This is apparently the case in biofuel production, where researchers are excited about the potential of algaculture, which is the farming of single-celled photosynthetic algae, or phytoplankton, to replace dependence on foreign fossil fuels.

One of the most fertile fields being sown in the challenging race to provide a one-size-fits all solution to the energy crisis, algae cultivation shows tremendous promise when compared to more complex vegetation.

Estimates indicate that some species of algae may yield as much as 30,000 gallons per acre of biodiesel, a figure which impresses even the skeptics who dispute it, claiming that 800 gallons/acre is more realistic. Even conservative estimates indicate that algae is very likely to be the feedstock of choice for biofuel manufacture in the near future.

Several characteristics combine to give a clear lead to algae. The rate of growth far outstrips that of macroflora crops like soybean and corn, because there is no specialization of parts or development of infrastructure. Each cell is a self-contained organism, independently producing fats and sugars from the energy of the Sun and water in holding tanks. Wastewater, which would otherwise require costly treatment, can be converted into energy by several species of microflora.

Additionally, algae can be grown in vats or on marginal lands, and some species can be cultivated in seawater, which could be vital for large-scale production. In fact, some inventive high-school students have successfully distilled biodiesel from seawater as part of a science project. The US Department of Energy has reported that, based on preliminary results, the fuel needs of that nation could be met by devoting an area one-seventh of that currently employed for agricultural purposes to producing micro-algae for fuel.

Most of the focus on fuel from algae has centered on the potential for biodiesel, but in truth, a variety of different formulations are possible, including bioethanol, biobutanol, and biogasoline, which is a hydrocarbon very similar chemically to the petrochemical variety. The latter two can be added to conventional gasoline engines without any modifications to the vehicle whatsoever, while bioethanol can be mixed into blends at a concentration of up to 85% or used in engines modified for that purpose.

From Toyota and Honda to Ford and GM, most of the major auto lines now sport at least one version of flex-fuel in several major classes, and the trend will very likely sweep the industry. Unlike traditional gasoline engines, flexible fuel sedans, trucks and, most recently, sport utility vehicles, are able to fill up on either gasoline, a biofuel such as ethanol, or some mixture in between.

When combined with electric hybrid capabilities, these vehicles truly do go the extra mile, getting the fuel ratio of a light compact in the body of an SUV, which so recently was the mechanical symbol for wasteful eco-villainy among critics of oil-based energy policies.

Also referred to as FFV’s, flex-fuel vehicles retain the option of using regular gasoline when alternatives are not available, making them an attractive option for drivers who are wary of committing to a fuel for which the supply is irregular.

The majority of FFV’s are designed to make use of 70-85% ethanol blends known commercially as E85. This mixture has been used with great success for several years in Brazil, which prompted US automakers to hit the assembly lines with refits to their standard models in order to meet the domestic and foreign demand.

As with all budding technology, what holds back consumers from taking the flex-fuel plunge is the price tag. Despite tax rebates, buyers of FFV’s face stiff sticker shock in a time when the economy is lagging and going green is a luxury many strapped families feel they can do without,

Those who do let their conscience override their accountant may have to quest a bit to locate reliable sources of their alternative-often coping with irregular hours and shortages. The reality is that auto manufacturers have rapidly moved ahead of alternative fuel deployment, and until the supply surges to meet demand, it may still be a rough road for those who want to drive and promote clean air as well.

Water requirements, fertilizer contamination, and competition for prime farmland all combine to render corn and soybean models of biofuel unsustainable for the future, despite government mandates and a strong public impetus toward green vehicle alternatives.

Others have turned their sights on sources which are not a part of the food supply. While the dietary needs of humans and other animals require nutritious seeds grown on premium land, some species of oily plants promise much higher yields without impacting the food supply.

In fact, the Jatropha tree, common in parts of Africa and Asia, is a hardy desert brush that is drought resistant and thus can be cultivated on lands which are otherwise barren. Hailed as a boon to poverty-stricken farmers of the Third World, the oil-rich seed of the obscure Jatropha may turn out to be an answer not only to the ever-growing energy needs of the Industrial west, but to the struggling inhabitants of arid regions the world over.

Estimates for the potential yield of large-scale production efforts vary greatly, but in all events show a steep improvement over the cultivation of current sources. In addition to providing one of the most efficient sources of seed oil to date, Jatropha, which bears seeds for five decades, also promises to ease soil degradation and help restore fallow lands.

Byproducts of biodiesel production include glycerin, which has many applications in industry and consumer products such as soap, biomass for cellulose alcohol, and nutrient-rich natural fertilizer from the pressed seed pulp. The extracted seed can also be used in a secondary cycle as methane.

Overall, estimates indicate that Jatropha yields will be up to four times greater than soy on the same acreage-causing farmers and governments to leap into production on this little-known tree which may someday power most of the diesel engines on Earth.

We have already seen the mighty potential of hydrogen…empires have been built and crumbled on the mere threat of missiles containing the explosive energy of a small star. Indeed, all the energy on the Earth ultimately derives from the ferocious hydrofusion reactions at the core of the Sun.

Containing that force, however, has proven to be a dangerous and elusive task. While inventors have striven to capture the unique properties of Nature’s commonest substance to power everything from balloons to the very electric grid itself, the volatile atom has evaded nearly every attempt to tame it.

Nevertheless, the dream of running an automobile on simple tap water has driven research dollars as well as scientists scurrying after a practical application for hydrogen in the powering of motor vehicles. Most of the attention has focused on the fuel cell, which is a device to dynamically store electricity from the chemical interactions of a variety of substances, including hydrogen and oxygen.

While a host of promising prototypes have been developed as early as the 1960’s, none of the designs have been able to overcome the issues which plague development of the hydrogen-powered automobile enough to become a viable option for consumers. Despite a global clamoring for renewable alternatives to petrochemicals, only a handful of hydrogen-fueled vehicles have entered the roadways to challenge the dominance of Big Oil.

The problem is Newton and his pesky Second Law of Thermodynamics…so far, so much energy is required to separate the hydrogen from water that the bottom line simply doesn’t add up. Pairing the technology with other green power sources, such as geothermal and solar, is yielding positive results in environmentally aware nations like Iceland, where a hydrogen fueling station has been in operation for six years.

There is a promising future in the possibility of switching our power focus from coal and nuclear power to the most simple and basic of all: hydrogen.

Most of these formulations work off the same basic concept: the internal combustion engine is monstrously inefficient, leaving a significant amount of your expensive gasoline or diesel fuel unconsumed in the tailpipe emissions. Not only is this bad for your pocketbook, it’s bad for the environment, helping bring about smog, acid rain, and the greenhouse effect.

A bit like cough medicine, these remedies are available in liquid and pill form. Also like many popular over-the-counter cures, many of these treatments contain little more than various forms of alcohol or the octane which is already added to premium gasoline.

Wading through the radically contrasting reviews and questionable marketing tactics of these products, it is impossible to verify the claims of any of these products without encountering the term “snake-oil”. On the other hand, the underlying science is sound, insofar as that there is clearly room for improvement in the typical rate of combustion, and it seems that at least some of these catalytic enhancers and oxygenators really do deliver.

At least, that’s what the testimonials say.

As of yet, the EPA has not endorsed any of these products as enhancing fuel efficiency or reducing emissions, which is a bit like many herbal supplements’ disclaimers which state that “The FDA has not evaluated these statements.” Furthermore, the EPA has warned that some of these products may damage your vehicle. Users of E10, which is now mandated by law in several US states, are specifically cautioned against using alcohol-based additives to improve mileage.

The day may come when some garage chemist concocts a mixture that optimizes the performance of internal combustion engines and reduces harmful pollutant at the same time. That day might already be here, but without sufficient independent testing, don’t hold your breath too close to the tailpipe.

It’s renewable, too-unlike fossil fuels, which experts say may be entirely diminished before the century’s end. The supply of ethanol can be replenished each year, bringing fallow farmlands back into production and returning farmers to the field.

Crop-based fuel can be produced domestically, removing the element of international strife from each visit to the pump. Ethanol is not without political problems, however, as implementing alcohol-blended gasoline on a widespread basis stirs controversy among the very environmental groups who demanded change in the first place.

In large part, the challenges to ethanol are exaggerated. The fuel is primarily manufactured using feedlot corn, which just a few years ago was in surplus. The corn used to manufacture ethanol is not generally intended for human consumption, but rather to fatten cattle and chickens housed in confinement lots.

Corn is certainly not without problems, however. Those golden stalks turn out to be a poor source of energy for vehicles, yielding just 18-20 gallons of fuel per acre, a mere fraction of the possible yield from other crops such as algae. The demands of water and particularly petroleum-based synthetic fertilizers also bring the ecological equation of corn ethanol into question. In the end, it is clear that corn is not a good candidate to fuel a greener future.

In large part, the transition to biofuel is being hampered by outmoded ideas about agriculture. Certainly there is nothing “green” about overworking the land to grow fuel. And crops which we are familiar with cultivating for their food value, while being obvious choices for farmers, clearly do not make the optimum sources of energy when applied to machinery.

Fortunately, ethanol does not need to be manufactured from corn-cellulose alcohol can be made from a variety of sources, including many plants which are traditionally thought of as weeds, such as switchgrass. These can be grown with minimal effort and water on land that is relatively poor for the cultivation of food crops. Because most non-food plants use different nutrients than food plants, these grasses can even restore fallow lands which have been battered by the high demands of growing food.

Thanks to advances in the development of cellulose alcohol sources for fuel, we don’t need to choose between sources of food and fuel.

So taking the next step toward a fully electric car was one of the earliest answers to the looming shortage of petroleum fuels. As early as the 1980’s, prototypes were unveiled which used electrical rather than internal combustion motors.

These early models were not without difficulties, however. All versions were plagued by a limit in range, long recharge times, and the lack of convenient recharging stations. The laws of physics weighed in a protest as well; the battery storage required to bring an electric automobile through a typical driving day occupied as much volume and mass as the heavy V-8’s and diesel engines they were intended to replace.

Moreover, the concept of plugging automobiles into residential grid-power raised alarm bells among environmentalists, who realized that the energy would be ultimately coming from coal and nuclear sources, and that rather than reducing emissions, these cars would simply shift the burden to power plants.

Auto manufacturers, eager to comply with new government guidelines on emission control and the public demand for cleaner cars, produced a half-loaf answer: electric hybrids. These cars, from the sensible Prius to the flashy $100,000 Lamborghini-Chaser Tesla Roadster, have become a status symbol in green circles, boasting overall gasoline mile-per-gallon ratios of 100 or more.

Electric hybrids, when integrated with flex-fuel engines capable of burning biofuels, combine the best of both worlds. The excess electricity generated by the alternator, which is usually wasted once the battery is charged, is instead recycled to operate the electric-only phase during long stretches of highways.

Many roads will be traveled before the solution to the transportation enigma is found. Increasingly, it looks as if no single source can ecologically supply society’s hunger for energy, but by combining strategies, tomorrow’s vehicles will operate on a mere fraction of the footprint they leave today.

The majority of developments have looked in two directions: biofuels, and electric-based solutions. Each of these have shown both tremendous potential as well as pitfalls, and proponents of each method are vocal in pointing out the shortcomings of the other.

Biofuels are made from plant sources or from organic waste. For gasoline-based engines, the fueling options encompassing various types of alcohol blends, including ethanol, made primarily from feedstock corn, and methanol, which can be manufactured from landfills or animal manure. Engines must be retooled to run purely on these fuels, although most vehicles are able function, without modification, using an ethanol blend of up to 85%.

Biodiesel is made from transesterification of fatty oils, particularly the seed oils of plants. The original Diesel engine was designed to operate on pure peanut oil, and only later came into use in heavy industry using the unrefined petroleum product which now bears the same name.

Some farmers have always known that the flexible invention of Rudolph Diesel could burn oil pressed from seeds as easily as that drilled from the ground, but the mainstream only recently learned of this compelling option.

During the 1990’s, biodiesel was rediscovered by pioneering environmentalists, who began recycling used waste oil from restaurants as an ecological and inexpensive alternative. Many installed a second tank and heater in order to burn straight vegetable oil, touring the country to spread world of this remarkably simple natural solution to the fuel crisis.

Unlike pure vegetable oil, biodiesel can be used in most diesel engines without any modification, although newer models may void warranties by doing so. In addition, the rubber fuel delivery lines of vehicles manufactured before 1992 must be replaced prior to the use of biodiesel, and the fuel filter replaced after the first tank, because the tar-like deposits from previous petro-diesel use will be swept away by the cleansing effect of the biodiesel.

There are a number of fuel and hybrid alternatives which can be used to allow us to maintain our mobility and free us from nonrenewable oil sources at the same time.

The oil crisis of the 1970’s sent many a backyard inventor to the workbench for an answer that would stand the test of time. Many intriguing novelties ensued, though few which have entered mass production. Here are a few of the lesser-known developments in alternative fueling which are on the verge of feasibility:

The Air Car:

We’ve all witnessed the force of compressed air. In the late 1970’s, a strange visionary engineer named Terry Miller built an odd-looking tricycle powered by three large tanks that took up the length of the frame and seated only a driver.

He never managed to overcome the inherent problems in his design, but more recently, the Indian manufacturer Tata has released the Onecat Air Car, which is a diminutive, flex-fuel hybrid driven primarily on compressed air, which is heated to achieve speeds above 35 mph.

Boasting lower emissions than the Toyota Prius and scheduled for US delivery by the beginning of next decade, the pneumatic car may soon be an attractive compact car option for the emerging Asian auto market…and then, perhaps the world.

Methane from landfills, animal waste and sewage

Recapturing methane from large garbage dumps has been an increasingly common practice in some municipalities, especially since the EPA initiated a program to guide such reclamation efforts in the mid-90’s.

Other active experiments with different types of waste products show great potential, since after all, the source in question is rich organic matter which emits carbon in either event.

Compressed Natural Gas (CNG)

Principally used in city transit and some fleet semis, Compressed Natural Gas is a petrochemical, but one which burns at greater efficiency, especially in large vehicles able to sustain greater storage demands. Because it burns more cleanly than traditional gasoline or diesel and is much less expensive, CNG is rapidly becoming an important component of the alternative fuel revolution.

Internal combustion driven transportation is used by us all for everything from recreation to delivering and receiving food and other goods. Fuel sources are as diverse as our vehicles and with the release of upcoming technology there will be a readily available alternative fuel solution for everyone.

Runaway cost was once a compelling reason to explore biofuels, electric hybrids and hydrogen-based technologies, but it may be several years before the supply of renewable alternatives reigns in the expense of filling up. Until then, consumers must consider the total global cost of petrochemical dependence, and take that into account when considering joining the green car revolution.

These are some of the most important reasons to reduce or completely avoid the use petroleum fuels:

• Oil reserves will are finite and will not be renewable. While geologists disagree (according to their employer) as to the exact amount of available oil remaining, there is little doubt that demand is already outstripping supply. The ongoing industrialization of large developing nations means that competition for the remainder will be fierce. The most optimistic estimates include shale oil deposits, which are of low quality and require strip-mining to extract.

• Burning petroleum-based fuels is causing local and planetary pollution, from plainly visible smog in most major cities, to acid rain documented since the 1970’s, and a measurable and rapid decline in the polar ice caps on an annual basis.

• The drilling of petroleum itself is problematical, affecting wildlife and, in many cases, disturbing the lifestyle of local inhabitants, who frequently earn no revenues from their valuable land and are sometimes slain to quell protest, as occurred in East Timor. Moreover, every accidental supertanker spill represents an ecological disaster that threatens sensitive coastal habitats.

• Conflicts over petroleum supplies have been continuous since the Second World War and have dominated politics in producing nations, bringing several to the point of war and invasion, particularly in the Middle East. The cost of preserving the oil lines has been great indeed in terms of military expenditures, rights of indigenous people, and human life in these regions.

One day, for better or worse, the wells of “black gold” will run dry, and the world’s vehicles will be fueled by one or another alternative. Until then, the question is: as a driver, are you part of the problem…or part of the solution?