Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
Options
and with minimal risk to KIUC. On the other hand, its economic viability is strongly
linked to the price of diesel compared to ethanol and the future and applicability of
ethanol subsidies for power generation.
Other applications utilizing existing KIUC equipment are more complicated.
Although it is technically possible to burn ethanol in combustion turbines, manufacturer
support of this option has been limited to date. Further, as discussed earlier, mixing
ethanol with diesel for reciprocating engines is currently not technically viable. Within a
10 to 20 year timeframe it is likely that these issues may be addressed and additional use
of ethanol for KIUC will be limited largely by available supply. Considering these
factors, the table below summarizes the developable power potential from ethanol on
Kauai.
Table 3-10. Developable Potential from Ethanol for Power Production.
Year Energy,
GWh
Capacity,
MW
Notes
3 52.6 10.0 Constrained to use at 10 MW steam plant at Port Allen
5 52.6 10.0
10 262 37.4 Assumes availability of 25 million gallons per year of
ethanol
20 525 74.9 Assumes availability of 50 million gallons per year of
ethanol
3.3.2 Biodiesel
Biodiesel is a non-toxic, biodegradable, and renewable fuel that can be used in
diesel engines with little or no modification. Biodiesel can be produced from oils and
sources of free fatty acids such as animal fat, vegetable oil, and waste greases. Biodiesel
is produced by removing excess hydrocarbons from these oils to create a shorter chain
molecule that is chemically more comparable to diesel fuel. Sodium methoxide is added
to the oil causing the mixture to settle into two simpler constituents: glycerin and methyl
ester. The methyl ester is collected, washed and filtered to yield biodiesel. The glycerin
has several commercial uses, the most common one being the manufacture of soap.
The actual facilities where biodiesel is created are relatively simple and easily
scaled to meet local needs. Two kinds of biodiesel production facilities are in operation
today: batch plants and continuous flow plants. Batch plants tend to be much smaller
than continuous flow plants, and produce discrete “runs” of biodiesel. Continuous flow
plants are usually much larger, run continuously, and are capable of implementing more
21 March 2005 3-27 Black & Veatch