Select your localized edition:

Close ×

More Ways to Connect

Discover one of our 28 local entrepreneurial communities »

Be the first to know as we launch in new countries and markets around the globe.

Interested in bringing MIT Technology Review to your local market?

MIT Technology ReviewMIT Technology Review - logo


Unsupported browser: Your browser does not meet modern web standards. See how it scores »

{ action.text }

For the next few decades at least, liquid hydrocarbons–gasoline, diesel, and jet fuel–will continue to be the mainstays of transportation. They’re cheap; refueling is fast; and their energy density, crucial to long-distance travel, is hard to beat.

“Advanced technology is going to happen slowly,” says Daniel Sperling, the director of the Institute for Transportation Studies at the University of California at Davis and a member of the California Air Resources Board. “The focus needs to be on making conventional technology more efficient.”

It should be possible to reduce the fuel consumption of a midsize sedan by up to 60 percent without sacrificing size or performance, using mostly existing technology. Lightweight materials will help. Advanced turbocharging and fuel-injection technology will extract more power from smaller engines that lose less energy to friction (see “Research to Watch”). Similarly, making airplanes lighter and their engines more efficient could cut their fuel consumption 30 to 50 percent by 2020.

Biofuels should help curb petroleum consumption, although the contribution they make will depend on many factors, including the price of oil and the development of new technologies. The International Energy Agency has estimated that by 2050, ethanol and biodiesel could meet 13 percent of global demand for transport fuel. The U.S. Energy Information Administration estimates that biofuel consumption in the United States will increase from 7.7 billion gallons per year in 2007 to 35 billion gallons by 2030 while consumption of gasoline, diesel, and jet fuel combined holds steady at about 220 billion gallons per year.

At first, most biofuels will be ethanol made from corn or sugarcane. The amount of ethanol that can be produced from these sources, particularly corn, is constrained by the need for farmland. What’s more, the greenhouse-gas reductions achieved are minimal, because producing corn ethanol takes a lot of fossil fuel. But cellulosic sources of ethanol, such as switchgrass and wood, can be grown on marginal lands, greatly increasing potential fuel production. And the process of making ethanol from these materials consumes less fossil fuel. Corn ethanol contains roughly 1.3 to 1.7 times the energy of the fossil fuels used to make it; for cellulosic ethanol, it’s about 4.4 to 6.1 times as much. By 2030, a significant portion of biofuels will be synthesized from biomass using biological and thermochemical techniques to create gasoline and diesel fuels. Such biofuels could even eclipse cellulosic ethanol.

2 comments. Share your thoughts »

Credits: David Rosenberg/Getty Images, Tommy McCall

Tagged: Energy

Reprints and Permissions | Send feedback to the editor

From the Archives


Introducing MIT Technology Review Insider.

Already a Magazine subscriber?

You're automatically an Insider. It's easy to activate or upgrade your account.

Activate Your Account

Become an Insider

It's the new way to subscribe. Get even more of the tech news, research, and discoveries you crave.

Sign Up

Learn More

Find out why MIT Technology Review Insider is for you and explore your options.

Show Me