Transformation of Generated Electricity by Renewable Energies to Grid
Alan Saeed; Kamil Yousif; Maiwan Abdulrazzaq
Abstract
The Gali Zakho Tunnel in Dohuk, Iraq consumes 12,704.44 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 ...
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The Gali Zakho Tunnel in Dohuk, Iraq consumes 12,704.44 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 $0.129/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, 5,558 kW PV) is the economic winner: NPC $3.28M, COE $0.0187/kWh, 68.5% 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, 5,768 kW PV) is the environmental winner: NPC $5.27M, COE $0.0380/kWh, 84.1% renewable fraction, 78.6% CO2 reduction versus grid-only. A two-layer battery framework separates daily economic cycling (10.4 hours) from a locked emergency reserve of 2,954 kWh (~5.6 hours). Combined, the system sustains uninterrupted tunnel operation for approximately 16 hours without any external input. Comprehensive sensitivity analyses on discount rate (0.95%–10% real), battery cost ($175–$300/kWh), and land/civil works ($0–$250k) 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.