A Monte Carlo Assessment of Distributed Battery Storage for Rural Grid Reliability in India

Rural electrification in India has achieved remarkable progress in grid connectivity, yet reliable powersupply remains elusive. Frequent outages force rural households to rely on expensive, polluting dieselbackups. This study quantifies the reliability benefitsof distributed battery energy storage systems (BESS)in rural Indian feeders using stochastic simulation.We made a Monte Carlo framework with 2,500 scenarios capturing realistic load variability and outagepatterns based on publicly available Indian energydata. Nine battery configurations (25–75 kWh capacity, 10–30 kW discharge power) are evaluated usingcommon random numbers to ensure a fair comparison. Results show that reliability gains increase withbattery size but exhibit strongly diminishing returns:a 25 kWhbattery provides 62.5±14.3 kWh of backupenergy monthly, while doubling capacity to 50 kWhadds only 5–6 kWh, and 75 kWh adds just 2–3 kWhmore. Marginal gains per kWh decline from ∼2.5to ∼0.95. Diesel displacement is modest (7-11 kWhmonthly) as batteries cover the majority of outageloads. Feeder characteristics significantly influenceoutcomes, with the same 50 kWh battery delivering85.5 kWh gain on a high-load feeder versus 61.3 kWhon a low-load feeder. All metrics are reported with95% confidence intervals, reflecting the variability ofrural grid conditions. These findings provide ampleguidance to planners on cost-effective battery sizingfor rural energy access programs.