A ‘Green Airport’? Meet the StarPort
This airport is inclined to reduce pollution
Economic Development Through Environmental Design
Thousands of new airports are set to be built worldwide within the next decade. An innovative design called the StarPort could produce fuel savings of 300 million gallons a year at each airport, would require only one-third of the land as a conventional facility and yield four times the revenue. Worldwatch Editor Ed Ayers calls the StarPort design a "breakthrough... a much more intelligent way of using techniques we humans have had all along."
Airports designed to handle 350 flights per day 30 years ago are now scrambling to handle 700.
A modern airport consumes nearly 500 million gallons of fuel a year – nearly half as much fuel as burned by a large city’s automobiles. But because aircraft are not required to install catalytic converters, airports are responsible for more than half of the local urban air pollution.
We have gridlock at most major airports, with more than 20 planes lined up on runways waiting their turn to take off while washing enormous amounts of partially burned fuel into the atmosphere.
The fumes from idling diesel jet engines are about 14 times more polluting than gasoline exhaust. At many airports, levels of carbon monoxide, hydrocarbons and nitrogen oxides are at least 10 times higher than in surrounding cities. This isn’t progress, it’s suffocation.
A Boeing 747 jet consumes more than 500 gallons of fuel during taxiing – enough fuel to operate a car for a year. One thousand taxi-to-takeoffs consume 12 million gallons – sufficient to power 200,000 cars for a day. Only four percent of the fuel burned goes into actually moving the aircraft: The rest is thrown to the wind as exhaust and noise.
The sprawling 52-square-mile Denver International Airport was built to handle 2,000 flights daily – a landing or takeoff every 20 seconds. Denver International offers 100 gates and five 12,000-foot (2.3 mile-long) runways. The StarPort could save $200 million in fuel costs for an airport with the air traffic of Denver International while cutting taxiing distances by 48 percent.
Gravity not Kerosene
The solution? The StarPort incorporates inclined runways that use gravity to help planes slow down on landing and accelerate on takeoff. Inclined runways would be shorter, requiring a smaller footprint.
Planes taking off down an inclined runway would reach takeoff speed sooner, saving 1,000 gallons of jet fuel per flight. The runways would be slightly concave to help planes stay centered. They would be wider at touchdown, narrowing as they approach parking gates atop the terminal dome.
FAA officials have said that it is against regulations to permit inclined runways but a number of existing US airports already feature sloped runways – Colorado’s Telluride Airport is built on a 4 percent incline.
In fact, FAA regulations do permit inclines up to 1.5 percent. It would be possible to design a runway that starts at a 1 percent incline and slowly rises to a 4 percent grade.
Put on the Brakes
Regenerative braking systems installed on electric cars not only slow down speeding cars, they simultaneously transform the braking force into electrical energy that is stored in batteries for later use. If lightweight vertical armature electric motors were installed in aircraft wheels, the tires could be pre-rotated before touchdown (eliminating damaging structural shock and tread burn). From the moment the plane touches down, the tires could begin generating electric power. Combined with an inclined runway, they would eliminate the need for noisy 30-second thrust-reversal engine burns that can easily burn 300 to 500 gallons of fuel for each landing.
The Subsurface Terminal
An incline of 2 percent would eventually lift a 6,000-foot-long runway 120 feet above the surrounding landscape. The central terminal, where planes park and wait to take on passengers, could tower as high as a 10-story building.
Most airport customers now endure a 1.5-mile trek from their cars to departure gates. At many airports, this means that each day 200 passengers on 700 flights wind up walking 70,000 miles to build up their Frequent Flyer accounts.
StarPort passengers would board from below, moving almost directly to their aircraft from a subsurface terminal in less than six minutes. For an airport the size of Denver, this design would reduce the average travelers’ curb-to-counter commute by 80 percent. In addition to terminal space, the sub-terminal space would include several floors of parking, restaurants, shopping, hotels, convention and meeting space.
Instead of circling a traditional airport and waiting in long lines to enter a single entrance, the StarPort would have traffic entering and leaving the airport from four directions.
Runways would be laid out side by side with a 600-foot separation, allowing simulatneous takeoffs and landings. Taxiing distances would be reduced 80 percent, with additional fuel savings. Lights beaming upward from the terminal could serve as runway lights. In winter, the terminal’s heat would serve to melt the ice and snow offthe runways.
Major US cities are scrambling to find airport sites that meet a simple, but impossible, description: "50 square miles of unpopulated land – close to downtown." A StarPort could be built on only 15 to 25 square miles. Instead of turning valuable open space into new mega-airports, StarPorts could be built at hundreds of smaller existing airfields that were abandoned with the move toward larger aircraft and longer runways.
If the 2,000 new airports were StarPorts, the fuel savings would amount to two billion gallons a day – more than 1,000 times the oil the Bush administration hopes to extract from the Arctic National Wildlife Refuge.
Jim Starry is the director of Economic Development Through Environmental Design, Inc [PO Box 1931, Boulder, CO 80306]. He has worked as an engineer at Martin Marietta and the National Center for Atmospheric Research. Articles on the StarPort design have appeared in Popular Mechanics, Popular Science, The Wall Street Journal and will be cited in a forthcoming Worldwatch Report.