Seattle City Light Time-of-Use Rates: Complete Guide and Rate Breakdown

Seattle City Light offers Time-of-Day (TOD) rate plans—commonly referred to as Time-of-Use (TOU) rates—allowing residential and commercial customers to lower their electricity bills by shifting power consumption away from peak demand hours. By charging higher rates during high-demand peak periods and lower rates during overnight and weekend off-peak hours, this pricing structure rewards strategic energy management, particularly for electric vehicle (EV) owners and homes with automated energy systems.

Understanding Seattle City Light’s Rate Structures

Seattle City Light (SCL), the municipal electric utility serving the City of Seattle and several surrounding franchise cities, traditionally bills residential customers using a two-tiered block rate structure. Under standard residential rates, customers pay a set price for a baseline amount of electricity each day (Block 1, covering up to 10 kilowatt-hours per day) and a higher rate for any usage exceeding that baseline (Block 2).

While the standard tiered structure is straightforward, it does not account for when electricity is consumed. Electrical grids experience severe stress during specific windows of the day—typically when residents wake up and start their morning routines, or when they return home from work in the evening to cook, run HVAC systems, and charge devices. Generating and distributing electricity during these peak windows costs the utility substantially more.

To address grid congestion and encourage regional decarbonization, Seattle City Light introduced voluntary Time-of-Day (TOD) rate schedules. Under a Time-of-Use framework, the price per kilowatt-hour ($\text{kWh}$) fluctuates based on the time of day, day of the week, and seasonal factors. Customers who can automate or manually shift flexible electric loads—such as charging electric vehicles, running dishwashers, or heating domestic hot water—can reduce their total utility costs compared to standard block rates.

Seattle City Light serves both customers inside the Seattle city limits and residents in surrounding service areas, including Shoreline, Lake Forest Park, Burien, SeaTac, Tukwila, Normandy Park, and parts of unincorporated King County. Rate schedules vary slightly between Seattle proper and these suburban franchise cities due to local municipal taxes and franchise contract agreements, making it essential to evaluate the specific rate schedule applied to your service address.

Seattle City Light Time-of-Day (TOD) Rating Periods

Seattle City Light divides the day into distinct pricing windows for customers enrolled in Time-of-Day rate programs. These time windows reflect regional power demand patterns across the Pacific Northwest grid.

1. On-Peak Hours (Highest Rate)

On-Peak hours correspond to the two primary demand surges on the municipal grid each weekday:

• Morning Peak: 6:00 AM – 10:00 AM (Monday through Friday)
• Evening Peak: 5:00 PM – 9:00 PM (Monday through Friday)

During these periods, wholesale electricity market prices rise, and regional transmission networks operate near peak capacity. Electricity consumed during On-Peak hours carries the highest charge per kWh under the Time-of-Day schedule.

2. Mid-Peak Hours (Moderate Rate)

Mid-Peak hours occur during daytime and late-evening hours when grid activity is steady but not strained:

• Midday Window: 10:00 AM – 5:00 PM (Monday through Friday)
• Night Window: 9:00 PM – 10:00 PM (Monday through Friday)

Mid-Peak rates are priced moderately, sitting close to or slightly below the average rate of standard residential electricity plans.

3. Off-Peak Hours (Lowest Rate)

Off-Peak hours represent periods of low grid demand across the Pacific Northwest:

• Nighttime Window: 10:00 PM – 6:00 AM (Monday through Friday)
• Weekends & Major Holidays: All hours on Saturdays, Sundays, and official utility-observed holidays (including New Year’s Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day).

Off-Peak rates offer the lowest cost per kWh. For households with high flexible energy usage, maximizing electricity consumption during this 8-hour overnight window provides the primary pathway to rate savings.

Residential Rate Comparison: Standard vs. Time-of-Day

To evaluate whether switching to a Time-of-Use schedule is beneficial, it helps to examine how charges are calculated under standard residential rate structures versus optional Time-of-Day rate structures.

Seattle City Light rate schedules include a daily base service charge (a fixed fee assessed regardless of consumption) plus volumetric charges measured in cents per kilowatt-hour ($\text{¢/kWh}$). Official rate schedules are reviewed and established by the Seattle City Council through municipal rate ordinances and published on the Seattle City Light Rates portal.

The following table provides a structural comparison of Seattle City Light's standard residential rate framework against the Time-of-Day schedule for residential service inside the Seattle city limits.

Note: Specific per-kWh rates are adjusted periodically through City Council ordinances and power cost adjustment factors. Refer to official Seattle City Light rate cards for current effective figures.

Understanding Suburban Franchise Differences

For customers living outside Seattle proper—in franchise cities like Shoreline, Burien, or Tukwila—Seattle City Light applies a franchise contract differential. This administrative fee or percentage multiplier accounts for local taxes and right-of-way costs negotiated between Seattle City Light and the respective municipal government. While the Time-of-Day hours (On-Peak, Mid-Peak, Off-Peak) remain identical across all service territories, the base rate per kWh in franchise cities includes this differential factor.

Who Benefits Most from Time-of-Use Rates?

Switching to Time-of-Day rates is not guaranteed to lower every customer's bill. Because On-Peak rates carry a cost premium, households that consume high volumes of electricity between 6:00 AM–10:00 AM and 5:00 PM–9:00 PM on weekdays without shifting load could see higher monthly bills.

• High Savings Potential
  
  
  • Electric Vehicle (EV) owners
  • Programmable heat pumps/HVAC
  • Home battery storage systems
  • Smart water heater controllers
• Low Savings Potential
  
  
  • Home full-time during peak
  • Inability to shift laundry/wash
  • Resistance heating during peak
  • High weekday morning/eve load

1. Electric Vehicle (EV) Owners

Electric vehicles represent one of the largest single electrical loads in a residential home. A typical EV battery capacity ranges from 50 kWh to 100 kWh. Charging an EV from 20% to 80% requires between 30 and 60 kWh—equivalent to several days of standard household electricity usage.

If an EV owner plugs in at 6:00 PM upon arriving home under a TOD rate, they charge during the evening On-Peak window, incurring the maximum rate. However, by using an onboard vehicle timer or a smart Level 2 EV charger (such as ChargePoint, Wallbox, or Tesla Universal Wall Connector) scheduled to begin charging at 10:00 PM, all vehicle charging occurs at the lowest Off-Peak rate. EV owners who commute regularly often realize substantial financial savings under Time-of-Day pricing.

2. Homes with Ductless Heat Pumps or Smart Thermostats

Heating and cooling represent significant energy expenditures in Western Washington homes. While Seattle's mild climate means air conditioning needs are moderate, winter heat pump or electric resistance heating load can be substantial.

Residents with programmable thermostats (e.g., Nest, Ecobee) can utilize "pre-heating" or "pre-cooling" strategies:

• Winter Strategy: Warm up the house between 4:00 AM and 6:00 AM (Off-Peak), then set back the thermostat by 2–3 degrees during the morning peak (6:00 AM – 10:00 AM).
• Summer Strategy: Cool the residence during Mid-Peak hours (10:00 AM – 5:00 PM), then minimize compressor activity during the evening peak (5:00 PM – 9:00 PM).

3. Integrated Home Battery Systems

Homeowners with installed energy storage systems, such as Tesla Powerwall, Enphase IQ Batteries, or SolarEdge Energy Bank, can take direct advantage of tariff arbitrage:

• Charge Phase: Store energy from the grid during Off-Peak hours (10:00 PM – 6:00 AM) or from rooftop solar arrays during midday.
• Discharge Phase: Program the battery inverter to supply all household loads during On-Peak windows (6:00 AM–10:00 AM and 5:00 PM–9:00 PM), preventing high-cost grid draws entirely.

4. Direct Water Heater Controls

Electric tank water heaters continuously cycle to maintain water temperature. Installing a timer or smart controller on a standard 240V electric water heater allows homeowners to disable heating elements during peak windows while ensuring hot water remains available from storage, reheating the tank overnight during Off-Peak rates.

How to Calculate Potential Savings: A Case Study

To see how Time-of-Day pricing functions in practice, consider a representative Seattle household consuming 800 kWh per month during the winter season.

Consumption Breakdown Scenario:

• Unoptimized Household (Standard Habits):
  
  
  • On-Peak (Weekday Peak): 35% of energy (280 kWh)
  • Mid-Peak (Weekday Midday/Late): 35% of energy (280 kWh)
  • Off-Peak (Nights & Weekends): 30% of energy (240 kWh)
• Optimized Household (Load-Shifted Habits with EV):
  
  
  • On-Peak (Weekday Peak): 10% of energy (80 kWh)
  • Mid-Peak (Weekday Midday/Late): 30% of energy (240 kWh)
  • Off-Peak (Nights & Weekends): 60% of energy (480 kWh)

In the unoptimized scenario, high On-Peak usage results in overall costs that equal or slightly exceed standard Block 1/Block 2 billing. In the optimized scenario—where EV charging, dishwashing, and laundry are automatically scheduled after 10:00 PM or on weekends—60% of total energy consumption falls into the lowest rate tier, yielding net monthly utility savings.

Customers considering a switch can analyze their historical consumption patterns using Seattle City Light's online customer portal, which provides hourly interval data recorded by smart meters.

Eligibility and Requirements for SCL Time-of-Day Rates

Before requesting a rate switch with Seattle City Light, ensure your account meets the following operational prerequisites:

1. Advanced Metering Infrastructure (AMI): Your property must have an operational digital smart meter installed by Seattle City Light. Standard smart meters transmit 15-minute or hourly interval consumption data to the utility. If your property still has an older electromechanical meter or an uncommunicative meter, SCL will need to exchange or update the unit before enrolling you in TOD pricing.
2. Account Status: The account must be active and in good standing without pending service disconnection notices. Both residential homeowners and renters (where electricity is billed directly to the tenant) are eligible for rate schedule modifications.
3. Solar Net Metering Considerations: Customers enrolled in Net Energy Metering (NEM) with rooftop solar panels should consult with Seattle City Light’s Solar Team before switching. Under TOD pricing, solar energy generated during Mid-Peak hours (daytime) offsets consumption at Mid-Peak rates, while evening peak consumption occurs when solar output drops, requiring careful alignment between generation and battery storage systems.
4. Commitment Period: Rate plan changes typically require a minimum commitment period (often 12 months) to allow for an accurate annual comparison across summer and winter billing cycles before switching back to standard tiered rates.

How to Enroll or Switch Rate Plans

Enrolling in Seattle City Light's Time-of-Day rate schedule can be completed online or over the phone.

1. Log in to the Seattle Services Portal (seattle.gov/city-light)
2. Navigate to Account Management > Rate Options
3. Review hourly consumption history via AMI meter charts
4. Select "Time-of-Day Rate Schedule (TOD)"
5. Confirm enrollment and note effective billing cycle start

Step-by-Step Online Process:

1. Access the Portal: Visit the official Seattle City Light Portal and log into your primary utility account.
2. Review Meter Data: Navigate to the "Usage" tab to examine your 24-hour interval data over recent months. Identify what percentage of your current electricity consumption falls into weekday peak windows (6–10 AM and 5–9 PM).
3. Submit Request: Select "Change Rate Schedule" under account options, choose the Residential Time-of-Day plan, and submit the request.
4. Confirmation: Seattle City Light will process the request, verify AMI meter interval connectivity, and notify you of the official start date—typically beginning on the first day of the subsequent billing cycle.

If online access is unavailable, customers can reach Seattle City Light Customer Care by calling (206) 684-3000 during standard business hours.

Practical Load-Shifting Strategies for Seattle Residents

Transitioning to a Time-of-Use rate schedule requires minimal manual effort if you take advantage of modern smart home technology and automated schedules.

1. Automate Heavy Appliances

• Dishwashers: Most modern dishwashers feature a "Delay Start" button. Set the dishwasher to delay operation by 2 to 4 hours after dinner so it runs past 10:00 PM.
• Washing Machines & Clothes Dryers: Electric dryers draw between 2,000 and 5,000 watts. Run laundry loads on weekends when Off-Peak rates apply all day, or during weekday mid-day hours (10:00 AM – 5:00 PM) rather than the 5:00 PM – 9:00 PM peak.

2. Configure EV Charging Schedules

• Set your EV's onboard charge timer or your wall-box charger app (e.g., Tesla App, JuiceBox, ChargePoint) to a fixed window of 12:00 AM to 6:00 AM.
• Disable "Charge Immediately Upon Plug-in" settings to prevent automatic charging when plugging in right after work during the 5:00 PM – 9:00 PM peak.

3. Smart HVAC Scheduling

• Install a smart thermostat capable of scheduling seasonal temperature setbacks.
• In winter, program heat pumps or furnaces to lower indoor temperatures by 2–3 degrees at 6:00 AM and 5:00 PM, returning to standard comfort settings during Mid-Peak or Off-Peak hours.

4. Monitor Standby Loads and Phantom Draws

• While minor electronics (TVs, routers, computers) consume relatively little power individually, using smart power strips to turn off entertainment centers or home office equipment during peak windows ensures baseline energy draw remains low.

Frequently Asked Questions

What happens if I use electricity during On-Peak hours on a Time-of-Day plan?

If you use electricity during On-Peak hours, you are billed at the higher On-Peak rate per kWh for that specific consumption. You do not incur penalty fees or lose program eligibility; your bill simply reflects the higher rate for energy consumed during those specific hours.

Are weekends included in Peak hours for Seattle City Light?

No. All weekend hours (Saturday and Sunday) are classified as Off-Peak under Seattle City Light's Time-of-Day schedule. You pay the lowest rate per kWh all day long on weekends.

Can renters enroll in Seattle City Light Time-of-Use rates?

Yes, as long as the Seattle City Light electric account is directly in the tenant's name and the property is equipped with an AMI smart meter. If utility costs are included in a flat rent payment or managed directly by the landlord, rate selection remains under the property owner's account control.

How do official city holidays affect Time-of-Day rates?

On official utility-observed holidays—such as New Year's Day, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day—all 24 hours are billed at the lowest Off-Peak rate, matching weekend billing policies.

Is Time-of-Day pricing mandatory for Seattle City Light customers?

No. Time-of-Day pricing remains voluntary for residential customers in Seattle City Light's service area. Customers who prefer predictable baseline rates regardless of time can remain on the standard residential tiered schedule.

Next Steps and Action Plan

To decide whether switching to Seattle City Light's Time-of-Day rates makes financial sense for your household, follow this action plan:

1. Analyze Your Interval Data: Log into your Seattle City Light Account and review your hourly usage graphs for the past 30 to 90 days.
2. Identify Shiftable Loads: Estimate how much energy you can relocate to off-peak hours (e.g., EV charging, laundry, water heating). If EV charging or flexible loads make up more than 30–40% of your total consumption, a TOD rate plan will likely reduce your monthly bills.
3. Automate Before Enrolling: Set up built-in timers on your EV charger, appliances, and smart thermostats to verify that shifting usage fits your daily schedule.
4. Submit Your Rate Switch Request: Contact SCL customer service or submit a rate change request through the online portal to start saving on your next billing cycle.