HOMER Pro 3.16

The biomass carbon content is the amount of carbon contained in the biomass feedstock, expressed as a mass-based percentage. HOMER uses this value to calculate the emissions of carbon dioxide, carbon monoxide, and unburned hydrocarbons.

Tip: If you want HOMER to calculate the system's gross carbon emissions, enter the gross carbon content of the biomass feedstock, which is typically around 50%. On the other hand, if you want HOMER to calculate the system's net carbon emissions, enter the net carbon content of the feedstock, which is typically near zero. The net value takes into account the fact that the carbon in the biomass feedstock was originally absorbed from the atmosphere, so consuming the feedstock as fuel puts that carbon back into the atmosphere. The net effect on the atmosphere is near zero if the feedstock is harvested in a sustainable manner, meaning that the rate of consumption of biomass feedstock does not exceed the biosphere's ability to regenerate the feedstock.

A precise estimate of the net carbon content of a biomass feedstock considers the carbon emissions associated with the harvesting and processing of the feedstock. It may also account for avoided methane emissions related to the natural decomposition of the feedstock that would have occurred were it not for the consumption of that feedstock to produce energy.

See also:

How HOMER Calculates Emissions