 Out of Sight, Out of Mind
Gasoline used to power our cars—making it possible for us to go where we want, when we want—flows up out of the ground by magic and into our fuel tanks. Then we drive safely away. No effort—magic, right? Hardly. The five minutes you spend each week to pull up to the pump and fill your gas tank is the culmination of a tremendous amount of effort you don’t see. Effort by the distributor to channel specially formulated gasoline products to different areas of the country. Effort by a trucker to replenish gasoline supplies at your retail outlet. Effort by the retail establishment to serve customers while meeting stringent government regulations. Effort by researchers to develop more fuel-efficient cars, safe gas pumps, and new types of fuels to power the motor vehicles of the future. Effort by the state and federal governments to constantly monitor underground storage tanks to make sure they meet strict pollution limits.
We take a lot for granted, especially considering that the price of gasoline has remained low relative to other costs in our lives. This fact makes the magic of gasoline distribution even more remarkable. So how does it all work now, and how will it work in the future? What’s next for your local gas retail station? What kind of vehicle will you be driving in 10 years, and more importantly, how will that vehicle be powered? In effect, the sky’s the limit when it comes to automobile fuel technology. And it promises to be a clear sky at that!
Your ‘Friendly’ Neighborhood Gas Station
In the late 1960s, the typical gasoline service station featured a cinderblock building with an office at one end and two service bays at the other. A staff of one to three mechanics worked at the station. Two or three gas pumps stood outside, with a hose stretching across the pavement from the pumps to the station. A car driving over the hose activated a bell inside, alerting the mechanic that a customer needed service. The mechanic pumped the desired amount of gas for each customer, cleaned the windshield, offered to check the oil, and even changed wiper blades in a flash. This was called full service. These gas stations sold leaded fuel using pollution control systems that weren’t very advanced. If fuel spilled over while refilling, that was the price of convenience.
Today’s 175,000 retail gas outlets offer a different experience. We often choose to pump our own fuel, and many mechanics have been replaced by a clerk who collects money for gas as well as sells sandwiches, newspapers, soft drinks, and hundreds of other products. From an environmental standpoint, the experience is far different as well. Thanks to some major improvements in pump design, gas formulations, and more leak resistant underground tanks, the fuel dispensed into the car is cleaner—as is the air we breathe as we stand at the pump refueling our cars.
The number one change in gasoline is, of course, the removal of lead beginning in the 1970s. But that’s only one aspect of America’s remarkable clean air story (2). Sulfur is down by more than 90 percent, and other critical emissions are down as well in the ongoing U.S. effort to improve air quality through the use of reformulated gasoline products.
In the past, underground storage tanks at gas stations were prone to spills or leaks from overfilling or corrosion that contaminated surrounding ground water. Today’s generation of gas storage tanks have proven to be much friendlier to the environment. They are composed of fiberglass and corrosion-resistant steel and armed with leak detection devices as well as sensors, ball floats, and automatic shut-off valves that prevent overfilling. Secondary containment features collect any overflows that might inadvertently occur. And as a final safeguard, tanks are inspected frequently.
Another underground tank issue that posed serious hazard in the past involved gasoline vapors, which remain in storage tanks long after the gasoline is gone. Vapors within the tank are so dense that when an empty fuel tank is refilled, the vapors are displaced into the air. And considering that gasoline is moved from one tank to another several times between the refinery and your car, gasoline vapors become a very serious threat indeed. To combat it, vapor recovery units now vapor balance the tanks by collecting vapors forced out as new gas is pumped in. For example, at your neighborhood gas retail establishment, as gasoline flows from a delivery tanker truck into to an underground tank, vapors flow from the underground tank into the truck.
 Similarly, in areas where air quality fails to meet National Ambient Air Quality Standards, the oil and natural gas industry has developed and installed vapor recovery units right in the pump nozzle, which siphon off vapors and return them underground as you pump your gasoline.
Vapor balancing through vapor recovery units now offers protection at the pump just as the automatic nozzle shut off did a generation ago, assuring the safe and convenient flow of gasoline into your car. And, all cars manufactured after 2000 have advanced onboard vapor recovery systems, which provide even better vapor protection and increased fuel efficiency. Mounted in the car, these charcoal canisters absorb fueling vapors and pass them to the engine, where they are burned for power when the car is started. As older cars are scrapped, more and more cars will have onboard vapor recovery systems. Eventually, air quality may improve to the point that vapor recovery technology at station fuel pumps will become obsolete.1
It’s safe to say that many people in the United States take their gasoline for granted. Gasoline is often as close as the nearest convenience store around the block, and its price has historically been low. In addition, America has wrestled with, and surmounted, many issues related emissions-related pollution. It would take about 33 of today’s cars to equal the emissions from just 1 car made in the late 1960s.
Powering the Cars of Tomorrow
The next environmental advance can be found in the cars themselves—a fleet of new electrically-powered, low-polluting automobiles that promise in just a few years to ride quieter, lighter, and cleaner than today’s typical vehicles. The most promising technology involves the proton-exchange membrane (PEM) fuel cell, a radical departure from the internal combustion engine we’ve known all our lives. Used on board NASA space shuttles for years, this type of fuel cell is a remarkably simple device. It converts hydrogen and oxygen into electricity, water, and heat. However, PEM fuel cells generate less than a volt of electricity at a time, which necessitates the stacking of many fuel cells to produce enough electricity to power a car.2
 The hydrogen-powered fuel cell may offer big-time payoffs to American drivers. This type of fuel cell runs at lower temperatures. It is lighter than conventional engines. It is more fuel-efficient and produces less waste. In fact, the only byproduct of the PEM fuel cell is pure water! By far, PEM fuel cell stacks are the closest to success of all the alternative transportation technologies.
PEM fuel cell technology is fairly well advanced. But, hydrogen is difficult to store and move, and because it does not occur in a pure form in our atmosphere, it must be derived from (or “reformed” out of) another source, such as propane, methanol, or gasoline.
Various technological solutions are being developed and tested to find practical, safe, and cost-effective methods for hydrogen storage, delivery, and refueling. Hydrogen could be reformed from natural gas via fuel processing subsystems at present retail gasoline stations. The downside is that it will be costly to install such subsystems in each station. Hydrogen could also be manufactured using a polymer electrolyte electrolysis system—technology that’s not too far away. Or hydrogen could be produced within the vehicle itself, using an onboard reformer.
It’s unclear right now which type of fuel will best serve the fuel cell that powers tomorrow’s automobile. It could be methanol, gasoline, or propane converted to hydrogen by a reformer. Or it could be hydrogen itself if better storage designs can be achieved.
The oil and natural gas industry is working on several hydrogen storage designs, and it is keenly interested in the research and development of these and other alternative fuel technologies. Now it’s a matter of time as such fuels become ever more practical and cost effective for the traveling public. In May 2002 for instance, a modified GM S-10 Pickup became the first test vehicle to be completely powered by fuel cell technology, using gasoline converted to hydrogen by an onboard reformer and then routed to a fuel cell stack. GM researchers think that the current gasoline infrastructure makes gasoline the most practical source fuel for the modified S-10, which weighs 2,500 pounds more than a regular S-10 but cuts carbon dioxide emissions in half while doubling fuel mileage.
The automobile marketplace is being revolutionized by cutting-edge gasoline/electric hybrid vehicles from several popular manufacturers. In 2004, advanced fuel cell vehicles such as the DaimlerChrysler Jeep Commander, the Ford P2000, and new models from Honda, Toyota, Mazda, and Nissan, will move America toward ever cleaner and more efficient fuels.
1 http://www.des.state.nh.us/ard/vapor.htm
2 Sources: http://www.wired.com/news/technology/0,1282,51698,00.html, http://www.howstuffworks.com/fuel-cell.htm
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