Factored planning mitigates the state explosion problem by avoiding the construction of the state space of the whole system and instead working with the system's components. Traditionally, finite automata have been used to represent the components, with the overall system being represented as their product. In this article, we change the representation of components to safe Petri nets. This allows one to use cheap structural operations like transition contractions to reduce the size of the Petri net before its state space is generated, which often leads to substantial savings compared with automata. The proposed approach has been implemented and proved efficient on several factored planning benchmarks. This article is an extended version of our ACSD 2013 paper [Jezequel et al. 2013], with the addition of the proofs and the experimental results of Sections 6 and 7.