SRP customer-generation planning

SRP E-27 Customer-Generation Core-Charge Worksheet

Reproduce E-27 core-charge arithmetic from measured billing data, then compare a separate on-peak energy shift and maximum-demand reduction without changing your baseline.

Page reviewed September 4, 2026

Assumptions and exclusions are shown below the result.

Salt River Project: 2025 Ratebook with Temporary FPPAMSalt River Project: Customer Generation Price PlanSalt River Project: How to read your residential electric bill

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.

Your E-27 bill details

Keep your SRP bill and usage history nearby. Use one billing period.

Where do I find these numbers?

Check the plan in your bill’s customer information: this worksheet covers Customer Generation, E-27. Average Demand and Manage Demand use different demand calculations.

For maximum demand, look for On-Peak kW Max in the metered-energy section. Enter the kW value, not its dollar charge or an average-demand figure. Use the same billing period for every input.

Enter electricity bought from SRP (imports) separately from electricity sent back (exports). Do not use the total made by your solar panels. If your bill already subtracts electricity sold from electricity bought, get the two separate amounts from your usage data first. Otherwise, you could subtract the same electricity twice.

Match the monthly service-charge tier to your bill. If your plan or figures are unclear, the SRP schedule planner can help with timing without a bill calculation.

Bill-field guidance checked September 4, 2026: SRP’s illustrated bill guide. No bill upload or account number is needed here.

Electricity you bought from SRP (kWh)

Use your usage history to find electricity bought during on-peak and off-peak hours. kWh measures the amount of electricity. The maximum-demand field below uses kW, which measures how quickly electricity was used.

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 the measured maximum shown for the billing cycle.

kW

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

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

Compare one load-shift scenario

Move part of the entered imported energy from on-peak to off-peak while keeping total imports and entered exports unchanged. A kWh shift does not automatically lower the maximum 30-minute demand, so model that separately.

kWh/month

Limited to the on-peak imported kWh entered above.

kW

Enter only a reduction supported by interval data or a specific load-control plan.

Worked July-August comparison

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. The comparison moves 100 on-peak imported kWh to off-peak and separately enters a 3 kW demand reduction. It is not a household-usage default.

Baseline core charges

$258.10

Scenario core charges

$196.09

Energy-period savings

$2.10

Demand-charge savings

$59.91

The combined $62.01 difference is for this one illustrative billing cycle. Moving kWh between periods does not prove the maximum 30-minute demand will fall; the two effects stay separate.

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.

Why moving energy and lowering demand are separate

E-27 prices imported and exported kWh by time-of-use period, but it defines billing demand as the maximum 30-minute integrated kW during the cycle's on-peak periods. Moving monthly imported energy to off-peak hours can change the energy portion without changing that single highest interval. The comparison therefore asks for shifted kWh and a supportable demand reduction separately; it never manufactures a demand reduction from the energy shift.

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.

Does moving energy out of on-peak hours automatically lower demand?

No. E-27 energy charges use on-peak and off-peak kWh, while the demand charge uses the billing cycle's maximum 30-minute on-peak demand. The worksheet models those changes separately and never infers a demand reduction from shifted kWh.