By Connie Hardy, content specialist, AgMRC, Iowa State University, chardy@iastate.edu.

Revised June 2011.
 

Overview
Biodiesel is a clean burning alternative fuel made from renewable resources. The most common process employs transesterification whereby methyl esters are produced from fats and oils, yielding a non-toxic, biodegradable fuel that can be burned in diesel engines, and glycerin, which can be used in industrial and pharmaceutical applications. Biodiesel contains no petroleum, but it is usually mixed with petroleum diesel fuel and sold as, for example, 'B2', 'B5' and 'B10' to reflect the percentage of biodiesel (2%, 5%, 10%) included in the mix. It is also used alone as a diesel fuel, called B100. In the United States, biodiesel is produced from plant oils, animal fats, recycled restaurant grease and waste grease. Research continues to develop other feedstock sources for biodiesel, including algae, to make biodiesel production affordable in many different locations. Oils from non-food plants, such as camelina, jatropha and pennycress, are potential feedstocks for biodiesel.

Rapid growth in construction of U.S. biodiesel production facilities in 2006-2007 was supported by favorable feedstock prices, federal mandates for future targets of biofuel production and the federal tax credit of $1 per gallon. Unfavorable economic changes in late 2008 forced several operating plants to cut back or stop production, and that trend has continued into late 2009 with the unexpected expiration of the $1 per gallon tax credit. In early February 2010, the Environmental Protection Agency reversed its earlier finding that soy biodiesel did not meet federal carbon emission standards. Congress reinstated the tax credit, opening the way for soy biodiesel production to resume. The average price of on-road biodiesel in mid-April 2011 was $4.10, according to the U.S. Energy Information Administration. Considering the blenders' credit and RIN prices, the per-gallon cost of biodiesel drops to approximately $2 per gallon, hopefully leading to increased demand and higher profitability for biodiesel producers. (Voegele, E., Biodiesel magazine, June 2011.)

The industry publication, Biodiesel magazine, shows that the 180 existing biodiesel production plants have a total production capacity of 2,847 million gallons per year (mgy), and 11 more plants are under construction, which would add 385.5 mgy. The Renewable Fuels Standard passed by Congress in 2007 establishes a production standard of 36 billion gallons of fuels from renewable resources per year by 2022. This mandate has been the primary driver for expansion in the biofuels industry.

Production
The production of biodiesel is a proven science and an efficient process. Simplified to its core steps, the process is accomplished by combining refined soy oil with an alcohol and a catalyst. When the catalyst is removed, the remaining components are biodiesel and a small amount of glycerin. The final product can be burned as 100 percent pure biodiesel (B100), but because of cost differences, it is generally marketed as either a B2 blend or a B20 blend. It is also marketed as a fuel additive for traditional diesel fuel because of its lubricity properties. Lubricity benefits and emission reduction are significant at levels as low as 2 percent blends (B2).

Soybean oil was the feedstock of choice by most biodiesel processors because of its abundant supply and its favorable fatty acid profile. When the price of soybean oil became prohibitive, other plant oils and animal fats began to be used to produce biodiesel, some requiring modifications in the process or more involved clean-up procedures. New production technologies will allow for the use of less-expensive feedstocks with a variable free fatty acid (FFA) range, giving producers more flexibility in feedstock purchase. The Mcgyan Process is one such process that uses a specific catalyst to produce biodiesel using no water, sodium hydroxide or sulfuric acid and produces no byproducts. Another promising technology uses supercritical processing and does not require a catalyst or hazardous chemicals, and it allows for variable FFA profiles in the feedstock.

BQ-9000
BQ-9000 is a voluntary fuel quality assurance program, overseen by the National Biodiesel Accreditation Commission (NBAC) and adopted by the National Biodiesel Board and the Canadian Renewable Fuels Association. It couples the foundations of universally accepted quality management systems with the product specification ASTM D 6751 and has become the premier quality designation in the industry. The program covers storage, sampling, testing, blending, shipping, distribution and fuel management practices. Both producers and marketers are eligible to become either a BQ-9000 producer or BQ-9000 marketer. Currently, more than 40 companies are accepted into the BQ-9000 program, covering about one third of the total biodiesel production.
 

Sources
Biodiesel Economics--Costs, Tax Credits and Co-product, AgMRC Renewable Energy Newsletter, 2009.

Profile created May 2004 and revised June 2011.