A Brief Introduction
“Fuel” is a very vague term. It is simply defined as something consumed to produce energy. In a more scientific sense, a fuel contains energy that can be converted into a more useful form to do work. This means things like powering the lights in our homes, the engines in our cars, heating our buildings, etc. Fuel sources are absolutely essential for everyday life; without them civilization as we know it today could not exist. The vast majority of fuels we use today come from just three main sources: fossilized carbon, radioactive elements, and the sun. Of these three, the only long-term renewable source is the sun.
When analyzing the way we use and develop fuel sources, it’s helpful to utilize these four perspectives:
Before looking more closely into these four perspectives, it will be helpful to first discuss our current fuel situation, and the reasons why a change must be made.
Our Current Situation and Reasons for Change
The various sources of energy in the US are shown in Figure 1. Notice the heavy dependence on fossil fuels (natural gas, coal, and petroleum), which make up 86% of all fuels used. There are many problems with this lopsided dependence. First and foremost, fossil fuels, and even nuclear energy, are non-renewable sources of energy. This means that one day in the not-so-distant future, the fossilized carbon supply and the radioactive elements used in nuclear reactions will run out. Estimates for the total consumption of fossil fuels and uranium are on the order of hundreds of years, but with the discovery of new reserves these change frequently. The impermanence of fossil fuels creates the need for renewable energy sources, which in one way or another all come from the one energy source that we know will last for at least four billion more years: the sun.
Figure 1 - Sources of Energy in the US. Source: US Department of Energy. URL: http://www.eia.doe.gov/cneaf/solar.renewables/page/rea_data/figh1.html
Note that not only “solar” energy comes from the sun. All forms of renewable energy come (indirectly) from the sun. Take biomass, for instance, from which energy is taken from living organisms (like ethanol distilled from corn or Biodiesel from animal substances). Plants are at the root of every food chain, and they get their energy from the sun via photosynthesis. In the case of hydroelectric generation, it is the sun’s heat that evaporates water and lifts it into the atmosphere. Rainwater then falls, maintaining continuous flow through dams. Since the sun constantly warms the core of the Earth, geothermal energy comes, too, from the sun.
Besides the fact that fossil fuel reserves will run out in the foreseeable future, there are also many other problems associated with their use. The biggest among them is the release of fixed carbon into the atmosphere. Free carbon, in the form of carbon dioxide, traps the heat that usually is reflected from the surface of the Earth into space. This leads to a phenomenon called global warming. The causes and effects of global warming have been researched fairly thoroughly and will not be discussed here. What’s important to know is that releasing fixed carbon from fossil reserves has serious environmental effects like global warming, like sea level rise and large-scale climate change.
Another deleterious effect of the burning of fossil fuels is the release of harmful gases into the atmosphere. The two main perpetrators are Carbon Monoxide and NOx gases (nitrous oxide variants). These gases are poisonous to most forms of life, and also contribute to the depletion of the ozone layer, which protects us from harmful ultraviolet radiation.
It should be noted, however, that the use of fossil fuels in recent years has become much cleaner and more efficient. I interviewed Bud Michini, an automobile repair shop owner from Philadelphia who has seen much progress, at least in transportation, over the past 20 years. “With catalytic converters in 1975, and fuel injection around 1981, cars produce less carbon monoxide, NOx, and unburned hydrocarbons than ever. Actually those pollutants make up less than 1% of the exhaust out of newer model cars.” Mr. Michini attributed this increase in efficiency to both better design and also to mandates set out by state governments. In Pennsylvania, he says that cars must be inspected every 12 months and the emissions tested must be within standards set out by the state in order for the car to be driveable. Interestingly, he noted that most standards start in California and make their way eastward, and that the standards are getting stricter every year. Even as an auto mechanic who has worked on gasoline engines his whole life, Mr. Michini sees the need for change. “Gas prices just aren’t going down; car makers are going to have to start making more hybrids or other alternative solutions.”
Thus we have seen that there are many problems with our current fuel situation, not to mention the rising cost of energy everyday. It is clear that a wide-scale changeover in our fuel sources must be made, and though this seems like a distant pipedream, many solutions are more feasible than we think.
The Technological Perspective
There are many different types of alternative fuels and uses for them, too many to discuss herein. Thus, the focus will be on alternative fuel uses in transportation, which is where a large part of today’s environmental problems lie. Specific sources discussed will be hydrogen fuel cells, electricity, ethanol, Biodiesel, and hybrid-electric. While there are more alternative fuels in transportation, these are the most researched, most popular, and most feasible. For each source, the science behind the technology and its pros and cons will be discussed.
Hydrogen Fuel Cells
Hydrogen fuel cells are based on a simple chemical reaction. Hydrogen is oxidized (using Oxygen from the atmosphere), yielding free electrons that are channeled to flow through an electric motor, which turns the wheels of the car. Hydrogen is stored in a fuel tank onboard, usually in highly compressed liquid form.
The biggest advantage of hydrogen fuel cells is that the only emission of this process is water vapor. This would obviously greatly decrease the production of greenhouse gases like CO2, and no harmful pollutants are formed. Hydrogen fuel cells themselves are also extremely efficient; about 60% efficiency as compared to the 30% efficiency of internal combustion engines. Fuel cells are almost completely noiseless.
The main drawback of hydrogen fuel cells is the same as we will see with electricity; hydrogen is not a naturally produced compound, and must be synthesized. This takes a particularly large amount of energy and is expensive, especially via the hydrolysis of water. Hydrogen can be synthesized from Methane, but the by product is, again, Carbon Dioxide. The process of synthesizing hydrogen also has its own inefficiencies, which when combined with the efficiency of the fuel cell reaction yields an overall efficiency not that much better than internal combustion. Also, the high pressure that must be maintained to form liquid hydrogen in the fuel tank also poses the risk of explosion.
Electricity
The technology involved here is extremely simple. A battery is connected to a motor, which drives the wheels. The benefits of this are obvious. Electric cars produce no emissions and are extremely efficient, not to mention ultra-quiet. They have roughly the same power and pickup of gasoline engines. Electricity is also relatively cheap, as a full recharge of the battery costs about $1. To many people electric cars seem like the ultimate solution, but there are actually many drawbacks.
Many overlook the fact that the electricity used to charge the battery doesn’t come from “magic”. It comes from the main power grid, which includes many coal and fossil fuel plants which contribute to the environmental problems discussed earlier. Batteries are very heavy, and the best ones today only last for about 50 miles. Also, they take 7-12 hours to charge, which could put a damper on long distance travel. Many of these problems can be solved, however, if cheap renewable sources of electricity (like hydroelectric plants or wind power) can be proliferated.
Ethanol
Ethanol engines work exactly like gasoline engines with designs nearly identical to those used in cars today. Ethanol is fermented from sources of glucose and other sugars, corn being the most common in use right now. Ethanol is already being used as an additive to make gasoline burn cleaner and more efficiently. There are even cars in production today ready to accept E85 fuel (85% Ethanol, 15% Gasoline).
The major benefit of ethanol use as opposed to gasoline is the shift from dependence on foreign oil to something we can grow right here in the US. Not only does this reduce the annual trade deficit, but also increases jobs and household income. The combustion of ethanol is relatively clean, producing less Carbon Monoxide and NOx than gasoline engines. While ethanol combustion does produce Carbon Dioxide, the difference is that the source of ethanol (corn for instance) takes Carbon Dioxide from the atmosphere and fixes it into organic manner via photosynthesis. Thus ethanol fuel essentially comes from solar energy (which makes it renewable). This closed carbon cycle doesn’t add to the Carbon Dioxide problem. There is also very little adjustment in transportation technology, and people can refuel their cars in the same exact way as they do with gasoline.
A big drawback of ethanol fuel is its high production cost. On a per gallon basis, ethanol would be more expensive than gasoline today. There is also less energy per unit volume in ethanol, which means that a car would get less mileage from a tank of ethanol as compared to the equivalent amount of gasoline. This adds even more the price issue; not only are you paying more for ethanol, you must buy more of it. Even so, ethanol is perhaps the most feasible and most ready-to-use alternative fuel source available today.
Biodiesel
Biodiesel is synthesized from natural oils and fats. Vegetable oils and animal fats a processed with an alcohol and a catalyst to form compounds called esters. These esters combust just like diesel fuel, except that they are biodegradable and made from natural sources. Biodiesel is a renewable source of fuel (it comes from organic matter), and although it combusts to form Carbon Dioxide, there is no net addition of CO2 to the atmosphere for the same reasons as in ethanol fuel. Biodiesel is a renewable source of energy and can directly replace the fossil fuels used in diesel engines. Biodiesel is non-toxic and completely biodegradable, so a spill wouldn’t harm the environment.
However, like other alternative fuels, Biodiesel is simply more expensive than conventional diesel fuel. Due to the chemical nature of esters, it is also very corrosive to rubber engine parts and fuel lines. Biodiesel becomes very viscous in cold temperatures, and does not combust properly, bringing about the need for a heating system that would, too, require energy. Like ethanol, though, Biodiesel is a very ready-to-use technology that requires little modification of modern technology, making it a very feasible solution at least in the short-term.
Hybrid-Electric
Hybrid-electric technology is not actually an alternative fuel source, but rather a way to make automobiles more efficient. When the brake is applied, a clutch engages an electric generator, which charges a battery. The battery is then used to power a motor which helps moves the vehicle. Essentially this process captures energy that would usually be lost as heat from friction-braking. Hybrids are being used today, most commonly in conjunction with a small-displacement gasoline engine. The efficiency of these systems is astounding; some reach up to 80 miles for one gallon of gasoline. Hybrid-electric devices are almost certain to be integrated into every automobile in the future, as they are a no-cost way of making transportation more efficient. The only drawback to this technology is that it is not stand-alone, and another fuel source is needed.
The Economic Perspective
It’s becoming apparent that one of the major reasons why alternative fuels are not yet in widespread use is because they are simply more expensive than current fuels. Given the choice between lessening damage to the atmosphere and saving money by using cheaper fossil fuels (money that can be used for things like food), most people would probably choose fossil fuels. This brings about the need to find ways to lessen the cost of alternative fuels. There is some governmental policy in place to do this. For example, in the US now there is a 52¢/gallon tax incentive for producers of ethanol. 4 This means that for each gallon of ethanol produced here, the tax on that gallon is 52¢ less than the excise tax on imported gasoline. This is surely one reason for the success of ethanol as an alternative fuel today.
The price of alternative fuels themselves is not the only concern, though. Developing the technology to utilize alternative fuels is expensive and generally not profitable. Corporations are therefore hesitant to undertake such a venture. This certainly limits the amount of progress that can be made in the use of alternative fuels.
There are, however, potential economic benefits of alternative fuels. Take the case of ethanol; the production of ethanol for use in fuel is responsible for the creation of more than 40,000 jobs in the US. 3 Ethanol produced here cuts the imports of gasoline and additives by 98,000 barrels a day, which represents about a $1.1 billion reduction in the annual trade deficit. 3 Other alternative fuel sources would also help to cut dependence on foreign oil as well, a dependence that many cite as a main reason for current economic woes in the US today.
The Political Perspective
Perhaps the most effective and most immediate impetus that has driven the development of alternative fuels has been governmental policies which mandate them. In most states, laws mandate that gasoline be mixed with an oxygenate (like ethanol) that makes it burn cleaner and more efficiently. Imposing limits on the amount of harmful emissions released into the atmosphere in certain regions have forced the use of lower-emission vehicles. For example, California’s Renewable Portfolio Standard (SB 1078) requires that use of renewable resources increases annually by at least 1%, aiming for a goal of 20% by 2017, and facilitates the use of flexible compliance and penalty mechanisms. 7
One setback in the area of policy is the low priority assigned to environmental issue. Historically, issues like healthcare, the economy, war, etc. come before alternative fuels on the “political platter.” It is unfortunate that until we become more alarmed by our environmental situation, dramatic change will not spur from policy and mandated reform. Public interest in policy change, or lack thereof, brings us to the next perspective.
The Social Perspective
It would be interesting to find out exactly what percentage of the population knows about global warming and its many harmful consequences. And how many know about the depletion of fossil fuels within a few hundred years, or the buildup of carbon monoxide, NOx, and other harmful gases in the atmosphere? Public awareness has long been a problem in the area of environmental protection. It is social impetus that ultimately drives the research, development, policy, and mandates that will make alternative fuels work. An indifferent population will see no change in the way things work today.
There are, however, many organizations in place dedicated to the sole purpose of spreading information to the general public about issues like global warming and renewable fuels. The Environmental Protection Agency and the US Department of Energy are extremely active in the distribution of information about these issues. The US DOE website offers a plethora of information and resources. If nothing else, at least the seed for change is present.
Yet lack of awareness is not the only societal factor holding back the use of alternative fuels. The use of current fuels has become so embedded in everyday life that a change in this process would be resisted. For example, there would be widespread resistance to a mandate requiring the use of electric cars because of the mileage limitations of the battery. People are accustomed to pulling into a gas station, filling up, and being on their way. They are also well-accustomed to the power and speed of gasoline automobiles that hybrid vehicles just can’t match. Changes in things so fundamental to our way of life have historically been the slowest to take place.
The Big Picture
It is clear that on our current energy consumption path, something is bound to give; whether the depletion of non-renewables comes first or irreversible damage to our environment, no one really knows. What is certain is that we need to start consciously making a change in the way we utilize fuel. This means slowly but surely transferring the fuel burden from non-renewable sources to renewable sources, and working to fix or at least stop adding to emissions problems that lead to global warming.
In my research, the thing that surprised me most was the armada of alternative fuel technology already available for use. In an age during which we have sent a man to the moon, unveiled theories like special relativity, and designed computers smaller than the naked eye can see, it is no wonder that technology for the clean, efficient use of alternative fuels is available. Problems with these technologies have been identified objectively and scientists are working on solutions every day. I think that the challenge for our generation is not to invent the alternative fuel source of the future, but to expedite the development and use of today’s technology in the modern world before too much damage has been done.
1. National Conference of State Legislation. http://www.ncsl.org/programs/energy/ALTFUEL.htm ( 20 Oct. 2004).
2. California Energy Commission. http://www.energy.ca.gov/index.html ( 20 Oct. 2004).
3. US DOE: Energy Efficiency and Renewable Energy. http://www.eere.energy.gov/ ( 21 Oct 2004).
4. Fuel Ethanol: Background and Public Policy Issues. CRS Report for Congress. http://www.ncseonline.org/nle/crsreports/03Aug/RL30369.pdf ( 28 Oct 2004)
5. Hochgraf, Lisa. “Rounding the Curve”. http://www.graduatingengineer.com/articles/feature/09-28-00d.html. 2003. ( 28 Oct 2004)
6. US DOE: Renewable Energy Annual 2002. http://www.eia.doe.gov/cneaf/solar.renewables/page/rea_data/rea_sum.html ( 28 Oct 2004)
7. State of California Energy Access Plan. http://www.energy.ca.gov/energy_action_plan/2003-05-08_ACTION_PLAN.PDF ( 28 Oct 2004)
Essays
This page is best viewed using a standards-compliant browser.
You are using an old, non-CSS-supporting browser. This site will look better with a newer browser (we recommend this). However, the site is still otherwise functional (completely, we believe, but feel free to try to prove us wrong).
