Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
Options
In addition to electrical generation, there are many industrial plants that burn their
own biomass waste to produce thermal energy for heating and process applications. The
small scale production of combined heat and power is seen as one of the more promising
biomass applications.
Resource Availability
Wood and wood waste are the primary biomass resources and are typically
concentrated in areas of high forest products industry activity. In rural areas the
agricultural economy can produce significant fuel resources that may be collected and
burned in biomass plants. These resources include bagasse, corn stover, rice hulls, wheat
straw, and other agricultural residues. Energy crops, such as switchgrass and short
rotation woody crops, have also been identified as potential biomass sources. In urban
areas, a biomass project might burn wood wastes such as construction debris, pallets,
yard and tree trimmings, and railroad ties. Locally grown and collected biomass fuels are
relatively labor intensive and can provide substantial employment benefits to rural
economies. Generally, availability of sufficient quantities of biomass is not as large of a
concern as delivering the biomass to the power plant at a reasonable price.
Cost and Performance Characteristics
Table 3-1 provides typical characteristics of a 30 MW biomass plant using a
traditional stoker boiler and Rankine steam cycle. Three different fuel prices are included
for comparison: $0/MBtu, $3/MBtu and $6/MBtu. The zero cost fuel is indicative of a
plant using a biomass fuel that the supplier would otherwise need to dispose of. The
highest price, $6/MBtu, is equivalent to a price of about $100 per dry ton, which is at the
very upper range of estimates for energy crops. The final price, $3/MBtu is probably a
reasonable estimate for the average price of delivered biomass on the island. Further
investigation would be required to better define the expected price.
21 March 2005 3-5 Black & Veatch