On a manual design, you may notice a custom production value keeps getting overwritten back to a different number every time the design is saved.
Why This Happens
Production on these designs is auto-calculated from panel count × the selected panel model's wattage rating, rather than being freely editable. If your actual expected production differs from the calculated value — for example, due to shading a manual design can't account for — entering a custom number will not hold.
The design plugin includes a setting that determines how production is caculated.
Any admin can click Settings > Org > Plugins > Designs
Expand the Org settings and click into the Production Calculator Menu
Manual
Reps enter production numbers directly on the design card, either as monthly or annual values.
Calculated
This requires array specific production to be entered on the design card, and then uses a weighted curve to calculate monthly production numbers based on that total production. In other words, the rep/designer enters a total production number per array, and Enerflo applies a weighted curve to distribute it across the months.
PVWatts
This sets the org to utilize the PVWatts integration to calculate their production, both total and for each array, based on each array's information. This requires that the azimuth and pitch be entered for each array. This is the default setting.
Under the hood, PVWatts is a web application used for estimating the production that a PV system could potentially generate, maintained by the National Renewable Energy Laboratory, using weather data, as well as other assumptions about potential losses a system might experience (such as from soiling on the panels, snow, and shading concerns), to calculate how much energy from sunlight that lat/long part of the world will get over a period of time. In v2, each array in the design is converted into parameters needed to call the PVWatts API to receive back production estimates for that array; once all arrays have received production, those are combined and the total production is used for items such as Offset.
Since both the Installer and Authorized Dealer each have PVWatts settings, the org that owns the deal template's settings are referenced.
PVWatts API assumptions (weather, soiling, snow, etc) can be fine-tuned in Settings>Tools. Defaults are provided, but can be changed.