It's been fun and interesting to watch how the system performs through the winter weather and the impact of the winter inclination of the Sun. Although I was expecting it, I guess I have been little surprised at how low the sun drops on the horizon this time of year in relation to our roof and my neighbor's roof... which throws a shadow on ours. The power generation on a cool clear sunny January morning will start in the 1400 watts range, then drop during the day to 200-400 watts as the shadow moves across the roof during the day. Then it pops up again in the afternoon until sundown. Below, this shot was taken at about 10:00 AM on January 31st and you can see the shadow start to creep onto the panels.
Also as interesting has been to observer when energy is generated on overcast and even rainy days. On your average gray, overcast and drizzly Portland day, I see a couple hundred watts being generated at times.
I have been tracking all the solar generation and overall consumption number for the household and put them into the graph below. You can see the obvious increase in overall consumption (+ XMAS lights...) and decrease in generation as the days get shorter. We've yet to have net-zero month of curse, but we remain hope for the coming summer!
