Hi Zaman,
You could use the combine cases macro to combine the generation profile of a marine energy system and a standalone battery that charges and discharges from the grid, but it is not possible in the current version of SAM to model a battery that charges from a marine energy system.
UPDATE: As of SAM 2021.12.02, the Combine Cases macro is replaced by the Calculate generation profiles and nameplate capacity from open cases option on the Power Plant page for the Generic System model and Generic Battery model. See the SAM YouTube channel for a
short tutorial
.
Best regards,
Paul.