Arizona · TEP net billing

Charging your EV on solar surplus with TEP (net billing)

Tucson Electric Power pays you 5.7¢ for each kWh of solar you export, and charges about 13.5¢ for each kWh you buy back. Putting that surplus into your car instead of the grid keeps the difference.

See your number How the math works
The spread

What TEP pays for solar vs. what it charges for power

Export credit
5.7¢/kWh
What an exported kWh earns
Blended import rate
13.5¢/kWh
What a kWh from the grid costs, averaged

A kWh you keep is worth 2× what it earns exported.

Tariff: RCP Net Billing · Rates as of July 2026. A reference figure, not a bill quote — your own rate depends on your plan, season and time of use.

TEP nets instantly and pays a fixed export rate locked at signup. Each new vintage can step down, so newer systems get less.

Worked example

One July month: export it, or drive on it?

An 8 kW system with 20 kWh/day of July surplus, and an EV driven 40 miles a day at 3.5 mi/kWh (about 11.4 kWh/day). The car can absorb 11.4 of the 20 kWh, so 343 kWh a month goes to the car instead of the grid.

Where the 343 kWh goesRatePer month
Exported to TEP5.7¢/kWh credit$19.54
Charged into your EV (grid imports avoided)13.5¢/kWh avoided$46.29
Difference from charging on solar$26.74

Illustrative; the calculator uses your zip and plan.

Does this apply to me?

Three things to check

Went solar before 2018? You may still be on legacy retail net metering, which credits exports 1:1 at retail for 20 years from interconnection — the gap on this page doesn't apply to you until that ends.

Compatible gear

Works with the equipment TEP homes already have

SolarEdge

Live SolarEdge production, plus grid and battery when you have a meter.

How it works →

Enphase

Enphase production, plus grid and IQ Battery when your system meters them.

How it works →

Tesla Wall Connector

Solar-only charging for a Tesla on any charger, including the Wall Connector.

How it works →

Your TEP number, from your zip

The calculator starts from TEP's rates for your zip and plan, then lets you adjust your system size and driving.

FAQ

Frequently asked questions

Does SundialEV work with TEP's RCP net billing?
Yes. SundialEV charges your EV from whatever solar your home would otherwise export, on any TEP plan. Your plan matters for the savings math: SundialEV values each kWh at your plan's rates (RCP Net Billing by default, and you can change it), and you can set avoid-hours so grid top-ups skip your peak window.
Do I need to install anything?
No. SundialEV connects through the cloud APIs of the gear you already own — your Tesla, your solar or battery system, or your wall charger. No extra meter, no new wall connector, no electrician.
How much will I save with TEP?
It depends on how much surplus you export and how much you drive. In the illustrative example on this page (20 kWh/day of July surplus, 40 miles a day), charging the car instead of exporting is worth about $26.74 a month at TEP's rates as of July 2026. The calculator runs the same math with your zip and plan.
Does this work without a Powerwall?
Yes. A Powerwall adds battery-priority options, but SundialEV works with solar and an EV alone: when there's surplus, it goes to the car.
Do I need a Tesla?
No. Tesla vehicles are controlled directly, and any other EV works through a supported wall charger — the Wallbox Pulsar Plus over OCPP, or an Emporia charger through Emporia's cloud — which SundialEV starts, stops and throttles to match your surplus.

Keep your TEP surplus in the car

SundialEV charges from your surplus automatically.

Get started on web Estimate your savings →