Techno-economic Optimization of PV-battery-diesel Systems for Reducing Diesel Use at Eleven Off-grid Telecom Sites in Niger

Remote off-grid telecommunication sites in Niger depend heavily on diesel generation, leading to high fuel use, operating costs, and direct emissions. This study evaluates site-specific photovoltaic (PV)-battery-diesel retrofit configurations for eleven operational sites using measured baseline data, analytical component sizing, and hourly hybrid optimization of multiple energy resources (HOMER) Pro simulations over one year. Technical performance, generator dispatch, diesel use, lifecycle economics, sensitivity to diesel price and total capital expenditure (CAPEX), and avoided direct CO 2 emissions are assessed jointly. Rather than representing the network with one typical site, the analysis retains the measured differences in electrical demand, solar resource, storage requirement, generator operation, and investment cost across all eleven sites. Across the portfolio, annual diesel consumption decreases from 161,749.75 to 34,757 L, a 78.5% reduction, while cumulative generator runtime falls by 82.4%. Aggregate annual operating expenditure (OPEX) decreases from approximately USD 302,159 to USD 88,259, yielding savings of about USD 213,899/year. Site-level payback periods range from 1.83 to 8.12 years; all configurations have positive net present value (NPV), and their internal rates of return (IRR) range from 10.7% to 54.8%, exceeding the 8% discount rate. Positive aggregate NPV is retained under ±20% variations in diesel price and total CAPEX. Avoided diesel use corresponds to approximately 340.3 tCO 2 /year. Overall, the results show that site-specific hybridization can substantially reduce diesel dependence while retaining generator backup and favorable investment performance.