Rapid recharge for electric cars.

[swansont]

Sure it would matter even if you're plugged in -- you're drawing less power from the grid.

 

But the grid will likely be cheaper, and doesn't add weight to your car. I don't doubt that some cars might come with such an option. I just don't see that it solves a big problem.

 

I get that you're shining a realistic light on some of these ideas, but we've already got people standing in line to buy hybrid versions of cars that won't pay for their price differences over the regular models for 5-6 years -- even a $4/gallon. I think if we get these ideas on the street, these shortcomings will be working out by engineers and gradually improved over time.

 

I'm just trying to point out where the real problems are. I think electric cars are the future, but it's a grid upgrade — production, preferably green, distribution and charging stations everywhere — that's needed most. That and an attitude recalibration for the long trips.

 

Depending on the adoption schedule, this too will be solved over time. If such a car were available with a 100 km range, some people would buy them, and outfit their houses, if need be, to recharge the cars overnight. The impact to the grid would be minimal, and once critical mass has been achieved, the rest will happen as a matter of basic capitalism. But a battery's ability to be charged quickly is not what's preventing this from moving forward.

 

And here's the key point. My thought was that with sufficiently mainstream electric cars, all charging up at night, night-time will no longer be off-peak -- there'll be as much demand then as any other time. That clearly would not be the case unless there were a very large number of electric cars.

 

(I'm not entirely sure how the demand from charging automobiles compares to the usual night-time demand, so I may just be making crap up. But that's my job.)

 

I'll make a little less up, in a back-of-the-envelope calculation.

http://www.eia.doe.gov/cneaf/electricity/epa/epates.html shows that US residential, commercial and industrial demand is roughly equal (to first order), with residential being the largest at ~37%. Presumably much of the industrial is dormant at night, so that's daytime demand.

 

In the US the average household draws about 1 kW on average, so, 24 kWh per day. That's roughly the equivalent of 50 miles of driving. If you're recharging that, you've replaced more than the entire industrial load. Certainly residential and commercial go down at night, so the nighttime demand is still lower, but not by a lot.

 

Yeah, the idea was to balance the load by leveraging all those batteries sitting there in the cars. I just threw the solar panels in there, but as panels are reduced in price, as would be accelerated if a major car company starts putting them on cars - well, then the payback period is reduced. Obviously, the main focus for the infrastructure would be reducing peak loads.

 

http://www.sciencedaily.com/releases/2007/12/071203133532.htm

 

Interesting article. The numbers I've been using don't quite jibe with the recharging times and distances I'd seen and was using (factor of two or so discrepancies; I may have gotten older performance data), but the article doesn't mention how much current is being drawn or what the battery capacity is.

 

edit: it's a Toyota Scion, which has a 35 kWh battery. The listed range is indeed a factor of two better than the numbers I was using (4 miles per kWh vs 2 I had seen a few places). It also means his special 240 V plug is delivering ~75 Amps if he can do a full charge in 2 hours.

Edited July 14, 2008 by swansont
multiple post merged

[Sayonara]

And here's the key point. My thought was that with sufficiently mainstream electric cars, all charging up at night, night-time will no longer be off-peak -- there'll be as much demand then as any other time. That clearly would not be the case unless there were a very large number of electric cars.

 

(I'm not entirely sure how the demand from charging automobiles compares to the usual night-time demand, so I may just be making crap up. But that's my job.)

 

Well, this is the thing isn't it. From the quoted/linked article, "one hour a day of car usage is the average in America". If that's true then the demand from mainstream vehicles might not actually be that great. How many times a week do you charge the average car, based on 7 hours of use?

 

I'm not saying you're wrong, just that there should still be a question mark over claims like that.

 

Let's assume a high consumption scenario, just for the sake of argument. Even if demand for power from recharging cars effectively obliterates the off-peak period, any supplier who provides a discount tariff for that period might lose cents per unit but that would be offset by market share. It's just good business sense.

[Cap'n Refsmmat]

Let's assume a high consumption scenario, just for the sake of argument. Even if demand for power from recharging cars effectively obliterates the off-peak period, any supplier who provides a discount tariff for that period might lose cents per unit but that would be offset by market share. It's just good business sense.

At least in the US, power companies are government-sanctioned monopolies, so they won't gain or lose market share.

[Sayonara]

Hah, sucks to be you guys. We're all filling up buckets and pans with cheap midnight electricity over here.