MIT Study Examines 'Fleet Effect'
14 June 2000
Automotive Steel Exec Warns of Negative Environmental Impact of Increased Aluminum Use, According to American Iron and Steel Institute
DETROIT - A significant increase in the use of aluminum to build fleets of
aluminum-intensive vehicles would bring severely negative environmental impacts,
according to a steel industry executive who issued the warning in a presentation
to the Society of Automotive Engineers at its Total Life Cycle Conference last
April.
Peter T. Peterson, director, Marketing Automotive - Flat Rolled Products,
U.S. Steel Group, A unit of USX Corporation, who spoke on behalf of American
Iron and Steel Institute (AISI), noted, "Our concern is carbon dioxide,
including both the amounts released in automobile tailpipe emissions as well
as the amounts released in the production of materials used in the manufacture
of automobiles." Citing findings of a Massachusetts Institute of Technology
(MIT) study currently underway, Peterson noted that the production of
sufficient quantities of virgin aluminum necessary to build large volumes of
all-aluminum or aluminum-intensive vehicles would so severely overload the
environment with carbon dioxide that it would take decades to recover.
Peterson refuted the assumptions behind the aluminum industry's claim that
a one tonne increase in the use of aluminum in automotive applications in
place of two tonnes of steel would reduce 20 tonnes of carbon dioxide
emissions over the life of an average vehicle. In his presentation, he
countered that:
* Recycled aluminum, capable of satisfying increased automotive
applications, is not plentiful,
* Hydroelectric capacity to significantly ramp up production will not be
available,
* Energy sources which will be necessary to satisfy new automotive
requirements for virgin aluminum production do pollute,
* Weight reduction of 10 percent does not result in fuel economy
improvement of six to eight percent in a typical North American vehicle,
* Claims that use of aluminum results in a 50 percent weight reduction
over steel substantially exaggerate the case,
* Manufacture of one pound of primary automotive aluminum generates much
more than 6.7 pounds of carbon dioxide,
* The impact of a fleet of aluminum vehicles cannot be extrapolated from
the effect of a single vehicle.
Peterson's presentation centered on the effect of the creation of a fleet
of aluminum-intensive vehicles, as opposed to the single-car scenario
typically cited in life cycle analyses. Challenging the perception that
aluminum is the single solution to the challenge of greenhouse gas emissions,
Peterson asserted that any claimed advantages of increased automotive aluminum
use would be outweighed by the environmental impact of producing the
incremental virgin aluminum necessary to support that greater use.
Counter to aluminum industry claims, Peterson noted that recycled aluminum
for automotive applications is not available in enough volume to support
aluminum industry projections, nor would the new energy for incremental virgin
aluminum come from non-polluting sources. Aluminum industry claims rely on
the use of non-polluting hydroelectric power to achieve its highly touted
emission results. However, hydroelectric power generation in North America
and many other parts of the world is projected to remain stable over the next
two decades. To produce the virgin aluminum required to create a new fleet of
aluminum-intensive vehicles, aluminum producers must draw their additional
power requirements from other sources such as coal- or natural gas-powered
electrical generation facilities.
The aluminum industry has claimed that weight reduction of 10 percent in a
typical North American vehicle results in a fuel economy improvement of six to
eight percent. This claim assumes a vehicle that weighs 3377 pounds and
achieves 23 miles per gallon of fuel. Using current Corporate Average Fuel
Economy (CAFE) of 27.5 miles per gallon as a benchmark, the six to eight
percent figure would be too great. Susan F. Skerner, senior director, global
public policy for Ford Motor Company, recently stated that, "for every ten
percent reduction in (vehicle) weight, there is a three to four percent
improvement in fuel economy."
When lightweighting is the issue, the aluminum industry asserts that every
pound of aluminum replaces two pounds of steel -- a 50 percent weight savings.
This unproven assertion assumes a non-optimized steel body structure.
Comparing the weight savings of the aluminum-intensive body structure of the
Taurus/Sable to the baseline vehicle shows a savings of 46 percent, but
compared with the optimized steel auto body developed through the UltraLight
Steel Auto Body project, that figure drops to only 28 percent.
Another myth that the aluminum industry encourages is that only 6.7 pounds
of carbon dioxide results from the production of one pound of aluminum. This
claim relies entirely on the use of a mixed product called, "automotive
aluminum," comprising 63 percent recycled aluminum and consisting almost
entirely of castings. According to Peterson, this mixed product could not be
used as a direct replacement for sheet steel to supply a fleet of aluminum
intensive vehicles. According to a study by the International Primary
Aluminum Institute, the current worldwide average for sheet aluminum
production is 15.1 pounds of carbon dioxide per pound of material produced --
more than double the figure touted by the North American aluminum industry.
Peterson also contended that it is misleading and inaccurate to use the
effect of the production of a single aluminum-intensive vehicle to extrapolate
the effect of an entire new fleet of aluminum vehicles. Traditional life
cycles analyses have concentrated on single products and treated greenhouse
gas emissions as a single, net sum event without regard for the time involved.
It is more accurate and useful to analyze the lifetime impact of a fleet of
vehicles across their useful lifespans, taking into account that CO2 emissions
from aluminum manufacture occur at one time, near the beginning of the life
cycle. The payback of that CO2 debt occurs in very small increment over many
years.
Peterson cited an analysis of this "fleet effect," developed by
Massachusetts Institute of Technology (MIT), in which its researchers examined
the cumulative nature of carbon dioxide creation in the aluminum production
phase, and the additive effects of tailpipe emissions of carbon dioxide during
the use phase. CO2 would build up from the production of enough incremental
virgin aluminum to build an aluminum fleet, as the fleet would come into being
over at least a decade. At the same time, a growing fleet of aluminum
vehicles would emit incrementally smaller amounts of carbon dioxide into the
atmosphere.
The MIT study found that when the aluminum-intensive vehicle is compared
with the UltraLight Steel Auto Body (ULSAB) with UltraLight Steel Auto
Closures, it would take 27 years for an actual net reduction in carbon dioxide
emissions to occur.
For its analysis of a fleet of aluminum vehicles, MIT researchers assumed
a realistic production volume of 100,000 units per year, an average lifetime
of 13.1 years, curb weight of 3340 pounds and base fuel economy of 26 miles
per gallon. They also assumed that for the first 10 years, production of the
virgin aluminum necessary to build this fleet would come from coal-fired
electricity plants.
Peterson said that any improvements in powertrain efficiency and
corresponding reduction in CO2 emissions will lengthen the time it takes to
offset aluminum's initial CO2 burden. As cleaner automotive power sources
become more prevalent, the need for expensive and difficult solutions, such as
those provided by aluminum, diminishes and steel solutions become increasingly
attractive. This will be especially true once totally clean automotive power
sources such as fuel cells become more commonplace.
He concluded by saying that, with continued exploration of the uses of
steel through innovative programs such as the ULSAB and its companion
projects, ULSAC (Closures) and ULSAS (Suspensions), reducing greenhouse gases
is advantageous with existing technologies, without the higher monetary,
energy and environmental costs of aluminum.
To download the Powerpoint presentation or to review other information
about steel and its applications, view American Iron and Steel Institute's
website at http://www.autosteel.org .
The American Iron and Steel Institute (AISI) is a non-profit association
of North American companies engaged in the iron and steel industry. The
Institute comprises 46 member companies, including integrated and electric
furnace steelmakers, and 175 associate and affiliate members who are suppliers
to or customers of the steel industry.
The Automotive Applications Committee (AAC) is a subcommittee of the
Market Development Committee of AISI and focuses on advancing the use of steel
in the highly competitive automotive market. With offices and staff located
in Detroit, cooperation between the automobile and steel industries has been
significant to its success. This industry cooperation resulted in the
formation of the Auto/Steel Partnership, a consortium of Daimler Chrysler,
Ford and General Motors and the member companies of the AAC.
Automotive Applications Committee member companies:
AK Steel
Bethlehem Steel Corporation
Dofasco Inc.
Ispat Inland Inc.
LTV Steel Company
National Steel Corporation
Rouge Steel Company
Stelco Inc.
US Steel Group, a unit of USX Corporation
WCI Steel, Inc.
Weirton Steel Corporation