Engineers at Shep Technologies Inc., in the U.K. (, have devised the Shep system (stored hydraulic energy propulsion) to do the same for conventional internal-combustion-powered vehicles. The system also provides the stored energy when it is needed most, when the vehicle accelerates from a dead stop (when the engine is at its least efficient and emitting the most pollutants).

The Shep system has three major components: a pump, tank, and controller. The Ifield motor-pump attaches to the driveshaft. The pump "grabs" the spinning driveshaft to slow the vehicle during braking. According to Ford Motor Co., this alone should boost brake life by 77%. The pump transfers the energy to a unitized accumulator, a hydraulic tank that stores pressurized fluid. Energy is sent back to the pump, helping it turn the driveshaft when the vehicle accelerates from a dead stop. An electronic controller uses software to determine when to run the pump and in which direction. In a test vehicle, a 2001 Lincoln Navigator, Shep improved fuel economy by 38% going from 13 to 18 mpg, added 85 hp to its dead-stop acceleration, taking it from 275 to 360 hp, and cut dirty emissions by 50%. The company is tight-lipped on when consumers might see it in the showrooms.