Electricity Rate Plan Optimizer
Find the most cost-effective electricity rate plan for your household. Compare flat, Time-of-Use, and tiered plans based on your usage, EV charging schedule, and solar system.
Flat Rate
Same price per kWh all day. Simple and predictable. Best for households without EVs or solar who use electricity evenly.
Time-of-Use (TOU)
Lower rates overnight, higher rates during peak evening hours. Best for EV owners who charge overnight and solar owners who export during peak hours.
Tiered Rate
Low base rate for first kWh, progressively higher for more usage. Works for low-consumption households. Penalizes high users — especially EV owners.
Disclaimer
This calculator provides estimates for informational purposes only. Actual solar production, savings, and payback periods depend on site-specific conditions including local weather, roof condition, shading, equipment selected, installer pricing, utility rate structures, and policy changes. Always obtain multiple quotes from qualified solar installers and consult a tax professional for incentive eligibility. Results should not be considered financial advice.
Choosing the Right Electricity Rate Plan
Your electricity rate plan has a larger impact on your monthly bill than most people realize — especially when you add an electric vehicle or solar panels. Different rate structures reward different consumption patterns, and choosing the right plan for your household can save $400 to $2,000 per year without changing how much energy you use.
TOU Plans and EV Charging
For EV owners, switching from a flat rate to a Time-of-Use plan is often the single highest-impact change you can make to reduce charging costs. Most utilities set off-peak rates (midnight to 6 AM) at 40 to 60 percent below the flat rate. An EV consuming 300 kWh per month at a flat rate of $0.20/kWh costs $60 monthly. On a TOU plan with $0.11/kWh overnight rates, the same charging costs just $33 per month — saving $27 monthly or $324 annually simply by charging while you sleep.
Tiered Rates: Watch Out With High Usage
Tiered rates are a trap for EV owners. The low first-tier rate looks attractive, but adding an EV pushes total monthly consumption well into the second and third tiers where rates can be 40 to 90 percent higher. A household that used 700 kWh per month now adds 300 kWh of EV charging, pushing 300 kWh into a higher tier at $0.35/kWh instead of $0.18/kWh. The incremental cost of that EV charging is nearly double what it would be on a flat rate — and triple what it would cost on a TOU overnight rate. If you're on a tiered rate with an EV, switching plans should be an immediate priority.
Frequently Asked Questions
What is a flat electricity rate and when is it best?
A flat rate (also called a fixed rate) charges the same price per kWh regardless of when you use electricity. It's the simplest plan and works best if you have predictable, evenly distributed consumption throughout the day. Flat rates are often best for households without EVs or solar that charge or export at odd hours. They eliminate the need to shift loads to off-peak times but miss out on potential savings available with time-of-use plans.
What is a Time-of-Use (TOU) rate and who benefits most?
Time-of-Use rates charge different prices depending on the time of day. Peak periods (typically 4 PM to 9 PM) are more expensive, while off-peak periods (overnight) are much cheaper. EV owners who charge overnight benefit significantly from TOU plans — off-peak rates as low as 10 to 14 cents per kWh compared to peak rates of 35 to 55 cents. Solar owners can also benefit by using more electricity during solar production hours (avoiding peak import) and exporting during peak hours when export credits are highest.
What is a tiered electricity rate?
Tiered rates (also called inclining block rates) charge progressively higher prices as monthly usage increases. For example: the first 500 kWh at $0.15/kWh, 501–1,000 kWh at $0.22/kWh, and above 1,000 kWh at $0.35/kWh. Adding an EV pushes usage into higher tiers, increasing the effective rate. Solar panels reduce overall usage, potentially keeping you in lower-cost tiers. EV owners in tiered-rate states often save the most by also adding solar to keep total consumption in lower tiers.
What EV-specific electricity rate plans are available?
Many utilities offer dedicated EV rate plans that provide very low overnight rates specifically for EV charging. Examples include PG&E's EV2-A in California (nighttime rates under 15¢/kWh), Southern California Edison's TOU-D-PRIME, and similar plans at Duke Energy, Xcel Energy, and others. These plans typically require a separate meter for the EV charger or use a smart EV charger that reports charging times. They can save EV owners $50 to $150 per month compared to charging on standard rates.
When is overnight EV charging most cost-effective?
Overnight EV charging (typically midnight to 6 AM) is most cost-effective for households on Time-of-Use or EV-specific rate plans. During these hours, many utilities offer rates that are 50 to 70% lower than peak daytime rates. Most EVs and home charging stations can be programmed to start charging at a specific time, allowing you to set it and forget it. Even on flat-rate plans, some utilities offer optional off-peak discounts for smart charging enrolled devices.
How can solar owners optimize electricity rate plans?
Solar owners should choose rate plans that maximize the value of exported electricity. Under Net Energy Metering (NEM) plans that credit solar exports at the full retail rate, time-of-use plans benefit solar owners who export during peak hours (when the export credit rate is highest). In California under NEM 3.0, where exports are credited at much lower rates, solar owners benefit most from maximizing self-consumption with battery storage and shifting load to solar production hours.
How much can I save by switching to the optimal rate plan?
Savings from switching to an optimal rate plan depend on your usage patterns, whether you have an EV or solar, and available plans in your area. EV owners switching from a flat rate to an EV-specific TOU plan can save $400 to $1,800 per year on charging costs. Solar owners on a favorable NEM plan vs a poor one can see $500 to $2,000 annual differences in bill credits. Most utilities allow free rate plan changes once per year, making it worth analyzing your options annually.
Data Sources
Data current as of February 2026. Rates and incentives are subject to change.