As the Quasar Wikipedia article explains, a quasar is powered by gas falling into a supermassive black hole at the center of a galaxy. The Luminous infrared galaxy article says that, in extreme cases, the radiated energy is larger than the Eddington Limit permits. The article mentions some possible mechanisms.
Recently LIGO observed a merger of two black holes. 3 solar masses was converted to gravitational radiation in a fraction of a second. If some of that gravitational radiation could be converted to other forms of energy, this might be another way to generate more power than you would expect.
But as discussed in Where does gravitational waves' energy go?, this is not likely. Gravitational waves couple very weakly to matter.
But near a quasar, there can be enough hot gas to push the Eddington limit. In this environment, is there any realistic mechanism that would convert gravitational waves to electromagnetic radiation? E.G. Would a gravitational wave compress the gas, making it hotter and radiate more? Magnetic fields can be very strong near a black hole. Can gravitational waves do work against them?
