Overview
Under the Smallscale Renewable Energy Scheme for the Australian Government, eligible smallscale renewable energy systems are entitled to a number of smallscale technology certificates (STC). Once created and validated, these certificates act as a form of currency and can be sold to recoup a portion of the cost of purchasing and installing the system, or transferred to other individuals and businesses at a negotiated price.
The number of certificates that can be created per system is based on its geographical location, installation date, and the amount of electricity in megawatt hours (MWh) that is generated by the smallscale solar panel, wind or hydro system over one or five years, or a single maximum deeming period.
As a guide, one certificate is equal to one megawatt hour of eligible renewable electricity either generated or displaced by the system.
This example focuses only on the rules for calculating STC's for solar.
Rules for Calculating STC's (Smallscale Technology Certificates)
Rule #  Description 

1 
When the SGU  Solar (deemed) is selected from the Small Generation Unit lists on the web form, show the following fields to capture additional data:

2 
Based on the Postcode of the installation, determine the Zone and the Rating. A sample of these can be seen in the table below  the full table is available on the Clean Energy Regulator website. 
3 
Depending on the year of installation the maximum number of years certificates can be calculated for is determined  this is the Deeming Period. The table below shows the Deeming Periods: 
4 
Calculate the STCs (Smallscale Technology Certificates) using the following formula:

5 
Save the Number of STCs, the Postcode Zone and System Type and present the results to the end user. 
6 
Save a log of the calculation for audit purposes. 
North52 Decision Suite Solution
The North52 Decision Suite solution works like this:
 Two Formulas are created:
 A ClientSide Formula is set up for the Entity Form to hide and show relevant fields on the Portal Form depending on the Type of Small Generation Unit and whether there is a calculation result (Number of STCs has a value)
 A Formula is set up on the Small Generation Unit Calculation entity which:
 Determines the Zone and Rating
 Determines the applicable Deeming Period
 Calculates the number of eligible STC's
 Logs a calculation audit trace file as a Note on the Small Generation Unit Calculation entity
Set up Formulas
Formula 1: Portal Form (ClientSide)
This Formula has the logic for Rules 1 and 5 to show/hide fields and sections on the form.
 Create a new Formula, setting the following values in the Formula Guide:
 Source Entity set to Small Generation Unit Calculation
 Set Formula Type to ClientSide  Perform Action
 Select the Decision Table editor
 Change the Name of the formula to Small Generation Unit Calculation  Portal Form
 CtrlSelect OnLoad and Small Generation Unit Type for the Web Form under the Source Property list
 Select Community Portal from the Portal Deployment drop down list under the Deployment Settings section (when the Formula is saved it will automatically add the necessary bindings to the Portal Entity Form)
 Click Save
Decision Table
The Decision Table for the Form rules is configured like this:
The Decision Table Rules in action on the Power Apps Portal Entity Form:
Formula 2: Smallscale Technology Certificates (STC) Calculation
This Formula has the logic for Rules 2, 3, 4 and 6 to calculate the number of STC's.
 Create a new Formula, setting the following values in the Formula Guide:
 Source Entity set to Small Generation Unit Calculation
 Set Formula Type to Save  Perform Action
 Select the Decision Table editor
 Change the Name of the formula to Small Generation Unit Calculation  Save  Calculate STCs
 CtrlSelect the following fields under the Source Property list (a change to any of these fields will trigger the Formula):
 Calculation Period
 Expected Installation Date
 Postcode
 Rated Power Output (kW)
 Small Generation Unit Type
 Click Save
There are 3 Decision Table Sheets in this Formula which implement the business rules:
 Solar  Determine Zone and Rating
 Calculate Deeming Period
 Calculate Number of STCs
Decision Table Sheet 1: Solar  Determine Zone and Rating
This Decision Table sets two variables based on the input in the Postcode field; Zone and Rating  the ((0,799)) notation represents a between function. The values used are outlined in Rule 2:
Decision Table Sheet 2: Calculate Deeming Period
This Decision Table sets the Deeming Period variable based on Year from the Expected Installation Date field. The values used are outlined in Rule 3:
Decision Table Sheet 3: Calculate Number of STCs
This Decision Table calculates the Number of STCs (using the variables set in Sheet 1 and 2), and updates the Small Generation Unit Calculation record with the calculated Number of STCSs value, the Postcode Zone (from Sheet 1), a fixed System Type value, and logs a calculation audit trace file as a Note. The logic used are outlined in Rule 4 and 6:
This example uses publicly available information on the owners website and has not been endorsed by the owner of the information.