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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engine performance and emissions. These different properties can affect the injection
timing and the diesel combustion process causing lower power output. In contrast,
biodiesel has a higher concentration of oxygen (by weight) which lends itself to more
complete combustion, and biodiesel’s higher cetane number provides smoother
combustion and less engine noise.
Environmental Impacts
When compared to petroleum diesel, biodiesel offers a variety of benefits.
Testing has shown that biodiesel has lower sulfur emissions and particulate emissions
than regular diesel fuel. While biodiesel yields significantly lower sulfur emissions,
particulate matter, and unburned hydrocarbons, emissions of nitrogen oxides can be
higher for biodiesel than diesel depending upon engine configurations. Not only does
biodiesel emit few harmful gases when combusted, but in almost every circumstance,
fewer greenhouse gases are emitted in the production and transportation of biodiesel than
are released in the production, transportation, and refinement of petroleum diesel. In
addition to the aforementioned benefits, biodiesel boasts higher full-fuel cycle efficiency,
and, in certain niche applications, a lower cost than petroleum diesel
Kauai Outlook
Given Hawaii’s high fuel prices and agricultural productivity, biodiesel is
especially attractive in the state. Overall prospects for biodiesel in Hawaii are good both
in the transportation and power generation sectors. This is evidenced by Pacific
Biodiesel, which already has biodiesel production facilities on Oahu and Maui. The
company sells biodiesel for $2.315 per gallon on Maui (retail price including all taxes)
compared to $2.61 - $2.65 per gallon for regular unleaded and up to $2.85 per gallon for
retail diesel (as of July 23, 2004). 21 The Maui plant has been open since 1996 and
produces 200,000 gallons of biodiesel annually. The Oahu plant is double the capacity.
The feedstock for the plants is used cooking oil and restaurant trap grease. These are the
lowest cost resources, but also the most limited.
There are several resources available on Kauai that could provide required
feedstocks for biodiesel production. A study completed in 2002 estimated Kauai’s
recycled grease resources at roughly 800 tons annually, which could be used to produce
approximately the same weight of biodiesel. 22 As for animal fats, the current livestock
production on the island suggests that there is limited potential to obtain animal fats for
21 “Biodiesel Discussion Board”, available at: http://biodiesel.infopop.cc/eve, accessed August 2004.
22 University of Hawaii, Hawaii Natural Energy Institute, “Biomass and Bioenergy Resource Assessment
State of Hawaii”, available at: http://www.hawaii.gov/dbedt/ert/biomass-assessment.pdf, December 2002.
21 March 2005 3-30 Black & Veatch