Rate Plan Optimization
Pick the plan that fits your solar—and actually use it right
Why Your Rate Plan Matters More Than Ever
Under modern net billing rules (like California’s NEM 3.0), the value of a kilowatt-hour depends entirely on when you use or export it. The right rate plan combined with smart timing can cut your bills by 30-50% without buying any new equipment.
The opportunity: Most solar homeowners are on their utility’s default rate plan—which is rarely the best option. By switching plans and adjusting just a few behaviors, you can dramatically reduce what you pay for grid electricity.
The 5-Step Rate Plan Optimization Method
Your Action Plan
Get Your Interval Data
Download hour-by-hour (or 15-minute) usage data from your utility’s website. Most utilities provide this through their online portal under “My Usage” or “Green Button Data.” This shows exactly when you’re using electricity throughout the day.
Overlay Your Solar Production
Pull production data from your solar monitoring app (Enphase, SolarEdge, Tesla, etc.) for the same time period. This lets you see when you’re making power vs. when you’re using it—the gap is what costs you money.
Identify Flexible vs. Fixed Loads
Flexible loads can be shifted to different times: EV charging, pool pumps, laundry, dishwasher, water heater (with timer). Fixed loads run when they run: refrigerator, WiFi, always-on devices. You can’t change fixed loads, but flexible loads are your opportunity.
Test Different Rate Plans
Use your utility’s rate plan calculator (most have one) or build a simple spreadsheet. Input your actual usage patterns into each available plan. Don’t forget to model simple changes like shifting EV charging to off-peak hours.
Pick & Implement
Choose the plan with lowest projected cost after applying realistic behavior changes. Switch plans through your utility’s website or customer service. Then actually implement those timing shifts—set EV charge timers, adjust pool pump schedules, use appliance delay timers.
Common Rate Plan Types Explained
Time-of-Use (TOU)
Electricity costs different amounts at different times of day. Typically: super off-peak (midnight-6AM), off-peak (morning/afternoon), and on-peak (4-9PM when demand is highest).
✓ Best For:
- Flexible schedules
- Ability to shift loads
- Battery storage owners
- Work-from-home with daytime solar use
✗ Watch Out If:
- Heavy evening cooking/AC loads you can’t shift
- Large family with rigid evening routines
- Can’t avoid 4-9PM usage window
Best for: Solar owners who can shift even 30% of evening usage to midday or overnight
Tiered / Flat Rate
Price per kWh is the same regardless of time (flat), or increases as you use more total energy in the month (tiered). Simple to understand, no timing games required.
✓ Best For:
- Unpredictable schedules
- Heavy evening usage that’s fixed
- Households where timing shifts are difficult
- Low total usage (self-consume most solar)
✗ Watch Out If:
- You can easily shift loads—leaving money on the table
- Using battery storage (timing matters)
- Very high evening usage vs. daytime
Best for: Solar owners with rigid evening loads who can’t meaningfully shift usage timing
EV-Specific Plans
Special rates designed for electric vehicle owners with dramatically cheaper overnight electricity (often 10-15¢/kWh vs. 40-50¢ peak). Usually requires separate meter or whole-home enrollment.
✓ Best For:
- EV owners who charge at home
- Overnight charging capability
- Can avoid charging during peak hours
- High annual EV mileage
✗ Watch Out If:
- Peak-hour rates are much higher than standard TOU
- You can’t always charge overnight
- Small home battery can’t cover evening loads
Best for: EV owners with consistent overnight home charging who can avoid all peak-hour usage
The Goldilocks Principle
There’s no universal “best” rate plan. The right plan matches your actual usage pattern plus realistic behavior changes you’ll stick to. A plan that theoretically saves $100/month but requires changes you won’t maintain is worse than a plan that saves $75/month with changes that fit your lifestyle.
Typical Time-of-Use Pricing Windows
Example TOU Rate Structure (Your Utility May Differ)
This represents a common California TOU plan structure. Check your specific utility for exact hours and rates.
Off-Peak
6AM – 4PM
9PM – 12AM
~$0.30/kWh
On-Peak
4PM – 9PM
~$0.55/kWh
Solar Production
Peak: 10AM – 2PM
Use it or lose value
The Evening Problem for Solar Owners
Notice the timing mismatch? Your solar peaks at noon when off-peak rates are low. Your home’s usage peaks at 6-8PM when on-peak rates are highest. This is exactly why rate plan optimization + timing shifts are critical under modern net billing.
High-Impact Load Shifting Strategies
EV Charging
Charge overnight (super off-peak) or during midday solar production. Never 4-9PM. Use your car’s built-in charge scheduler or EVSE timer.
Pool Pump
Run during peak solar hours (10AM-2PM) instead of evening. Most pumps need 6-8 hours daily—schedule for midday when solar is free.
Pre-Cooling/Heating
Cool your home to 68°F at 3PM (with solar), let it coast to 72°F by 9PM. Avoid running AC during on-peak hours. Smart thermostats make this automatic.
Water Heating
Heat water during off-peak or solar hours using a timer. Heat pump water heaters have scheduling modes. Set to heat 6-10AM and 2-4PM, not evenings.
Laundry & Dishes
Use delay-start timers to run dishwasher and laundry during off-peak hours (overnight or midday). Most modern appliances have this feature built-in.
Battery Strategy
If you have storage: charge from solar midday, discharge during on-peak evening hours (4-9PM). Avoid exporting when credits are low. Maximize self-consumption.
💡 The 80/20 Rule for Load Shifting
You don’t need to shift everything perfectly. Focus on the big three: EV charging, HVAC, and pool pumps. These typically represent 60-80% of your flexible loads. Get these right and the savings follow naturally.
Real Example: The Impact of Rate Plan Choice
Case Study: Same Solar System, Different Plans
Family of 4 in Southern California with 8kW solar system, one EV, pool pump. Here’s what their annual cost looked like under different plans:
Default TOU (No Changes)
Evening EV charging, pool runs 6-10PM, AC during dinner
$2,845/year
Baseline – no optimization
EV Plan + Load Shifting
Overnight EV charging, pool runs 11AM-3PM, pre-cooling before 4PM
$1,620/year
↓ $1,225 annual savings (43%)
This family spent zero dollars on new equipment. They simply switched rate plans and adjusted three timers: EV charger, pool pump controller, and smart thermostat. The changes took 30 minutes total.
Warning Signs: Time to Re-Shop Your Rate Plan
🚨 Check Your Rate Plan If You Notice:
- True-up bill grows year over year despite same solar production—your usage pattern or rates may have changed
- High evening charges despite strong daytime production—timing mismatch needs addressing
- Added major loads: EV, pool, heat pump, hot tub, or second refrigerator in garage
- Work-from-home status changed: Now home during the day (favor TOU) or back in office (may need different plan)
- Your utility introduced new rate options—utilities update plans regularly; new options may fit better
- Added battery storage—different rate optimization strategy with storage vs. without
- It’s been 2+ years since you last reviewed—good practice to check every 2 years minimum
Frequently Asked Questions
Q: Can I switch rate plans mid-year, or am I locked in?
A: Most utilities allow one or two rate plan changes per year. Some have restrictions like 12-month minimum enrollment for certain plans (especially EV plans). Check your utility’s specific terms. In California, TOU plans typically allow switching with 30 days’ notice.
Q: Is TOU always the best choice for solar owners?
A: No. TOU plans reward flexibility—if you can shift loads to off-peak hours, they’re usually best. But if your evening usage is fixed (large family, rigid schedules, medical equipment), a tiered or flat-rate plan might actually cost less even with solar. Run the numbers with your actual usage patterns.
Q: Do EV rate plans help if I don’t have an electric vehicle?
A: Generally no. EV plans offer very cheap overnight rates but compensate with higher peak-hour rates. Without an EV’s large overnight charging load to take advantage of the cheap hours, you’ll likely pay more during peak times than you save overnight. Exception: If you have large overnight loads (pool heating, etc.), run the numbers.
Q: How much can rate plan optimization really save?
A: Typically 20-40% annual reduction when combined with basic load shifting. Households with EVs and flexible schedules see the biggest gains. The key is picking the right plan AND actually implementing the timing changes—one without the other won’t deliver full savings.
Q: Will my utility notify me when better plans become available?
A: Rarely. Utilities aren’t incentivized to proactively move you to lower-cost plans. It’s your responsibility to check available options periodically (every 1-2 years) or when your usage patterns change significantly. Consider setting a calendar reminder to review annually.
Q: What if I have a battery—does that change my rate plan strategy?
A: Yes, significantly. With battery storage, you can shift solar from midday to evening, making TOU plans much more valuable. Your battery should charge from solar during the day and discharge during on-peak hours (4-9PM). This maximizes the value of time-based rates. Make sure your battery’s operating mode is set to “Self-Consumption” or “Time-of-Use” optimization, not “Backup Only.”
Wondering If You’re on the Right Rate Plan?
Our free calculator estimates your solar offset and recommended battery size — two key factors that affect which rate plan works best for your home.
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