Off-peak time for California is probably also off-peak time for anywhere else that can buy electricity from California. If they don't have the option of storage

Off-peak time for California is probably also off-peak time for anywhere else that can buy electricity from California. If they don't have the option of storage, they do try sell excess capacity, to the extent that other markets are willing to pay for it. They say this in TFA: "The first tool currently available is to find electricity generators to submit bids to reduce their output, Greenlee said. If that doesn't work, then there's an effort to export the electricity elsewhere — often at negative prices, which means power generators pay someone to take their electricity." The article is kind of mis-representing the purpose of the system: it wasn't built to store energy from renewables, but rather, to even out demand spikes on the grid. Losing a system like this just means that they've lost a tool for managing fluctuations on a short-term basis. They have to resort to selling excess power at low-demand times (possibly at a loss), or disconnecting generators in order to keep the grid stable. They'll do whatever is most cost-efficient, but both options are probably inferior to the storage system. A big ol' capacitor like this gives the grid manager an extra margin of safety before having to do something drastic to keep things stable.