SRP Time-of-Use Rates 2026: The Complete Guide for Solar & Battery Owners
Salt River Project serves over 1 million customers across the East Valley: Mesa, Tempe, Scottsdale, Gilbert, Chandler, and surrounding areas. If you are an SRP customer considering solar or batteries, the rate plan matters more than the panels themselves. SRP's rate structure is different from APS, and the savings strategies change accordingly.
SRP vs APS: the key differences
What makes SRP different from APS:
- Most SRP plans include a demand charge based on your highest single hour of usage during on-peak periods. APS does not have this charge.
- SRP replaced net metering with the Customer Generation Plan, which has higher fixed charges for solar customers.
- SRP peak is 2-8pm (vs APS 4-7pm), so the battery strategy is different.
- Summer rates (May-Oct) are significantly higher, similar to APS.
SRP E-27: the standard TOU plan
SRP E-27 Weekday Schedule (Year-Round)
SRP's 6-hour on-peak window (2-8pm) is twice as long as APS's 3-hour window. There's no super off-peak period.
E-27 is SRP's most popular residential TOU plan for customers without solar. It has both energy charges and demand charges.
| Period | Summer (May-Oct) | Winter (Nov-Apr) | Hours |
|---|---|---|---|
| On-Peak | ~$0.11/kWh + demand | ~$0.08/kWh + demand | 2-8pm weekdays |
| Off-Peak | ~$0.07/kWh | ~$0.06/kWh | All other hours |
| Demand Charge | ~$14.50/kW | ~$10.50/kW | Highest on-peak hour |
Note: Exact rates vary by billing cycle. Check your SRP bill or mysrp.com for current rates.
Understanding demand charges (this is the big one)
SRP E-27 Monthly Cost Breakdown — Typical Arizona Home
Based on 1,200 kWh monthly usage + 8 kW peak demand hour in summer.
This single charge is based on your HIGHEST peak-hour kW draw. Shaving peak demand with a battery directly cuts this line item.
Illustrative only — actual bills vary with seasonal rates, monthly adjustments, and fixed service charges. Winter demand charge drops to ~$10.50/kW.
The demand charge is what makes SRP different from APS, and harder to optimize. How it works:
- SRP looks at your highest single hour of electricity usage during on-peak periods (2-8pm weekdays).
- If your AC pulls 8 kW during one hot afternoon, you pay ~$14.50 × 8 = $116 in demand charges for the entire month.
- That one peak hour defines your demand charge for the whole billing cycle.
- This is why batteries are more valuable on SRP than APS. They shave the peak demand spike directly.
Real example: how demand charges add up
A typical 2,000 sq ft Mesa home with AC running might see 10-12 kW peak demand in summer. At $14.50/kW, that is $145-$174/month just in demand charges, on top of energy usage charges. A battery that caps the peak draw at 5 kW could save $72-$100/month in demand charges alone.
SRP Customer Generation Plan (E-27 CGP): for solar owners
If you install solar, SRP requires you to move to the Customer Generation Plan. This plan has:
- Higher monthly service charge: ~$32/month base fee (vs ~$20 on standard E-27)
- Lower energy credits for exports: Excess solar sent to the grid earns roughly $0.03-$0.04/kWh — much less than what you pay for grid power
- Same demand charges: The demand charge structure still applies
- Grid access charge: An additional per-kW charge based on your solar system size
This is why self-consumption matters more on SRP than on APS. Every kWh you use from your own solar panels avoids paying $0.07 to $0.11 per kWh and reduces the demand charge. Exporting to the grid only earns $0.03 to $0.04 per kWh.
Strategy 1: battery peak shaving (the biggest win on SRP)
Because of SRP's demand charges, batteries deliver more value on SRP than APS. The strategy:
- Charge battery from solar during the day (free energy)
- Discharge during 2-8pm to reduce your peak draw from the grid
- Target: Keep grid draw under 5 kW during on-peak — let the battery handle spikes
- Savings: Reducing peak demand from 10 kW to 5 kW saves ~$72/month in summer demand charges
Combined with energy arbitrage (avoiding on-peak energy rates), a well-sized battery on SRP can save $100 to $150 per month in summer. Use our Battery Calculator to estimate your specific savings. Even without solar panels, the math works. Our battery ROI guide breaks down standalone battery payback on APS and SRP TOU rates.
Strategy 2: solar self-consumption
With SRP's low export rates, oversizing your solar system doesn't help much. Instead, right-size your system to match your daytime usage. If you're new to solar, a DIY solar kit sized for your daytime loads is a low-cost way to start.
- Pool pump + AC: Run your pool pump during solar hours (9am-2pm) so solar covers it
- Pre-cool your home: Set your thermostat to 73°F at 1pm, then let it drift to 78°F during on-peak (2-8pm)
- EV charging: Charge your EV during the day while solar is producing
- Avoid exporting: Use a smart inverter or battery to soak up excess production
Strategy 3: load shifting (free, no equipment)
Even without solar or a battery, you can save on SRP by shifting high-draw activities away from on-peak (2-8pm weekdays):
- Run dishwasher, laundry, and dryer after 8pm or on weekends.
- Pre-cool the house before 2pm and avoid running AC hard from 2-8pm.
- Use a programmable thermostat with a pre-cool schedule.
- Avoid running multiple high-draw appliances at the same moment during peak. That single spike sets the demand charge for the whole month.
SRP vs APS: which is better for solar?
| Factor | SRP | APS |
|---|---|---|
| Peak Hours | 2-8pm weekdays | 4-7pm weekdays |
| Demand Charges | Yes (~$14.50/kW) | No |
| Export Rate | ~$0.03-$0.04/kWh | ~$0.076/kWh |
| Solar Fixed Fees | Higher (~$32/mo + grid access) | Lower (~$15/mo) |
| Battery Value | Very High (demand shaving) | High (arbitrage + VPP) |
| Best Strategy | Self-consume + peak shave | Battery arbitrage + VPP |
Bottom line for SRP customers
SRP's rate structure makes solar slightly less attractive than APS because of higher fixed fees and lower export rates. Batteries are more valuable on SRP because of demand charges. The combination that produces the best 2026 economics:
- Right-size your solar. Do not oversize, since exports earn almost nothing.
- Add a battery. Demand charge savings alone can justify the investment. See our best batteries for Arizona guide.
- Maximize self-consumption. Every kWh you use yourself avoids both energy and demand charges.
- Pre-cool aggressively. This is the single best free strategy for SRP customers.
- If your AC is due for replacement, you can stack up to $4,500 in heat pump rebates from federal and SRP programs.
Ready to see your numbers? Try our Solar ROI Calculator for a personalized estimate, or check the Battery Calculator to see how much a battery saves on SRP demand charges.
Tools to lower your SRP bill
SRP's demand charges make peak-hour usage especially expensive. These tools help shift load and reduce peak demand, the two biggest levers on an SRP bill:
Smart thermostat: flatten your demand spike
SRP charges $14.50/kW for peak demand in summer. Pre-cooling before 2 PM on-peak and ramping down during peak can shave 2-3 kW off the demand charge, saving $29-44/month just from the demand component.
ecobee Smart Thermostat Premium
~$220 — automates pre-cooling, learns your schedule. Pays for itself in one SRP summer billing cycle.
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Smart power strip: kill phantom loads
Electronics draw power even when "off." A smart power strip cuts phantom load during peak hours automatically. Useful for home offices and entertainment centers.
Smart Power Strip with Energy Monitoring
~$30 — WiFi-connected, schedule individual outlets, track energy usage. Eliminates phantom load during SRP peak hours.
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Kill A Watt meter: measure before you manage
Plug any appliance in and see exactly how many watts it draws. Essential for identifying which devices spike your SRP demand charge.
P3 Kill A Watt Electricity Usage Monitor
~$28 — see real-time watts and kWh for any device. Find the appliances driving your SRP demand charges.
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