That's why the efficiency of the power plant (if this energy would have been captured) would have been a sight to see on paper. The energy they put into the fracking would have been tiny compared to this.
He did imply it would likely not be possible. He said that if it could be captured, it would be an absolutely mind-boggling ROI in terms of energy in vs energy out.
However, think of the sheer amount of potential energy cause by plate tectonics... we're talking about continents... moving.