Evaluating Emissions Reduction by Replacing Diesel Generators with Solar-Powered Water Systems in Manyara, Tanzania

This study evaluates the environmental, energy, and economic impacts of transitioning from diesel-powered generators to solar-powered water supply systems across 71 rural schemes in the Manyara region, Tanzania. Diesel generators, historically the primary energy source, have contributed significantly to greenhouse gas (GHG) emissions and operational inefficiencies. Using a mixed-methods approach and applying IPCC Tier 1 methodologies, the study quantified GHG emissions from historical diesel consumption and compared them with post-transition performance data from solar systems. Findings reveal that the shift to solar energy eliminated 734,832.81 kg of CO? emissions annually, with an 80.3% reduction (590,563.38 kg CO?) when factoring in residual generator use. Solar systems improved operational efficiency, increasing daily pumping hours from 5–7 under diesel to 10–11 hours, resulting in enhanced water output and elimination of ongoing fuel costs. Economically, although solar installations required higher initial capital investment, the systems demonstrated long-term cost savings through reduced fuel and maintenance expenses. Remaining challenges include a 14% dependence on diesel for backup, technical capacity gaps, and limited monitoring data. Overall, the study reinforces the sustainability of solar-powered water schemes and offers empirical support for scaling renewable energy adoption in line with Tanzania’s climate targets and SDGs 6 and 7.