This paper presents a concept of bistable dielectric elastomer generator (DEG) and investigates its performance via numerical simulations. Whereas resonant DEG designs are largely used to achieve large convertible energy density over specific frequency ranges, bistability represents a potential alternative approach, suitable to scavenge energy over broad low-frequency ranges. In contrast to resonant designs, which demand for large inertia and are thus hard to down-scale, bistability might be an enabling solution for low-frequency harvesting at small scales. In this work, we study a DEG made of silicone. We first develop an electro-mechanical model of the system, based on established approaches and experimentally validated material properties. We then use the model to compare the performance of a monostable resonant implementation of the system and a bistable one, proving that the bistable system can potentially provide significantly higher convertible energy densities in a broad range of excitation conditions.