The system includes a reversible meter, so when the panels exceed our electricity use, the excess goes into the Portland General Electric (PGE) grid. While the excess rolls over from month to month, it does not roll over years. So we will likely build up excess production over the summer that will be offset in the winter. We will see for sure when our PGE bills start rolling in.
Our 24 solar panels generate up to 7.68 kW of DC power and 5.76 kW when converted to AC power. The system includes an app that allows us to track the energy generated by the system. It has some nice reporting features that allow us to compare different days. The app does not track how much energy goes into the grid, although we can read that off our reversible meter. The app also allows us to have a public Web page so anyone can look at the data for our system. While the app has more data to show, the public Web page does allow viewing of daily electricity generation:
As the solar electricity is purportedly cheaper than that delivered by PGE, the system is estimated save about $34,000 over its lifetime. It doesn’t hurt that we will get a 26% federal tax credit this year and additional incentives from the state of Oregon. All in all, we believe it is a sound investment not only in our house, but also in the global energy future.
Our energy usage will also be reduced by the 6.5-inch R35 insulation under the new roof. This will be beneficial both with our electronic air conditioning in the summer and our gas heating in the winter.