Technology Review - Published By MIT
Advertisement

Friday, September 01, 2006

Ethanol vs. Biodiesel

Diesel from soybeans is a far better biofuel bet, research shows

By Kevin Bullis

smaller text tool iconmedium text tool iconlarger text tool icon

Amid a U.S. ethanol boom, new research offers another take on the long-debated question of whether corn grain ethanol provides more energy than its production consumes. A recent study that takes into account all the energy used in farming and processing corn to make ethanol concludes that there is a small energy gain, but that the gain from using soybeans to make diesel is far greater--and that biodiesel is less of a greenhouse-gas polluter, too.

Energy in, energy out
Farming and processing corn grain to make ethanol yields about 25 percent more energy--in ethanol and co­products such as animal feed--than it consumes. In contrast, biodiesel and coproducts yield 93 percent more energy.

Greenhouse-gas emissions
Producing and burning ethanol results in 12 percent less greenhouse-gas emission than producing and burning gasoline. Producing and burning biodiesel from soybeans offers a 41 percent reduction compared with regular diesel.

September/October 2006

Would you like to read more articles from the September/October 2006 issue?

This article is from the September/October 2006 Issue of Technology Review. To read other articles from this issue simply register for My.TechnologyReview.com. It's free.

Subscribe today and save up to 41% »

Comments

  • Cellulosic Ethanol Competes Well With Biodiesel
    m_albertson on 11/01/2006 at 9:18 PM
    Posts:
    4
    Avg Rating:
    4/5
    Those are some good points about how corn ethanol stacks up against biodiesel.  However, I'm surprised there was no mention of the next generation ethanol...cellulosic ethanol.  Here are the stats you can find almost anywhere by doing a Google search:
    <li>cellulosic ethanol creates 85% less greenhouse gases than gasoline
    <li>cellulosic ethanol has a net energy gain ratio of 2.62:1

    According to this site: <a href="http://www.investincellulosicethanol.com">www.InvestInCellulosicEthanol.com</a>, Al Gore, Alan Greenspan and many others are strong supporters od cellulosic ethanol.  Oddly enough, the corn industry stands to gain the most from cellulosic advancements given that ethanol producers will be able to use the whole kernal and the rest of the plant.
    Rate this comment: 12345
    • Re: Cellulosic Ethanol Competes Well With Biodiesel
      zifos on 04/10/2007 at 3:42 PM
      Posts:
      11
      Avg Rating:
      4/5
      Look into algea biodiesel.  It eats pollutants to grow and the oil is very easy to extract.  Just squeeze it out of the algea and its ready to use.  Plus it has a much higher energy density then ethanol or gasoline.  I.E. more miles per gallon = produce less gallons of it to keep up with demand.
      Rate this comment: 12345
      • Re: Cellulosic Ethanol Competes Well With Biodiesel
        Chad on 05/04/2007 at 7:40 PM
        Posts:
        6
        Avg Rating:
        4/5
        There was recently a program on the History Channel talking about alternative fuel systems that talks about a company in Arizona that has found a way to pump CO2 into water-filled tubes that contain a form of algae.  The algae eats the carbon, resulting in a direct release of only oxygen.  Since the algae has so much to eat and sits outdoors in the sun, it has an increased photosynthesis level, allowing it to grow and increase exponentially.  This algae will then be harvested and converted into ethanol which has a higher energy/lower "bad" gas release than soy-based biofuels (almost 3x corn-based) and just lower energy/almost equal gas than sugarcane-based (almost 7x corn-based).

        And it can simply be grown and harvested as a by-product of other industries.
        Rate this comment: 12345
Advertisement

Current Issue

Technology Review November/December 2008
Sun + Water = Fuel
An MIT chemist has opened the way to making hydrogen fuel from water using sunlight.
•  Subscribe
Save 41%
•  Table of Contents
•  MIT News

Magazine Services

Career Resources

MIT Technology Insider

Stories and breaking news from inside MIT about the latest research, innovations, and startups--in a convenient monthly e-newsletter. Subscribe today

Follow us on Twitter

Twitter

Get Technology Review updates via the web, cellphone, or Instant Messager – Follow techreview on Twitter!

Advertisement

More Technology News from Forbes

Advertisement
Advertisement
TECHNOLOGY RESOURCES
Advertisement
MIT Massachusetts Institute of Technology