* Consider that a few days ago there was a discussion of what Denmark's going to do with the excess electrical energy their offshore wind farms are generating [

* Consider that a few days ago there was a discussion of what Denmark's going to do with the excess electrical energy their offshore wind farms are generating [1]. They're dumping some of it off as heat into district water heating; it could be charging electric cars. * As noted above, electric car charging generally would happen at night, so its 8 KWH of energy draw would not happen at the same time as most of the other home's average draw of 20 KWH. KWH is energy, whilst KW and GW are power (energy over time). Distribution and service are built first to a power (KW / GW), not energy (KWH / GWH) demand specification. One must integrate varying power over time to get the resultant energy involved. So the comparisons of KWH to KW seems to me like trying to compare areas (energy) to distances (power); there's a dimension missing on one side of the two quantities, so they can't be directly compared. * I don't think California is all that special in that it draws the least of its statewide power during the night [2]. Looking at today's demand graph [2], 11 PM to 7 AM appears to be below the average for the rest of the day; that's 8 hours to charge those 8 KWH, which means a 1 KW power draw (that's less than 5 Amps at England's 230 mains voltage). * 1KW seems to me a not-unreasonable additional night time power demand once everyone's in bed -- though the licensed electrician who inspects your electrical service before you commit to an electric car and the requisite charger should be consulted first. 1 KW will charge that 8 KWH requirement in 8 hours (ignoring conversion inefficiencies for discussion). If the car charger varied its draw subtractively against the whole-home's power draw, then charging could start slow but when one gets home then ram up (increase power demand) as lights, TVs, and other home loads were turned off, keeping home demand constant (though of course using more energy than without the car, so you'd of course pay for that extra energy). If smart meters reported their total-home draw at six second intevals to the consumer, then the consumer's car charger could self-regulate its draw. None of the smart meter reporting I've researched informally report anything better than on 15 minute intervals to the consumer when they do so at all. You could get a home energy monitor installed to get that information yourself (cited in [1]). * Even at the largest scale, of utility scale generation, night time charging evens out the load rater than adds to peak demand -- as long as charging starts after hours. If so, this becomes an opportunity, not a problem for the electric utility. They can make more money selling more power per day because with electric cars, now there increased demand at night that wasn't there before. --- [1] https://news.ycombinator.com/item?id=5547979 https://news.ycombinator.com/item?id=5547979 [2] http://www.caiso.com/outlook/SystemStatus.html http://www.caiso.com/outlook/SystemStatus.html