## 3 Results and Discussion
### Power Generation Unit  
Based on the producer gas composition results from the gasifier simulation in Cycle-Tempo, the engine was evaluated for electrical power outputs ranging from 25 kW to 80 kW in 5 kW increments. The corresponding values of the engine-generator set for each biomass feedstock (olive cake pellets and pruning chips) are presented below.  
From the charts presented in Figure 9 and the data shown in Table 2, one can note that, as the moisture content of the biomass feedstock decreases, the gas consumption in the engine-generator set increases. Nonetheless, when analyzing the system from a holistic perspective, it becomes evident that, for a given power electrical power output, the biomass consumption decreases as the moisture content of the biomass feedstock decreases.  
The minimum water consumption required for olive oil extraction in the olive mill is 21.4 L per minute. As can be observed in Figure 10, for all the load percentages of the engine generator-set operation, a flow rate of water at 45 \"C higher than that required by the olive oil mill was obtained, making the gasification plant self-sufficient in delivering  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \multirow{3}{*}{**Biomass** **Feedstock**} & \multirow{3}{*}{\begin{tabular}{c} **Biomass** **Moisture** **Content** **(wt.\%, as Received)** \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} **Biomass** **Consumption (kg/h, as Received)** \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} **Producer** **Gas Flow** **Rate** **(kg/Nm3)** \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} **Producer** **Gas Flow** **Rate** **(MJ/Nm3)** \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} **Producer** **Gas Yield** **(Nm3/kg)** \\ \end{tabular} } & \multirow{3}{*}{\
\begin{tabular}{c} **Cold Gas** **Efficiency** **(\%)** \\ \end{tabular} } \\ \cline{1-1}  & 5 & 81.83 & 1.143 & 235.80 & 5.02 & 2.88 & 67.3 \\  & 10 & 85.39 & 1.137 & 232.92 & 5.05 & 2.72 & 67.3 \\  & 15 & 84.87 & 1.115 & 213.12 & 5.41 & 2.51 & 69.7 \\  & 20 & 90.96 & 1.113 & 215.28 & 5.35 & 2.36 & 69.0 \\ \hline \multirow{3}{*}{
\begin{tabular}{c} Olive \\ pruning \\ chips \\ \end{tabular} } & 5 & 87.78 & 1.151 & 228.24 & 5.22 & 2.60 & 69.0 \\  & 10 & 88.53 & 1.126 & 209.52 & 5.56 & 2.37 & 70.2 \\  & 15 & 94.50 & 1.130 & 214.20 & 5.46 & 2.26 & 69.8 \\  & 20 & 100.83 & 1.121 & 210.96 & 5.50 & 2.09 & 68.4 \\ \hline \end{tabular}
\end{table}
Table 2: Performance parameters of the downdraft gasifier fueled with olive cake pellets and olive pruning chips for different moisture contents.  
Figure 9: Producer gas consumption in the engine–genetator set for gasification of olive cake pellets and pruning chips at different moisture contents.  
the thermal output. An almost linear trend can be observed, with minimum values of 25.1 L/min at 31% load and maximum values of 56.2 L/min at 100% load. It should be noted that the mass flow rate of hot water does not depend on the moisture content or type of biomass. This is because the power required to generate electricity comes from the mass flow rate and the lower heating value of the producer gas. Therefore, with biomass with higher moisture content, it will be necessary to increase the mass flow rate of the producer gas to reach the same load percentage. Figure 10 also shows that, regardless of the load percentage, the gasification CHP plant is able to supply all the hot water at 45 \({}^{\circ}\)C demanded by the olive oil extraction process.  
The electrical and CHP efficiencies of the engine-generator set were calculated and are presented in Figure 10. The results indicate that the efficiencies are not significantly influenced by the biomass type or moisture content, consistent with the findings on hot water production. The electrical efficiency ranges from 19% to 27.6% with typical values, while the CHP efficiency ranges from 51% to 59.2% at full load.