Tough new fuel efficiency standards have pushed automakers
to look at aluminum, carbon fiber and other lightweight metals so they
can make lighter vehicles that release fewer emissions into the
BMW is making its i3 model with a carbon fiber
composite frame, and Audi and Jaguar have replaced steel bodies with
aluminum in some models. The automakers are racing to meet new rules,
which for instance require cars to reach an average mileage of 54.5 mph
in the United States by 2025.
Steelmakers have been pushing back
against the growing use of alternate metals in one of the biggest
markets for steel. They have developed lighter grades and new designs
for auto parts that weigh less but are still made of steel. They also
are pushing for federal regulations that look at not only the emissions
that come from a car's tailpipe, but also the factory that built the
metal that went into the car and how much of the metal is recycled after
the car ends up in the junkyard.
A car's entire life cycle must
be considered to account for the full environmental impact, said
Lawrence Kavanagh, president of the Steel Market Development Institute, a
joint effort by major steelmakers to promote the use of steel.
why: An aluminum-framed car would emit less than a steel-framed vehicle
if it weighed less. But aluminum production is far more
energy-intensive than steelmaking, and can release as much as five times
as much greenhouse gases, Kavanagh said. The production of carbon fiber
and magnesium â€“ two metals that also are making inroads in cars â€“ also
results in more emissions.
Any reduction in emissions over the
200,000-mile life of the vehicle would fail to make up for all the extra
gases released into the atmosphere during the production phase,
The Aluminum Association, a rival trade group,
contends the lighter metal is fact better for the earth. A study it
commissioned found every pound of aluminum used in an automobile saves
20 pounds of CO2 emissions over the lifetime of the vehicle.
said the contention is short-sighted and looks only at the emissions
that occur when the vehicle is being driven. Studies by the University
of California-Davis and the University of California-Santa Barbara have
found that the emissions from materials and vehicle manufacturing can
account for half a vehicle's total emissions.
environmental advantages, particularly when viewed over a vehicle's
entire life cycle instead of just through the measurement of tailpipe
emissions, new U.S. Steel Chief Executive Officer Mario Longhi told a
business crowd at a recent speech in Pittsburgh, according to a
transcript provided by the company.
'If vehicle lightweighting is
accomplished by substituting materials that are emissions-intensive to
make, then the net impact on the environment is more greenhouse gases,'
Longhi said. 'The steelmaking process emits one-twentieth to one-fifth
the amount of greenhouse gases of other materials, and steel is by far
the most recycled material on the planet.'
Steelmakers have been
lobbying the U.S. Environmental Protection Agency to consider new
emissions regulations that could for instance extend credits to
manufacturing processes that release fewer greenhouse gases.
at stake is whether the steel industry can defend its market share in
the automotive industry, which accounts for a fourth of its overall
business. Much of the steel made at mills in Northwest Indiana gets
loaded onto Detroit-bound semi-trailer trucks and ends up in cars,
trucks and sport-utility vehicles.
Mill operators ArcelorMittal
and U.S. Steel have been developing advanced high-strength steels that
are lighter than conventional steel. Steelmakers also have been working
on new designs for steel parts that will lessen the weight of vehicles.
efforts have been paying off. A major domestic automaker recently
started using a new design for a front lower control arm, which it had
made with aluminum but now makes with steel, Kavanagh said.
'This is about defending existing market share, and also growing market share,' he said.