We had a hydraulic accumulator in the machinery for making MDF at work, and it scared the crap out of me. Priming it involved filling the reservoir with roughl

We had a hydraulic accumulator in the machinery for making MDF at work, and it scared the crap out of me. Priming it involved filling the reservoir with roughly 10 standard high pressure nitrogen bottles, and then compressing that further. The basic idea is that it is an air spring that you use to store energy. I am ok with sitting in the stands while cars fly through the air, but I am not comfortable knowing that these three guys are going to make a big breakthrough storing that much energy, in a very unstable form and then put it near paying customers. I have no problem believing that the first stage of the project can work, but this is the sort of thing that won't scale that well.