# Characterization of Congolese Woody Biomass and Its Potential as a Bioenergy Source
## 4 Discussion  
In this study, we assessed the potential of six types of woody biomass for bioenergy production and characterized these biomasses. We demonstrated that using wood biomass for bioenergy does not negatively impact the environment, such as causing deforestation. Additionally, we estimated the amount of electricity that can be generated from this wood biomass.  
These species thrive in evergreen forests, especially on the edges, as well as in gallery forests, rainforests, dry forests, wooded savannah, fallow land, and grasslands with trees. They can also be found on termite mounds and in \"chipya\" woodland on rocky ground, typically at altitudes of 100 to 1000 m. Considering the ecology of these woody biomasses, they could be grown alongside agricultural crops such as cassava and beans in agroforestry systems.  
However, not all biomass energy solutions are equal. Some environmental disadvantages of bioenergy can be mitigated through sustainable forest management, as mentioned by [PERSON] et al. [31], and wise choices about what kind of biomass is harvested and how it is harvested. [PERSON] et al. [32] recommend using branches and stumps rather than cutting down whole trees for bioenergy production. [PERSON] et al. [33] concluded that woody biomass significantly contributes to reducing fossil emissions in heat and power generation in Northern Europe. Excluding biomass from heat and power generation could lead to higher costs during the transition to a low-carbon energy system.  
The Republic of Congo has a large forest area with many forest residues that have not been properly exploited. Estimating the biomass potential is crucial before biofuel and bioenergy production. Charcoal use in the Republic of Congo is high and leads to deforestation of the Congo Basin. The quantities of woody biomass such as WB1, WB2, WB3, WB4, WB5, and WB6 are abundant and can provide a sustainable energy source for rural communities, especially in Nguela village. These woody biomasses are not widely used for food and their availability has not been well reported.  
\begin{table}
\begin{tabular}{l c c c c c c} \hline
**Elements (ppm)** & **WB1** & **WB2** & **WB3** & **WB4** & **WB5** & **WB6** \\ \hline Ca & 1189 & 1145 & 862 & 2051 & 1639 & 1771 \\ Ti & 148 & / & 135 & 106 & 103 & ND \\ Mn & 36 & 28 & 21 & 33 & / & 29 \\ Fe & 27 & 31 & 16 & 43 & 48 & 26 \\ Cl & / & 71 & 109 & 52 & 104 & 182 \\ \hline \end{tabular}
\end{table}
Table 8: _Cont._Our results showed high levels of aboveground biomass (AGB) in WB6, WB1, WB3, and WB5. By quantifying the biomass of five forest species and savannah species over half a hectare, we estimated 13.54 t for forest species over 1/2 ha. Extrapolating to one hectare, we found 27.08 t for forest biomass. This amount of forest biomass (13.54 t) can produce 203.1 GJ for 1/2 ha and 406.2 GJ for 1 ha.  
The Republic of Congo's total electrical energy consumption is 912.00 million kWh [34], corresponding to an annual consumption of about 161 kWh per inhabitant, equivalent to 0.5796 GJ. Therefore, 1/2 ha of forest biomass (203.1 GJ) could potentially produce enough electricity for 350 households, while 1 ha (406.2 GJ) could supply 700 households. For savannah biomass, 1/2 ha (109.2 GJ) can supply 191.6 households, and 1 ha (218.4 GJ) can supply 376.81 households.  
In terms of physico-chemical analysis, all woody biomasses have low nitrogen and sulfur content and fewer heavy metals, making them unsuitable for anaerobic digestion but suitable for thermochemical processes such as pyrolysis and gasification for bioenergy production. The HHV of woody biomasses indicates that the energy content of the samples is relatively low. The statistical analysis showed that these wood biomasses are suitable for thermochemical processes, particularly gasification, with results similar to [30].