Slashdot Mirror
Electric Cars Won't Strain the Power Grid
thecarchik writes "Last week's heat wave prompted another eruption of that perennial question: Won't electric cars that recharge from grid power overload the nation's electricity system? The short answer is no. A comprehensive and wide-ranging two-volume study from 2007, Environmental Assessment of Plug-In Hybrid Vehicles, looked at the impact of plug-in vehicles on the US electrical grid. It also analyzed the 'wells-to-wheels' carbon emissions of plug-ins versus gasoline cars. The load of one plug-in recharging (about 2 kilowatts) is roughly the same as that of four or five plasma television sets. Plasma TVs hardly brought worries about grid crashes."
I admit I didn't have time to read the study thoroughly, but:
(a) The study specifically talks about hybrid cars, not pure electrics; the headline is misleading.
(b) Let's take a very conservative estimate and say an electric car draws an average of 10hp when driving. That's about 7.5kw. Let's round that up to 8 for simplicity's sake, and if we assume 100% efficiency, the car needs to spend 4 minutes on the charger for every 1 minute it spends on the road. If we charge it overnight (8 hours), that's 2 hours of driving time, or 60 miles if you average (as many drivers do) somewhere around 30mph - before you have to plug it back in for another 8 hours. And that's in the absolutely best case.
I might be missing something, but 2kw to charge sounds very unrealistic to me.
Yes but plasma TVs replaced CRT TVs.
And I expect there was a rather large switch from incandescent to compact fluorescent globes around the same time - which may have given greater savings than losses from those plasmas....
But what on earth kind of argument is that? Electric cars wont be a problem coz plasma TVs weren't.... How absurd.
Never happened. True story.
Probably because households buying plasma televisions purchase one, maybe two, and they are replacing cathode tube (with shadow mask) televisions which have been consuming electric load since the 1950s. And those plasma TVs are not operating for too many hours (hopefully), never mind that LCD televisions are far more popular. It's not surprising that many people are at least more concerned when typical two-car households each might add the equivalent of 8 to 10 plasma televisions of net new electricity consumption to the grid. Thankfully that consumption should be off-peak, especially if timed chargers and peak electricity pricing are mandated, but the plasma TV analogy breaks down very quickly.
Just like most working people, the first thing I always do when I get home is turn on my 4 or 5 plasma TVs. Since that wasn't a problem, I'm sure the electric car I buy won't be a problem either!
It may very well not be a problem, but that statement is goddamn stupid. Most of us aren't drawing that much power regularly when you get home.
Breaking Into the Industry - A development log about starting a game studio.
I think the bigger question, which I didn't see answered in TFA, is whether these things are truly better than ICE vehicles on the environment. I mean sure we know they'll probably be better than a Hummer, but has anyone figured out what the mining of lithium for the batteries, the toxic components used in such batteries, the amount of carbon put out in production, the amount used by the grid (many places still have coal plants you know) and finally the disposal and replacement of those batteries after 3-5 years, how all of that compares say to a Kia or other small 4 cyl ICE vehicle?
Because as we saw with the "get rid of teh evil lead solder!" stupidity we can often make things worse instead of better by not thinking things through. in the case of solder we ended up with a lot more e-waste because the crap solder they replaced lead with broke down much faster than the old, and thrown into a burn pit in China frankly isn't any better than the old. So I would like to see what a "birth to death" study of elec VS ICE would show before I say that elec is the way to go. After all it won't be doing us much good if we just trade carbon at the tailpipe for carbon at the plant PLUS piles of dead batteries PLUS lots of waste in mining and disposal. We need to look at the entire cycle before judging one tech or another.
ACs don't waste your time replying, your posts are never seen by me.
I think the major load on the charging systems would either be early morning when you just get to work and plug in, or early evening when you just get home and plug in. Not exactly prime time for brown outs..
My understanding, based on the time-of-use billing coming soon to a power company near me, is that early evening when you just get home and plug in is exactly prime time for power shortages.
You could centrally control when recharging stations activate, but is somebody plugging in at 5:30 pm because they want to recharge it overnight, or because they want to pick up their kids from (band/soccer/whatever) practise at 9pm?
- RG>
Hey pal, this isn't a pleasantforest, so don't waste my time with pleasantries!
In future, it won't be enough to let a consumer make the decision on when to consume and encourage him with discounts in low peak hours. The model should be that for those loads where "time doesn't matter" we (the consumer) can indicate our constraints and then the electricity company will work within those boundaries. Of course, the more lenient the consumer is, the better rate he gets.
For this example, if I park my car at the office I don't care if the battery gets reloaded at 11 am of after lunch. As long as it's done before I drive home at 5 PM. Same for the return trip, the car could be rechared at 11PM or at 3AM, I don't care.
The crucial thing here is that fore heavier, but also time independent loads like this, your utility company gets control over when you are using electricity. We're still quite a bit away from that, but with smart grids, that's the way we're going.
And it will all benefit green power that produces electricity at "unexpected moments".
Browsers shouldn't have a back button!! It's all about going forward...
Removing lead is progress and in time the restriction will become a non-issue for even those that believe in the goodness of lead.
In the US, people spent ages bellyaching about the low-flush toilets. Initially the toilets that came out often did perform poorly because when you could use half a lake to flush the toilet you didn't need good design. Designs have improved and one of the greatest wasters of fresh water was reduced.
Realize that government is a process and that there are always trade-offs. Usually they aren't even entirely clear trade-offs.
Still , as someone pointed out , statistically , it's very likely that electric cars will charge at night , as most people will be working in the day , and will have to recharge there cars when they get home in the evening.
Hmmmm. What about a company perk of being able to charge your vehicle at work? That would seem to be a great incentive to get people into EV's in the first place (ie make it a non-taxable perk to charge at work).
Eclectic beats from Leeds, UK
handmadehands.co.uk
Looking at the actuals vs. the predicted costs in the graph you linked, they underestimated by 30%. Maybe they were just having a bad day.
If the electric cars go home and charge at night, no, they won't strain the grid. Power is overproduced at night (you actually can't spin down the generators all the way, so they produce power even if nobody wants it.)
What I read in IEEE spectrum a few months ago was that it wasn't the production capacity that would be strained, but the transformers in residential areas. This surprised me, but the article stated that in many areas, the cooling capacity of the local transformers was undersized since they would be underutilized at night and would therefore cool off at that time.
That seems strange to me, since in the temperate climes, the hottest part of the year also has the shortest nights -- I wouldn't think the cooling benefit of lower usage at night would be so great, and it's not like your gonna swap out transformers on May Day and Halloween and ship them to the other hemisphere on an exchange program. I also don't think that this is a common practice in my part of the US because my Dad was a power EE, and he talked to me a lot about his job and never once mentioned this. They had a lot of transformer problems: squirrels grabbing two terminals, birds building nests (it's nice and warm), wrong oils used in filling them, PCB remediation, guys at the fiberglass plant busting the nearby insulators with glass beads shot from slingshots. But I sure don't remember anything about undersized radiator capacity. Hardly proof -- and maybe things changed since -- but it makes me skeptical.
I am not a crackpot.
People won't pick a car with the same performance if a more powerful option is available, marketers know that and will will bolt high kW motors in given the option. Saying but you can achieve the same performance with a lower power engine appeals to greenies only. End result, high load on the grid.
Ah, so nobody buys the V4 Accord, V4 Mustang, or any other car with a more powerful engine available?