The SDI is...
An essential equipment in kWh cost reduction.
It plays two roles:
While the SEB can deliver power supply for up to 2 kW appliances, users might decide to use a less costy and redundant DC/AC inverter, instead of a single SEB version with 4kW capability;
The SDI can be purchased by neighbors of a G-ESS Node owner, so as to get access to excess energy from the Node. The equipment is installed at neighbor's home and is connected to the SEB battery by a <100 meters three-wires cable.
In summary, the SDI allows a given number of neighbors to subscribe to a Node at relatively reduced cost, while keeping the capability to fine tune their electric energy purchases to their needs.