On the first day of the year, the battery (yes, only 1) is discharged to a SOC of 30%.  The battery is not recharged nor is it used again.  I am wondering what HOMER is thinking when it uses a battery only once.  this case is only $0.001 more expensive than the case without the battery, so I would not use a battery.  But, why use the battery only once?  and on the first day of the year?

HOMER assumes that the battery starts the year at 100% state of charge. When fully charged, it can cover the load for the first day, but after discharging to meet that first load it does not have sufficient energy to cover another day of load.  So it needs to be recharged in order to be used again. But the opportunity to charge the battery never occurs, since the load is either 0 kW, in which case HOMER does not want to start the generator just to charge the battery, or 13.2 kW, in which case the fuel cell is maxxed out meeting the load, with no spare capacity with which to charge the battery. If the load was ever greater than zero but less than the fuel cell capacity, HOMER would use the spare capacity to charge the battery.