Most people think electricity has one price - when you use your dishwasher, it’s the same price to run at 8 AM or 8 PM. While that’s how it used to work, millions of Americans are now on Time-of-Use plans, which charge people for their energy use depending on the time of day, with the price of electricity nearly doubling during certain hours of the day.
I found this out the hard way when I started digging into actual utility tariff filings. Buried in a PDF that no normal person would ever red was a chart showing that the electricity coming out of your wall at 6 PM costs almost twice what it costs at noon.
What frustrates me wasn't the pricing itself – there's actually a reasonable explanation for why it works this way. What frustrates me is that nobody explained it to me. You're just supposed to figure it out on your own while staring at a number on your bill that keeps going up.
So, why does electricity pricing work this way?
How the Duck Curve Drives Peak Electricity Prices
Most people think of electricity like water: turn on the faucet and you pay per gallon that comes out. Water is sourced from various natural springs across the country, stored in water tanks ready to be deployed when needed. However, electricity doesn't work that way. Electricity can't be stored in large amounts for long periods of time. Every single watt you use has to be generated at the exact moment you flip the switch.
In states with a lot of solar energy, like California, this spike is even more dramatic. During the middle of the day, solar panels flood the grid with so much cheap electricity that wholesale prices can drop close to zero. Around 4 PM, the sun starts setting and solar generation drops fast at the exact moment demand is ramping up. In about two hours, the grid has to replace millions of kilowatts of disappearing solar with other power sources like expensive natural gas peaker plants.
If human behavior reflected the natural ebb and flow of energy generation, this wouldn’t be much of a problem. However, electricity demand follows a predictable pattern. It's low overnight when most people are sleeping, rises in the morning and stays moderate through the afternoon. Then, between 4 PM and 9 PM, demand spikes. Everyone comes home from work at roughly the same time. They turn on the heat or air conditioning, cook dinner, run the dishwasher, charge their phones, turn on TVs and computers. All of this hits the grid at once.
Energy experts call this the "duck curve" because the shape of the demand graph looks like a duck. It's the reason electricity at 6 PM can cost five to ten times more to generate than electricity at noon.
Think of it like rideshare pricing. At 2 PM on a Tuesday, an Uber across town might cost $12. At 11 PM on New Year's Eve, that same ride could cost $45. The car and distance are the same. However, demand is through the roof, and the cost of supplying that ride goes up. Now, add the fact that there might be fewer cars at 11 PM on New Year's Eve because fewer people want to drive at that time – that spikes demand even more.
Why Utilities Started Charging Different Prices at Different Times
For decades, most Americans paid a flat rate for electricity. When everyone paid the same rate, people who consumed most of their power during cheap, off-peak hours were effectively subsidizing people who consumed most of theirs during expensive peak hours. A retired couple running appliances during the day paid the same rate as someone blasting the heat from 5-9 PM every night, even though the evening electricity cost far more to produce.
Time-of-Use pricing is the utility industry's attempt to fix that. The idea is straightforward: charge more when electricity costs more to generate, and charge less when it's cheap. If enough people see the price difference and shift their usage away from peak hours, then the evening demand spike shrinks, fewer peaker plants need to fire up, and the whole system gets cheaper for everyone.
This isn't just a California thing anymore. It's spreading fast:
- California made Time-of-Use the default residential rate plan. Most PG&E and Southern California Edison customers are already on TOU unless they opted out.
- Colorado's Xcel Energy switched to TOU as the default rate structure in late 2025. On-peak rates are now 2.7 times higher than off-peak.
- Texas has variable-rate and "free nights" plans that function similarly, where the time you use electricity directly affects your cost.
- Utilities across the Northeast, Southeast, and Midwest are rolling out TOU options as smart meter adoption passes 75% of US homes.
What This Actually Costs You
The price difference between peak and off-peak electricity is significant. Here's a rough sense of what it looks like across different utilities:
Utility / Region
Peak Hours
Off-Peak Rate
Peak Rate
PG&E (California)
4-9 PM daily
~$0.35-$0.40/kWh
~$0.50-$0.60/kWh
SCE (California)
4-9 PM daily
~$0.30-$0.36/kWh
~$0.45-$0.55/kWh
Xcel (Colorado)
5-9 PM weekdays
~$0.08-$0.10/kWh
~$0.22-$0.27/kWh
Texas (varies)
1-6 PM summer
Varies by plan
Varies by plan
The percentage premium varies by region, but the pattern is consistent: peak electricity costs 40-70% more than off-peak in most markets, and in some cases nearly double.
Let's put that in real dollars. Say you're a household using 500 kWh per month, meaning you usually pay ~$225 per month for your electricity bill. If 40% of your usage happens during peak hours, which is typical for someone who works outside the home, you're paying roughly $30-$50 more per month than you would if you could shift all of that usage to off-peak. Over a year, that's $360-$600 in peak pricing premiums that most people don't realize they're paying.
Where Time-of-Use Pricing Hits Hardest
Not every part of the country feels this equally. The impact depends on how your state's electricity market works, how much solar is on the grid, and how aggressively your utility has adopted time-based pricing.
California
California has the most aggressive TOU adoption in the country. Most residential customers are already on Time-of-Use by default. Because California has so much solar generation, Californians face the widest peak-to-off-peak price spread of any state, on top of rates that are already the highest in the continental US. If you're on TOU in California and most of your usage hits the 4-9 PM window, peak pricing is likely adding at least $40-$80 per month to your bill.
Texas
Texas runs a deregulated electricity market, which means consumers can choose from dozens of rate plans, many of which have time-based pricing baked in. "Free nights" and "free weekends" plans sound great, but they offset those free hours with significantly higher daytime rates. If you're on a variable-rate plan in Texas, wholesale price swings reach you much faster than in regulated states. Summer afternoons can be brutally expensive when AC demand peaks statewide.
Colorado and the Mountain West
Colorado is early in its TOU rollout, but Xcel Energy's new default rates set on-peak pricing at 2.7 times the off-peak rate. That's one of the steepest peak multipliers in the country. Customers can opt out to a flat rate, but the flat rate is set between peak and off-peak, meaning it's more expensive than off-peak for everyone. If you can shift your usage, TOU saves you money. If you can't, you're paying more than you would have on the old rate.
New England and the Northeast
TOU adoption in the Northeast is still mostly optional, but the region faces its own version of the peak pricing problem. New England relies heavily on natural gas for electricity and has limited pipeline capacity, which makes winter evening electricity especially expensive. When everyone comes home and turns on the heat at the same time that natural gas supply is constrained, wholesale prices can spike dramatically. Households in deregulated states like Massachusetts and Connecticut who are on variable-rate or TOU plans feel this immediately.
Most Insulated Regions
The Pacific Northwest (Washington, Oregon) is the least exposed thanks to cheap hydroelectric power that runs around the clock. States with heavy nuclear or wind generation (Illinois, Iowa, Kansas, South Dakota) also have a natural buffer because their generation costs don't swing as dramatically between peak and off-peak hours. If you live in these areas, TOU pricing has less bite.
A 5-Minute Peak Pricing Check
Here's how to quickly figure out whether peak pricing is quietly making your bill more expensive than it needs to be.
Step 1: Find your rate plan
Log into your utility account and look at your most recent bill. Find the name of your rate plan. If it says "Time-of-Use," "TOU," or includes the words "peak pricing," you're on a plan where the time of day affects what you pay. If you're in California and haven't actively chosen a plan, you're almost certainly on TOU already.
Step 2: Check your peak hours
Look up when your utility's peak hours are. For most utilities, it's something like 4-9 PM or 5-8 PM. This matters because it tells you which hours are costing you the most.
Step 3: Look at your hourly usage
Most utilities now have an hourly usage chart in their online portal, thanks to smart meters. Pull up a recent month and look at when your usage spikes. Do you see big bars between 4-9 PM? That's the most expensive window. If most of your usage lands there, peak pricing is hitting you hard.
Step 4: Estimate the impact
A rough rule of thumb: if more than 30-40% of your electricity is used during peak hours, you're paying a meaningful premium. The question becomes whether you can realistically shift any of that usage, or whether a different rate plan would cost less for your specific pattern.
How to Reduce Your Time-of-Use Electricity Costs
I'm not going to tell you to never cook dinner or sit in the dark until 9 PM. Here are the realistic levers:
- Delay your dishwasher and laundry. Most machines have a delay-start timer – set them to run after your peak window ends.
- If you have an EV, charge it overnight. Charging during peak hours can add $30-$60 per month compared to charging after midnight, depending on your rate plan.
- Pre-heat or pre-cool your home before peak hours start. If you're home in the afternoon, run the heat or AC before the peak window, then lower it during peak. Your home holds temperature for a while, and you'll avoid paying the highest rate for the most energy-intensive appliance in your house.
- Check if a different rate plan saves you money. Many utilities offer multiple TOU options with different peak windows. Some have narrower peak periods. Some have weekday-only peaks. If your usage pattern is concentrated in a specific window, a different plan might save you money. The frustrating part is that most utilities don't make it easy to compare what you would have paid on each plan.
Why We're Building Nura
Your utility doesn't show you how much peak pricing is costing you. They don't show whether a different plan would be cheaper for the way you actually live and people are often left trying to decode tariff sheets that were designed for regulators, not for people.
That's what we're building with Nura. We connect to your smart meter data, show you what's actually driving your costs, and tell you whether a different plan would save you money. No hardware, no behavior change lectures. Just clarity.
You can join the Nura beta waitlist here. We're starting with PG&E and expanding to more utilities soon.