Electric Car Charging Best At Night: Study

From EarthTechling's Aaron Colter:

The Institute of Physics has published a study that suggests the best time to charge electric vehicles, in terms of impact to air quality, is at night.

While electric vehicles do not produce emissions, electricity generating units do, a lot.

Researches from the Massachusetts Institute of Technology (MIT) and the University of Texas have specifically been studying ozone pollutants under three different charging scenarios in Texas for plug-in hybrid vehicles.

The first scenario was based on charging cars at off-peak times during the night, the second under the conditions of maximizing battery life by charging vehicles just before use and only enough to complete the journey, and the third by charging the vehicles just after use.

The study found that overall, across all cities and hours tested, the least amount of harmful emissions occurred at night, especially because the sunlight wasn't around to interact with the particles.

The eleven-page report is available for PDF download on the Institute of Physics website.

With more and more smart-meter programs being rolled out, night may be the best time in terms of electricity rates as well. But as we recently reported, not only are consumers largely unknowledgeable about the smart grid, but the infrastructure itself may not be ready for the large scale implementation of electric vehicles.

Comments

[craigsquirrel]

05:35 PM on 05/03/2011

oops, in my last post "has" should be "have"...

[craigsquirrel]

05:30 PM on 05/03/2011

For a good history on fuels and why electric cars and electric transportation has been held back 100 years read the book Internal Combustion by Edwin Black. Borders has a good deal on it at $10 for a hardback copy. Substantial length and WELL worth the investment in time.

[Warren Lauzon]

05:20 PM on 05/03/2011

One of the biggest wasters of gasoline is city sprawl and the often very long drives in city traffic.

Perhaps we should be looking at that instead of EV's.

[Ron Shook]

04:10 PM on 05/03/2011

This post, this study, this analysis ignores a very simple and obvious fact, that in a finite, resource constrained world, the automobile as we know it as a form of personal transportation is an obsolete anachronism for this century. The quicker we realize this, the quicker we will make better decisions on the way forward.

You probably now expect ranting entreaties for public transportation. Nope! We need to keep our personal transportation so that we can continue to live our day to day lives on our own schedules, but we simply don't have the energy, resources and space to continue with the automobile, with 1 to 3 ton conveyences for our puny bodies.

It's as simple as that and the answer is equally simple, bicycles, not the simple bicycles out of which most of today's mammoth car manufacturers evolved in the early 20th Century, but the increasing high tech electric bicycles of today, which will evolve in the early 21st Century into the enclosed or partially enclosed bicycles, tricycles and quadricycles that weigh no more than the folks and cargoes they carry and are appropriate to our far more energy efficient economies. All of the cons listed above or in the comments for electric cars are eliminated or greatly ameliorated for electric bicycles because they use an order of magnitude less energy.

Save the expensive public transport for long range travel that is beyond our everyday needs of almost universally less than 50 miles round trip.

[mlaiuppa]

11:56 AM on 05/03/2011

Duh.

Off peak hours are cheaper plus the electricity generated at night isn't utilized.

We've known this for decades.

[dennisrs]

07:36 PM on 05/02/2011

As there are more and more e-cars being charged at night this will end up causing the night not to be " off-peak" times.

[mlaiuppa]

11:57 AM on 05/03/2011

Nope. It will be decades before the night charging of electric cars balances the peak hour usage. Our current grid can handle it fine.

[apeweek]

07:10 PM on 05/02/2011

Interesting study, but largely irrelevant, because coal plants are mostly baseload. This means they run at or near full output all the time.

It doesn't matter when you charge, because the coal plants can't run much faster than they already do. If your EV calls for more electricity than baseload, a "peak" plant will come on line. This would likely be natural gas, hydro, solar, wind, etc. All cleaner than coal or gasoline (nuclear tends to be baseload, too.)

But there's another reason charging at night is better. Ask your utility for an "off-peak" electric rate. Here in my city (Detroit), I get half-rate by charging overnight.

[mlaiuppa]

11:59 AM on 05/03/2011

What it means is currently the night, off peak, generation from those plants is wasted. So charging cars at night will be a more efficient use of power generated by these plants.

[BlackbirdHighway]

05:55 PM on 05/02/2011

Wrong, the best time is the afternoon of a bright sunny day. That's when the solar panels are making lots of electricity.

[ThinkCreeps]

06:12 PM on 05/02/2011

And when all the air conditioners are running flat out, and when electricity prices are highest, and the dirtiest plants are running hardest to keep up with demand. When do brownouts happen?

[LeFlaneur]

10:48 PM on 05/02/2011

I think that was why he said solar panels.

[BlackbirdHighway]

08:37 AM on 05/03/2011

Why are you getting electricity from "the dirtiest plants"? Get with the program!

Solar!
Wind!
Geothermal!

[Warren Lauzon]

05:17 PM on 05/03/2011

I suggest that you Google peak load hours for various parts of the US, education and facts are a wonderful thing to behold.

[Kenz300]

05:28 PM on 05/02/2011

Bring on the electric vehicles. Gas prices keep going up. It is getting expensive to use oil for transportation fuel.

[apeweek]

07:17 PM on 05/02/2011

We have all been told how expensive the Volt and Leaf are, but did you know both of these electric cars can be leased for just $350/month?

And that number is even better when you realize that you can offset that monthly payment with your fuel savings - an average driver (15,000 miles/year) can save $150 to $200 per month by burning electricity instead of gasoline.

That makes the Volt or Leaf the equivalent of a conventional car lease costing less than $200 per month.

Leasing these cars arguably makes more sense than buying, as we can expect the technology (and prices) to change rapidly over the next few years.

[dennisrs]

07:43 PM on 05/02/2011

What about the mileage penalties and other small print on the
leases ? do these exist on this E-cars?
If it cost $ 40 for 10 gal of fuel and you get 300 miles from that $ 40 how does that work with an E-car. In other words how much does the electricity cost for 300 miles

[Warren Lauzon]

05:18 PM on 05/03/2011

Where do you get that $150 to $200 savings from? Have you looked at electric rates lately?

[sunsetter]

04:33 PM on 05/02/2011

Hope that guy in the picture brought along a good book and his sleeping bag. Standing around waiting for charge to complete will take forever.

[LeFlaneur]

10:55 PM on 05/02/2011

Why? He can just across the street to his office.

[LeFlaneur]

10:55 PM on 05/02/2011

walk across...

[MISTERUNCONVENTIONAL]

04:15 PM on 05/02/2011

More breathtaking news from Captain Obvious.

[dennisrs]

09:40 AM on 05/03/2011

How long does it take to fully charge on these cars and how far does it go on a single charge?
These cars also have a gasoline engine to use after the charge runs out right or a least I heard the Volt does. Is that correct?

[mlaiuppa]

12:01 PM on 05/03/2011

Depends on the hook up. Could take 4-8 hours. Range depends on speed but it's 80-100 miles.

The Leaf does not have a gas engine, only electric motor. It warns you when you're running low.

Only the Volt has a gas engine.

[apeweek]

11:59 PM on 05/03/2011

The Leaf has a fast-charge mode to get a nearly full charge in 30 minutes. But that's not for home use. At home it would take several hours, so you would likely charge overnight.

The Leaf has a longer range on electricity only, up to 100 miles. The Volt has a longer driving range than the Leaf, but that's because it has a gas engine. After 25 to 50 miles on electricity, the gas engine turns on and lets you drive another few hundred.

Most Volt owners try to avoid the gas engine, and keep it charged up on electricity instead. The gas engine is only for when you need to take long trips.