EPJ Photovoltaics 16, 3 (2025)
https://doi.org/10.1051/epjpv/2024044

Original Article

Reversing LeTID in PV power plants: a feasibility study

¹ Fraunhofer Institute for Solar Energy Systems ISE, Heidenhofstr. 2, 79110 Freiburg, Germany
² Institute of Semiconductors and Microsystems, Technische Universität Dresden, 01062 Dresden, Germany
³ Institute for Renewable Energy Technologies (in.RET), University of Applied Sciences Nordhausen, Weinberghof 4, 99734 Nordhausen, Germany

* e-mail: esther.fokuhl@ise.fraunhofer.de

Received: 28 June 2024
Accepted: 28 November 2024
Published online: 8 January 2025

Abstract

Light and elevated Temperature Induced Degradation (LeTID) is likely causing strong yield losses in a significant number of photovoltaic (PV) power plants which were commissioned in the late 2010s. In this work, a procedure for an in-field recovery using overnight current injection to trigger temporary recovery of LeTID is presented. The general feasibility of such a procedure is first demonstrated by climatic chamber experiments on strongly degraded mc-Si PERC PV modules. Within the screened test conditions, a temporary recovery procedure with high currents and low module temperatures is most promising for an economic application in PV power plants. An outdoor experiment with current injection during nights and MPP tracking during days confirmed the possibility to recover LeTID in PV power plants. By injecting a pulsed current, the heating of the modules caused by the current injection was strongly reduced compared to the heating at constant current injection. Recommendations for the application of a procedure in PV power plants are given based on the required energy expenditure and cost.