Gee...I would have to estimate it the old fashioned way by recognizing that its escape velocity would have to be about 11 kilometers/sec and the total mass of the spacecraft and the rocket used is listed as 4032 kg, of which the Voyager was 792 kg. From a kinetic energy of 1/2 m V^2, this gives you 0.5 x 4032 x (11,000)^2 = 2.43 x 10^11 Joules of energy.