A day maybe, otherwise it is simply a lie.
A quarter will buy you about 2kW/h of electricity in California - at best.
That amount of energy is enough to charge two standard car batteries (75 Amp/hours each) without losses.
2kW/h of electricity is about 2.68 horsepower for an hour. Again without losses.
So if he drives 15 minutes a day he'd be picking up about 10.7 horsepower from the batteries total over the duration of the trip without losses. There are losses.
If he travels 10 miles a day (he lives in San Francisco so that is easily possible) and his Prius gets 45 mpg normally he’ll use about 0.222 gallons of gas a day (or $0.62 @ $2.80 a gallon) without adding his batteries. If he now gets “80 mpg” then he’ll use about 0.125 gallons of gas a day instead (or $0.35 @ $2.80 a gallon). That translates into a net gas cost savings of about $0.27 a day. So electricity costs of “a quarter” a day would be close.
I doubt he knows exactly how much power he’s using to charge his batteries every night. Nothing else in the article is specific.
The point is that you're not using electricity constantly. The car sometimes uses electricity and sometimes uses gas. In any event, I just have a hard time understanding the knee-jerk cynicism about this. I don't think the government should do anything to interfere in the market, but if demand exists for cleaner cars and the manufacturers are responsive to that demand, that's fine by me.