Impaler is right; there is no point and much difficulty and risk in trying to drive a grid directly. The capacitors and whatever inverter is required will be standard.
Also, Tesla Motors is building a GigaFactory to crank out LiIon batteries for its cars, equal in size to the entire world’s current production, and 30% will be dedicated to “static storage”, or UPS buffers for home, commercial, or utility applications. Power can be “saved up” at low demand periods and used in peak demand to smooth out the load. https://www.youtube.com/watch?v=zWSox7mLbyE
