price of oil or tax incentives. The transitional barriers can be overcome by new policy, however, and it appears that in the last few years there has been at least some policy reaction, e.g. EPAct 2005. It is clear that we have surpassed their 2010 projection already, with about three percent of fuel consumption coming from alternatives, and it is also clear that consumption is a long way from attaining their best case scenario.
The Energy Information Agency’s, Energy Outlook 2005, projects fuel usage to the year 2025 based on factors such as GDP growth, vehicle miles traveled, oil prices, and changes in policy and technology. Their projection for the year 2025 is that alternative fuels will comprise 2.2 percent of the transportation fuel market (including gas, diesel, jet fuel and alternatives) compared to their figure of 1.7 percent in 2003. Thus, the likelihood that alternative fuels will be able to displace significant amounts of petroleum seems minimal at best.
Another interesting item involving security and alternative fuels is that the two most used and widely available fuels, propane and CNG, are from non-renewable sources. Propane is a co-product of natural gas and oil, and natural gas comes either from the well or as a by product of oil production. Those who promote near-term “peak oil” conditions tend to believe the peak for natural gas production isn’t more than 15 to 30 years later. Currently, natural gas reserves in the US account for about three percent of world total; whereas the Middle East is positioned over roughly 40 percent of world reserves and Russia holds another 28 percent. The list of top twenty countries holding reserves, accounting for 89.3 percent of the supply, reads like a laundry list of nation’s that the US doesn’t want to business with, or conversely, don’t want to do business with the US government.
But what about other alternative fuels and their chances of displacing oil? Methanol, it appears has been dropped from consideration. In 2000, an NHTSA report listed only two methanol refueling stations in the nation and Federal use dropped to zero gallons in 2004. Electricity is still very promising, but battery technology until very recently has restricted the usability of these vehicles, necessitating short distance trips with long charge time; it therefore still seems a distant possibility. But new technology, like lithium-ion batteries, just now coming into wider production with a plant in Austin, Texas, and a brand new plant in Milwaukee, Wisconsin, hold promise of increased usability of these vehicles perhaps bringing them more into the mainstream. Hydrogen for use in fuel cells still is a distant possibility, although intriguing. At current technology, production of hydrogen consumes far more fossil energy than the fuel delivers.
That leaves ethanol and biodiesel, two fuels which make excellent choices for different reasons but still have their specific constraints. Biodiesel’s newness, combined with lack of light-duty diesel engine availability restricts its ability to displace petroleum. On the positive side, it needs no new infrastructure nor does it need engine modification for model year 1992 and beyond, making it very promising indeed. Ethanol made from corn has a slight, positive energy balance making it less likely to displace large amount of oil. Cellulosic ethanol (from plant materials like switchgrass and kudzu) is very promising, however, producing roughly seven gallons output for every one unit of petroleum input. It is believed by the EIA that technologies will be sufficient by the mid-2010s to begin producing this type of ethanol.
Hybrid-electric vehicles (HEV) are also promising. While not considered alternative by definition, they are essentially a “blend” of electricity and petroleum, like B20 or E85. Due to current prices for gasoline, HEVs are becoming a very popular option, with many manufacturers introducing new models of varying body types just this year. Add to this the possibility of a plug-in hybrid option, and fuel economies could easily reach well above the 100 mile per gallon mark. With fuel economies as high as double their gasoline-only counterparts (with increased horsepower as well) and the possibility of the plug-in option, this technology appears the best near term, and perhaps long term means of reducing transportation’s consumption of fuel and thereby increasing national security.