Live in San Francisco or Oakland? Before shopping for solar, call PG&E and ask if you are in a “secondary network”. If your home or business is in one of these networks, solar interconnection and net metering are not possible.
Secondary Networks Explained
Most of PG&E’s territory use radial networks, where there is one path for electricity to flow from to the customer’s home or business. Any damage to the line along the way will cause power loss. In contrast, secondary networks have parallel lines, improving reliability.
PG&E uses devices called “network protectors” to prevent electricity from back-feeding from one transformer to another. These devices will break the circuit if any back-feeding is detected.
PG&E offers a non-export interconnection option. This requires specialized inverters and equipment, and are manufactured by top solar inverter brands such as Enphase. Any solar electricity generated must be used immediatly. If not enough electricity is used, the inverters must “tone down” their production. Battery storage can be combined with these installations to offset electricity used during minimal or no sunlight.