Estimating the limits of renewable energy from phytomass

Abstract

The energy production from phytomass on agricultural and forest lands can be calculated on the basis of the annual production of hydrocarbons (cellulose, starch, sugar, etc.), without needing to take into account the type of phytomass and the mean-weighted specific power production per unit of land area. Land with a mostly uniform climate and soil class produces similar specific power per unit of land area. It was proved in the case of the Czech Republic, where the meanweighted value of specific power production has been calculated as 3.16 kW/ha. Biomass energy can be released in three ways in which conversion takes place. i) direct phytomass combustion, ii) conversion to methane (biogas), iii) conversion to bioethanol. Conclusions about the effectiveness of different conversion methods were obtained by executing the enthalpy balances of the individual transfer processes. The method using methane (raw gas) seems to be the most energetically advantageous. The close connection between the circulation of CO2, H2O, and O2 has been quantified. The same amount of water as CO2 is produced and remains int in the atmosphere, and it significantly reflects radiation away from the ground. Cooling heat flux can be lowered about 1.6 times, thus contributing to climate change.