Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
Options
better define the expected price. The low end of the capital cost range corresponds to a
direct fuel mixing system, while the upper end reflects a biomass gasification system.
Table 3-4. Cofired Biomass Technology Characteristics.
Performance
Typical Duty Cycle Typically baseload, depends on host
Net Plant Capacity, MW 1-50 (typically 1-25 percent of host)
Net Plant Heat Rate, Btu/kWh 9,000-12,000 (same as host)
Capacity Factor, percent
Economics
50-90 (same as host)
Incremental Capital Cost, $/kW 100-800
Incremental Fixed O&M, $/kW-yr 7-26
Levelized Cost, $6/MBtu Fuel, $/MWh 76-113
Levelized Cost, $3/MBtu Fuel, $/MWh 39-64
Levelized Cost, $0/MBtu Fuel, $/MWh
Technology Status
2.7-15
Commercial Status Commercial
Installed US Capacity, MW 2,100 *
Kauai Potential
Notes:
Poor without host coal plant, otherwise
very good
*
Black & Veatch estimate for the biomass portion of plants that cofire coal and
biomass. Actual capacity is unknown as the degree of cofiring varies substantially.
Environmental Impacts
As with direct fired biomass plants, the biomass fuel supply must be collected in a
sustainable manner. Assuming this is the case, cofiring biomass in a coal plant generally
has overall positive environmental effects. The clean biomass fuel typically reduces
emissions of sulfur, carbon dioxide, nitrogen oxides and heavy metals, such as mercury.
Further, compared to other renewable resources, biomass cofiring directly offsets fossil
fuel use.
Critics are opposed to cofiring biomass with coal because they feel it is a form of
“green washing” dirty coal plants. They believe that biomass could be used to justify
extended lives for coal plants. For these reasons, they argue that the cofired biomass
should not be counted as renewable.
21 March 2005 3-13 Black & Veatch