I got an electric car. My electric bill went down


Here's a moderately surprising result of switching to an electric car. Here in California, my electric bill went down. Just by a little, but in essence the (green) energy for my car is coming for free.

On my recent bill I used 900kwh and paid $168. 2 months ago I used 700kwh and paid $178. I drove around 900 miles. A small amount of my car electricity came from Tesla superchargers or other charging stations. Most was from my house. Yes, I use an above average amount of electricity already.

Why this this happen?

California has very expensive electricity delivery. The electricity is tolerably priced, but the delivery by PG&E, the former monopoly provider in much of the state, costs as much as 3 times as much as the electricity. (And PG&E just filed for bankruptcy.)

Ordinary customers get 300kwh at a total rate of 21 cents/kwh, and pay 28.4 cents for the next 900kwh. They pay 44 cents over that. The national average is about 11 cents.

If, and only if, you buy an electric car, you are allowed to switch to a "time of use" plan that charges you more for on-peak electricity (2pm to 9pm) and much less for off-peak electricity (11pm to 7am weeknights, 7pm to 3pm weekend-nights.) It's large -- in the summer peak power is 3.5 times the price of off-peak. Again, much of this is in the distribution charges.

If you switch to time-of-use and have constant loads (like my always on computers) the TOU price is very slightly cheaper. But if you can move loads to the night, you save a lot. I charge my car almost exclusively at night. I also moved my pool pumping (my otherwise largest load) into the night. The total result slightly lowered my bill.

There is a TOU plan for non-electric cars, but it's not nearly as useful.

It would be a different story if I had a lot of loads during the peak. In particular, if I had to use a lot of air conditioning. In Northern California that's not needed very much. I only have a small window air conditioner for one upstairs room. Chances are your oven or electric range will cost more. The electric dryer is the other big one you might be tempted to use during the peak, but many people mostly do laundry at night or on weekends. A gas dryer is a good option (for cost -- emissions are another story) if you like to do drying mostly on-peak. A dryer load on-peak probably costs about $1.50.

If you have an electric hot tub, you can usually program it to do most of its heating during the night, with a small boost just before peak. Back when I used the hot tub (it's off now) I tended to get in just before bed anyway.

I have an article in the queue about my source of electricity and whether it's green or not. I switched my power to a plan which pays my generation money only to solar and wind farms. Of course the night electricity does not physically come from the solar farms, so there is some very interesting debate about what this means and how it works, and whether the money flow or the electron flow are the important factor. Stay tuned.

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