Reference Plant: Comet Solar Uses Solar-Log Grid Export Control

Installer: Comet Solar

Location: Island Harbour, Anguilla

Nominal Power: 8kW

Inverter Type: SMA SB8000TL-US

Storage System: Sonnen ECO16, 16kW

Monitoring and Control: Solar-Log 1200, Solar-Log 2050, Solar-Log WEB Enerest™ XL

Chris Mason, the owner of Comet Solar, has been installing and servicing solar PV plants in the Caribbean for almost 15 years. Installing solar plants in the Caribbean can come with some unique challenges. The local utility companies do not allow excess energy to be exported to the grid. In fact, the utility meter will actually run in the same direction when you feed-in as it does when you consume grid power. This is called metering in absolute mode. If energy is being fed into the grid, the utility company will charge the plant owner by metering in absolute mode.

“In some cases, solar plant owners could actually end up with a higher electricity bill than what they had before,” explained Chris.

One of Comet Solar’s areas of expertise is retrofitting existing solar plants with storage and control technology. In 2019 Comet Solar installed an 8kW rooftop solar PV plant in Island Harbour, Anguilla. By installing a Sonnen storage system and using Solar-Log’s control technology, the plant owner is able to make use of the solar power produced while limiting the amount of power exported to the grid. They purchase less power from the utility company and avoid feed-in charges.

“The Sonnen system is AC coupled to an SMA SB8000 inverter,” Chris said. “Sonnen is a great battery solution to deal with larger loads because it is AC coupled, but it does not have a zero grid-export solution. This is where Solar-Log® comes in.”

Comet Solar needed to be able to monitor the power being produced and reduce the output of the inverter to prevent any export. Solar-Log® can act as a bridge between the Sonnen battery and the inverter. The Sonnen battery acts as a consumer. Once the battery is fully charged, and no longer “consuming” the Solar-Log® will kick on the power control feature. The Solar-Log® measures consumption and curtails inverter power. When production matches consumption, it means no excess power will be sent back to the grid.