Article - Greenbyte

July 7, 2021 — Product News

Are your performance losses within your budget?

Budget Deviation Waterfall is a new widget that we’ve added to the Greenbyte Platform to show you how far your solar farms are deviating from the default budget for the site.

Product Manager, Greenbyte

What’s the idea behind the Budget Deviation Waterfall?

In spring we launched the Loss Analysis Waterfall, which compared energy losses and gains to the Energy Theoretical - the energy a device could have produced if it were running optimally in perfect conditions. This is great for comparing concrete losses because it shows exactly how much energy in MWh your device has lost compared to what it could ever have achieved. As an empirical measure, Energy Theoretical gives you the machine value.

However, the day-to-day reality of most of our customers is that the performance of their assets is almost always compared to the default budget for that site or device. We recognise that you are held accountable to your owners, investors or employers against this very budget - or maybe several (P90, P50 etc.)!

Budgets typically include expectations as to what sort of losses are likely to affect the asset or what sort of resource will be available (Resource Index). These could include:

  • Amount of sunshine (irradiation) likely to hit the panels this month
  • Budget for performance losses
  • Budget for curtailment losses
  • Budget for downtime losses

This means that a budget is not an empirical measure of what a solar array (measured at inverter) could produce, but is rather a human estimate of what it should produce in a given month, given the likely amount of sunshine and availability.

What is the Budget Deviation Waterfall?

For this version of the Budget Deviation Waterfall we have included a Weather Adjustment bar, which visualises the (Budget - (Budget * (Irradiation Actual/Irradiation Forecast)). This means that the extra sunshine not included in the budget is displayed here as a green gain.Using the Performance Ratio (IEC) calculation, we have calculated a Performance Ratio Deviation: (Performance Ratio Forecast - Performance Ratio (IEC)) * Energy Budget. This includes all budgeted performance, curtailment and downtime losses included in the overall budget bar at the top MINUS all the actual losses to these categories. That is why this bar is called a deviation: it is showing the deviation of the losses/gains that happened in real life compared to what was budgeted for these losses.


An explanation for the data above may be something like this:
there was more energy-giving sunlight during this month than expected, giving a green bar on the waterfall for Weather Adjustment. However, despite this, the solar sites actually performed under what was predicted for Performance Ratio. This may be due to any number of factors, including the site being curtailed. Residual - "the whatever is left" category - shows that there were other uncategorised energy gains, so overall the sites produced more energy for this time period than was budgeted for them. Good news!

How does this work with the Loss Analysis Waterfall?

The Budget Deviation Waterfall is designed to be a companion widget to the Loss Analysis Waterfall - so we recommend displaying them both together on the same dashboard. This should allow you to compare and contrast losses in a meaningful way.

For example:

“Oh no - I have big losses on Performance!
But when I look at the BDW I see that the Performance Ratio Deviation is pretty small, so actually most of these losses were already budgeted for. Hooray!”

What other widgets are you planning?

We have other ideas for improvements we would like to make to this widget! But since this is a long-anticipated feature we have decided to release this version to customers now so you can begin to make use of it. Do let us know what you think and feel free to feedback any improvement suggestions!

We also hope to release a wind version at some point along with other exciting upcoming product news, so stay tuned!

How to get started?

The widget works best on a one-widget dashboard, so either you can select the Budget Deviation Waterfall widget and add it to an existing widget-wide dashboard in Analyze / Portfolio, or you can create a new one. You can also create reports with this widget.

Would you like a tour of the widget in the platform? Check out this video!

If you are interested in using this widget, please contact



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