Understanding Rate Polarity

Overview

Rate polarity in our system determines whether a rate is treated as a charge or credit. This concept aligns with industry-standard billing determinant polarity and rate sign conventions. Understanding rate polarity is essential for correctly interpreting costs, ensuring accurate bill reconstruction, and optimizing tariff scenarios.

Each rate is associated with a transaction type, which defines whether the charge applies to energy imported from the grid, exported back, or involved in other energy transactions. Our data team ensures that rates are configured correctly, but it’s useful to understand how polarity works, especially when reviewing results.

Transaction Types and Energy Unit Polarity

Energy transactions inherently have a unit polarity based on whether energy is being consumed or delivered. This is separate from the rate amount itself, which may be positive or negative depending on how the tariff is structured.

There are five transaction types:

Net – Represents net energy use (imports minus exports).
Buy – Represents purchases from the grid.
Sell – Represents sales back to the grid.
Import – Specifically tracks energy drawn from the grid.
Export – Specifically tracks energy sent to the grid.

Default Energy Unit Polarity

Transaction Type	Energy Unit Polarity	Reasoning
Net	Positive	Net usage is typically measured as positive
Buy	Positive	Buying energy increases usage
Sell	Negative	Selling energy decreases net usage
Import	Positive	Importing energy increases usage
Export	Negative	Exporting energy offsets usage

While these conventions are standard, rate values can be adjusted using credits or variable lookups based on tariff design.

How Rate Polarity is Configured

Rates can be set up as standard values or variable lookups, which reference external data tables. Additionally, a credit flag (isCredit) can be applied to reverse a rate’s polarity in certain cases.

Standard (non-lookup) rates are always entered as positive values. If a rate should be treated as a credit, the isCredit flag is set to true.
Variable lookup rates can be positive or negative, depending on the transaction type and tariff structure.
The credit flag (isCredit) flips the polarity for non-lookup rates. The default for this flag is false. For variable lookups, this flag exists but is rarely modified.

Standard Rate Polarity Guidelines

Buy, Sell, Import, Net: Rates are entered as positive values.
Export: Rates are entered as positive values, with isCredit = true to indicate a credit.

Variable Lookup Rate Polarity Guidelines

Buy, Sell, Import, Net: Values are entered as positive.
Export: Values are entered as negative to reflect standard export credit behavior.

Identifying Potential Rate Configuration Issues

While rates generally follow a structured polarity logic, incorrect configurations can occasionally occur. Some key things to be aware of:

Export rates should not be positive unless isCredit = true.
If an export rate is positive but isCredit is not applied, the rate may be incorrectly treated as a charge.
Buy rates should not be negative unless they are explicitly modeled as credits.
Lookups that apply to both Import and Export must be carefully managed.
A lookup that is a charge for Import but a credit for Export should have a corresponding negative value or be duplicated with opposite polarity.
Switching a rate from Sell to Export requires polarity validation.
If a rate’s transaction type is changed, the polarity must also be reviewed to ensure accurate calculations.

How Arcadia’s Team Ensures Rate Accuracy

Our data team follows strict guidelines to ensure that rate polarity is correctly configured:

We apply consistent polarity conventions for each transaction type.
We validate rate polarity when modifying existing rates, particularly when changing transaction types.
We review variable lookups to ensure they follow expected polarity rules.
We verify that export credits are properly marked and that positive values are not incorrectly used without isCredit = true.
We run regularly scheduled automated Data Quality checks against our database to ensure that only valid combinations are present.

Rate Polarity Demonstration Tariff

To see examples of how rate polarity is applied across different transaction types, credit flags, and rate configurations, refer to our Rate Polarity Demonstration Tariff in Explorer:

View the Rate Polarity Demonstration Tariff

This tariff includes sample rates for each possible combination, helping to illustrate how charges and credits are handled in our system.

Summary

Rate polarity is a key factor in accurate tariff modeling, affecting how charges and credits are handled. While most rates follow a consistent pattern, some tariffs introduce exceptions that require careful handling.

If you notice a discrepancy in rate calculations or have any questions, please reach out to [email protected]. Our team is continuously monitoring and improving data accuracy, and we’re happy to investigate any concerns.