Renewable Energy Technology Assessments - Kauai Island Utility ...

Kaua’i Island Utility Cooperative
Renewable Energy Technology Assessments
3.0 Renewable Energy Technology
Options
biomass gasification combined cycle and biomass pyrolysis, are currently under
development and are not considered for commercial applications in this study.
Applications
Wood is the most common biomass fuel. Other biomass fuels include agricultural
residues such as bagasse, dried manure and sewage sludge, black liquor, and dedicated
fuel crops such as fast growing grasses and eucalyptus. There are also many municipal
waste burners installed throughout the world employing similar conversion technology.
However, the construction of new municipal waste combustion plants has become
difficult in the United States due to environmental concerns regarding toxic air emissions.
(See the waste to energy section for further discussion).
Figure 3-2. 35 MW Biomass Combustion Plant.
The capacity of biomass plants is usually less than 50 MW because of the
dispersed nature of the feedstock and the large quantities of fuel required. Furthermore,
biomass plants will commonly have lower efficiencies than modern coal plants. The
efficiency is lower because of the smaller scale of the plants and the lower heating value
and higher moisture content of the biomass fuel compared to coal. Additionally, biomass
is typically more expensive and lower in density than coal. These factors usually limit
use of direct fired biomass technology to inexpensive or waste biomass sources.
21 March 2005 3-4 Black & Veatch