From plug-in hybrids to low-sulfur diesel fuel, the options for greener driving are growing as cheap fuel becomes a thing of the past. Check out the current state of the art of the different energy alternatives.

The diesel motor was, until now, taboo in the United States, where this German surname is synonymous, paradoxically, with contamination and inefficiency. While half the cars sold in Europe are diesels, market share for diesels in the U.S. is just 3.5%, according to R.L. Polk & Co.

That may be about to change.

The success of hybrid cars in the world’s biggest automobile market signals an increasingly bright future for gasoline alternatives like ultra low-sulfur diesel and biodiesel. These fuels are now available in the U.S. and auto manufacturers are working to provide the cars. According to the U.S. Department of Energy (DOE), “the use of alternative fuels, such as ethanol, biodiesel, and CTL (coal-to-liquid), is projected to increase substantially… as a result of the higher prices projected for traditional fuels and the support for alternative fuels provided in recently enacted Federal legislation.”

In Europe, where the environmental laws are much stricter than in the U.S., the more contaminating conventional diesel engine is also moving toward biodiesel. The Europeans still don’t trust, however, hybrid cars, at least commercially. One fact that may help change this lack of success: in the European Union, the price of diesel fuel is now close enough to that of gasoline that there is no longer an economic advantage to relying on diesel fuel as an alternative to costly gasoline.

The end of cheap oil

With a growing awareness that the days of cheap oil have ended, car manufacturers and consumers have begun to think seriously about more efficient vehicles. The cost of oil, as well as, tax policies, are increasing gas prices, which will never return to their pre-2000 lows. Between 2000 and 2006, the average price of a barrel of crude oil (in constant 2006 dollars) rose by 64%.

There still is no “green fuel” accepted by all and distributed in all gas stations. And hybrids, with their double motor- one a classic combustion and the other electric-, are at the moment only popular among the consumers most conscious of climate change and most worried about the price of fuel or by their country’s energy dependence with respect to other countries.

Despite the confusion in the market, it seems clear that sustainable cars have reached a new level of development and are no longer simply the territory of obscure university departments or research and development offices with little influence over the decisions of commercial brands. The auto industry is selling, or has plans to market, several technologies that will compete with the internal combustion motor with increasing efficiency:

• Hybrid cars: currently on the market, with a huge success in some big markets. The Toyota Prius model was the first best-seller in this category. The success of the Prius in the US (the waiting list to buy a Toyota Prius in Palo Alto, California, was 600 in February of 2006) hasn’t been matched up until now in the European market. Until June of 2006, 500,000 Prius cars had been sold worldwild, more than half in the United States (266,212 cars). Some major business and entertainment celebrities have opted to buy a Prius, despite the criticisms by some of the aesthetics of the car and the quality issues of some interior components. Among them are Google co-founder Sergey Brin, Apple co-founder Steven Wozniak, actors Ewan McGregor, Edward Norton and Gwyneth Paltrow and Prince Charles of England. Microsoft owns a Prius fleet on its huge headquarters in Redmond, Washington (next to Seattle), which are used for their shuttle service between different parts of the campus (for more information on the celebrities that drive a Prius, in Wikipedia).
• Electric cars: its commercialization among the general public raises big doubts. Along with the lack of power of a purely electric motor is another difficulty: the need for a recharging infrastructure. Its application for public transportation in the coming years seems more likely. An added difficulty is the current model for electricity generation, based on the still cheap and contaminating burning of coal. The large utilities talk about fabulous technological plans to eliminate the CO2 emitted by the burning of coal, although they will have to wait for it to be possible to generate their energy through clean methods. Electric cars don’t emit any gas, but since electricity is still not widely generated by renewable energies, the massive increase of electric cars isn’t sustainable with the current energy model. However, the performance of the new lithium batteries, more efficient than the nickel used until now, has increased the benefits and autonomy of the prototypes. The recharge time has also been reduced.
• Hydrogen models: in recent years, hydrogen has gained media prominence as a clean fuel capable of replacing fossil fuels. Researcher and Wharton Business School professor Jeremy Rifkin explains in his book The Economy of Hydrogen that our dependence on fossil fuels is over and hydrogen will allow us to create an energy that is clean, cheap and capable of contributing to a system like that of the Internet: an energy network that is decentralized and interconnected, all of us will be converted at once into consumers and energy generators. When we return from work and park our car next to the house, according to Rifkin, we will connect it to a domestic network that will allow us to take advantage of the kinetic energy created during the journey. Since our domestic energy network will be connected to the global network, we will be able to discount the energy that we have contributed to the network from our energy bill. Hydrogen could be the fuel of the future, even though currently the only method of producing this energy on a large scale is through the burning of fossil fuels (coal, petroleum) in large transformation plants, or to opt for the more controversial and dangerous nuclear energy, which generates residues that will outlive us. Hydrogen offers better performance than electricity, even though the global balance of its adoption will only be profitable if it is produced from renewable energies. To understand what interests have motivated the big automobile, and energy, companies to bet on hydrogen, it’s advisable to view the documentary Who Killed the Electric Car? (Chris Paine, 2006). Hydrogen does not seem able to help the auto industry much in the short-term, something that perhaps pleases the sector, and above all, the large energy companies and their petroleum interests.
• Improved gasoline motors: conventional motors can continue to be optimized, through the reduction of fuel consumption and using increasingly more efficient particulate filters. Motors using high pressure direct injection, which will become widespread in the coming years, will consume 10% less. In the U.S., simply buyer demand- rather than technological advances- can radically improve fuel efficiency, given that the average fuel economy of US cars is 20.4 mpg, about half of that for European cars which average 40 mpg.
• Improved diesel engines: diesel cars are inherently more efficient than those that burn gasoline, because they run longer on less fuel though in the past they’ve been criticized for their dirtier emissions. In 2008 a new generation of diesel vehicles will hit the market in the US that burn a low-sulfur, and less contaminating, version of diesel fuel. In 2006, the fuel- which is 97% cleaner than the old formulation- was available for trucks and buses.
• Biofuels: those who bet on hydrogen as a long-term solution also are conscious of the necessity to transition from our current, almost exclusive dependency on fossil fuels to a energy future dominated by renewable sources and hydrogen motors. From their the main energy companies see biofuels as a solution for the next 10 years, considering the transition from our current model to the “hydrogen economy” proposed by Rifkin. Natural gas, ethanol E85 and biodiesel, the last two from vegetable oil, are the best positioned for massive distribution in gas stations worldwide. Cities in the US and Europe have growing fleets of buses fueled by natural gas. The use of biofuels is very easy and cheap for the automobile industry, given that the current motors barely need to be modified (if at all). Additionally, taking into account the extraction and use of oil, the reduction of CO2 emissions can reach 80%. Ford, Volvo and Saab are preparing to make this alternative popular. There already exists a Ford Focus that uses gasoline and ethanol.
• Plug-in hybrid electric vehicles (PHEVs): a plug-in hybrid works like a standard hybrid in that it can operate in both electric and gas-powered modes, but it has a larger battery pack and can be plugged into a household outlet to run on grid power instead of petroleum. While PHEVs can save more oil than conventional hybrids, much of this savings depends on what type of energy generation is being used- clean versions like wind and solar or dirtier sources like coal or petroleum. According to the National Resources Defense Council, “a plug-in running on renewable energy emits only as much global warming pollution as a 74 mpg car“. They recommend promotion of PHEVs in areas of the country (the U.S.) with a relatively clean generation mix. “However, in regions that are heavily dependent on dirty, coal-fired power plants, there is a possibility for significant increases of soot and mercury.”

With more compact cities and better developed public transportation infrastructure, the European Union has created a public transportation system that is increasingly less dependent on petroleum, thanks to buses that run on natural gas and biodiesel and transportation that is connected to the electrical network.

The United States, with an urban development model that has encouraged the development of huge suburbs for the country’s large middle class, has a much higher dependence on private transportation than the EU and Japan. According to the United Nations Economic Commission for Europe (UNECE), the US has 765 vehicles per 1,000 people, while Europe has less than half that, with an average of about 300 vehicles per 1,000. The extensive highway network and free roads, a mobility model designed around the automobile, has made the US market the main testing ground for the launch of commercially sustainable models.

California isn’t just the richest and most populous state in the union. It houses, as well, two industry models being called upon to lead the cultural and technological change necessary so that private transportation can cease to be one of the principal causes of atmospheric pollution and, thus, climate change:

• The extensive and sprawling city of Los Angeles, full of freeways whose traffic jams produce constant smog clouds that cover the Valley for days. The state’s southern city also houses the film industry; no one can escape the actors and movies which can educate the population and encourage, through the example of celebrities, the use of hybrid cars, the call for quality public transportation and related projects.
• The San Francisco Bay Area, capital of the established American counterculture, Berkeley and Stanford Universities and, above all, the technology industry of Silicon Valley. The values of tolerance and sustainability preached by Northern Californians, like the inhabitants of Oregon and Washington in the Pacific Northwest, mix in the San Francisco Bay Area with a more established entrepreneurial culture than anywhere else in the world. Proof of this are businesses like the veterans HP and Apple, as well as giants of the Internet era like Yahoo! and Google, all illustrious inhabitants of the zone.

Arnold Schwartzenegger, Republican governor of California and promoter of alternative energy and sustainability, believes that if the population of San Francisco morally promotes the use of more efficient cars, Silicon Valley creates their own from the technological point of view and the celebrities of Los Angeles preach through example, California can again become a driving force for change that will later arrive at the rest of the world.

The automobile industry must confront a dilemma that could change the current market situation: while they have been improved upon, the current gasoline, and diesel, engines haven’t changed from the basic internal combustion engine that arrived on the assembly lines in 1924. While we wait for longer-term alternatives like hydrogen or electric vehicles, in the short-term, perhaps there won’t be a radical departure from this trend.

As opposed to hydrogen, electricity or natural gas (currently limited to public transportation), ethanol E85 and biodiesel are already a reality and it is expected that their use will take off when auto manufacturers have adapted to the new reality. It’s relatively inexpensive to convert a gasoline motor into a flexible system capable of using ethanol. The same is true of the popular, and contaminating, diesel motors, that will soon accept biodiesel.

Europe is preparing for the massive deployment of cars with gasoline motors that use ethanol E85 as an alternative fuel, as well as diesel motors capable of using biodiesel. In Sweden there are more than 30,000 cars capable of functioning with a mix of fuel composed of ethanol and gasoline. Even though biodiesel will arrive later than ethanol E85 in the gas stations in all of Europe, the widespread use of diesel motors assures its future.

The big challenge for the biofuels and automobile industries is to make a change toward a more sustainable private vehicle that doesn’t increase the cost, and above all, the bill to users, sellers or fuel providers.

What no one should forget: the diesel engine was successfully established in Europe and in countries as technologically conservative as Spain because its use was advantageous to users. If driving a sustainable car doesn’t represent losses for the user, the new offer will be irresistible. No one likes to drive a contaminating machine if there are good non-contaminating alternatives.

• List of hybrid vehicles.
• 2007 most and least fuel efficient vehicles, ranked by city mpg.
• Best vehicles on CO2 rankings (UK Department of Transport).