Why don't electric utilities charge lower rates when demand is lower

Factual Questions
1

My son has a electric vehicle. It has a feature to only charge during certain time-of-day based on the owner’s setting. His town offers a lower rate if he sets his charger to only work from 22:00 to 07:00, but he is on his honor not to change the setting.

With today’s technology, why don’t power companies offer two rates to better offload peak demand. Electric water heaters, clothes dryers, and car charging come to mind.

Fifty years ago, my water heater had such a feature, but the clock was electric. If we had a power failure, the internal clock no longer showed the correct time.

2

They absolutely do, unless you choose a fixed-tariff plan.

3

Rather, many do. If you live in a place where yours doesn’t, the solution is to move.

4

the other (less charitable) way to look at this is that some charge more for electricity when there is peak demand

5

What an odd question. Time of Use plans are very common, especially since the ubiquity of electric vehicles.

It’s trivial to program my car to not charge during peak time and to remember to not use appliances in that zone as well.

6

As above - it is still a common offering in many places. I can charge my EV from midnight 'till dawn at a rate one tenth of the peak rate.

The problem for the utilities isn’t offloading peak usage, rather it is getting people to use “base load” production. They like to sell as much poer as they can at peak rates. This comes about because for large traditional heat engine driven power - coal and nuclear - it is difficult to vary the power production over short time scales. They like to spin generators at a constant power delivery with furnaces or reactors delivering steady energy. Overnight it makes a lot of sense to price power so that this capacity is used.

Renewables - solar and wind - are a problem is this traditional model. On one hand their power delivery can be throttled by the second, on the other, they are unreliable - and of the sun isn’t shining and the wind isn’t blowing you need to fall back to baseload generation. Batteries are expanding their reach, but a long way to go to fill the gap. Batteries go looking for the expensive times. No solar at night so nothing to offer at a cheap rate anyway.

Then you have gas turbine and diesel driven generators. They sit in the middle. More expensive overall, and smaller scale, they can ramp up and down with demand easily. So no value in offering off peak rates.

If you don’t have access to off peak power rates, it is likely because of the mix of power generation modes your supplier is using.

7

Jumping off of this point, my utility only offers time of use plans for people who have electric vehicles or electric heating/cooling. So those people who can make a big difference by changing their usage habits. (In reality they don’t ask for proof when you change your plan so anyone can participate)