I have a 10 KW, grid tied battery backed up system in an all electric house. Everything except my deep well pump, washer/dryer, hot water, range and geothermal compressor are connected on the critical loads panel. Generally over the last 5 years or so, the system produces more power than used with the rest going to charging the batteries and powering the grid. However, there has only been a few times over the last several years that system has produced more than consumed from the grid. I estimate that I would need 30-50 kw to power everything. However, the geothermal compressor draws perhaps 5 kw for 4-5 minutes at a time and cycles several times an hour. Since the geothermal system works mostly at night or if we went off grid, the storage capacity of the battery backup would have to be increased substantially from the 16 KWH that we have now since the compressor would deplete the batteries in a few hours. None the less our electric bill is down at least 80% from pre-PV days.