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June 2004

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Action needed now to deal with U.S. energy and greenhouse gas challenges

In coming years the global demand for petroleum is projected to grow rapidly while production of the finite resource begins an inevitable decline. How can the United States maintain its mobility and lifestyle under these conditions? Professor John B. Heywood, director of the Sloan Automotive Laboratory at the Massachusetts Institute of Technology, proposed that new technologies—combined with regulatory and behavioral changes—offer promise if action is taken now. He presented his ideas in the opening session of the conference in a speech titled "On the Road in 2030: Technologies for More Sustainable Transportation."

To set the context, he first described the country's petroleum and greenhouse gas (GHG) problems. Currently the U.S.—with 5 percent of the world's population—uses 20 percent of the petroleum. World consumption in 2003 was 77 million barrels per day and is expected to climb to 125 million barrels per day by 2025.

U.S. consumption in 2003 was 20 million barrels per day, 55 percent of which was imported; 69 percent was consumed in transportation. This accounts for 11 percent of world oil and 20 percent of U.S. greenhouse gas emissions.

For the future, "nothing gets better," Heywood said, "and many numbers get worse." In 2025, U.S. consumption is projected to reach 28 million barrels per day—70 percent imported and 73 percent consumed in transportation. This would represent 10.5 percent of world oil and 19 percent of U.S. greenhouse gas emissions. And from reading summaries of global warming research, it's "hard to believe we don't have a problem," he said.

The supply outlook is also worrisome. Some experts believe world production of conventional oil may peak in as little as 10 years, Heywood said, while others feel it might take 20 to 30 years. Combined with steadily rising demand and reliance on imports from the Middle East, the result could be major and recurring shocks to the U.S. economy.

To see what role automotive technologies may play in future scenarios, MIT researchers led by Heywood analyzed an array of possibilities. These included more efficient gasoline engines; improved diesel engines with efficient emission controls; more efficient transmissions; light-weight materials; batteries, electric motors, and hybrids; and hydrogen fuel cells.

Their findings indicate that mainstream technology should improve steadily, leading to a 30 percent drop in fuel use in 20 years but tacking on an extra $500–$1,000 per vehicle. Hybrids can improve on this by another 30 percent, but add a few thousand dollars more. "Very little comes for free," he noted. Diesel could be attractive from a fuel consumption and CO₂ perspective, but its use is uncertain due to stringent U.S. environmental regulations and low fuel costs.

Fuel cells would be more efficient—but again, more costly—than the internal combustion (IC) engine or diesel, but Heywood warned that low-cost hydrogen production from natural gas generates enough CO₂ emissions to wipe out the overall benefit. Fuel cells using hydrogen produced from renewable or low carbon-emitting sources may reduce CO₂ emissions, but the technology currently looks expensive. Biofuels could be a long-term option, but it may take 15 to 20 years until they are in the fleet.

Thus, the realities are daunting, and "there just isn't a better way because of the way we've chosen our vehicles to evolve," Heywood said. Average IC engine performance and efficiency have been improving at about 1 percent per year for the past 25 years, but we "gave it away with bigger, heavier vehicles." Continuing on this path to 2030 will increase the annual gasoline consumption of the U.S. in-use fleet of light-duty vehicles some 60 percent above today's value. And "right now, we are not behaving in a way that says we'll do much about it," he said.

Technology, however, does offer some reason for optimism. Heywood's research developed various scenarios showing the benefits of advanced IC engines, advanced IC engines plus hybrids, and optimal aggressive action including regulatory changes (see figure). "If we delay action for 10 to 15 years," he said, "all the curves move to the right and up."

Currently, Heywood's team is exploring ways to "pull and push" a mixture of technologies and policies that would reduce fuel consumption and GHG emissions. Their strategy—which asks manufacturers, the petroleum industry, and consumers to take on their share of the responsibility—might make some progress, he suggested, because it is less exposed politically than a more focused approach. A possible combination might include:

• Mileage standards of 38 mpg for cars and 27.5 mpg for trucks by 2020, and 43 mpg for cars and 31 mpg for trucks by 2030
• Fees of $1,000 or $2,000 for gas guzzlers, and rebates for gas "sippers"
• A gas tax increase of 5 cents per gallon per year
• Increased renewable content in fuels

The potential impact is a 6 to 10 mpg improvement in average new vehicle fuel economy by 2025 and a 5 mpg improvement in the overall fleet fuel economy by 2025, along with a 30 percent reduction in oil use and CO₂ emissions by 2030. "It's about the best we think we can do, but we need to take action soon," he said.

Technology alone, he stressed, will not solve the country's challenges. The U.S. will need to develop integrated regulatory and fiscal measures to create "a synergy that produces change bigger than individual measures," he said. We must steadily improve mainstream technology, encourage more efficient technologies like hybrids, promote biofuels, and explore low CO₂ options. "The key is that we must start taking action now." Heywood will present MIT's findings to congressional staff and community leaders this fall.

In conclusion, Heywood said we all need to "drive lite": use more efficient, lighter, smaller vehicles, and drive fewer miles, less aggressively. "We could do this without impacting our mobility and lifestyle anywhere near as much as we sometimes fear."

To learn more about Heywood's research, visit Laboratory For Energy and the Environment publications.