Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
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that may not be completely controllable. Virgin feedstocks are controlled by the
available agricultural resources.
In the United States, soybean and corn oil are the two leading vegetable
feedstocks for biodiesel production. These two feedstocks are readily available
throughout most of the country and can be grown in the large quantities necessary to
meet large scale biodiesel production demands. The pork and beef industries dictate the
supply of white grease and tallow that is available for biodiesel production. The supply
of recycled fats and oils is largely determined by the demand for fried food products,
lubricants, and other oil dependent industries. While biodiesel demand has been known to
have moderate impacts on corn and soybean production, it is unlikely that increases in the
demand for biofuels will significantly impact the supply of animal fats or recycled
greases. 20
Cost and Performance Characteristics
Currently the production cost of biodiesel can range from competitive with diesel,
to as much as 2.5 times higher. Because the majority of biodiesel production cost is
directly derived from the cost of the plant feedstock, potential for cost reduction is less
than that of ethanol. Biodiesel can be more cost effective when produced from low-cost
oils (restaurant waste, frying oils, and animal fats), compared to commodity crops.
Integration of biodiesel into the transportation sector has been limited due to the
fact that nearly every major diesel engine manufacturer has imposed blend limits on
biodiesel for warranted operations. Typically the fuel composition is restricted to a
maximum of 5 percent biodiesel (B5). Recently some manufacturers have raised their
limits to 20 percent. Some users have elected to run their engines on B100 and other high
percentage blends, conceding the manufacturer’s warranty coverage; however, this is a
risk that few operators are willing to take.
Gasoline and diesel fuel, and their biofuel counterparts ethanol and biodiesel, are
quality controlled based on ASTM specifications. The recent establishment of the ASTM
biodiesel specification was a major advance for manufacturers who now have an
industry-accepted standard for quality. This new standard will likely lend itself to an
increase in large-scale biodiesel production, as well as a greater acceptance of the biofuel
by diesel engine manufacturers.
While biodiesel can be used in any standard diesel engine with little to no
modification to the engine, due to its different properties, such as a higher cetane number,
lower volatility, and lower energy content, biodiesel may cause some changes in the
20 Agricultural Marketing Research Center, “Biodiesel as a Value-added Opportunity,” available at
http://www.agmrc.org/energy/info/biodieselopportunity.pdf, accessed 3 August 2004.
21 March 2005 3-29 Black & Veatch