Appendix A: Powerwall+ and Powerwall 3 Permanent Non-Export

Overview

Where required by utilities, Powerwall+ and Powerwall 3 can be placed in a permanent non-export mode. This means that in the following scenarios, Powerwall+ / Powerwall 3 will curtail solar to prevent power from being exported back to the grid:

The battery is fully charged and more solar is being produced than the system is consuming
Solar is being produced at a higher rate than the battery can charge at, e.g. 7.6 kW of solar on a 5 kW battery

This feature is available beginning with Powerwall software version 22.18. One important note is that, in a Powerwall+ or Powerwall 3 system, Powerwall+ / Powerwall 3 is the only solar inverter capable of curtailing solar as described above. As such, Powerwall+ / Powerwall 3 is referred to as “controlled solar.” Third party solar inverters cannot be controlled by the Powerwall system Site Controller in the same manner and are referred to as “uncontrolled solar.”

This document describes three possible permanent non-export configurations: one with exclusively controlled solar, one with uncontrolled (third party) solar that is allowed to export solar to the grid, and one with uncontrolled (third party) solar that is not allowed to export solar to the grid.

Note

When configured to Permanent Non-Export mode, Powerwall+ / Powerwall 3 additions to existing third party systems comply with UL 3141 - 8.8.5 NEM Integrity Mode. In this configuration, the net export of the combined third party and Powerwall systems will not exceed the real time output of the third party system.

Install Metering for a Permanent Non-Export System

Metering in a permanent non-export system is essentially the same as in any Powerwall system:

Site metering must capture all loads and generation, including non-backup loads
Solar metering must capture all solar generation, including third party solar inverters

In addition to the Powerwall system metering, any third party solar inverter also requires its own Site meter if it is configured for non-export. Third party Site metering should follow the third party inverter’s installation instructions and should not be modified by the Powerwall system.

The following examples illustrate some common metering configurations for a permanent non-export system.

Note

See Additional Metering Configurations for Permanent Non-Export Systems for Powerwall+ system diagrams.

Example 1: Powerwall 3 Permanent Non-Export System with Only Controlled Solar

Figure 1. Powerwall 3 with Backup Switch (or Gateway 3)


Energy to be Metered	Meter	CT(s)	Meter Configuration
Site backup loads	Backup Switch (pictured in example diagram above) or Gateway 3 Meter Z	Backup Switch / Gateway 3 Meter Z	Preconfigured as Meter Z: Site
Powerwall 3 Solar Generation	Powerwall 3 integrated energy meter	N/A	N/A

Figure 2. Powerwall 3 with Backup Gateway 2


Energy to be Metered	Meter	CT(s)	Meter Configuration
Site backup loads	Backup Gateway 2 Meter X	Backup Gateway 2 Meter X	Preconfigured as Meter X: Site
Site non-backup loads	Backup Gateway 2 Meter Y*	Field-installed Tesla 100 A CTs	Field-configured as Meter Y: Site
Powerwall 3 Solar Generation	Powerwall 3 integrated energy meter	N/A	N/A

*If the non-backup loads were greater than 100 A, or if they were greater than 330 ft (100 m) from Backup Gateway 2, a field-installed Tesla Remote Energy Meter and CTs would be required to monitor them.

Example 2: Permanent Non-Export System with Uncontrolled Solar Configured for Non-Export

Figure 3. Powerwall 3 with Gateway 3 (or Backup Switch)


Energy to be Metered	Meter	CT(s)	Meter Configuration
Site loads (backup and non-backup	Field-installed Tesla Remote Energy Meter	Field-installed 200 A Tesla Remote Energy Meter CTs	Meter paired with Powerwall 3 and CT field-configured as Tesla Remote Meter: Site Note In this example, the Gateway 3 Meter Z CTs must be configured as NONE.
Powerwall 3 Solar Generation	Powerwall 3 integrated energy meter	N/A	N/A
Third party Solar generation	Field-installed Tesla Remote Energy Meter	Field-installed 200 A Tesla Remote Energy Meter CTs	Meter paired with Powerwall 3 and CT field-configured as Tesla Remote Meter: SolarCTx2
Third party Site loads	Third party Site meter	Third party Site CTs	Configured by inverter installer to measure Site

Note

In this configuration, a system operating in Permanent Non-Export mode meets the requirements of UL 3141 - 8.8.5 NEM Integrity Mode, such that the net export of the combined third party and Powerwall systems will not exceed the real time output of the third party system.

Figure 4. Powerwall 3 with Backup Gateway 2


Energy to be Metered	Meter	CT(s)	Meter Configuration
Site backup loads	Backup Gateway 2 Meter X	Backup Gateway 2 Meter X	Preconfigured as Meter X: Site
Site non-backup loads	Backup Gateway 2 Meter Y*	Field-installed Tesla 100 A CTs	Field-configured as Meter Y: Site
Powerwall 3 Solar Generation	Powerwall 3 integrated energy meter	N/A	N/A
Third party Solar generation	Backup Gateway 2 Meter Y*	Field-installed Tesla 100 A CT	Field-configured as Meter Y: SolarCTx2
Third party Site loads	Third party Site meter	Third party Site CTs	Configured by inverter installer to measure Site

*If the non-backup loads and/or third party solar were greater than 100 A, or if they were greater than 330 ft (100 m) from Backup Gateway 2, a field-installed Tesla Remote Energy Meter and CTs would be required to monitor them.

Example 3: Permanent Non-Export System with Uncontrolled Solar NOT Configured for Non-Export

Figure 5. Powerwall 3 with Gateway 3 (or Backup Switch)


Energy to be Metered	Meter	CT(s)	Meter Configuration
Site loads (backup and non-backup	Field-installed Tesla Remote Energy Meter	Field-installed 200 A Tesla Remote Energy Meter CTs	Meter paired with Powerwall 3 and CT field-configured as Tesla Remote Meter: Site Note In this example, the Gateway 3 Meter Z CTs must be configured as NONE.
Powerwall 3 Solar Generation	Powerwall 3 integrated energy meter	N/A	N/A
Third party Solar generation	Field-installed Tesla Remote Energy Meter	Field-installed 200 A Tesla Remote Energy Meter CTs	Meter paired with Powerwall 3 and CT field-configured as Tesla Remote Meter: SolarCTx2

Figure 6. Powerwall 3 with Backup Gateway 2


Energy to be Metered	Meter	CT(s)	Meter Configuration
Site backup loads	Backup Gateway 2 Meter X	Backup Gateway 2 Meter X	Preconfigured as Meter X: Site
Site non-backup loads	Backup Gateway 2 Meter Y*	Field-installed Tesla 100 A CTs	Field-configured as Meter Y: Site
Powerwall 3 Solar Generation	Powerwall 3 integrated energy meter	N/A	N/A
Third party Solar generation	Backup Gateway 2 Meter Y*	Field-installed Tesla 100 A CT	Field-configured as Meter Y: SolarCTx2

Configure a System for Permanent Non-Export Mode

In the Tesla One Device Setup App, go to Settings > Import & Export Limits.
Set Export Permissions to Permanent Non Export.
If the system has standalone solar, uncontrolled by the Powerwall system, determine whether the solar inverter is allowed to export and if that solar inverter is configured with its own controls to prevent export.
1. If it is allowed to export solar, set Solar Export Limitation to No.
2. If it is not allowed to export solar, and is configured with its own non-export controls, set Solar Export Limitation to Yes.
  Note
  This provides the Powerwall system with the knowledge that it needs to regulate a small amount of import power to prevent the standalone non-export solar inverter from curtailing. This ensures the best overall system performance for these systems that have two devices both responding to site power measurements.
Take screenshots of this page and the system Summary page after completing commissioning. These will be required as part of the interconnection submission.