Charge and discharge Batteries into grid? 1

[epepito]

Does anyone have plans for building such a system? It will be used to demonstrate the effect of electric cars on the grid. They invision people just charging at night and using the cars batteries as a spinning resrve during the day. As I see it the crux will be building a synchronous inverter. Does anyone have plans for building one or should I tell them they have to spend $2000 for a small grid tie in inverter. Any input on the subject would be welcomed. Thanks.

 

[itsmoked]

That's a non trivial,(potentially dangerous), exercise. I'd go for the grid tie inverter.

Frankly I'd reach for the simulator.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[rmw]

The part about charging at night I can see (envision). The part about using the car's batteries as spinning reserve during the day I can't see or don't understand. If I charge my car at night and partially discharge it driving it to work (assuming I have enough charge to get back home and don't need a freshening charge while at work) how do they envision using my battery as spinning reserve? If they have to call on the "spinning reserve" how do I get home?

Even if I had enough charge to 'donate' some back to the grid during the day, how do you ensure that I still have enough to get home (since the afternoon peak comes right before or about the time I want to depart the office) or have a little extra in case someone mentions dollar beers at some pub off my regular route?

rmw

 

[cranky108]

I think battery storage systems have been tried in the several MW range.

Question: Who, or is allowed to, plug in there car at work?
Would your employer be willing to pay for you to top off your car charge at work?

Yes they make small grid tie inverters as small as a few hundred watts.

Question: If you have a limited number of charge-discharges on a set of batteries, what would be your incentive to allow them to be used by the power company?

 

[epepito]

http://www.acpropulsion.com/reports/V2G Final Report R5.pdf

This website has a full study on how they will be used as spinning reserve. The idea is that the people providing the plugins will be so well rewarded for providing spinning reserve that they will be able to allow people to charge their cars for free and still make money. Most cars are idle 22+ hours a day and can be utilized in this way. The study estimates that if 5% of cars in California were connected like this they could supply 10% of the peak demand. The cars use wireless communication to speak to the ISO every 4 seconds and are never fully discharged. Check it out this technology has many upsides.

 

[davidbeach]

Heck, if there had been a large base of plug-in electric vehicles in the Pacific Northwest this spring they could have been charging overnight for less than free as the electric market went negative several nights.

 

[epepito]

" electric vehicles with bi-directional grid power capability are well-suited to providing regulation due to their ability to respond rapidly to power commands, and because the long term net energy requirement for regulation usually nets out to zero if the nominal generation level is set at zero. This means that the vehicle would be both sourcing and sinking power under real time commands from the ISO. Over an extended time period, the net total energy balances out to approximately zero. Because of this, a battery electric vehicle could perform regulation function indefinitely, without discharging the battery. The battery state of charge would be maintained at a level high-enough to afford the driver most of the available range, but not high enough to place a limit on the ability to sink power as required by the regulation AGC commands."

 

[ykee]

I'd second Keith's suggestion of getting a COTS grid-tie inverter -- anything else would be really dangerous, especially if you do not have proper anti-islanding.

I think the idea itself has merit, although, there are lots of people that need to drive home during the afternoon peak, and presumably would want to charge up their car at that time (I guess that depends on capacity).

 

[epepito]

Maybe spinning reserve was bad nomenclature they would really be used as a regulation resource.

 

[cranky108]

Sounds to much utopia, what's the down side?

I think the negative power cost has to do with having to much wind and base load generation. Maybe they should be shutting down the highest cost units.

 

[UtilityDave]

In order for the idea to work on a large scale, lots of things have to happen that haven't yet.

Who gets paid for the electricity we extract from the battery? How do we pay you?
The building owner, who provides the plug-in point can't because he would be selling electricity the car owner bought. That isn't polite.

So the car owner must get paid and we have to figure out how. Does each plug-in have a card reader so we can credit the card? Who pay for the reader? The building owner? Why would he do that?

Does the car have an identified owner, like those toll paying machines? That might work I guess, but a lot on infrastructure is needed.

Finally this seems more suited to plug in hybrids than straight EV. With a hybrid the buy back cost would have to be high enough to make it attractive to sell the electricity you already bought and drive home on gasoline, plus enough to make the charge/discharge cost attractive.

 

[UtilityDave]

Also I agree with those who say buy an inverter.

 

[epepito]

The cars would never be fully discharged. They would maybe operate in the 70% to 90% range. Because they are used for regulation they would be both sink and source. The net power required for regulation is around zero, but because power plants must now stay on standby to provide this power it is very expensive. Third pary aggregators would provide the service to IOUs or ISOs and could compensate car owners with things like free parking and free charging. Simple software would tell the charging mechanism when the driver needs a full charge and could easily be updated via cell phone. In the event you get off work early or have an unepected emergency the car would always have at least 70%.

 

[roydm]

As soon as electric cars become popular the government will have to figure out a way to tax them to death, how will that work?
In the North plug ins are already provided by lots of employers for freeze protection.
Does anyone have a number for KWH / Km (mile) at different speeds?
Roy

 

[davidbeach]

The negative market this spring was due to too much water and not being able to throttle back the hydro units; probably little combustion source power in that mix but there would be whatever wind power was available.

 

[jghrist]

As soon as electric cars become popular the government will have to figure out a way to tax them to death, how will that work?

Considering that highway maintenance funds are generally provided by the tax on gasoline, there will have to be a replacement tax. Unless electric cars don't need highways.

 

[UtilityDave]

epepito,
I understand that the intention of the regulation would be to even out, never the less there is the real possibility that I would want to drive home immediately after a drain period and I would have to be compensated for any net drain. So all the payment issues would remain.

Also the text suggests it would net out over the long term not necessarily over the period I am parked.

Finally, with due respect I take the results that say the batteries won't be discharged with a grain of salt.

Regards Dave

 

[epepito]

Dave,
The software that controls how much and when your car is used for regulation resides inside the car. You input these parameters. Nothing could be done without you first allowing it through plugging your car in and opting in or out via the software. Are you worried that your power will be stolen? It seems a little ridiculus that an aggregator who relied on a large pool of cars would bother stealing from batteries, besides, the charge monitoring software and hardware are all onboard. They make their money aggregating a large quantity of cars into a product that is useful to the ISOs and IOUs and communicating immediate need to the individual cars. It would be counter productive for them to alienate car owners by stealing power. Because they are dealing with large quantities weather or not your car is plugged in or if you decide to just let them use 20% of your battery capacity is irrelavent. Take a look at the study I posted if you are interested. And as I said no individual car would ever be drained more than say 30% percent of its total capacity. Compensation will be an issue because I'm sure a lot of people will be tying to get a piece of the pie, but right now the climate is such that green technologies are pretty well compensated and as I said earlier having power plants for regulation requires them to be up and running when not in use. Keep in mind we are talking sources that can be activated in seconds not minutes or hours so compensation is much higher than scheduled generation. Many aggregators already exist that make money just by shedding load when asked to do so.

 

[UtilityDave]

epepito,
I am not worried about theft of my energy (or anything else, and I didn't mean to sound negative). I was simply trying be point out that some means of compensation would be necessary.

The point I was making is that fact that the regulation function should mean close to zero long term difference to my battery the system for monitoring and compensation had to be in place.

I suppose an aggregator could tempt me to sign up regardless of how much energy he resold (provided it was less than 30% of my capacity). Even then though wouldn't he need to prove he provided the capacity to his customers?

 

[ykee]

It occured to me that a facility with large power demands could use this as a means of peak shaving, and set the charge control on various parking stalls so that whatever gets put into the car at low demand periods can be taken out again at high peak demand periods. Obviously there would need to be compensation, lots of thought given to metering and control etc.

In any case, I think that the idea has some merit, in fact if you did have a huge amount of battery storage, it would make sense to try and use it to smooth out demand.

I think a worthwhile question is whether or not there will ever be enough cars with deep cycle batteries on the road for this to ever work.