Techno-economic and environmental assessment of photovoltaic–battery microgrids across diverse U.S. states

The global shift toward cleaner energy is continuously increasing the demand for PV-Battery as these technologies not only cut emissions but also strengthen resilience and provide attractive financial prospects. In this study we present a techno-economic and environmental assessment of PV–battery microgrids across seven U.S. states. In this finance and hardware assumptions are standardized so that differences arise directly from solar resource, tariff structures, and operating patterns. California was the most favorable case with an NPV approaching $7.7M, ROI 93%, with payback period of about 5 years. While, Arizona produces the greatest energy yield and the lowest LCOE around $0.069/kWh, yet limited electricity prices limits its ROI 36%. Maine shows that strong tariffs can compensate for weak solar yield, achieving ROI 49% with the lowest energy output. The comparison reveals number of outcomes. States as California, Arizona, and Maine deliver NPVs in the range of $4M-$8M and ROIs between 36 and 93%, while marginal states Florida and Kansas barely touched feasibility with ROIs barely reaching 7%–12%. Montana proves the weakest economically with NPV only $0.33M and ROI below 4%, though it provides the most substantial environmental benefit with avoided emissions exceeding 56,000 tonnes of CO 2 owing to its carbon-heavy grid. Performance indicators across all states span considerable ranges, with LCOE values between $0.069-$0.101/kWh, first-year savings from $0.33M up to $1.22M, and load offsets from 47%–65%. A ± 20 % tariff sensitivity preserves the ranking of states but shifts the threshold of viability, often pushing lower-tier states into negative NPVs. • This work presents a consistent techno-economic assessment of photovoltaic(PV) paired with Battery Energy Storage System(BESS) across seven U.S. states, with finance and hardware held fixed so outcomes trace to solar yield, tariffs, and operating patterns. California exhibits the strongest case, Net Present Value(NPV) about $7.69M, ROI near 93%, payback around 5.0 years, (Levelized Cost of Energy)LCOE near $0.077/kWh, first year savings close to $1.22M, and a 60% load offset. • Arizona delivers the highest energy yield near 1981 kWh/kW and the lowest LCOE near $0.069/kWh, yet a modest tariff near $0.128/kWh keeps Return on Investment(ROI) near 36% and payback around 8.2 years. Maine shows the power of prices, though its yield is the lowest near 1336 kWh/kW, ROI is about 48.83% with LCOE near $0.101/kWh and NPV near $4.02M. • New York holds a balanced profile, NPV near $3.78M and SPB around 7.3 years, while Florida and Kansas sit at the edge of viability with ROIs near 11.86% and 7.15%, and discounted payback often beyond project life. Montana performs the weakest economically, NPV near $0.33M and ROI near 3.98%, despite the most significant lifetime CO2 reduction near 56,916 tCO2e, consistent with a carbon-intensive grid near 1056 lb/MWh. Across states, LCOE spans roughly $0.069 to $0.101/kWh, first-year savings range from about $0.33M to $1.22M, and load offset lies between 47% and 65%. • A ±20% tariff shift preserves ranking yet moves feasibility, pushing NPV negative for Florida, Kansas, and Montana at the low case near $-0.21, $-0.52, and $-0.73M, and compressing or stretching payback by up to three years, confirming tariff design dominates investment viability more than yield alone. • Moreover, robustness and stress testing beyond point estimates, including tariff rate of plus or minus 20%, sizing variations for the highest and lowest NPV states,and P10, P50, P90 uncertainty bands for PV energy and avoided CO2e, clarifying which states remain bankable under plausible shifts and which ones sit close to feasibility thresholds.