REGISTER | LOGIN
Breaking News
News & Analysis

EVs Strain Clean-energy Supply, But Could Help Balance Grid

EVs could account for 12.5 percent of electricity generation by 2040 in Europe and the U.S.
6/28/2017 06:41 PM EDT
11 comments
NO RATINGS
More Related Links
View Comments: Newest First | Oldest First | Threaded View
Page 1 / 2   >   >>
sw guy
User Rank
Author
Re: EVs and clean energy
sw guy   7/4/2017 7:30:52 AM
NO RATINGS
Regarding atmospheric pollution, you forgot to factor in comcrete and consumables.

I do not know how pollution generated during building whatever powerplant compares to the one generated during lifetime by a fossile stuff burning one, but even it is negligible, it should be mentionned. Ditto for pollution during decommissioning

Beside, for a nuclear power plant, I am pretty sure managing consumables need lot of thermic engine around.

Beyond plain pollution, it has been noted that hydro-poweplant could directly generate lot of CO2 due to decayng of vegetation is that last is not removed before water invades. But I do not count that against hydro powerplants, just against bad work.

 

Another point: I found very interesting the remark regarding grid load-balancing EV would bring.
Too bad I am not sure it would apply in France, were electric heating is heavily used :-(

Les_Slater
User Rank
Author
Re: EVs and clean energy
Les_Slater   7/3/2017 8:37:34 AM
NO RATINGS
Right!

Les_Slater
User Rank
Author
Internal combustion efficiency
Les_Slater   7/3/2017 8:16:38 AM
NO RATINGS
I don't see any particular reason why an internal combustion engine can't approach 100% efficiency.

Les_Slater
User Rank
Author
Re: EVs and clean energy
Les_Slater   7/3/2017 8:13:23 AM
NO RATINGS
My 2017 VW Golf Alltrack 1.8l gasoline takes 2 minutes and 15 seconds to fully warm up under light loads. This is summer starting from 60F but don't suspect it would take too much longer in much colder wheather. That warm up is roughly 140F. Starting from 0 would be roughly 200F, a 43% increase. In a first order approximation that might translate to about a minute increase in warm up time.

jamestate
User Rank
Freelancer
Re: EVs and clean energy
jamestate   7/1/2017 10:22:42 PM
NO RATINGS
This is bogus. You have to see that electric vehicles have regenerative breaking. In stop and go traffic (city traffic) electric is a lot more efficient than an ICE (internal combustion engine vehicle). Also a power plant can be much more efficient than a car engine for several reasons. First, you can use much more heavy construction in a stationary application, hence you can increase the operating temperature significantly more. Second, you can use a flowing river as a water source for a condensation tower, further increasing efficiency, unlike a car which must reuse the same water over and over. Third, a car constantly revs the engine up and down reducing engine efficiency even more.

If you remember Thermodynamics class, if you have a higher temperature heat source (say 800-1000 deg C), and a lower temperature cold source, you get more efficiency out of the engine. A combined cycle natural gas power plant can easily operate at 50-60% efficiency which is like twice that of a car engine. If you do district heating or process heating with the excess low grade heat (usually less than 100 deg C) you can even reach efficiencies above 95%. The trick is to use the power plant in baseload mode.

Also a lot of power sources do not emit atmospheric pollution: hydro, wind, solar, nuclear.

Last but not least typically a lot of the baseload generation capacity typically gets wasted. Energy consumption is a lot lower in the night and this is when a lot of people would plug in their vehicles to recharge them. I've seen estimates that we could have like 20-25% of cars running on electric with no extra generation capacity required because of this.

Also the typical European citizen travels much shorter distances on average per year than the typical American citizen so range anxiety is much less of an issue. You can easily assume that the average European will travel half the distance daily than the average American.

 

realjjj
User Rank
CEO
Re: EVs and clean energy
realjjj   7/1/2017 6:46:36 AM
NO RATINGS
When you look at efficiency, there are additional differences at the powertrain level, not just the motor/engine.

And as a joke, what should we compare that Toyota with, rooftop solar?

gah4
User Rank
Author
Re: EVs and clean energy
gah4   7/1/2017 6:07:24 AM
NO RATINGS
From: https://en.wikipedia.org/wiki/Combined_cycle

new combined cycle gas turbines get to about 54%, but there are still a lot of 33% coal, oil, and nuclear plants out there.

 

On the other hand, where I live a large fraction of power is hydroelectric.

Which number do I use to figure out the fossil power I use, and the CO2 I generate?  The most or least efficient, or the average?

 

From: http://www.greencarreports.com/news/1091436_toyota-gasoline-engine-achieves-thermal-efficiency-of-38-percent

 

typical gasoline engines are 20%, but Toyota is working on getting up to 38%.

 

But all that is after the gasoline engine is warm. It takes a lot to warm it up, and all that doesn't go into motion. For short trips, electric cars are much better.  For longer trips, not so much.

realjjj
User Rank
CEO
Re: EVs and clean energy
realjjj   7/1/2017 3:35:09 AM
NO RATINGS
33% is not typical ,that's for coal and oil, With a modern gas plant EVs would be well over 2 times more efficient, all factored in.

A recent study on EV emissions based on 2014 EPA data http://blog.ucsusa.org/dave-reichmuth/new-numbers-are-in-and-evs-are-cleaner-than-ever

If you compare to the existing fleet (not the average new ICE vehicle or most efficient), EVs are many times more efficient and their emissions will decrease over time as power generation becomes greener relatively fast. Aside from that, EVs are better cars in almost every way and very soon they'll be cheaper too.

gah4
User Rank
Author
Re: EVs and clean energy
gah4   7/1/2017 2:53:53 AM
NO RATINGS
Typical power plants are 33% efficient at turing fossil energy into electricity. Older plants might be lower, newer ones a little higher.  Automobile engines are a little worse, but getting better.  (After warm up, so worse for short trips.)  It might be 25% for gasoline engines, compared to 33% for electric power plants.  Then there is transmission line loss and power conversion loss for the electric car.

Manulo
User Rank
Rookie
Good to know
Manulo   6/30/2017 7:38:35 AM
NO RATINGS
A very interesting document in any case, I admit that I am a fan of technology and this interests me well

Page 1 / 2   >   >>
Most Recent Comments
realjjj
 
Wilco1
 
realjjj
 
realjjj
 
calendar
 
realjjj
 
spike_johan
 
photonic
 
chipmonk0
Like Us on Facebook
EE Times on Twitter
EE Times Twitter Feed