This paper presents the implementation of natural gas vehicles (NGVs) in Tanzania’s road transportation sector. The peculiarity of this analysis is the evaluation of the technical and economic performance of the converted gasoline and diesel engines to use compressed natural gas (CNG) as the cleanest-burning hydrocarbon. The technical performance involved vehicle mileage (MiCNG), fuel consumption (Fcons), speed drop, engine fuel enhancement (Fenh), and fuel saving, while the economic performance involved conversion cost (Cc), fuel cost saving (FCsaving), and payback (PB). Considering the conversion of gasoline vehicles, the MiCNG could reach an average of 100 to 500 km per filling, depending on the CNG cylinder size. The Fenh and fuel saving were ranging between 1.9 and 3.9 and 71 and 78%. With a proportion of 30:70 diesel-CNG fuel, the heavy-duty truck with 180 kg of CNG could reach 1300 km, saving about 440 L, which is 78.6% per roundtrip, while the medium passenger car with 15 kg of CNG could reach 350 km, presenting a fuel saving of about 75%. From an economic point of view, gasoline retrofitted NGVs cost about 50 to 200 TZS/km, yielding a fuel cost saving of up to 79% and starting to pay off between 2 and 7 months or 10,000 and 40,000 km, depending on the engine capacity. Considering dual fuel, the heavy-duty truck consumes about 496 TZS/km, saving about 62.3% of diesel fuel and starting to pay off after 2.5 months or 29,304 km. To conclude, NGV technologies have been successfully implemented in Tanzania’s road transportation sector, presenting significant fuel savings and reducing reliance on imported oil. While taking measures, this study paves a way for Tanzania and other sub-Saharan countries to promote NGV growth.

This study assesses the energy, economic, and environmental implications of switching Tanzania’s road transport sector to natural gas, which is slowly transitioning. In energy, the main goal is to identify the energy demand for petroleum fuel (diesel and petrol) and natural gas during the transition, while in the economy, the government revenue in the form of taxes for shifted and unshifted vehicles, as well as the loss in government revenue from petroleum fuel revenue post-transition, is assessed. In the environment, carbon emission in terms of carbon dioxide equivalent (CO_2e), carbon tax revenues, and carbon credit revenues post-transition is estimated. The shift involved 10, 20, and 30% of the road vehicle population. The 10, 20, and 30% shift targeted about 142,247, 183,893, and 225,540 vehicles, which in turn dropped diesel and petrol demand by 7 and 3.68%, 7 and 3.8%, and 15 and 7.5%, respectively. In natural gas, the demand started at 0.0916 billion kg and grew exponentially by 200% and later by 300%. The transition has consequences in government revenue, which takes the form of taxes on petroleum products. The shift from 10 to 30% could lead to foregone taxes amounting to Tanzania shilling TZS 0.09, 0.31, and 0.54 trillion (US$ 33,358,680, US$ 11,490,212, and US$ 20,015,208), indicating a tax loss of about 3, 9, and 15%. Contrary, the government may benefit from these losses by lowering the amount of foreign currency necessary for oil importation. In environmental benefits, the 10, 20, and 30% shift could offset approximately 8,959,198.92119, 8,438,863.65528, and 7,918,528.38937 tCO_2e, equivalent to 5.4, 10.97, and 16.47% of the road emissions. The post-transition road emissions might result in a carbon tax revenue of about US$ 71,673,591.37, 67,510,909.24, and 63,348,227.11 per year. The post-transition carbon credit revenue of about US$ 20,813,410.64, 41,626,821.27, and 62,440,231.91 is expected annually. The findings are critical for policy design and promoting a transition in the road transport sector.

This study assesses the feasibility of implementing a small-hydropower plant on the Ruhuhu River in Mavanga Village, Njombe Region, Tanzania, with a focus on both technical and economic performance. The technical analysis involved hydrological data (rainfall and flow rates) and field data collected via surveys and interviews. Key parameters included estimated hydropower capacity and civil works such as intake and penstock design. The findings indicate a water flow rate of 71.8 m³/s, power output of 98.67 kW, and a generator specific speed of 434.22 rpm, aligning with the use of a Kaplan turbine. The inlet structure showed a mean velocity of 1.162 m/s across a 3.68 m² trash rack flow area with a 4.28 m³/s flow rate. A penstock diameter of 20.8 cm and a wall thickness of 2.4 mm were determined to be appropriate for the design. In terms of economy, the investment cost was found to reach USD 200,000, with the net present value (NPV) of between USD 286,597.21 and USD 498,510.35 at a discount rate of 4 and 12%. The small hydropower plant demonstrates strong financial viability, with an internal rate of return (IRR) of 25.5%, far above typical discount rates, and a payback period of just 2.32 years, indicating rapid capital recovery. A return on investment (ROI) of 330.6% and a profitability index (PI) of 2.49 further confirm its high profitability and investment appeal. The proposed small-hydropower plant demonstrates both technical feasibility and high economic return, making it a viable solution for enhancing rural electrification in Tanzania. Its successful implementation can serve as a replicable model for other off-grid communities seeking sustainable and cost-effective energy access.

Amid rapid population growth in Sub‐Saharan Africa (SSA), electric trains are increasingly seen as vital for decarbonizing passenger transport. However, the true benefits of this modal transition in SSA remain unclear. This study examined the short‐term implications of operational energy use and emissions on shifting from road to rail across different coach configurations (CC1–CC4) and route sections. In terms of energy, the main parameters are operational energy demand and energy savings, whereas in environmental aspects, the focus is on emissions released and emissions saved. The short‐term effects were assessed over 1‐, 5‐, and 10‐year periods. The findings reveal that electric train configurations (CC1–CC4) consume between 2000 and 3000 kWh/day, whereas equivalent 2 × 2 and 2 × 3 diesel buses use 9772–16,450 L/day and 8300–14,109 L/day, equivalent to 87,980–174,370 kWh/day. Corresponding CO ₂ e emissions from SGR trains (223.5–1016.6 kgCO ₂ e/day) are 96%–99% lower than those from diesel buses. The modal shift saved about 1.9–5.1 million liters of diesel avoided per year and 5030–13,286 tonnes CO ₂ e avoided annually, equal to 18–54 GWh/year equivalent in energy savings. Over a decade, cumulative benefits could reach 540 GWh and 132,860 tonnes CO ₂ e avoided. Compared with electric trains, diesel buses emit up to 45 times more CO ₂ e. These results demonstrate the substantial operational energy and environmental advantages of transitioning from road to rail transport.