Solar photovoltaic hybrid energy modelling with fixed and TOU tariffs for decarbonization in unreliable grids

Abstract

Tackling decarbonization in regions with unreliable grids and no net-metering is hindered by tariff structures that discourage renewable integration. This study introduces a novel Outage-aware simulation framework analyzing Solar PV-Battery-Diesel hybrid system for commercial facilities under fixed and dynamic Time-of-Use (TOU) tariffs with a stringent CO₂ emissions cap, attaching different Grid supply schedules under each fixed tariff represented in Bands reflecting lower price for less reliable service common in outage prone regions, addressing a critical gap in prior studies assuming constant grid access and no emission limit. Through techno-economic optimization using HOMER Grid with real commercial load data (133,360 kWh/yr), we demonstrate that TOU pricing is decisively superior. It achieves the lowest Net Present Cost of $375,557, Levelized Cost of Energy of $0.218/kWh, and a 61% reduction in emissions, primarily by enabling intelligent load shifting to off-peak periods. Sensitivity analysis across Diverse climates/GHI (Niamey, La Paz, Kathmandu, & Kampala) confirms TOU’s consistent outperformance over fixed tariffs, with NPC reductions of 2.6–3.4% and LCOE reductions of 2.7–4.7%, showing that the economic and environmental superiority of TOU pricing is robust and consistent, regardless of solar irradiance variations or local climate. This finding underscores that policy-driven tariff reform is a more decisive lever for decarbonization when meeting blackout survivability and saving cost than location-specific solar potential. Excess generation supports applications like electric vehicle charging, offering a replicable, globally relevant framework for achieving resilient, low-cost, and low-carbon Solar PV Hybrid systems in outage-prone regions worldwide, offering vital insights for policymakers and planners.