The Utilization of Terrestrial Biomass

Noteworthy, the formation of hydrogencarbonate (Equation 13.1) is the process in which C02 is fixed, while the separation of calcium carbonate (Equation 13.2) causes the release of half of the fixed C02. 

The emission of C02 from anthropogenic activities (the combustion of C-based fossil fuels, deforestation, combustion of woods) amounts to approximately 7.5 Gtc per year, or about 3.5% of the total amount cycled in the natural cycle. However, as the natural systems are unable to use such C02, this leads to its accumulation into the atmosphere. The assumption that an increase of the concentration of C02 in the atmosphere would have boosted both the photosynthesis and the dissolution into the oceans has not been proven to be true. In fact, the solubility of C02 is governed by complex equilibria, while photosynthetic fixation is limited by several factors so that, under the increase of the atmospheric concentration from 280 ppm of the preindustrial era to the present-day 380 ppm, there has not been any sensible improvement of the uptake. Therefore, under natural conditions the uptake of C02 has reached an equilibrium state, and the further increase in atmospheric concentrations may more likely cause climate changes through the greenhouse effect and destabilization of the thermal structure of the atmosphere, than improve the elimination of C02 from the atmosphere. 

The higher such difference, the more performing is the process. A process with a negative energy balance has no sense, as such a process is a net emitter of C02. 

The terrestrial biomass has been used as source of energy since man lit the first fire on Earth. The direct combustion of any form of biomass is not the best process 

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