An increase in the use of alternative power sources results from the transition to a green economy and the reduction of greenhouse gas emissions. Their deployment contributes to increasing energy self-sufficiency and independence from other countries. Despite the highly positive effects associated with the operation of alternative power sources, it is necessary to pay appropriate attention to providing their operational safety. Using the Failure Mode and Effects Analysis method (FMEA), this paper assesses the causes and effects as well as estimates the Risk Priority Number of photovoltaic system failures possibly resulting in fire. The paper assesses the causes of fire in the manufacturing, transportation, installation and operation phases. The Failure Mode and Effects Analysis method allowed for estimating the Risk Priority Number, with the highest being estimated for six causes, including inverter failures, malfunctioning lightning protection and fuse box failures. In total, 20 different causes were assessed, of which more than 50% can be considered acceptable. [ABSTRACT FROM AUTHOR]