# Toward More Sustainable River Transportation in Remote Regions of the Amazon, Brazil
## 4 Alternatives to Improve the Performance of Small River Boats in the Amazon Region
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Gas**} & **Emission Factor \({}^{*}\)** & **Reduction of Emissions per Day \({}^{**}\)** & **Reduction of Emissions per Year \({}^{**}\)** \\  & **(in g/kg fuel)** & **(in g)** & **(in g)** \\ \hline Carbon Dioxide (CO\({}_{2}\)) & \(3.2\times 10^{3}\) & \(91.20\times 10^{3}\) & \(33.28\times 10^{6}\) \\ \hline Methane (CH\({}_{4}\)) & 1.70 & 48.50 & \(17.68\times 10^{3}\) \\ \hline Nitro Oxide (N\({}_{2}\)O) & 0.08 & 2.28 & \(0.83\times 10^{3}\) \\ \hline Carbon Monoxide (CO) & \(1\times 10^{3}\) & \(28.50\times 10^{3}\) & \(10.40\times 10^{6}\) \\ \hline Nitrogen Oxides (NO, NO\({}_{2}\)) & 9.7 & \(0.28\times 10^{3}\) & \(10.09\times 10^{4}\) \\ \hline Non-Methane Volatile Organic & & & \\ Compounds (NMVOCs) & 34 & \(0.97\times 10^{3}\) & \(35.37\times 10^{4}\) \\ \hline \hline \end{tabular} \({}^{*}\) IPCC default emission factors for European ships and boats on inland waterways for gasoline 4-stroke engines [62; 63]. \({}^{**}\) Considering fuel density as 750 g/liter.  
\end{table} 
Table 1: Possible reduction in gas emissions by the optimized school boat. also worth mentioning that solar challenges have been introduced in Brazil, which has encouraged universities and research centers to develop solar-powered devices in national and international competitions [81; 82; 83]. The use of solar energy to power marine vessels is currently increasing. For instance, solar energy is being considered by automobile companies for electric yachs [84]. Wind energy could be harnessed using small commercial wind turbines placed on the roof of a boat for small-scale power generation, such as those shown by [85]. Although wind currents are not constant in the Amazon region, these small devices could take advantage of the currents when they occur, thus contributing to battery charging. With respect to hydrokinetic energy, water currents offer constant availability in the numerous rivers of the region. The flow velocity close to the water surface is small in some rivers (\(\sim\)0.4-0.6 m/s) but can reach \(\sim\)2 m/s in other places (for details, see [86]). An array of small turbines could be deployed beneath the water surface to take advantage of river currents (see a simplified concept in Figure 6). While the boat moves forward, this may not be convenient due to the possible increase in hydrodynamic resistance. However, when the boat is at rest, these currents could be made use of. Some commercial devices that work at low current velocities (e.g., \(\sim\)0.9 m/s [87]) could be adapted for this application. Some of these are practical and sufficiently portable to charge small electronic devices by harnessing wind or water currents [88]. Arrangements of these devices could be used to generate energy for electronic devices on the boat, particularly when it is at rest. For all these innovations, a feasibility analysis should always be carried out to evaluate possible environmental impacts in the Amazonian environment. Figure 6: Possible improvements in the efficiency and sustainability of the existing boats used for daily activities in remote regions of the Amazon and similar regions elsewhere. Adapted image credits: commercial propulsors [89]; hydrofoil technologies [90]; solar technologies (left: [80], right: [83]); wind energy [91].