I read that article and do not understand what Nissan and EnelSpA are doing.
The EV is "grid tied", and is that done through a storage battery? Is the storage battery charged by the EV? That can't be right. First you charge the EV and then the EV charges the storage battery which feeds it back into the grid? Seems circular.
Quote from the article: "Dubbed “xStorage,” the energy storage unit will be available in October and was developed by Nissan and Eaton Corp., a Cleveland-based company that has also entered the partnership. The system will be priced starting at 4,000 euros ($4,556)."
No kWh value is provided.
That article is confusing. So I searched and found this one that clarifies some things:
Nissan's xStorage is its take on Tesla's Powerwall battery
It explains that xStorage is a product that uses a used Leaf battery (or at least part of one). The battery is stated to be "roughly 4.2kWh" and the cost is about US$4,500 including installation.
That is more costly than the Powerwall, which uses brand new cells, by the way. Also, Nissan is not exactly renowned for its BMS technology, which Tesla appears to excel at.
The EnGadget article also makes clear that Nissans V2G system (vehicle-to-grid) system is a separate thing from their xStorage.