Why Are SolarNexus Bill Estimates Different than Historic Actuals?

SolarNexus uses Genability's bill calculation services to project the expected before and after electric bill amounts IN THE FUTURE. So you should never expect bill calcs to match past bill amounts.* Future projections use current electric tariffs (which may have changed since your customer's historic bill came out).

If you find significant differences, there are several potential causes:

1. (Common) Input usage does not match actual usage. The bill estimates will probably not match if you input an average monthly load, or the kWh monthly use was not input matching the actual billing periods.
2. (Common) Utility's rates have changed since the actual bills were sent out (in this case, estimates are usually higher since we are estimating future bills using higher rates that are now in effect).
3. (Common) Local user utility tax rates do not match. Genability's bill calculation service leaves out the local utility tax rate, so we add it based on your input rate. These rates vary by city/county. You should find out these rates for your service areas (should be shown on customer utility bills). You can input a default average rate in the Project Settings. If the rates vary widely in your service area, you may want to provide your sales team with a chart of these rates so that they can input the proper rate for each customer.
4. (Uncommon) Time of Use (TOU) rates are already in-use, and the assumed customer load profile varies significantly from the actual customer's load profile. If you can get GreenButton XML file of customer's historic use, that's best. Unfortunately most utilities still don't provide that data. We also have features for modeling individual customer load profiles.
5. (Uncommon) The rates used by the bill calculation service are inaccurate. In Analysis results, click on the Utility Bills tab, then expand any of the monthly totals section to see its breakdown. You can see the rates applied and check with utility's current rates. NOTE: this feature is not available in all tariff cases. Some rates are too complicated to be displayed in this tabular format. If you find an inaccuracy, please submit a support request with links to the documented rates.

Before reporting a problem, please verify that your inputs are as accurately aligned with the actual customer's billing parameters as possible, especially usage and utility tax rate. If there are still unacceptable differences, let us know so that we can take a closer look.

* - One exception. There is a feature that allows you to force SolarNexus to use your input dollar amounts for the "no-project" case instead of calculating bill. To do this for a solution, open your Analysis Parameters, click on "Electric Tariff" and change setting on Pre-Project Bill to "Use Entered Bill Amounts." We do not suggest using this approach because past