How to Troubleshoot Losses in HelioScope

My design isn't producing any energy! I have two designs, and one of them is producing way less than the other! Why is my design not producing as much as I thought?

If you've found yourself asking these questions, don't worry, many people do! However, it's easy to quickly analyze where these losses are coming from by using the HelioScope Report. The best parts of the report to look at for this analysis are the Sources of System Loss Chart and the Annual Production table. Once you've looked below at where to find these charts and what they look like, make sure to check out the related articles at the bottom of the page if you want to examine specific losses.

Sources of System Loss Chart

So what is the Sources of System Loss chart? Simply put, it's a quick way to visualize the losses your design is currently seeing. You can find this midway down the report on the right side.

Around this chart, you'll be able to quickly see what the losses are for each stage of simulating your project. To get more information about the loss, hover over a section of the wheel to get a bit more context. If you're unsure what are typical values for each of these losses, we recommend taking a look at our help page on typical loss factors.

Annual Production Table

Those who are more used to working with PVsyst or other similar programs may prefer analyzing their losses with the Annual Production table. You can find this midway through the report on the left side. These are the same losses as the Sources of System Loss chart, and you can also hover over each of them to get a bit more contextual information.

 Clipping Losses ("Constrained DC Output")

Note that the "Constrained DC Output" step is actually 3 losses in one. This step includes all aspects of "Clipping" - and while most people think of clipping as over-power clipping (i.e. the array producing more power than the inverter can handle), there are two other types of clipping: under-voltage (string voltage is too low for the inverter), and over-voltage (string voltage is too high for the inverter). In fact, the most common driver for clipping loss is under-voltage, not over-power. 

You can see the specific source of clipping loss by mousing over the line in the Annual Production table

Why don't my losses sum up to my Production Ratio?

Losses are multiplicative, not additive. That means that at each stage of loss is a percentage of the stage before it. In the above example, you couldn't add a -2.7% loss from Inverter Output and -0.5% loss from Energy to Grid into a total loss of -3.2%.