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Dual Metering Challenge

Dual Metering Challenge

Looking at options for using a new residential solar PV generator and battery system for a new home in western NC where the local utility allows only "dual metering" vs. the common "net metering" grid-tie connection we use here in FL. Has anyone found a workable configuration?

Early planning indicates a major challenge with using the system as a "whole house" backup generator in a dual metering scenario, as the solar/battery system is not connected to the loads in the home....

Patrick | 21 janvier 2019

Already found one option - apparently certain solar inverters support a "Zero Export" capability. Using this approach one can skip the whole "dual metering" strategy and use a standard one-way utility meter for home electrical service.

If I understand this setup correctly, with the right inverter and the right system sizing, the solar panels and PW2 array are sized to provide enough energy to run the max projected home load and charge the PW2s during the day. Once the PW2s are fully charged, the inverter simply throttles back the generation so as not to send anything back to the grid. It's basically an off-grid solution, but it's still grid-tied (in one direction only). At night the home pulls from the PW2s like any other off-grid system.

This way the home still has power if/when the PW2s ever become depleted due to long periods of low solar generation from bad weather or whatever... In the event of an extended grid outage, I guess one would simply start turning off breakers for enough heavier loads to make sure the solar panels and PW2 array can power the home for longer than normal.

Sharing an example it here in case it will help others:

https://www.solaredge.com/sites/default/files/se_feed_in_limitation_flye...

Has anyone ever installed this type of system here in the US?