There are many alternatives to batteries, for longer term storage. Tanked anhydrous liquified ammonia may be common, particularly for smaller and more isolated utility districts, in part because tankage can be topped up from imports if it runs low.
Underground or sea-floor compressed air are practical, as is buoyancy, in many places. Many more places can use pumped hydro than have an existing dam, or watershed; either up a hill or down to an underground cavity.
The method used will be whatever is cheapest in the place and time constructed. Cost for most methods is falling fast.
Building a nuke is by far the most expensive baseline alternative, provided it can even be approved and built on a useful schedule.
