Some exemplary embodiments include hybrid vehicle systems including an engine operable to output exhaust, an exhaust aftertreatment system configured to receive the exhaust from the engine, the exhaust aftertreatment system including an SCR catalyst operable to reduce NOx in the exhaust and an electrical heater operable to heat the SCR catalyst, a motor/generator operable in a braking mode to receive torque to slow the vehicle and output electrical power, an energy storage device operable to output electrical power to drive the motor/generator and receive electrical power from the motor/generator, and a controller operable to control the electrical heater to heat the SCR catalyst using electrical power from the motor/generator in the braking mode.