In many parts of the U.S., electric companies can use the most efficient generators to produce all of their power during the night. During parts of the day, the efficient plants can't produce all the required electricity and thus they have to produce a fair amount of their electricity with less efficient plants.
Most residential customers don't use enough electricity, and don't deviate far enough from normal usage patterns, to justify the extra expense of day/night billing. If someone used a lot of electricty, however, and 90% of it was during the night time, they could probably negotiate for day/night metering and billing. Someone with an electric car may very well decide to do this.
In many parts of the U.S., electric companies can use the most efficient generators to produce all of their power during the night.
In my part of the state of Ohio, Duke Energy began 2 years ago installing new meters, advertising to the pubic as being lighting resistent, and being a benefit to the safety to the home. Since the meters installation my monthly electric bill has more than doubled. I talked to a Duke energy employee I knew personally about the meter replacement. He laughed at me, stating that the whole "lightning thing" was a rouse to get the new meters installed at the customers expence. This is true as I was forced to pay for the new meter. The Duke enegy empoyee also stated my bill will always be higher as the new meters now finely count the individual electrons passing through the meter to be used in my home.