Data from Analysis North Solar PV System

Analysis North has a 2.85 kW-DC grid-connected photovoltaic solar system installed at our place of business in Anchorage, Alaska (Alan Mitchell's house). The system consists of ten 285 Watt SW 285 SolarWorld panels coupled to ten Enphase S280 microinverters with a total capacity of 2.80 kW-AC. The system is roof-mounted, tilted at 45 degrees and oriented 8 degrees West of South.

The graphs below summarize the performance of the system to date. These graphs are updated every 10 minutes; press F5 to have your browser refresh the data.

The code for acquiring the solar data and creating this page is available at Alan Mitchell's GitHub site.

Recent Production

This shows the daily energy production from the system for the last two weeks. Note that the most recent day, shown at top, could be a partial day or could be yesterday if no production has been reported yet today. (There are sometimes delays in reporting production at the start of the day.)

daily production

Here is a graph of the power production today (thick blue line), yesterday (thin red line), and the days with minimum and maximum energy production during the last two weeks (thinner dashed lines):

today's production

Cumulative Energy Production for the Year

This graph shows the cumulative energy production of the system for the current year and for all previous years as separate lines. For example, a value of 300 kWh on the Y-axis for day number 80 means that a total of 300 kWh were produced for the first 80 days of the year.

cumulative production

This graph below is the same as above except it does not show days of the year beyond the current day.

cumulative production

Monthly Energy and Power

This graph shows the total number of kWh produced in each month; each year is shown on a separate line so monthly comparisons between years are possible. Note that the most recent month is usually a partial month so will appear to have a low value.

monthly production

This graph shows the peak power production that has occurred in each month. It finds the peak power across all of the years of data for each month.

monthly peak power

Below, an average production profile is shown for each month. The Y-axis value is average power in Watts produced for the hour (0 - 23) shown on the X-axis.

monthly profiles

Spread of Daily Production Values

This boxplot show the spread and the median daily energy production values for each month.

monthly box plot

In the plot below, each dot is data from one day. The Y-axis value is the kWh energy produced during the day, and the X-axis value is the day of the year. So, the graph also is good at showing the distribution of daily energy production values that occur at different times of the year.

daily production

Record-Setting Days

Here is the day where the most kWh were produced:

day with maximum energy

Here is the day that had the highest 5 minute power production. This is generally a day where the solar noon sun comes out from behind some clouds. As well as the solar panels receiving the direct sun, they also receive substantial radiation from sun rays redirected as they pass through the clouds adjacent to the sun.

day with maximum peak power

An Important Number: Normalized Annual Production

Here is a graph of an important performance number for the system. If you take the production of the system for a year in kWh (AC delivered to the grid) and then divide by the rated capacity of the system in kW (rated DC panel capacity), you have calculated normalized annual production for the system. For example, a normalized production of 850 kWh-AC / kW-DC means that each 1 kW of rated capacity in this system produces 850 kWh-AC of electricity for the year. For this particular system, this number will vary due to how sunny the year is, dirt and snow accumulation on the panels, and due to general degradation of output over time. When comparing to other systems, the number will vary due to additional factors such location of the system, tilt and orientation, shading, etc. Normalized production in California is quite a bit more than Alaska.

The graph below plots this normalized production on rolling year basis. The first point shown below is for October 1, 2017 and has a value of about 848 kWh / kW. That means for the 365 days prior to October 1, 2017, the system produced 848 kWh for each 1 kW of installed capacity. Each additional point on the line indicates the normalized production for the 365 days preceding the date on the horizontal axis.

rolling normalized production


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Solar data is acquired through use of the Enphase API (application programming interface).
All data analysis and graphing is custom programming done by Analyis North and is available at Alan Mitchell's GitHub site.