Tariff File Inputs
This section describes the format for utility tariff files that define retail energy and demand charges for a DER-VET case when the retail energy charge reduction and/or demand charge management services are active. This file is pointed to in the model parameters sheet by the input, customer_tariff_filename. Only the tariff file pointed to in the model parameters sheet will be used in the case.
DER-VET needs the flexibility to handle most of the incredible variety of retail tariffs in existence. Tiered demand rates, overlapping demand charge periods, different time resolutions for calculating demand charges, riders, standby rates, and many other factors make this a challenge. The tariff format described here does well in most cases with non-tiered demand charges where the time step of the time series data matches the time resolution of the demand charge calculation. In other words, if demand charges are calculated using the peak 30-minute period, then the time step of the data should be 30 minutes.
The tariff input file defines a set of ‘billing periods’ where the charges associated with each billing period sum to the total monthly bill. Attributes of each billing period include the start month, end month, start time, end time, weekday/weekend/both, rate, what kind of charge it is, a description of the billing period, and any hours in between the start time and end time that are excluded from that billing period.
The number of billing periods is unlimited, so very complicated tariffs with TOU energy rates, TOU demand charges, overlapping demand charges, and other complicated setups are possible.
An example tariff is available with DER-VET in .\storagevet\Data\tariff.csv. This can be modified to match a specific case.
| Billing Period | Start Month | End Month | Start Time | End Time | Excluding Start Time | Excluding End Time | Weekday? | Value | Charge | Name_optional |
| 1 | 6 | 9 | 13 | 18 | 1 | 0.39057 | energy | |||
| 2 | 6 | 9 | 9 | 23 | 13 | 18 | 1 | 0.18798 | energy | |
| 3 | 6 | 9 | 1 | 24 | 9 | 23 | 1 | 0.10472 | energy | |
| 4 | 6 | 9 | 1 | 24 | 0 | 0.10472 | energy | |||
| 5 | 1 | 5 | 9 | 21 | 1 | 0.13076 | energy | |||
| 6 | 1 | 5 | 1 | 24 | 9 | 21 | 1 | 0.08636 | energy | |
| 7 | 1 | 5 | 1 | 24 | 0 | 0.08636 | energy | |||
| 8 | 10 | 12 | 9 | 21 | 1 | 0.13076 | energy | |||
| 9 | 10 | 12 | 1 | 24 | 9 | 21 | 1 | 0.08636 | energy | |
| 10 | 10 | 12 | 1 | 24 | 0 | 0.08636 | energy | |||
| 11 | 1 | 12 | 1 | 24 | 2 | 11.89 | demand |
This example tariff describes time of day energy prices with three different levels each in the summer and winter. During the summer, on-peak hours are from 12:00 to 18:00, mid-peak hours are from 08:00 to 12:00 and 18:00 to 23:00 (note that they exclude the hours covered by the on-peak prices using the excluding_start_time and excluding_end_time columns), and off-peak times are from 00:00 to 08:00 and 23:00 to 24:00. This tariff assesses a single demand charge that covers all hours of all days of the year equally. Note that the winter billing periods are repeated - once for the months at the beginning of the year and once for the months at the end of the year.
The section below describes each tariff input file column in detail.
Billing Period
| Column Header | Description |
| Billing Period | This column should increment up, starting with 1, to provide a unique identifier to each component of the bill. This can be used to trace back electricity bill results to the tariff input file. |
Start Month
| Column Header | Description |
| Start Month | This column represent the first month of the year which this charge applies. 1 = January, 2 = February and so on.
Commonly, rates are broken into summer and winter rates. In cases like this, the winter rates will have to be defined twice - once for the first few months of the year and once for the last few months of the year. |
End Month
| Column Header | Description |
| End Month | This column represent the last month of the year which this charge applies. 1 = January, 2 = February and so on.
Commonly, rates are broken into summer and winter rates. In cases like this, the winter rates will have to be defined twice - once for the first few months of the year and once for the last few months of the year. |
Start Time
| Column Header | Description |
| Start Time | This column represent the first hour of the day that this charge applies. 1 = the hour from 00:00 to 01:00, 2 = the hour from 01:00-02:00, 15 = the hour from 14:00-15:00, etc. |
End Time
| Column Header | Description |
| End Time | This column represent the last hour of the day that this charge applies. 1 = the hour from 00:00 to 01:00, 2 = the hour from 01:00-02:00, 15 = the hour from 14:00-15:00, etc. |
Excluding Start Time
| Column Header | Description |
| Excluding Start Time | The tariff format allows for a billing period to exclude certain hours, defined by the "excluding start time" to the "excluding end time". These excluded hours will not be used in the bill calculation.
This is most commonly useful when there is a peak price interval in the afternoon with off-peak times in the beginning and end of the day. The off-peak times can be described by one row by setting start_time = 1, end_time = 24, and excluding the on-peak hours. |
Excluding End Time
| Column Header | style='width: 80%' | Description |
| Excluding End Time | The tariff format allows for a billing period to exclude certain hours, defined by the "excluding start time" to the "excluding end time". These excluded hours will not be used in the bill calculation.
This is most commonly useful when there is a peak price interval in the afternoon with off-peak times in the beginning and end of the day. The off-peak times can be described by one row by setting start_time = 1, end_time = 24, and excluding the on-peak hours. |
Weekday vs Weekend
| Column Header | Description |
| Weekday? | This input distinguishes charges that apply only on weekdays (Weekday? = 1), those that only apply on weekends (Weekday? = 0), and those that apply to both (Weekday? = 2).
Holidays are currently not considered in the tariff format. |
Value
| Column Header | Description |
| Value | This is the column that defines either the energy price ($/kWh) or the demand price ($/kW_peak monthly) (which is determined by the Charge column) described by the row. |
Name
| Column Header | Description |
| Name_optional | This column allows the user to enter a descriptive name for their own reference. This column is not used anywhere - it is purely to help keep track of the various charges in play. |
OpenEI United States Utility Rate Database (USURDB)
In the graphic user interface (GUI) version of DER-VET, there is a connection to the USURDB which can automatically find and format a tariff. This database lacks tariffs with overlapping demand charges and can contain inconsistencies, but can speed up the process of getting tariff information into DER-VET. This functionality is not available in the command line version of DER-VET.