To that end, we will likely see a mixture of technologies, including biofuels, plug-in hybrid electric vehicles (PHEVs), electric vehicles (EVs), and fuel cells, in addition to our conventional fossil fueled vehicles. -Dahlia Garas, Program Manager, PHEV (Plug-in Hybrid Electric Vehicle) Research Center, UC Davis
Within a remarkably short period of time, the growing scarcity of fossil fuels has been hammered home to virtually everyone as the price of gas climbs on a monthly basis, affecting even those of us who rely on public transportation. Perhaps only a generation ago, terms such as "global warming" and "greenhouse effects" were the exclusive domain of scientists and academics, now they pepper the vocabulary of everyone from the President on down to entry level factory workers, and putting us all on the same page about the importance of reducing our dependence on foreign oil and the need to address our worldwide climate change.
The fact that this nation has received what may be construed as a crash course in human induced global climate change in such a small span of time is not as mind boggling as the realization that we may be forced to undergo a drastic life style change in a similarly short period of time.
How things work
There are a surprising number of substitutes to choose from including substances such as ethanol, which is derived from the same alcohol that gives beer, wine, and hard liquor their potency, but are known to emit more pollutants then gasoline and have raised concerns about creating future food shortages since it has been traditionally made from food crops such as corn and sugar. Methanol has an extensive history of use in motor sports including drag racing and the Indianapolis 500, but has corrosive effects on many metals; and natural gas, which is cleaner but has a reputation for less then adequate power.
Thus far, the most viable alternative may be the plug-in hybrid. Currently, there are quite a few on the market, with any number being in development for release in the immediate future. They include hybrid versions of old stand bys like the Honda Accord and Civic, the Lexus GS Series, Nissan's Altima, the Saturn Aura, and a new version of Toyota's venerable Camry. In short order, variations are expected from such established marquees as Audi, BMW, Cadillac, Chevrolet, CMC, Ford, Land Rover, Mercury, Peugeot's Citroen, Porsche (a hybrid version of its Cayenne SUV), who coincidentally introduced one of the first hybrids back in 1898, and Volkswagen, end most likely several more flying under the radar.
Electric motors are more efficient then their gas counter parts because they only use the amount of power necessary to propel a vehicle. The downside is that they often need assistance via its battery when going up a hill, or to pass a large semi-trailer truck. Conversely, a gasoline automobile generally has enough power to negotiate most situations, but that power is wasted at least 90 percent of the time.
Electric vehicles have the additional ability to take advantage of "regenerative braking," that is using the electric motor to slow the car and collect its kinetic energy for storage in its batteries for later usage. The act of slowing down can also be used to charge the battery for additional efficiency. Toyota's Prius uses an innovation called the "power split device," which allows the vehicle to act as a "parallel hybrid," meaning it can use either its gas or electric engine to power the car, or together in tandem. Electricity usually propels it up to the 40 MPH range, after which the gas mode takes over. Reportedly this vehicle never needs to be recharged, with the only drawback being battery longevity, which is one of the chief concerns surrounding hybrids, along with their expense.
One option is lithium-batteries. First utilized in mobile phones and consumer electronics like lap top computers, have a distinct advantage of their light weight, but are susceptible to temperature fluctuations, as well as safety issues (remember those stories about iPods and laptops bursting into flames?). Separate groups within the U.S. are said to be experimenting with phosphates, while Japan and Korea are developing magnesium, which is highly flammable and can cause suffocation when exposed to air. Nickel metal hydride and lithium remain the leading contenders in the U.S. for battery research.
Another more traditional option of propulsion are diesel engines, which have the distinction of going much further on a tank then gasoline, but produce significantly more pollutants. Reportedly, Europeans have developed diesel engines so clean they won't even stain a facial tissue places over the exhaust pipe (although diesel is traditionally more expensive then gas without the additional costs of research and development). Each propulsion system has its benefits and limitations.