How does Salt River Project distributed energy resources measure system size?

The published limits do not say whether they are measured in alternating or direct current.

What does Class I, 20 kW or less require?

Only screens A, E and F apply, which are hosting capacity, transformer overload and 240 volt imbalance. No application fee or study deposit is published at any size. No insurance is required.

What does Class II, over 20 kW to 300 kW require?

All screens apply. Salt River Project states that it does not currently require technical studies or system modeling for projects below 1 MW.

What does Class II, over 300 kW to under 1 MW require?

All screens apply and an engineering review becomes mandatory.

Salt River Project distributed energy resources: tiers, fees and insurance

How the size is measured: not published

The published limits here are stated in kilowatts without saying whether that is the inverter rating in alternating current or the array rating in direct current. On a system near a threshold that decides which band it lands in, so the checker asks the question rather than choosing an answer.

Size bands and what each one obliges

Class I, 20 kW or less Size 0 to 20 kW	Only screens A, E and F apply, which are hosting capacity, transformer overload and 240 volt imbalance. No application fee or study deposit is published at any size. No insurance is required. Contractor submits the application before the system is installed Utility owned manual load break disconnect switch at customer cost Licensed dealer and installer under the specified Arizona classifications Two year installer warranty against defects and output degradation
Class II, over 20 kW to 300 kW Size 20.001 to 300 kW	All screens apply. Salt River Project states that it does not currently require technical studies or system modeling for projects below 1 MW. All published screens Utility disconnect switch, dedicated DER meter and system disconnect grouped within 10 feet
Class II, over 300 kW to under 1 MW Size 300.001 to 999.999 kW	All screens apply and an engineering review becomes mandatory. All published screens Mandatory engineering review
Class III and IV, 1 MW and above, three phase Size 1000 to 20000 kW	Detailed review. Three phase service is required at this size. Detailed review Three phase service

The screens that decide it

Within the 100 kW AC Renewable Export Program ceiling Limit 100 kW.
The Renewable Export Program takes a qualifying facility, with or without storage, of 100 kW AC or less. Storage only customers are not eligible.
Within the transformer overload rating
Screen E asks whether the aggregate generation including the proposal exceeds the transformer overload rating Salt River Project determines. Screen F adds a 240 volt imbalance ceiling of 20 percent of the service transformer nameplate between the two sides. Both need utility data.

Ask the utility this, before you sell it

Are the DER class thresholds measured on inverter AC nameplate? The handbook states them in kW AC but never defines the figure, and the lease requirement is written in kW DC.
What is the minimum hosting capacity on the most limited section of this circuit? Screen A is measured against it and the number is not public.
What administrative or study costs will be charged? Salt River Project reserves the right to charge for both and publishes no dollar amounts.
How long will review and permission to operate take? No timeline is published.

Worth knowing before you quote

There is no net metering. A new residential customer is paid an export credit, which Salt River Project itself distinguishes from net metering in writing. Published values are 3.45 cents per kWh on the time of use export plan and $0.0281 per exported kWh on E-14, with a temporary reduction of $0.0038 per kWh across the May to October 2026 billing cycles. The time of use export plan is being discontinued as of the November 2029 billing cycle, which is a material fact for a twenty five year savings model. No fifteen percent screen and no minimum load test exist; the screens are hosting capacity, fault current, protective device interrupting capability, transformer overload, 240 volt imbalance, transient stability and non inverter. The customer has six months from receipt of the program application for the facility to be installed and interconnected. Where the authority having jurisdiction issues no permit, the three line drawing must carry an Arizona professional engineer stamp. Prepay customers are force unenrolled when they take a customer generation price plan.

Source

Salt River Project Distributed Generation Interconnection Handbook, revision date 8 April 2026, with the Residential Distributed Energy Resource Program Requirements and price plan E-14

Read and recorded 2026-09-12. Publicly owned utility, outside its state's interconnection rule. Its own published documents govern. Salt River Project is a political subdivision outside Arizona Corporation Commission rate jurisdiction, so the state interconnection rules do not reach it.

All Arizona interconnection rules

Size bands and what each one obliges

The screens that decide it

Ask the utility this, before you sell it

Worth knowing before you quote

What to do with this