(3) Resource inventories (which can be performed through remote sensing
supported by statistical means from so-called ground truth) maintained on a
continuous basis (Parikka 2004), and(4) The Agro Ecological Zone (AEZ) methodology based on advances in remote
sensing, and the ability to model crop growth (Fischer et al. 2005).Figure 69 shows the trend in biomass utilization for energy in the United States since before the
1973 energy crisis, which stimulated a wide range of measures to utilize more biomass in the
energy system. Note that the data for electricity generation were not available from non-utility
biomass users until five years ago; prior to that period, the electricity generated was lumped
together with the industrial heat (CHP) generation (EIA 2000).
Figure 69 Biomass primary energy trend for the
United States (Source: EIA 2000)Combustion
With the exception of the production of biofuels such as methane in anaerobic digestion, and
ethanol or biodiesel, most biomass today is utilized in solid form and burned directly to produce
heat and/or electricity. The scale of biomass combustion devices ranges from less than 1 kWth in
developing country domestic cook stoves, to over 300–500 MWth input in the largest industrial
CHP units.
In the last two decades there has been an increasing use of biomass as a co-fire fuel in large
utility scale boilers fired with coal. While this option does not increase the availability of electric
power, it does provide offsets to both carbon dioxide and sulfur emissions, and has been
demonstrated to have very little effect on the overall efficiency of the coal boiler, up to 10–15%
biomass energy substitution in an individual combustion unit. The higher efficiency in this use is
often accompanied by better emissions control than with biomass-only fired units