On the horizon future fuels

Between elevated gasoline prices (which show every indication of staying that way) and the current concern about the environmental impacts of vehicle emissions, you've probably been hearing a lot of discussion about the use of "alternative fuels." It sounds like a good idea, you think...but do you know what alternative fuels are actually in the running? Here's the shortlist of the alternative fuels to keep an eye on, and a major advantage and disadvantage for each:

Electric

Electricity is a source of power that we already produce, store, and use. To power an electric vehicle (EV), electricity is produced by a power plant or other standard means and is then stored in the battery that will operate the vehicle.

Pro: A vehicle powered solely by electricity produces no emissions.

Con: In current models, batteries need to be recharged frequently.

Biodiesel

Biodiesel is a fuel that is made from vegetable oils and animal fats through a chemical process called esterification. When the oils and fats are mixed with alcohol, their molecules break down into methylesters, which are then used as fuel, and a waste product of glycerin. It can be used in some diesel vehicles with very little, if any, modification to the existing engine.

Pro: Potential fuel sources vary from grain crops to used cooking grease.

Con: Biodiesel thickens and freezes at low temperatures.

Ethanol

Ethanol is a type of alcohol that is created through the fermentation of substances with high starch or sugar contents, such as corn or sugar cane. In this process, yeast bacteria consume the sugars and starches and produce carbon dioxide and ethanol as by-products. The use of chemical catalysts can be used to make the process faster and more productive.

Pro: Ethanol can be produced from renewable agricultural resources.

Con: Contains less energy than the same amount of gasoline.

Hydrogen Fuel Cells

Hydrogen fuels cells harness the electrochemical reaction between hydrogen and oxygen. The bonding of hydrogen and oxygen atoms results in two products: energy, which is then stored as power in the cell, and—you guessed it: water.

Pro: Hydrogen engines are typically more efficient than gasoline engines.

Con: Current vehicle designs can only store enough hydrogen for short-range travel.

At first, you’ll most likely see these fuels used in combination with current gasoline-engine technology. Hybrid electric vehicles (HEVs) utilize both a standard gasoline engine and a rechargeable battery, and are already offered by several car manufacturers. Hybrid vehicles with a gasoline engine and a hydrogen fuel cell are currently in development, and are estimated to hit the market in 2008 to 2009. Vehicles that are designed or modified to run on mixtures of gasoline and biodiesel or ethanol show promise, and are already in use.

While some types of alternative-fuel vehicles aren’t yet readily available to the public, keep your eyes open—a combination of research, public encouragement, and lively market competition brings that day ever closer. Honda and Toyota, the first automotive manufacturers to market HEVs in the United States, have already been joined by a handful of others…and the rest are likely to follow suit.