As of 9:30am on September 29th our photovoltaic system was up and running (whistles, gongs, chimes!). PG&E came by to inspect and install our new time-of-use meter, all of which took about ten minutes. The meter gives a whole slew of data points -- power use at different times of day (corresponding to different rate tiers), power coming in from the p.v. system, power coming in from the grid, net use, etc., so we can monitor the situation. I have to avoid the temptation to check every hour. As of this morning, we have generated close to 145 kwH of power in those 11 days.
In order to analyze the efficiency of our system, particularly with our variably foggy climate in this part of San Francisco, we have set up a spreadsheet with the goal to collect data four times a day. We will be keeping track of weather, an instant reading of power generated, a total of the power generated for the day, as well as our power use figures based on PG&E's tiered rate schedule. For this week's figures, see the attached file. Download beausoleil_solar_data.xls
Our system has been sized to offset our peak time power use, in the afternoons, and so far our meter has consistently been running backwards during this time of day, even on October 6th, the rainy/foggy day last week. To date we are negative 17 kwH of peak power use.
Our average power use in October of last year was 25 kwH per day. Since our system was turned on, thanks to the offset of our solar system, and thanks to more vigilant kids turning out lights in unoccupied rooms, we have used a total of 62 kwH, an average of 5.6 kwH per day. We will let you know the comparative difference on our PG&E bill when it comes in!
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