Evaluation of a Grid-Connected Residential Hybrid PV-BESS Under Iran’s Regulatory Framework (Tavanir & SATBA): Load Supply During Power Outages and Techno-Economic Performance

Abstract

Frequent grid load shedding during summer months in Iran has increased the demand for continuous electricity supply in households. This study presents a techno-economic evaluation of a residential hybrid Photovoltaic-Battery Energy Storage System (PV-BESS) operating under the Tavanir and SATBA regulatory frameworks. A case study was conducted on a typical single-phase subscriber utilizing a 3 kW PV array integrated with a 6 kW all-in-one hybrid system equipped with a 5 kWh battery. The economic assessment, based on the Net Present Value (NPV) method, calculates revenue from surplus energy sold to the grid, thereby excluding the energy self-consumed during outages. Results show payback periods of 10.18 and 12.58 years at discount rates of 25% and 30%, respectively. While these periods may appear lengthy, the load supply evaluation demonstrates that the system covers the average household consumption during 3-hour outages year-round, and even meets the entire average daily consumption in most months. Furthermore, in a worst-case scenario operating at maximum contracted demand, the PV-BESS can sustain power for up to 2 hours. Ultimately, SATBA’s guaranteed power purchase program acts as a supportive financial mechanism, allowing users to gradually recover their capital investment while securing uninterrupted power availability.