A Practical Reliability Framework for Grid-Connected Hybrid Renewable Energy in Northern Iraq

The Gali Zakho Tunnel in Dohuk, Iraq consumes ۱۲,۷۰۴.۴۴ kWh every day. Lighting, ventilation, safety monitoring, and control systems operate continuously. Power failure is a life-safety event. This study designs and optimizes a grid-connected hybrid renewable energy system (HRES) for the tunnel using HOMER Pro, operating strictly within the Kurdistan Region of Iraq's current grid policy: a purchase tariff of ۰.۱۲۹/kWh, zero export credit for surplus generation, and monthly net metering with no carryover. Five configurations were evaluated against a hard zero annual capacity shortage constraint. Two met it. Case-B (PV–Generator–Grid, ۵,۵۵۸ kW PV) is the economic winner: NPC ۳.۲۸M, COE ۰.۰۱۸۷/kWh, ۶۸.۵% renewable fraction. The standby diesel generator burns zero fuel under normal conditions and activates only if both the grid and PV fail simultaneously. Case-C (PV–Battery–Grid, ۵,۷۶۸ kW PV) is the environmental winner: NPC ۵.۲۷M, COE ۰.۰۳۸۰/kWh, ۸۴.۱% renewable fraction, ۷۸.۶% CO۲ reduction versus grid-only. A two-layer battery framework separates daily economic cycling (۱۰.۴ hours) from a locked emergency reserve of ۲,۹۵۴ kWh (~۵.۶ hours). Combined, the system sustains uninterrupted tunnel operation for approximately ۱۶ hours without any external input. Comprehensive sensitivity analyses on discount rate (۰.۹۵%–۱۰% real), battery cost (۱۷۵–۳۰۰/kWh), and land/civil works (۰–۲۵۰k) confirm that both configurations remain economically viable across all tested scenarios. Both configurations are fully reliable and buildable today under regulations as they currently stand, without waiting for policy reform.

کلیدواژه ها:

HOMER Pro ، Constrained grid export ، Two-layer battery reliability ، Critical infrastructure ، Tunnel electrification