Supplying the national grid from car batteries is bad?

[treez]

**broken link removed**

Hello,
This new idea of supplying the national grid from peoples' electric car batteries is surely poorly thought out? I mean, due to the poor charging efficiency of car batteries, during a charge/discharge, 40% of the power is wasted as heat in the battery. Why are we even contemplating using electric vehicle batteries to supply back into the mains electricity? Its such a waste of energy.

 

[ads-ee]

I think it's more of a pass costs onto consumers, by reducing the life span of their vehicle's electric car battery (by number of charge discharge cycles). Wherever you park your car the owners of the lot can reduce their costs associated with the PF issues. It also means the electric companies save money by not installing more PF correction in their system. Seems like a lose-win-win (guess who loses) as opposed to a lose-lose-lose.

Wouldn't you just love it if the place you park your car has a power outage and you come out and your previously fully charged vehicle was dead because the shop-till-you-drop consumer couldn't be bothered with a power outage interrupting their shopping.

 

[FvM]

As far as I know, the technique is discussed for electric car batteries which are usually lithium-ion and similar. Battery efficiency is higher than lead-acid and can well compare well with technologies like pumped storage hydroelectricity.

And it's primarly intended as a grid stabilizing means. It's urgently needed with the increasing share of solar and wind power.
.

 

[treez]

It's urgently needed with the increasing share of solar and wind power.

I can well understand charging one's battery from solar and wind power....or sorry, rather, I can't, because solar power is surely not going to be quick enough to charge a car up. -probably not wind power either.

And once a car's battery is charged, then surely the best thing to do is to leave it charged until you want to make a journey? -not discharge it back into the mains?

Cars need fast charge, and even with lithium, you loose 20% of the energy on a charge, and also another 20% on a discharge.

Solar and wind power batteries should surely be separate to car batteries. Solar and wind batteries should have their own , more suited charger/grid tie inverter?

 

[Warpspeed]

I know someone that actually tried this.

His idea was to charge lead acid batteries at night, on half cost off peak power.
Then use an inverter during the day to power his refrigeration loads which were high, and pretty constant.
It was an economic disaster, mainly because of the very low storage efficiency of lead acid batteries.

Using high tech Lithium batteries may be workable, but maybe not after the very high capital cost of the batteries is taken into account.
Its only practical if solar or wind ""free energy"" is available.
Grid power is just too expensive to store.

 

[Audioguru]

Isn't it the other way around? Malls and stores have electricity jacks for charging an electric car that parks there, not to steal electricity from it.

 

[ads-ee]

Isn't it the other way around? Malls and stores have electricity jacks for charging an electric car that parks there, not to steal electricity from it.

That's the whole point of the paper to have malls and stores install this bi-directional unit to allow malls to stay open when the power grid goes down so consumers can keep shopping. Can't let those shoppers down...Of course they won't be able to take all their purchased items home, since their cars won't run without a charged battery.

 

[Audioguru]

But electricity is cheap. The jacks for charging electric cars are not bi-directional. The stores make a HUGE profit on everything they sell so the charging jacks might attract more customers to go there and buy their products.

Why does the power grid go down? My part of the world is civilized and power outages are very rare. Maybe bi-directional jacks can be used where they did not design the grid properly so they have "load shedding" frequently.

 

[ads-ee]

But electricity is cheap. The jacks for charging electric cars are not bi-directional. The stores make a HUGE profit on everything they sell so the charging jacks might attract more customers to go there and buy their products.

Why does the power grid go down? My part of the world is civilized and power outages are very rare. Maybe bi-directional jacks can be used where they did not design the grid properly so they have "load shedding" frequently.

Hey I didn't write that paper, I think it's completely BS and just a way to pass costs onto those that buy an electric vehicle. It even states that the reasoning behind the system is to improve the efficiency of the grid and protect against power outages, but doing so just uses your vehicle as an extension of the power grid without you getting paid for the service.

Your whole electricity is cheap theory isn't exactly true unless you have a pf = 1. Industrial facilities with tons of electric motors running will have very low power factors and they will get charged for it. I recall a long time ago some company in my local area that had installed a bunch of capacitive loads to offset their low PF. https://en.wikipedia.org/wiki/Power_factor
I don't recall when it was but it was decades ago I remember reading that the power companies didn't charge residential customers a surcharge for low power factors, because overall the loads across all residential customers had a reasonable power factor.

 

[D.A.(Tony)Stewart]

Industries that consume > 250MWh/yr or $2000/mo may get wholesale rates based on peak demand.

For the top Class A customers, the cost is determined by the ratio of customer peak demand as a percentage of supply and so this power is allocated by diversion of power.

This also defines allocation of grid power to a customer. But it is up to the customer to use this peak demand efficiently. If their consumption has a high peak to average, and thus raise the energy cost for an entire month it will justify this technology to be used to lower the peak power for low duty cycle.

For some industries, this is a valid option. Other means of storing electrical power are vacuum sealed magnetic bearing inertial mass turbines, used for storing alternative energy.

 

[BradtheRad]

At first I was dumbfounded that anyone would push people to discharge their car batteries into the power grid. But I just found a web article pointing out that an electric car could power an average home for a day or two.

This creates possibilities (per the story in post #5). Suppose people really could make money by charging their car during off-peak hours, then parking at the mall to sell electricity onto the grid at a higher price? Then the idea starts to make sense.

 

[D.A.(Tony)Stewart]

At first I was dumbfounded that anyone would push people to discharge their car batteries into the power grid. But I just found a web article pointing out that an electric car could power an average home for a day or two.

This creates possibilities (per the story in post #5). Suppose people really could make money by charging their car during off-peak hours, then parking at the mall to sell electricity onto the grid at a higher price? Then the idea starts to make sense.

1st you must pay for the car, then utility license to supply to the grid. Then the Storrage * Conversion efficiency must be less than the ratio of rates for peak rates to break even.

I think it m=only makes sense for industrial costs which are based on peak monthly demand.

 

[treez]

Thanks, you've all said it, and Sunny And FvM have basically said this...

And it's primarly intended as a grid stabilizing means

...and yes, we can all see the reasoning for it, but I think we all agree that there is one big problem.....customers will not want their fully charged up cars to discharge back into the grid, ..customers will switch off the bidirectionality of the car charger, and stop the grid company from taking energy out of their nice, full car batteries.

So why is anyone even contemplating making bidirectional car chargers? Someone has just asked us to design a 7kw bidirectional, mains isolated car charger for them. I think we should go back and tell them its a nice gesture, but could we take their money for something that is never going to sell, and even of it did, nobody would use it?
I am not saying its not a good idea for the country, etc etc.

 

[ads-ee]

So why is anyone even contemplating making bidirectional car chargers? Someone has just asked us to design a 7kw bidirectional, mains isolated car charger for them. I think we should go back and tell them its a nice gesture, but could we take their money for something that is never going to sell, and even of it did, nobody would use it?
I am not saying its not a good idea for the country, etc etc.

It will sell, it's just IMO that the owners of electric vehicles will get short changed. I can imagine going to your mall with a nearly full charge and coming out with half a charge because the bi-directional car charger decided it needed to help "support the grid".

 

[D.A.(Tony)Stewart]

No I was basically saying it is unfeasible for consumers but very feasible for industrial users with high peak to average power consumption and pay for an entire month based on their peak demand. Which can result in significant savings.

 

[ads-ee]

No I was basically saying it is unfeasible for consumers but very feasible for industrial users with high peak to average power consumption and pay for an entire month based on their peak demand. Which can result in significant savings.

Wonder if any of my friends who own electric cars are getting a hidden periodic "pay cuts" by their employers by using the companies "free" electric charge station, which instead sucks out the charge. ;-)

 

[treez]

thanks, I don't think people will use shopping mall chargers if they think charge may be drawn out of their electric car batteries.
I am wondering if the governments have decided that in future , people will not own their own car, but will simply rent them from huge car park sites. And you have to plug it in, you've no choice, and then the grid will use the charge in the battery. Ie people don't have a car on their drive any more, but you have to go to the car lot to get in a rented one.
Because otherwise, nobody will keep their fully charged electric car connected to the charger if they think that the grid will start taking charge out of it.

 

[Audioguru]

Many people will not know that the shopping mall charger is taking electricity from their electric car battery. Those people barely know which pedal is "go" and which pedal is "stop". If they use turn signals then they turn on the wrong one. Also they do not know how to turn on the lights at night if the car doesn't do it automatically.

 

[mtwieg]

So I've read quite a lot about the concept in academia, so I'll throw in my $0.02

The idea makes a lot of sense when framed properly. In order to make greater use (like >20% of overall generation) of renewable, intermittent power sources (wind, solar, etc), it's absolutely necessary to have huge amounts of energy storage available to the grid at certain times during the day. Unfortunately, filling hundreds of warehouses with batteries isn't an economically feasible way to do this.

But if it happened that a country had a fleet of EVs connected to the grid, then there is your storage right there. Of course there are immediate objections: "then my car might never charge," "Utilities will just steal my well-earned amp-hours," "my battery wear down too fast," etc. So someone had the idea that the federal government would be responsible for purchasing and replacing all the batteries, and regulate the hell out of how they are used by utilities. So consumers would get an enormous subsidy to the cost of their vehicles, and a guarantee that utilities could never leave them with less than a certain amount of charge, and at the same time a fully renewable grid would become feasible. If implemented as promised, it's a pure win-win.

On a technical level, this is easily the most practical option for mass grid storage I've seen so far. Politically... that's another story.

 

[treez]

I see your point well now. To be honest, I think it will happen as you have called it, and the electric cars will be rental ones in massive parking lots, because most people (at least in uk) live in houses or flats with no drive on which to charge a personally owned electric car. These massive rental electric car lots will be the storage that you describe.