Lifetime Assessment of PV Inverters Using Marco-Starkey Theory and Nonlinear Damage Accumulation

Ribeiro, Andrei Carvalho, Jimenez, Jorge Sebastian Morocho, Santos Filho, José Cândido Silveira, Santos Neto, Pedro José dos, Silveira, João Pedro Carvalho, Barros, Tárcio André dos Santos

ISES Solar World Congress 2025 · Fortaleza, Brazil · 2025-11-03
Published by International Solar Energy Society (ISES)
DOI: 10.18086/swc.2025.03.39

Abstract

The lifespan of a photovoltaic system is typically estimated at 25 years, with photovoltaic panel manufacturers guaranteeing at least 80% of the initial power output over this period. However, system performance can be compromised by failures and irregular operation of other components, such as inverters, which require frequent maintenance and remain prone to malfunctions. As the large-scale photovoltaic systems expand, accurate lifetime assessment of inverters becomes crucial to ensuring availability, optimizing maintenance schedules, and maintaining a competitive Levelized Cost of Energy. This study contributes to reliability analysis by incorporating Marco-Starkey Theory into the damage accumulation rule. We analyze the impact of the variation in the damage accumulation exponent on lifespan in three Brazilian cities. The proposed approach could enable calibration of the damage-accumulation exponent using historical failure data; however, this paper focuses on a sensitivity analysis and does not demonstrate such calibration with field failure records. We show that a seemingly small change of +10% in the exponent may increase the expected lifetime by approximately 300%, whereas a −10% variation can reduce it by about 75%, highlighting the sensitivity of lifetime predictions to this parameter.

Keywords

reliability, lifetime assessment, photovoltaic inverters, Marco-Starkey theory, damage accumulation

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