In his models, you over-provision PV and wind (doable because it is so cheap, and getting cheaper) so it can cover peak loads. Then during the 90+ percent of non-peak time there is super-cheap excess power available which he dubs “super power”.
Using pricing signals, this can be used to enable activities which would normally be cost-prohibitive under current models. When power is cheap, crank up the desalinators, electric steel and aluminum mills, pumped storage, hydrogen converters, bitcoin miners, and anything else smart people can devise to do with inexhaustible, inexpensive clean power on a somewhat intermittent basis.
His model also shows that you can choose trade offs between how much battery you invest in and how much generation you build, allowing you to optimize costs depending on how much or little of this “super power” you want to generate. More batteries = less generation and less excess power, and vice versa.
I think many find this unintuitive because they formed their opinions of renewable energy during the early, high cost parts of its ramp and have not adjusted their thinking to the current part of the S-curve.
But renewable energy is already the least expensive source of electricity in most markets. It is our amazing good fortune that it is also environmentally fairly benign, extremely safe, has very low maintenance costs, can be geographically distributed to reduce grid distribution costs, and is able to scale with few limits aside from simple land availability. And its Wright’s law cost declines appear unconstrained for the foreseeable future.