The house had an ideal south facing roof that fit a 25 panel 8 kW solar array beautifully. By using REC N-Peak solar panels that feature 'Twin cell' cell technology in combination with a SolarEdge inverter with DC Power Optimizers on the back of each panel, we were able to maximize production from the system under variable shading conditions from the trees in the backyard.
From the roof, the power flows through the SolarEdge inverter to a new electrical service panel called a 'critical loads sub-panel' where the Powerwall, EV charging, lighting, refrigeration, and other 'critical loads' are supported independently from the rest of the house and the grid in the event of a power outage. As part of the original design, OnSite future proofed the system to enable the addition of a second Powerwall if the owners decide they want to increase the amount of backup power.
Under normal operation, power from the solar system flows first to any loads within the home, then to charge the battery. Any excess production once the battery is full takes advantage of net-metering by flowing onto the grid. In the event of a power outage, the Powerwall communications device (called the Backup Gateway) isolates the critical loads sub-panel, solar and Powerwall from the grid; this enables them to operate independently, and the home to function as its own microgrid!