I don't doubt that the Diablo Canyon upgrade is expensive, and various interests have been set on killing that plant for decades, but there is no way on earth y

I don't doubt that the Diablo Canyon upgrade is expensive, and various interests have been set on killing that plant for decades, but there is no way on earth you're getting 40 GWh of storage in central California at any price within a decade. The total pumped and gas storage capacity of the United States is only like 25 GWh. Building that would require a majority of the total battery production of the entire planet for a year, and most of that wouldn't even be the right kind of batteries regardless of what technology they settled on. Some sort of dream moonshot project to build that would be awesome, but is completely outside the scope of any modern commercial endeavor.