University of Vermont Researchers Devise a Method to Prevent EVs From Crashing the Grid


These 3 Have Developed This Novel Solution for EV Charging

These 3 Have Developed This Novel Solution for EV Charging

In Vermont, a team of scientists consisting of Pooya Rezaei, Paul Hines and Jeff Frolik have created a solution that they believe will keep EVs from ever crashing the grid.

The scientists, from the University of Vermont, will present their full findings in an upcoming issue of IEEE Transactions on Smart Grid, a journal of the Institute of Electrical and Electronics Engineers.

But for now, here’s the general idea:

Jeff Frolik “The key to our approach is to break up the request for power from each car into multiple small chunks — into packets.”

Paul Hines“The vehicle doesn’t care. And, most of the time, as long as people get charged by morning, they won’t care either.  By charging cars in this way, it’s really easy to let everybody share the capacity that is available on the grid.”

More Than Capable...No Need to Worry

More Than Capable…No Need to Worry

“And the problem of peaks and valleys is becoming more pronounced as we get more intermittent power — wind and solar — in the system.  There is a growing need to smooth out supply and demand.”

Pooya Rezaei“Our solution is decentralized.  The utility doesn’t know who is charging.”

In essence, the idea is that a smart meter communicates back and forth between the utility and the vehicle.  The vehicle makes a demand to charge and then is allowed to do so for a few minutes.  If energy demand in the area is low, then the vehicle continues to charge.  If energy demand is high, the vehicle charges off and on for say 5 to 10 minutes at a time and then gets back in line to send another request to charge.  The idea is that the vehicle will usually still be fully charged by the time it’s needed, but electricity sent to the vehicle is done so in a more controlled manner to prevent crashing the grid when there’s millions of EVs out there plugging in at the same time.

Then there’s this:

“We assumed that drivers can decide to choose between urgent and non-urgent charging modes.  In the urgent mode the vehicle requests charge regardless of the price of electricity. In this case, the system gives this car the best odds of getting to the front of the line, almost guaranteeing that it will be charged as soon as possible — but at full market rates instead of the discount rate that would be used as an incentive for those opting-in to the new approach.”

Surely, there are other methods for distributing power to EVs, but as Hines says:

“Some of the other systems are way too complicated.  In a big city, a utility doesn’t want to be managing millions of tiny auctions. Ours is a much simpler system that gets the job done without overloading the grid and gets people what they want the vast majority of the time.”

But will it work?  The invention is in the patent-pending stage and there’s additional real-world usage that has to be conducted before we’ll ever see it in use, but will/could it work?

Categories: Charging, General


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20 Comments on "University of Vermont Researchers Devise a Method to Prevent EVs From Crashing the Grid"

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Why does anyone think this is a problem? I don’t think any utility has complained at all.

Well, if we all move to EVs, that will increase overall electricity demand by some 20%-30%. So it’s something that needs to be planned for.

I think even more important is to disseminate 2-way vehicle-to-grid chargers, especially in renewable-rich grids (which all grids will hopefully be pretty soon!). This way, EVs actually help the grid as temporary storage, then draw their charge when demand is lower.

But this idea from Vermont is nice, and is applicable in any grid.

100% EVs is at least a 30 year project. It’s a slow movement and even though you need to be prepared it’s a small problem stretched out during a long period of time.

Agreed Spec9. These guys are too young to realize it apparently, and apparently their professors are ‘green’ also. Why? Because this ‘problem’ was solved about 70 years ago with time-of-day metering. And the problem at the time was a big one, for many little utilities. Around my parts, New York State Electric and Gas, had only very tiny central stations. Some that would be considered today embarrassingly small. What to do? They used time of day metering to turn on the lower element of electric water heaters after midnight, using the ‘energy storage’ characteristic of cold water being heavier to in effect, cause all hot water tanks to arrive at ‘mostly cold’ at midnight (the discharge was still hot due to the top element). After midnight, the lower elements would turn on, taking roughly 7 hours to reheat. This was the only time when the utility had spare capacity. As a matter of fact, the heaters were basically shut off during the day since the utility couldn’t supply the load, they simply not having enough generation capacity. The basic idea of these students is wrong headed. Electric cars charging after midnight is not a “Potential Problem”. It is totally a… Read more »

Discounted EV electric rates after 11pm or midnight will be sufficient motivation to reduce home charging at peak times for many years. The market penetration of renewable generation and EVs will have to be really high for the methods mentioned to be even remotely necessary.

This makes the most sense for workplace charging today. The car doesn’t even have to talk to the utility, it could just talk to the company’s energy management system to avoid a higher peak demand than has already been reached for the month. That would avoid additional demand charges directly attributable to EV charging. In fact, this could be implemented in the charging station, not the cars, even today.

It’s called a smart grid. Pecan Street has been testing this in a neighborhood for some time now.

This is a benefit and should be done. Of course the utilities also need to realize that more and more EV owners will also be renewable energy generators and will be looking for better return on their peak supplied energy than wholesale pricing. If they disagree they can do and charge whatever they like. Just remember that if/when the price is right for energy storage, they will lose the opportunity to sell to EV owners in off hours. I personally would like a long term relationship with the power company but am prepared to do otherwise if necessary.

I was thinking an independent carport off the grid w/ battery storage to get around Ca ‘s restrictions on storage…..and TOU and all that.

Life is simpler and cheaper in AZ

Is this Mark Hovis? If so, Hi!. Seeing as you’re part of the Insideevs writer team, candidly what do you think of these nonsense articles that get on here? Every now and then these things get put in here, solving a non-problem and just promoting David Patreus’s ‘dishwasher spying system’. Remember him? TOU has been around 70 years, (for more detail, see my other post here).

As regards your suggestion about me writing an article of my experiences, 1). No one “of importance” shall we say, would want to read it, and 2). I did do an off the cuff you tube video 3 years ago when my cars were brand new. Go to you tube and search on “Buffalo Car Charging on a Budget”. Its a bit boring since I adlib’d it (If I was going to do it again I’d script it to make the flow better – plus its the first vid I’d ever done (not a big camera expert here).)

This makes sense during daytime/peak charging. I now have TOU so set my car to charge at lowest demand: 1am and finishes by 3 or 4am.

You can bet once we allow power companies to distinguish between regular power demand and EV demand from our homes for schemes like this they will certainly charge a different rate for that power. Under the guise of smoothing out the grid they will claim that they need to charge more for EV power consumption. Say $.10 kwh for regular utilities and then some peak rate like $.30 kwh that will come out to costing the customer about the same per mile as gas. Then they will be doing you a huge “favor” by charging you an off peak EV rate of only $.20 kwh.

I’m not sure this is much different from other approaches that have been described. Basically, it takes a new smartmeter, just like all the other approaches. Perhaps “packetizing” (should be called time slicing, imho) is new though I don’t think it’s particularly radical.

Frankly, I think the better approach is to embed the smarts in the EVSE and have it honor a standard protocol that not only sets charge time but current level as well. That way EV owners will bear more of the cost of the infrastructure than the utilities

Not understanding why we need more smarts in EVSE’s?

Just use the smarts and built in connectivity in EVs already!

BTW: In terms of needing grid management, it will be at least 25 years before EVs account fr more than 25% of all vehicles on the road. The researchers have solved a problem that won’t exist over the course of their career.

I developed even better method for balancing electricity demand using electric vehicles. And it does not need “smart grids” or other utopian future concepts:

Using Tesla Car as Free Storage for Renewables

By the time there are enough EV’s on the market to “crash the grid” I think that battery storage will smooth out and store more than enough power to get us through the night. I’m building a house right now with 3 50 amp runs to the garage and a south facing roof that will be all solar. As soon as Tesla markets it’s battery storage for residential use, I’ll have too!

this solution is inferior to a simple car controlled system that charges randomly over the charge time and avoids utility peaks in the morning and evening especially during temperature extremes. Nothing to see here as better solutions have been proposed for years. F the Smart meter to control my usage.
Once batteries are really good, maybe twice as good as today, they will catapult solar usage and every home may have 100kW-hr stored locally. That’s a pleasant thought and charged banks could save up for transfer to cars as well.

Let’s devise a Method to prevent microwave ovens from Crashing the Grid.
Come on, there is no such thing as crashing the grid with EV’s all at the contrary they are preventing exaggerated low drops at night and therefore optimizing the net and the power stations.

The real crash to the grid won’t be because of EV charging. It will be an off shoot of the battery industry that grows up around EVs. Eventually one of these battery companies is going to realize that the home storage of wind and solar is a much bigger market than EVs. They will also realize that much differnet cell architecture and cheaper materials can be used for home storage, since high power density and high energy density are not required. It is simply a cost per electron stored problem. This will affect the grid in that many will just go off, and then who will maintain the grid. It is now maintained through fees to consumers, and subsidies from the feds. But when the consumers have a choice to be free of the tethered monthly everlasting bills, many will chose freedom.

Actually this is a very good and clever idea. ToU and timers and random distribution ideas are only a partial step in the right direction. They’re crude hammers, when a scalpel is needed. The grid needs to balanced at ALL times, including at off peak times. Utilities PAY for access to loads that can be turned up and down to help them keep the grid balanced. (These programs are called ancillary services, and help accommodate the variability of intermittent renewables like wind and solar.) The article is about a very simple yet clever mechanism that can let an aggregator or even the utility easily interact with an ever increasing community of EV’s who’s charging load can be easily controlled (as long as it eventually completes in time). And the utility is willing to pay a premium for a load like an EV that can respond Quickly. So with this packet based energy allocation mechanism, the EV user could charge at a cost even LOWER than the off peak ToU rate. And this clever approach could be applied to any kind of load that is able to be spread out over time… e.g. electric water heaters. So kudos to this team… Read more »

Actually this is a very bad idea.

While the vehicle is waiting for the next chunk of power the control/communications electronics stay on drawing power. What you end up with is a very expensive charge for the owner and an overly complex grid management method.