Abstract: Mobile energy systems including a frame, an axle supported by the frame, a wheel mounted to the axle and in contact with the ground, the wheel being configured rotate about the axle when the frame translates relative to the ground, an energy storage device supported by the frame, and an electricity generator operatively connected to the wheel and electrically connected to the energy storage device, the electricity generator being driven by rotation of the wheel and generating electricity when driven. Mobile energy methods including rotating a wheel by moving it along the ground, producing electricity as the wheel rotates by driving an electricity generator, and storing at least a portion of the electricity produced by the electricity generator in an energy storage device.