| Equipment | Two sets of inverters (battery and solar), two transformers, two MV systems. | One inverter (solar/hybrid), a DC-DC converter, one MV system, one transformer. | One inverter (battery, grid-forming), a DC-DC converter, one MV system, one transformer. |
| Round-trip efficiency (solar charge) | Two AC conversions on the battery's solar-charging path. | 1 to 2% efficiency gain over AC; one DC-DC conversion replaces the two AC conversions. | 1 to 2% efficiency gain over AC; one DC-DC conversion replaces the two AC conversions. However, exported solar undergoes an extra DC voltage conversion, on top of the inverter. |
| Grid forming | Qualifies, with a grid-forming battery inverter. Provides system strength and fast FCAS. | Solar inverter is grid following. Pays system strength charges and misses out on FCAS. | Qualifies, with a grid-forming battery inverter. Provides system strength and fast FCAS. |
| Battery charging from grid | Yes | Not with a solar inverter. Possible with a hybrid inverter, but with losses from the inverter and DC-DC converter. | Yes |
| Land use, layout and fire setbacks | Battery in one compound near the substation, and the solar array sits separate. One set of fire-separation distances for each area. | Battery containers are distributed throughout the solar array beside inverter stations to prevent low-voltage line losses (which are high on DC side). Fire separation repeats at every container. Generally greater land use. |
| Retrofit compatibility | High. The battery adds on the AC side without touching the solar inverters or array. | Low. The PV array is unlikely to support a distributed battery layout, and older inverter models are unlikely to meet battery requirements, requiring expensive replacement. | Low. The PV array is unlikely to support a distributed battery layout; the inverters would need replacing and the solar rewired to DC-DC converters. |