Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
Options
annually. 29 This quantity is sufficient to generate about 44 GWh/yr of electricity from a 7
MW plant operating at 70 percent capacity factor. As discussed in the section on landfill
gas, plans are in place to close the landfill in 2009. The County has not identified a
future landfill site or developed plans to deal with the growing waste stream. The current
tipping fee at the landfill is $56/ton. However, this fee does no cover the capital cost of
the landfill, which is covered through taxes. The all-in cost for disposal including the
capital cost is about $90/ton. 30 A waste to energy facility looks increasingly attractive at
such high disposal costs. The development of a waste to energy facility would address
the county’s disposal issues while generating baseload power from an eligible renewable
resource.
The developable potential for MSW mass burn is summarized in the following
table.
Year Energy,
GWh
Table 3-13. Developable Potential from MSW Mass Burn.
Capacity,
MW
Notes
3 0.0 0.0 Highly unlikely in near term
5 43.8 7.1 Assumes construction of one 300 TPD unit
10 43.8 7.1
20 65.7 10.7 Assumes addition of a 150 TPD unit
3.4.2 Refuse Derived Fuel
Refuse derived fuel (RDF) is an evolution of MSW technology. Instead of
burning the trash in its bulky native form, trash is processed and converted to fluff or
pellets for ease of handling and improved combustibility.
To ensure a proper mix of fuel, trash is typically sorted to remove metals,
“heavies” and other undesirable materials. The remaining “clean” trash is conveyed to a
mulching facility that shreds the material into small pieces. These pieces are delivered as
fuel to a combustor. Due to the extensive pre-processing and sorting of the material,
RDF facilities are often considered to be more compatible with local recycling efforts
than mass burn facilities.
29
SCS Engineers for US EPA, “Landfill Gas Utilization Feasibility Study Kekaha Landfill”, April 2004.
30
Troy Tanigawa (Solid Waste Programs Administrative Officer, Kauai County Solid Waste Division),
personal communication, June 16, 2004.
21 March 2005 3-36 Black & Veatch