SRP customer-generation planning

SRP E-27 Customer-Generation Core-Charge Worksheet

Enter matching-period imports and exports, maximum 30-minute demand, and the applicable service tier to reproduce the published E-27 core-charge arithmetic.

Page reviewed July 27, 2026

Assumptions and exclusions are shown below the result.

Salt River Project: 2025 Ratebook with Temporary FPPAM

SRP E-27 Customer Generation Price Plan

E-27 is a solar customer-generation plan. It combines time-of-use energy, progressive demand tiers, a service charge, and matching-period export netting. Demand is based on the maximum 30-minute on-peak interval—not a flat dollars-per-kW rate.

E-27 inputs

Use figures from an SRP bill or interval-data screen when available.

Imported energy by E-27 period

Enter measured import kWh from SRP interval data for the billing cycle. The worksheet does not infer a timing profile from total household use.

kWh/month

Use imported kWh measured during the ratebook's seasonal on-peak windows.

kWh/month

Use all imported kWh outside the on-peak windows.

Entered imports: 0 kWh/month

E-27 prices the billing cycle's maximum 30-minute on-peak demand in three progressive tiers. Enter a reduction only for a scenario you can support with interval data or a specific load-control plan.

kW

Use the maximum on-peak demand shown for the billing cycle.

kW

Starts at zero. Enter only the reduction you want to model.

E-27 nets exports within matching TOU periods. Enter measured exports for each period rather than an inferred share.

Worked July-August example

This illustrative arithmetic uses 300 measured on-peak import kWh, 1,200 measured off-peak import kWh, 8 kW maximum 30-minute demand, and the $30 service tier. It is not a household-usage default.

Monthly core charges

$258

Energy charges

$93

Demand charge

$136

Why the old flat-rate model was wrong

E-27 does not use one summer rate, one demand price, or one fixed export credit. Its energy table separates May/June/September/October, July/August, and November-April. Demand is progressive, and exports are netted in their matching time-of-use period. This calculator preserves those distinctions.

How the minimum bill affects exports

SRP's E-27 ratebook says the monthly service charge is the minimum bill. The worksheet therefore values entered exports at the matching retail rate but does not let those credits reduce the modeled total below the selected $20, $30, or $40 service charge. Any value limited by that floor is shown separately; this worksheet does not assume it carries into another billing cycle.

July-August rates used

July-August energy is $0.0785/kWhon-peak and $0.0575/kWhoff-peak. Progressive demand is $11.90/kWfor the first 3 kW, $19.97/kWfor the next 7 kW, and $36.05/kWabove 10 kW.

Source: SRP's 2026 temporary ratebook. The temporary May-October 2026 adjustment means current summer figures are date-sensitive; the source was checked July 27, 2026 and should be rechecked before a major purchase decision.

Limits of the estimate

Your bill can include taxes, riders, and account-specific items that are not modeled here. Matching-period import and export values should come from SRP interval data for the same billing cycle. Annual mode is a simple four-month summer, two-month summer-peak, and six-month winter blend—not a forecast of your changing seasonal usage.

Frequently asked questions

Who is the SRP E-27 worksheet for?

E-27 is SRP's Customer Generation Price Plan for customers with qualifying generation such as rooftop solar. It is not a generic SRP residential rate.

How does E-27 calculate demand?

E-27 uses the maximum 30-minute on-peak demand in the billing cycle and progressive price tiers: the first 3 kW, the next 7 kW, and all additional kW have different seasonal rates.

Does E-27 use one flat solar export rate?

No. E-27 subtracts exported kWh from imported kWh within the matching on-peak or off-peak period. This worksheet therefore requires measured imports and exports for each period instead of inferring an export split.

Why does the worksheet ask for a service tier?

The published E-27 monthly service charge is $20, $30, or $40 depending on dwelling type and service amperage. It is also the plan's minimum bill. Use your SRP account information to identify the applicable tier.