Biodiesel and Sustainability 

How much energy does it take to produce biodiesel?

Studies by the U.S. Department of Energy show that for every one unit of fossil fuel used to produce biodiesel (usually from soybean oil), 3.2 units of renewable energy are gained.  Petroleum diesel returns only .88 units of fossil fuel energy for every one unit used in its production.  When biodiesel is made from used cooking oil and is consumed locally, the energy balance increases to approximately 7.4 units in return.  In other words, more energy is produced from biodiesel than is consumed by it, while petroleum diesel consumes more energy than it produces.  

Does biodiesel compete with food crops?

Biodiesel made from virgin oilseed crops (i.e. not from used cooking oil or from algae) is typically not seen as competing with food crops because the vegetable oil used is often a secondary product.  Most biodiesel made in the U.S. is from soybean oil.  Soybeans are primarily grown for animal feed and the oil is a byproduct.  Canola (an oilseed crop grown in Canada and the Northwest) is favored for its benefits to the soil and is often grown as a rotation crop.  Once harvested, canola meal is used as a livestock feed and the oil can be used for the food market or for biodiesel.  Therefore, the crops that are being grown for biodiesel also provide food, they are not decreasing the land available for food crops.

Is corn used for biodiesel?

Because biodiesel is made from oil or fat, and not from starch, corn is not a popular crop for biodiesel because the plant contains very little oil (only 7-8% of the plant is oil).  Corn is often used for ethanol which is replacement fuel for gasoline and is a different fuel from biodiesel.

What about the use of palm oil in biodiesel?

Palm is a popular vegetable oil used in food products and cosmetics throughout the world.  Palm grows in tropical climates around the equator.  Some palm is grown in long-standing, established plantations.  Other palm has been planted on rainforest land that was deforested.  Like any crop, palm can be grown sustainably or unsustainably.  Although palm plants produce more oil per acre than any other crop currently grown for biodiesel, less than 0.1% of all biodiesel made in the U.S. is made from palm oil.  Nearly one billion gallons of palm oil are imported in to the U.S. each year for food and cosmetics, while only a few dozen million gallons are made in to biodiesel.  Efforts have been made to decrease deforestation and unsustainable palm practices through the Roundtable for Sustainable Palm Oil.

How much carbon is saved by using biodiesel? 

Biodiesel has a closed carbon cycle, typically creating a 78% lower lifecycle carbon dioxide emissions than petroleum diesel (when made with soybean oil).  A closed carbon cycle means that the plants grown for biodiesel take carbon dioxide from the air as a nutrient.  The oil is then extracted from the plant and is converted into biodiesel.  When the biodiesel is burned, it produces carbon dioxide which returns to the atmosphere.  This cycle does not add to an overall increase in carbon dioxide because the next crop will reuse the carbon dioxide in order to grow.  It can be argued that biodiesel is 100% carbon neutral because of this closed carbon cycle.  However, because some fossil fuels are often used in the production and transportation of biodiesel, the recycling of carbon dioxide is typically reduced from 100% to 78%.  When biodiesel is made from canola or used cooking oil and produced and consumed locally, the carbon dioxide savings are closer to 90-95% because very little fossil fuels are used in the process.

The biodiesel industry continues to work towards increased sustainability through advancements in crops (including algae) and production technology.

Want more information on biodiesel?

(Click on the subjects below. Downloadable PDFs coming soon!)

Biodiesel Basics

Marine Use

Your Car or Truck

Health Benefits

Heating Your Home

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