Al-Qadisiyah Journal for Engineering Sciences

Techno-environmental comparison of residential rooftop PV systems with vs. without battery storage under the Middle Eastern climate: An Iraqi case study

Articles in Press

Document Type : Research Paper

Authors

Muqtada A Obaid 1
Alaa Liaq Hashem 2
Ahmed A. Majhool 1
Ahmed Al-ameri

1 Department of Mechanical Engineering, College of Engineering, University of Al-Qadisiyah, Room 16, Al Diwaniyah, Iraq.

2 Department of Mechanical Engineering, College of Engineering, University of Al-Qadisiyah, Room 16, Al Diwaniyah, Iraq

https://doi.org/10.30772/qjes.2026.170153.1933
Abstract
This paper presents a technical and environmental assessment of a 3 kWp grid-connected residential rooftop PV system in Al-Diwaniyah, Iraq, using PVsyst 8.0.19. Four scenarios were analysed: monofacial and bifacial PV panels with and without a 5 kWh LiFePO4 battery, plus an expansion sensitivity case using a 10 kWh battery. The battery-free system generated 6,444.8 kWh/year, with a performance ratio (PR) of 80.72%, specific yield of 1,790 kWh/kWp/year, solar fraction of 64.37%, and grid imports of 1,262.2 kWh/year. Adding a 5 kWh battery slightly reduced PR to 77.86% due to charge/discharge losses but increased the solar fraction to 93.00% and reduced grid imports by 80.4% to 247.98 kWh/year. Bifacial panels improved annual production by about 90 kWh/year (+1.4%) and increased PR by 1.13 percentage points in both storage and non-storage cases. Expanding storage to 10 kWh raised the solar fraction only from 93.0% to 96.7%, showing diminishing returns and doubling the cost. Environmentally, the system avoids about 118.4 tCO₂ over 25 years, equivalent to 5,381 trees or removing 25.7 cars annually, with an avoided carbon cost of USD 5,920. The 5 kWh monofacial battery system is the optimal configuration for residential energy independence in the Iraqi context.

Keywords

Rooftop PV
performance ratio. Battery storage
CO₂ mitigation
PVsyst
Iraq
Crossmark
Subjects
Al-Qadisiyah Journal for Engineering Sciences

Articles in Press, Accepted Manuscript
Available Online from 04 May 2026

  • Receive Date 16 March 2026
  • Revise Date 25 April 2026
  • Accept Date 04 May 2026

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