Estimate uncertainty without a calibration

Use the Uncalibration workflow for an emission source that has no reference measurements of its own. The workflow uses the calibration of a similar emission source as a reference. It creates an uncertainty parameter version for the uncalibrated source, and computes its uncertainty from that reference and from quality scores.

Before you start

• You must have the SuperAdmin role.
• The uncalibrated emission source must have a pipeline.
• A similar emission source must have a completed calibration.
• The process data of the uncalibrated source must be in WS.PEMS for the period that you want to use.

Start the workflow

1. In the menu, open Calibration workflows. The Workflow Manager opens.
2. Click the Uncalibration tab.
3. Click Start Uncalibration.
4. In Create uncalibration, fill in:
   • Pipeline: the pipeline of the uncalibrated emission source.
   • Reference emission source: the similar source that has a calibration.
   • Reference calibration: the calibration of that source.
   • Valid from: the date from which the uncertainty applies.
5. Submit the form. The new uncalibration workflow opens.

Steps

The workflow page shows the overview and the list of steps. Click a step to open it. Each step has a button that validates the step and opens the next step. Click Previous to go back one step.

Step 1: Create Uncalibration

This step is complete when the uncalibration is created.

Step 2: Create Uncertainty Parameter Version

1. Set the Timestamp of the new uncertainty parameter version.
2. Validate the step.

Step 3: Initialise Uncertainty

1. Fill in the pedigree matrix. The matrix gives the quality scores that the uncertainty calculation uses:
   • Each row is one quality criterion, with its description.
   • Each column is one quality level.
   • Select one level in each row. The page shows the resulting Factor.
2. Validate the step. You can validate it only when each row has a selection.

The criteria, the levels and their factors are set up in Uncertainty (Calibration Uncertainty) in the menu.

Step 4: Compute Uncertainty Parameters

1. In Get Load Ranges, set the Start Date, the End Date and the Time Zone of the period to use.
2. Set the Minimum Range Width and the Minimum Values per Range.
3. Click Compute Ranges. The Load Ranges table shows each range and its number of points.
4. Optional: change or remove a range, then click Update Ranges.
5. Select the Output Standard Tags.
6. Start the computation.

Step 5: Generate Documentation

This step has no content at the moment. The workflow is complete after step 4.

Result

The uncalibrated emission source has a new uncertainty parameter version, valid from the date that you set. The uncalibration shows on the Uncalibration tab of the Workflow Manager, with the asset, the emission source and the reference source.

To make a new uncertainty parameter version later, open the workflow and do step 2 again.

Common problems

Problem	What to do
"No load data found for the selected period."	The uncalibrated source has no process data in that period. Select a period with operation.
"Unable to compute load ranges."	Make the Minimum Range Width or the Minimum Values per Range smaller, or select a longer period.
The reference calibration is not in the list.	Make sure that you selected the correct Reference emission source, and that this source has a calibration.
An error says that the step is not allowed.	The workflow is not at that step. Complete the steps before it first.