Page 262 - Geothermal Energy Renewable Energy and The Environment

252 Geothermal Energy: Renewable Energy and the Environment

over many different power plants. As such, it is subject to change, and to local and regional physical
and economic drivers that may make the performance at a given facility different from the aggre-
gated value. The capacity factor is an indication of how closely an installed conversion technology
comes to producing the amount of power an installed generating facility is rated to produce. A
capacity factor of 0.9 (or 90%) for a specific conversion technology indicates that performance has
shown that technology is likely to achieve 90% of its rated output over time. Table 13.1 lists the
capacity factors (in percentage values) for various conversion technologies, which are also plotted
in Figure 13.1.

Table 13.1
capacity Factors for Various power Generation Technologies

power Generation Technology capacity Factor (%)
Geothermal Binary 95%
Geothermal Flash 93%
Biomass Combustion 85%
Biomass: IGCC* 85%
Nuclear 85%
Coal: IGCC* 60%
Hydro: Small Scale 52%
Wind: Onshore 34%
Solar: Parabolic Trough 27%
Solar: Photovoltaic 22%
Ocean Wave 15%
Source: Integrated Energy Policy Report, California Energy Commission, Sacramento,
California, CEC-100-2007-008-CMF, 2007.
*IGCC: Integrated gasification combined cycle.

Capacity factor (%)
0.0 20.0 40.0 60.0 80.0 100.0

Geothermal-binary
Geothermal-dual flash
Biomass-fluidized bed boiler
Biomass-IGCC
Advanced nuclear
Coal-IGCC
Hydro-small scale
Wind-class 5
Solar-parabolic trough
Solar-photovoltaic
Ocean wave

FIGUre 13.1 Capacity factors, as a percentage, for various conversion technologies. (Data are from the
Integrated Energy Policy Report, California Energy Commission, Sacramento, California, CEC-100-2007-
008-CMF, 2007.)