Solar Production Analysis

This error occurs because of one, or both, of these issues:
  • The difference between the first and last date is not greater than 2 years.
  • You do not have at least 365 * 2 = 730 rows of data (i.e. 2 years of daily data)

Typically, most solar panels come with a manufacturer warranty of retaining at least 80% of initial efficiency within the first 25 years. The yellow, dashed line shows the typical 80% threshold as linear degradation over time. If your estimated relative efficiency drops below the yellow dashed line, then there is a chance that there may be something wrong with your system.
The red, dashed line is the same as the yellow dashed line, but it takes into account the standard uncertainty of the analysis. This means that it is highly likely something is wrong with your system if the estimated relative efficiency drops below the red line.
Consult the manufacturer's specification sheet for your particular solar panel for the exact warranty specifications.

The warning label is there to inform you that, based on the data provided, there may be an issue with your system. The relative efficiency should stay above both the yellow and red dashed lines. If the relative efficiency is ever below either of those lines, a warning label will be displayed. Please reach out to ClearWatt PV if you suspect you may have issues with your solar system.

Over a decade of performance analysis has gone into the development of ClearWatt's proprietary analysis algorithm. This analysis algorithm has been tested against industry standard methods (year-over-year cummulative comparison, rolling year cummulative comparison, similar month cummulative comparison, etc.) over tens of thousands of curated, synthetic solar production datasets and real datasets. Metrics, such as mean squared error, for ClearWatt's analysis algorithm were, overall, better than industry standard methods. This is due, in part, to our ability to filter out some of the effects of unpredictable weather patterns and system outages that would affect the cummulative monthly or annual production. Essentially, this algorithm is about as close as you can get to knowing your system's relative efficiency without an I-V curve tracer or solar irradiance meter.

Yes! At the top right of the chart, there should be a button that will allow you to download your analysis as a .csv file.

There are two possible reasons for this:
1. Wide swings in weather patterns from year to year: While many effects of annual weather patterns and system outages are able to be filtered out, variations still remain in the estimated efficiency.
2. Changes to your system: If you have added more solar panels to your system, if you have changed the orientation of your panels, etc., then this will affect the estimated relative efficiency. The analysis assumes that the system has not changed over time.

The analysis history section allows you to pull up the analysis of every file you've run through the analysis program without reanalyzing the data. Selecting a different dataset from the history will pull up its chart and allow you to download the analysis .csv file for that particular dataset. If you navigate away from this page, all your history will be lost, though.

Yes! Depending on what you are needing, there are some very useful tools from the National Renewable Energy Laboratory (NREL, but now NLR).

PVWatts Calculator
Cost of Renewable Energy Spreadsheet Tool