In accordance with presently disclosed embodiments, a hybrid drive system that uses multiple sources of mechanical energy to drive a pump is provided. The hybrid drive system may include a first mover for generating first mechanical energy, a pump, a drivetrain for providing first mechanical energy from the first mover to the pump, and a second mover within the drivetrain to generate and provide second mechanical energy to the pump. The multiple sources of mechanical energy may provide flexibility with respect to system design and allow for alternative sources of fuel and energy to be used to drive pumping systems. This may reduce the total diesel fuel consumption necessary to perform a well stimulation operation as well as provide for configurations in which diesel engines may be excluded from the pumping process in favor of alternative energy sources that typically do not have sufficient torque capacity to power a pump.