Saturday, January 18, 2014

Solar in Seattle – One Year of Data

One Year of Solar Production Data for a Residential House in Seattle (Green = consumption, Yellow = production, Orange = net)


The graph attached to this post describes one year (2013) of data with our solar panels (in the "center of the universe" Fremont). At the beginning of 2013, we brought 14 panels on line, on the roof of our house. Each panel is a SolarWorld Sunmodule SW 255 W Mono Panel (rated for 255 Watts). Now, at the beginning of 2014, we are looking back and are surprised at the following:

  • 78% of our electricity for 2013 came from our solar panels. It is the ratio between the yellow and green line in the graph. Or, totally, we generated 4074 kWh over the year and consumed 5,253 kWh.
  • On average, we consume 14.4 kWh/day and generate 11.1 kWh/day.
  • Our gross usage kWh/day decreased during the year. We think this is because of our increased awareness of energy usage. This is the green line in the graph.
  • You really notice when you have guests! Note the points on the graph on 10/1/13 when we had guests and our energy usage spiked.

The graph has three colors:

  • Green: our gross KWh/day consumption.
  • Yellow: our KWh/day solar production.
  • Orange: the net between consumption and production.

Interpretation of the graph:

  • The points on the graph are data measurements. They are not equally spaced, i.e., there is a variable amount of days between points. 
  • When an orange data point (net) goes below zero, it means we were generating more than we were consuming.
  • A colored line reflects the average of the values up to given date.

In the post, Working with Your Solar Array data Using the Enphase API, we describe how we programmatically work with our solar data.

Here’s to a sunny 2014!

System details from Enphase Web Site. Selected Day, June 12 2013, was maximum production day.System details from Enphase Web Site. Selected Day, June 12 2013, was maximum production day.

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