The Report

Tomorrow's truck loses weight, but at what environmental cost?

Tomorrow's truck loses weight, but at what environmental cost?

Posting in Transportation | From Issue 12 March 3, 2014

A lighter gas-powered pickup truck that gets 30 miles per gallon looks great on paper, but glance up the supply chain and the energy-efficiency picture blurs.

Ford's F-150 pickup truck is the best-selling vehicle in the United States—it has been for 32 years. The automaker sold 760,000 F-150s last year, far outpacing the top car in retail sales, the Toyota Camry, of which just under 408,500 units rolled off lots. So when Ford revealed at the Detroit Auto Show in January that it would make the body of future F-150 models mostly from aluminum rather than steel starting in 2015, the news spread quickly across the automotive supply chain.

The move to aluminum is all about fuel efficiency. Overall, the new F-150 truck will drop 700 pounds by replacing steel with aluminum in its body panels. How much fuel is saved will depend on the type of engine. With the most efficient option, the 2.7-liter EcoBoost engine with start-stop technology, Ford estimates the truck could get "close to" 30 miles per gallon (mpg). That's because start-stop automatically kills the engine while idling and restarts seamlessly when you press the accelerator.

But stepping back and looking at the move to aluminum—not just in the F-150 but also across the luxury car segment, which has been embracing aluminum components since the early aughts—the impact on total energy efficiency is muddled. 

That's because ton for ton, aluminum production is highly energy-intensive: at least five times as intensive as steel production, says Larry Kavanagh, president of industry association Steel Market Development Institute. That's accurate, according to Charles Johnson, vice president of policy for The Aluminum Association, but not a clear or fair assessment because one ton of aluminum is not functionally equivalent to one ton of steel in automotive applications.

In a 2010 lifecycle assessment analyzing the greenhouse gas emissions associated with using high-strength steel and aluminum for lightweighting vehicles, researchers at University of Michigan found that for a car using 23 percent aluminum for lightweighting, it would take four to 10 years of travel before the "wheel to tank" greenhouse savings met and surpassed the greenhouse expenditure associated with the aluminum's production. This all assumes that the aluminum used in this vehicle is mined from ore rather than recycled. Greatly increasing the aluminum recycled content will require a closed-loop infrastructure for automotive-wrought aluminum, which doesn’t exist today. 

Gregory Keoleian, a coauthor of the 2010 University of Michigan research and the director of the school's Center for Sustainable Systems, notes that his research focused on a baseline car that gets 33 mpg. When considering that the F-150 is going to improve from just 22 mpg to almost 30 mpg, "taking weight off the less efficient Ford F-150 will result in a greater reduction in energy, and greenhouse gas emissions, compared to the vehicle we modeled," he says.

Another lifecycle assessment to be published at a Society of Automotive Engineers meeting in April suggests that aluminum-intensive vehicle design has a greater potential to reduce emissions and overall energy consumption compared to vehicles designed largely on lightweight steel. That assessment applies credit for wrought aluminum that is recycled, rather than primary production aluminum, which is all that will be available until suppliers can bring more recycled aluminum on board.  

Realistically, the quantity of high-grade automotive aluminum (much different than that used in, say, beverage cans) available for recycling is still very low, given the relatively small number of vehicles that use it today. This type of metal is also used in aerospace, but planes have very long life cycles.

The aluminum industry is likely gearing up for growth based both on the trend toward more aluminum in cars generally, but certainly because of Ford's move, specifically. Looking just at the F-150's first full year on the market, even if we assume no major growth in any other sheet or plate application, demand from the 2015 F-150 will amount to an extra 415 million pounds of aluminum, predicts John Mothersole, senior principal analyst at IHS Automotive.

A Ford spokesperson told me it's too soon to talk specifics with regard to the lifecycle energy picture or recycling infrastructure for the aluminum-rich F-150 models, but noted that the company "will have a lot to say about this later this year."

Metals race

Kavanagh says that "material competition is continuous," and stricter fuel-efficiency requirements are forcing automotive industry suppliers to constantly innovate to make ever lighter high-strength steel to address automakers' lightweighting goals. "Any competition is good for automakers, it provides alternatives, it's good for suppliers, it forces us to be our best," he says.

When I asked Ronald Krupitzer, vice president, automotive market, of Steel Market Development Institute, what impact Ford's move will have on the steel industry, he was a bit less diplomatic. "We're just really nervous about it," he says. "I feel Ford has thrown down the gauntlet." 

Still, like Kavanagh, Krupitzer sees the uptick in automotive aluminum applications keeping the steel industry innovative, which is leading to significant product improvements.

Just a slice of the energy pie

"At the end of the day, you can get 5 percent further reduction in weight with aluminum [beyond what high-strength steel offers]," says Phil Gott, a senior director at IHS Automotive.

So why would Ford invest so heavily in what seems like an incremental improvement? Because the boost in mpg performance, combined with F-150's huge sales volume will improve Ford's fleetwide average fuel efficiency, Gott says.

Increasing fuel efficiency is vitally important for reducing the overall transportation sector's overall greenhouse gas emissions. But it accounts for only the "wheel to tank" part of a vehicle's energy footprint. If federal policies accounted for each vehicle's lifecycle emissions—from mining ore to recycling auto components—automakers would have many more trade-offs to consider. That's something the steel industry—with its relatively lower energy footprint compared to aluminum, composites, carbon fiber and other cutting-edge automobile materials—would welcome.

"Unfortunately, [federal policy] only regulates the driving cycle, not the full cycle. We'd like to see the full lifecycle being considered," Kavanagh says.

Image: Courtesy Ford

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Mary Catherine O'Connor

Contributing Writer

Mary Catherine O'Connor has written for Outside, Fast Company, Wired.com, Smithsonian.com, Entrepreneur, Earth2Tech.com, Earth Island Journal and The Magazine. She is based in San Francisco. Follow her on Twitter. Disclosure