Solar update October 20, 2000

Our solar system came online earlier this month during glorious sunny weather here in San Francisco.  We were actually excited to see the clouds come in this past Saturday and then thick fog on Sunday to see how the system fared in less than ideal weather.  These charts come from our SolarCity montoring site and measure output in kilowatt hours over time in half hour increments. Peak power output tends to be around 1pm this time of the year.

October 16, 2008 - Sunny all day - beautiful curve perfectly showing the movement of the sun across the sky.  Total output for the day 13.55 kwH.

October 18, 2008 -Partly cloudy/partly sunny - clouds were in and out, therefore the energy output is much more sporadic.  An interesting note is that the peak power output, 1.13 kwH at 1:30 pm is higher that the maximum output above of 1.07 kwH.  Perhaps the cooler temperatures allowed for greater efficiency? Total output for the day 10.07kwH

October 19, 2008 - Thick fog all day - sad...total output 2.47 kwH

Though the system obviously does not fare as well under thick fog, we have already generated 272 kwH in these three weeks, and are negative 45 kilowatts of peak power use.  Our total power use is still averaging less than 6 kilowatts per day, which is less than 1/4 of our use of October 2007.  We have also offset 309 pounds of CO2 gas in these 3 weeks!  We were told by SolarCity that even with our fog, over the course of a year our system would generate approximately 80% of what a similarly sized system would generate in a sunny neighborhood with similar temperatures.  We will continue to gather data over the next year to compare and analyze for ourselves.

The full data for the week can be found on this spreadsheet. Download beausoleil_solar_data10.19.08.xls

Comments

[Jose Capo]

This is EXCITING!! Brian actually mentioned we should consider solar power for our house in the Castro. And we get quite a bit of sun here. I wish you lots of bright sunny days ahead!

[Christine Boles]

Thanks Jose,
It's a great time to look into solar right now, especially with the San Francisco subsidies in effect. With a lease option, we only had to pay $29 upfront for our system! The main caveat is that you need to have a PG&E bill of at least $100 for a lease to make sense. Check out our previous posts for more details if you're interested.