THE NEED FOR ALTERNATIVE FUELS
Since the 1970s, America’s fuel imports have almost tripled. The country is now importing over 12 million barrels of crude oil a day. That’s just over half of the oil we are currently using in America — over 20 million barrels a day. The majority of this fuel is going to power transportation, most of which is used in consumer motor vehicles. The more America increases its dependence on petroleum, the faster oil reserves become depleted. We are only decades away from the point at which there is too little petroleum left to make gasoline a feasible fuel. Americans cringe at $4.00 per gallon gas prices, but cringe is all we do. We continue to pay the asking price for the only fuel that can make our cars run. But what happens at $10.00, or $25.00 per gallon? The rate that gas prices have raised in the past couple years show us that these extremes are chillingly close.
While several fuel alternatives have begun to show promise, they all seem to also have distinct drawbacks. Some fuel alternatives could be too costly to become a commercially viable alternative to gasoline. Other more cost effective fuels do not appear to meet the range of requirements demanded by consumers. Few of these sources currently appear to be capable of matching the energy output of gasoline. Best estimates suggest that within 40 years, crude oil resources will be sufficiently depleted as to render gasoline commercially unviable. It is crucial that we quickly find an acceptable replacement for gasoline.
In addition, it takes no stretch of the imagination to understand what levels of pollution are being created by our nation’s oil addiction. One only has to look at the skies above New York City or Los Angeles to see where we have come in past century of automotive transportation. It is easy to see that alternative fuels will be needed very shortly to replace gasoline. Still, it is equally important that the next fuel we rely on does nothing more to pollute the environment. In the best-case scenario, our next national fuel should assist in alleviating our current levels of pollution.
WHY SHOULD ENGINEERS CARE?
Because of the booming industries that alternative fuels are creating, many more engineers will be required for research and development. These engineers will play principle roles in the biggest breakthroughs in alternative fuels in our lifetime. Furthermore, engineers will be needed to design the new infrastructure that will be used for the transportation and delivery of new fuel systems. With this in mind, it is imperative that engineers continue to invest time and intellectual capital to further scientific developments of alternative fuels. The research of today will be the answer of tomorrow.
WHAT ARE OUR OPTIONS?
Research in the field of alternative fuels is a booming industry. There are dozens of potential fuels that show some potential as a viable alternative to fossil fuels. For the purposes of our paper, we will review the six fuels that we believe to have the greatest likelihood of replacing traditional fossil fuels. These are: biodiesel; hydrogen; methanol; ethanol; electricity; and natural gas. Each of these fuels has had extensive testing to demonstrate substantial potential as an answer to America’s quest for a replacement of gasoline.
DIMENSIONS OF COMPARISONS
For a credible comparison, it is important that a standardized basis for evaluation be created and applied equally to each of the six fuels. To of this, we will be evaluating the fuels on the following criteria:
-Cost and ease of production
We have rated each fuel in each of these categories on a scale of 1-10, with 10 being the highest. This will allow quantitative comparison. Renewability is double weighted in our comparison due to its importance in solving the energy crisis in a sustainable manner. Continuing below is a full analysis of these six alternative fuels on the abovementioned dimensions of comparison.
Biodiesel is a fuel created from organic oils, such as vegetable or seed oils. The production process uses chemical reactions to create the liquid fuel. Biodiesel is an alternative to petrodiesel and can be substituted for petrodiesel in most diesel engines with little or no modifications to the engine itself. The fuel is already commonly added to diesel fuel in small amounts. B20, a common fuel mixture, is 80% petrodiesel and 20% biodiesel. Many countries already have laws requiring specific percentages of biodiesel additions to petrodiesel.
Biodiesel: Power Output
100% pure biodiesel (B100) has a power output of just slightly less than that of standard petrodiesel. B100 has a power rating of 118,296 Btu/gallon, about 8.5% less than petrodiesel’s 129,500 Btu/gallon rating. B20 (20% biodiesel) has a power rating only 1.73% less than petrodiesel. Because pure biodiesel has slightly less energy density as compared to its petroleum-based counterpart, a slightly larger volume of biodiesel is required as compared to petrodiesel to travel the same distance . Because of the relative energy density of biodiesel as compared to petroleum-based fuels, we have assigned biodiesel a rating of 7 for power potential.
Biodiesel: Cost of Production
Biodiesel is most commonly and efficiently produced using a process called transesterification. Through transesterification, the alkoxy group of an organic ester compound is replaced by another alcohol, usually methanol or ethanol. The process of creating biodiesel is relatively simple, but not nearly as cheap. Best estimates put B100 at about $3.50 per gallon [4-5]. Even though $3.50 is currently comparable to gasoline prices, the efficiency ratio of biodiesel to petroleum fuels must be taken into account. A gallon of biodiesel just doesn’t go as far as a gallon of petrodiesel. Therefore, it would cost more to travel a set distance using biodiesel as compared to gasoline. For these reasons, we have assigned biodiesel a value of 5 for cost.
Biodiesel and the Environment
Biodiesel is an environmentally friendly fuel. The liquid fuel itself is biodegradable, and therefore does not pose the risks associated with petroleum based oil spills. Biodiesel is actually 10 times less toxic than regular table salt, which makes the fuel much safer to handle than gasoline.
The combustion of biodiesel produces significantly less harmful emissions than petrodiesel.
Emissions from B100 have reductions of 67% unburned hydrocarbons, 48% less poisonous carbon monoxide and 47% less particulate matter, as compared to gasoline. However, biodiesel has around a 10% increase in nitrogen oxides, which are a large factor in the creation of smog . Because of the reduction in poisonous emissions, we have rated biodiesel an 8 for environmental effects. Biodiesel has many environmental advantages, but the increase in nitrogen oxide emissions has kept us from rating it any higher.
Biodiesel is an excellent example of a renewable resource. The material components used in the creation of biodiesel are entirely organic. In addition, there are hundreds of diverse plant species that have known potential in biodiesel production. As long as there are oil-producing plants in existence, as well as the organic material needed to create alcohol, there will be the means for producing biodiesel. We have therefore given biodiesel a 9 for the category of renewability.
Hydrogen powered fuel cells have often been touted by advocates of alternative fuel. In fact, when one thinks of alternative fuel possibilities, often the first image to come to mind is a hydrogen car. However, hydrogen fuel has problems under the surface, which could limit its use as a fuel in the future.
Hydrogen: Power Output
There are two ways to harness energy from hydrogen. The first, and less efficient method is through combustion of hydrogen, similar to the internal combustion of gasoline or diesel. The more efficient use of hydrogen is in a hydrogen fuel cell, in which the hydrogen reacts with oxygen to produce water and electricity. The electricity is then used to power electric motors that propel the car. Through this method, a hydrogen fuel cell would have 25% greater power efficiency than gasoline. Because of this high efficiency, we have rated hydrogen a 9 for power.
Hydrogen: Cost of Production
Hydrogen can be produced in various ways. Most production procedures for hydrogen gas involve fossil fuels such as coal, natural gas and petroleum gas. A more renewable method for creating hydrogen is through a process called electrolysis, which releases hydrogen from water. This is also a much cleaner process for collecting hydrogen.
Hydrogen production is prohibitively expensive. To make matters worse, the cheapest method of producing hydrogen is through using fossil fuels. Using renewable resources for hydrogen production is a very inefficient process, around 25% efficiency at best. In addition, fuel cell costs are enormous due to the fragility and the high cost of rare materials, like platinum, which are vital to their construction.
Some non-fuel cell type hydrogen cars are already on the road, thanks to the efforts of a small number of private entities. There are a few small companies that sell custom internal combustion engine hydrogen cars with fees well into the six figures. For example, one start-up company offers to convert a Hummer to hydrogen power via the less efficient internal combustion method for $60,000, not including the price of the Hummer. Because of the inefficiency of hydrogen production, as well as the price tag for the fuel alone, we have assigned hydrogen a 3 for cost.