Tariff Analysis - Charge Tab

Charge tab on Tariff Analysis dialog

Charge Selection

Number of charges

The number of charges applied in this tariff can be selected from this dropdown list.

Simple or Block?

Select the charge type according to utility rate settings from:

• 1-Simple is used to compute energy and demand charges that are very simple. It may also be used for taxes, surcharges and any other charges that occur on a utility bill. As many Simple Charge objects as needed may be defined for a single tariff and they will be added together.
• 2-Block is used to compute energy and demand charges that are structured in blocks of charges. It may also be used for Taxes, Surcharges and any other charges that occur on a utility bill but those are more commonly simple flat charges so Simple Charge is more commonly used for those functions. As many Block Charge objects as needed may be defined for a single tariff and they will be added together. Blocks are a structure used by almost all utilities for calculating energy and demand charges and they allow the utility to charge more or less per unit of energy or demand if more units are used.

Charge : Simple

Charge variable name

This is the name associated with the Simple charge object and will appear in the report, which is also used to store the results of the Simple charge calculation. Spaces are not significant in Charge variable names. They are removed during the utility bill calculation process.

Source variable

This is the name of the source used by the Simple charge. This is usually the name of the variable holding the energy or demand but may also be the name of any variable including the Subtotal or Basis if other charges are based on those. This should be typed exact as defined.

the Source variable is usually the name of the variable holding the energy or demand but may also be the name of any variable including the subtotal or basis if other charges are based on those.

The list of EnergyPlus pre-defined variable names is:

• totalEnergy
• totalDemand
• EnergyCharges
• DemandCharges
• ServiceCharges
• Basis
• Adjustments
• Surcharges
• Subtotal
• Taxes
• Total

If it is a time-of-use rate then:

• peakEnergy
• peakDemand
• shoulderEnergy
• shoulderDemand
• offPeakEnergy
• offPeakDemand
• midPeakEnergy
• midPeakDemand

In addition see the Tariff Report in the Summary output to see other native variables that may be available.

Also you can create additional user defined variables to model complex tariffs.

Season

This is the name (or number) of a season for which the Simple charge is calculated. If this is set to Annual, the calculations are performed for the entire year (all months), otherwise they are calculated only for the months in the season defined. The season is defined by the Season Schedule on the Tariff tab.

The choices for seasons are the following names:

• Annual
• Winter
• Spring
• Summer
• Fall (Autumn)

Category variable name

Charges are added in the hierarchy as described on Tariff Analysis page. This field shows where the charge should be added. The reason for entering this field appropriately is to get the charge reported in a reasonable category. The charge automatically gets added to the variable named after this category. The choices for this field are limited to:

• EnergyCharges
• DemandCharges
• ServiceCharges
• Basis
• Adjustment
• Surcharge
• Subtotal
• Taxes
• Total
• NotIncluded

Cost per unit value or variable name

This field contains either a single number or the name of a variable. The number is multiplied with all of the energy or demand or other source that is specified in the source field. If a variable is used, then the monthly values of the variable are multiplied against the variable specified in the source field (the variable should be defined on the User variables tab). If no value or variable is entered, a zero is assumed. For SellToUtility tariffs, the values in this field are usually expressed as negative numbers.

Charge : Block

Charge variable name

This is the name associated with the Block charge object and will appear in the report, which is also used to store the results of the Block charge calculation. Spaces are not significant in Charge variable names. They are removed during the utility bill calculation process.

Source variable

This is the name of the source used by the Block charge. This is usually the name of the variable holding the energy or demand but may also be the name of any variable including the Subtotal or Basis if other charges are based on those. This should be typed exact as defined.

Season

This is the name (or number) of a season for which the Block charge is calculated. If this is set to Annual, the calculations are performed for the entire year (all months), otherwise they are calculated only for the months in the season defined. The season is defined by the Season schedule on the Tariff tab.

The choices for seasons are the following names:

• Annual
• Winter
• Spring
• Summer
• Fall (Autumn)

Category variable name

Charges are added in the hierarchy as described on Tariff Analysis page. This field shows where the charge should be added. The reason for entering this field appropriately is to get the charge reported in a reasonable category. The charge automatically gets added to the variable named after this category. The choices for this field are limited to:

• EnergyCharges
• DemandCharges
• ServiceCharges
• Basis
• Adjustment
• Surcharge
• Subtotal
• Taxes
• Total
• NotIncluded

Cost per unit value or variable name

This field contains either a single number or the name of a variable. The number is multiplied with all of the energy or demand or other source that is specified in the source field. If a variable is used, then the monthly values of the variable are multiplied against the variable specified in the source field (the variable should be defined on “User Variables” tab). If no value or variable is entered, a zero is assumed. For SellToUtility tariffs, the values in this field are usually expressed as negative numbers.

Remaining into variable

If the blocks do not use all of the energy or demand from the source, some energy and demand remains, then the remaining amount should be assigned to a variable. If no variable is assigned and some amount of energy or demand is not used in the block structure a warning will be issued.

Number of blocks

This field gives number of blocks needed for this Block charge setting.

Block size multiplier value or variable name

The sizes of the blocks are usually used directly but if a value or a variable is entered here, the block sizes entered in the rest of the charge are first multiplied by the entered value prior to being used. This is common for rates that are kWh/kW rates and in that case the variable that holds the monthly total electric demand would be entered. If no value is entered, a default value of one is assumed so that the block sizes remain exactly as entered.

Block size 1 value

The size of the first block of the charges is entered here. For most rates that use multiple blocks, this will be the value for the first block size. Additional block sizes are entered with every other field

Block 1 cost per unit value

The cost per unit value of the first block is entered here. This value is also repeated for every other field in the charge when required. As many blocks may be entered as are needed. For SellToUtility tariffs, the values in this field are usually expressed as negative numbers.

Note: The above two fields run as a group can be repeated many times up to the number defined in Number of blocks field. For the last pair of the two, a default variable named “remaining” contains a large value may be used when the remaining amount should be included in that block. This “remaining” is EnergyPlus reserved keyword, which should not be altered or if manual input is required, this variable should be typed exactly.