Oh, jeez, that’s what happens when I sleep deprived!
I saw a xeroxed sheet of jokes many decades back, that was “redneck definitions of technical terms”, or some such. One of them was “Nitrate”, defined as “cheaper than the day rate”. So time-of-day metering is a lot older than widespread renewables or electric cars.
That may be true but I’m pretty sure that they were referring to cheap hotels that were rented by the hour.
I bet it’s about long distance telephone calls. They had day, evening, & night rates. I’m not remembering the cutoffs, but I think night started late, maybe 11pm.
Anyhow a long distance call at night rate was less than half of day rate.
Even earlier, referring to telegrams.
Western Union had both night messages and night letters, both accepted up to 2:00 am for delivery at start of business the next day.
Other businesses had night rates as well, including those mentioned above, but the joke started about telegrams. I traced it back to 1865. Buffalo Post, Oct. 24, 1865, p. 4.
Anybody can tell you about the day rate of gold, but who, now that the Evening Exchange is closed, can tell you about the nitrate of silver?
By 1880, the joke was slimmed down to “Is the nitrate of silver higher or lower than the day rate?”
At the time, nitrate of silver was used as an antiseptic, so it was a familiar household item.
All jokes, including dad jokes, are older than you think.
Time of use started in the 1970s with industrial customers. It required special mechanical meters that had a clock built into them. At the appropriate time, the clock would trigger a solenoid that would switch specific gears in and out of the meter to change the rate. The actual measurement was still done by spinny disks.
There were some small-scale programs to implement time of use for residential service, and those also used mechanical meters, but widespread time of use billing didn’t really take off until the 1990s and 2000s when the old fashioned meters started being replaced by smart meters.
This was long before electric vehicles became popular.
Utility companies don’t usually offer time of use billing until they have already put smart meters into widespread use. They don’t replace your meter just to add this service.
By now, most utilities have already replaced the old mechanical meters, and most areas do offer time of use billing.
Most gas and water utilites have also already switched to smart meters.
Yeah, as LSLguy pointed out, I got my water meter mixed up with my electric meter. The electric meter is new-ish. The water meter is ancient. I should find out in a week whether my electric meter is new enough.
I got a new electric meter back in 2021, a new gas meter in 2025 and a new water meter meter in February so I guess we’re all set.
The city utility offers TOU billing for power and, owning an EV, at first glance it sounds really attractive. For summer months the rate is 5.3¢ per kWh. With the TOU schedule from 5am to 11am, and 5pm to 11pm it stays at that rate while from 11am to 5pm it rises to 16¢ and from 11pm to 5am it drops to 0.2¢(!)
Unfortunately there is also an Electric Energy Supply Cost Adjustment which amounts to about 180% of the kWh charge and I have the sneaking suspicion that does not get changed with the time of day. When that is factored in along with the service charge and taxes I’m paying 17 to 19 cents instead of the nominal 5.2 cents per kWh. That would mean I would be paying about 24¢ during the day when I do have to run the heat pump.
There are also old “new” meters that are basically two spinning disks. A clock inside the meter or a radio signal switches between which of the disks is being used.
That was/is a common way to implement peak/off-peak pricing.
I’m in Hawaii, Oahu. The peak rate here in Mililani is between 3pm and 9pm, dinner and probably laundry time. We’re cheapest between 9pm and 3am. That’s when I set the car to charge. This “on your honor” thing is a misunderstanding by someone. Just set the car to charge during off peak hours 
Here we have three options:
- Tiered rates, with the first x kWh per month at a lower rate, everything above at a 20% premium.
- Traditional time-of-use with three rate bands Monday-Friday. The bands change in the Spring and Fall to match the seasonal change in loads on the system. Weekends and holidays are always at the lowest rate.
- Ultra-low overnight rates which changes the weighting to encourage overnight usage for EV charging.
You can switch your rates for the following month by going on the portal and a handy tool shows you what you would have paid for each by month based on your actual usage.
Since I work at home and don’t have an EV, tiered works best for us most of the time but probably by less than $10 a month on the the upside.
Independent of time-of-use pricing, some providers do offer the option of locking in a fixed rate for a given term, e.g., 12 months or 24 months, or you can take your chances with the market and go for a variable-rate contract.
I participate in a similar plan related to air conditioning in the summer: during high-use periods, the electricity system operator can remotely reduce the amount of AC we’re using. In exchange, we get $20 per year.
I had to send photos of my heat pump to get the lower rate for off-peak usage. Funny thing is , Con Ed paid for almost the entire cost of switching to heat pumps.
I got a partial rebate on my heat pump from my guys too but it was after I had already switched plans. I qualified from my EV which is where I am really saving money on the lower rate since I live in a temperate area and only use the heat in the cold months and only then periodically. I use the AC very infrequently.
That’s not unusual or novel at all. I had that setup on my HVAC in Las Vegas in 1985, ~40 years ago.
Now here in Florida there are similar programs to allow the utility to manage some or all of my high draw items.
I’m a bit surprised @Filbert is surprised. Then again, the UK is a much different place w a much different climate than either southern Canada or the southern USA.
Last fall Xcel here in Colorado modified the time of use so peak is only from 5pm-9pm, and off peak is everything else. They got rid of the mid level “shoulder” time, and extended off peak to run all afternoon.
I’m convinced this is because of the penetration of solar.
I adjusted when the car is allowed to charge, but I still need to change the thermostat’s programing before I turn on the AC.
A system where you cannot turn the heating or hot water on at all except overnight during the hours the energy company chooses is normal in the US? It was only a thing in the UK in a tiny bit of Scotland for a short period, because it was so obviously a terrible plan.
Very likely so.
Here in Oz, solar has changed the game hugely. My state (South Australia) has had a huge amount of churn in the electricity supply sector. Back in 1991 there was a major financial disaster when the state owned bank collapsed. The bailout was crippling. In 1999 the government (now the opposite party) sold the entire state owned monopoly electricity system to pay off the debt. At the time we had a large amount of coal fired electricity with wind and solar still little more than science fiction. One draw for private players buying into the market was the premium pricing for daytime power in the summer that was charged to run everyone’s air conditioning. (Obviously more than this, but this was a real thing.)
Fast forward to today. The coal power has gone. End of life, with no economic benefits path to upgrade or rebuild. And daytime power prices in the summer goes into negative numbers with an enormous amount of installed solar. Just about everyone who can has a solar array on their roof which generates excess power in addition to keeping one’s house blissfully cool.
Despite the political controversy that surrounded the sale of the power generation plants, they were almost certainly sold at the peak of their value and quickly became essentially stranded assets for their new owners.
My state is something of an extreme example, as we have so much installed renewable electricity infrastructure. Lots of domestic solar, lots of commercial solar, and lots of wind. There are days when that is enough to power the entire state. Right now, mid Saturday afternoon in our autumn, wholesale electricity is exactly zero dollars. Once the sun goes down it will jump up, and tomorrow evening when we hit the Sunday night peak it will spike. Lots of volatility. We also have lots of battery capacity, and you can see them sucking in energy during the day and making big when the evening peaks hit. The batteries also make money supplying grid stability. Which is import as with the loss of traditional generation we lose the inertia of big spinning generators. This became a clear issue about 10 years ago when a storm took out a countryside distribution pylon, triggering a total collapse of the state grid which took days to bring back. Installation of the first ever commercial battery occurred in direct response to this. That battery was such a huge commercial success, paying for itself quickly by selling stability, that batteries continue to be installed at an extraordinary rate, now playing time shifting as well.
All of this significantly changes the market. However despite all the above, country wide, we are still over 60% coal. Other states have significant coal infrastructure. Interconnections between the states allow power to be traded in a unified market and there are times when my state is sucking on interstate coal power for almost all it’s needs.
No. It doesn’t exist at all. You can set up your system to not do that to save money but you can override the system at any time.
In any event, there is no normal in the US. Every State and utility in that State will have different rules but that isn’t one of them