One of the currently technically feasible battery storage systems for large scale (but intermittent) sources of power from renewables such as wind, solar and wave is flow batteries.
These batteries can be scaled up to pretty large storage sizes such as tens of megawatt hours and so are definitely a technical solution to storage of intermittent power.
There are currently a few places in the world where there are ongoing trials, such as a wind farm in Ireland, a couple of places in Japan and some south Pacific islands.
The issue with these batteries is, however, that they are often complicated and made of rare materials such as Vanadium. Also required is a membrane to separate the two liquids between which electrons flow. This membrane has to be replaced every so often, adding to the expense.
A team at Stanford, however, has solved a couple of these problems at least in the lab by the creation of a flow battery without a membrane and also using the relatively inexpensive and abundant materials lithium and sulfur.
A utility scale system would be capable of being scaled up to handle many megawatt hours.