How Green Are Airplanes?

DECATUR, Ala. — Suppliers of a new generation of passenger jets are and taking jet planes to greener pastures.

Hexcel Corp. and Toray Carbon Fibers America are revolutionizing manufacturing by providing a lightweight substitute for the metals that give jets much of their weight. Carbon fiber is both lighter and more durable than the metal it replaces, creating enormous fuel efficiencies.

While both companies already supply carbon fiber for a few components in some airplanes, mainly military, the demand is about to increase dramatically as both Airbus and Boeing produce their next generation of passenger jets.

Engineering hurdles in the case of Boeing and slack demand in the case of Europe's Airbus have delayed full-scale production, but it is a given that the major change from the predecessors of the Boeing 787 Dreamliner and the Airbus 350 will involve huge quantities of carbon fiber.

The Decatur plants do not make carbon fiber, but its precursor, polyacrylonitrile, called PAN. The main ingredient, acrylonitrile, comes to the plants as a liquid. It leaves as a white thread on large spools.

The spools go to other Hexcel or Toray companies for processing.

Hexcel's main contribution to the Boeing 787 is the front fan blades in its General Electric engine. Toray is Boeing's main supplier, producing the composite for the fuselage, wings, engine casing, tail and even internal parts like storage racks and seat frames.

"This is the first plane where the fiber has been used in the fuselage and the wings," said Greg Clemons, Toray's director of administration.

Airplanes are not the only product made greener with the help of Toray's carbon fiber. The company has found a niche in producing the material for pressurized tanks as well. A major obstacle to using natural gas in vehicles is the weight of the metal tanks needed to withstand the pressure of the gas.

"If you're in California and you see a natural gas bus, the tank rides on top of the bus. That's our fiber that is in the tank," Clemons said. "It's using natural gas instead of gasoline, and the weight of the bus is lighter because it's not carrying the big (metal) tanks or the liquid gas."

The tanks have a thin layer of aluminum, with external layers of carbon fiber. Toray is working with Toyota to produce similar tanks that would contain pressurized hydrogen for use as a fuel in vehicles.

Wind energy is less significant in the United States than in Europe, but carbon fiber produced from Decatur PAN is in many components of U.S. windmills, too.

"These windmills that have 50- to 60-meter blades on them. We're talking 250- to 300-foot-tall structures," Clemons said.

Even nuclear energy uses carbon fiber. Clemons said Toray customers use the composite to make the centrifuges that enrich uranium for use in nuclear plants.

Bacal said another growing application for Hexcel products is in automobiles, especially with the implementation of federal Corporate Average Fuel Economy standards.

The easiest way to increase fuel economy is to reduce weight, and substituting carbon fiber for metal is a popular approach.

"We're dealing with automobile companies in terms of the drive trains, hoods and various parts of automobiles to help reduce the weight and get better gas mileage," Bacal said. "Anytime they are trying to reduce the weight of the car, they are looking at us."

Both companies expect the increasing demand for energy efficiency to increase investment and employment at their Decatur plants. "The marketplace is demanding improved fuel economy," Bacal said. "These materials are helping achieve it."