An idea that is invariably invoked when people discuss plug-in electric cars like the Volt is vehicle-to-grid technology. (see previous post)
The general concept is that when there is a large fleet of plugins on the road, users will plug them in at night during low demand and charge them. During the day, when demand is high, the cars could remain plugged-in (while not driven) and act as thousands (?millions) of little reservoirs feeding their electricity back into the grid as demand requires. This would produce a buffer helping the grid to meet demand and averting blackouts. Presumably, the drivers could be reimbursed by the utility cos for the power they contribute.
This new article from the Times, illustrates how an individual hooked their Prius up to the house during a blackout. The engine was turned on and off, letting the car power the house for hours, turning it into a $30K basic generator.
Certainly the idea of V2G makes sense from the standpoint of the utility companies, but how does it help the individual driver?
Imagine a drive to work, where one uses 20 miles of their electric range, then they plug-in at the garage at work. If it is a peak usage day, would they really want another 10 miles of range siphoned off?
Perhaps there are benefits to the individual. What are your ideas?
This entry was posted on Monday, September 3rd, 2007 at 8:43 am and is filed under Grid. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.
Sep 3rd, 2007 (10:22 am)Frankly, I would NOT want my vehicle to feed power back to the grid. Say I drive that 20 miles a day in my Volt, and then plug in at work. I wouldn’t want the rest of the power siphoned off, because if I had to go somewhere to run errands, I’d then be burning gas, which would cost me more.
At home, I wouldn’t mind if I could use the power for myself in the event of a blackout, but I wouldn’t want to wake up to go to work and find the car not topped off.
Using the most grid power with the vehicle will be the cheapest way to drive. Giving some of it back and possibly costing more due to having to run the generator wouldn’t make up for what you’d get for giving that power back to the grid.
Sep 3rd, 2007 (10:43 am)I think the only way this works is if the utility Co. replenishes the electricity back to the cars as demand decreases. So, at 2:00 pm in the middle of summer when everyone’s home A/C is running, the utility co. pulls excess energy from the plug ins, then as demand decreases throughout the day, the same amount of power that was pulled from the car gets put back in. Unfortunately, this assumes the car is plugged in for long enough to get it’s power back.
Sep 3rd, 2007 (12:09 pm)Another factor here is that the cost plugging in is bound to go up 30-40% to pay for lost gas taxes. At first the taxes will likely be left off as an incentive to use electric, however once enough people convert to electric the roads will still have to be paid for and maintained and the taxes will come. A possible consumer V2G benefit would be if the utilities paid back the borrowed power at say 1.5 to 1.0. In this way you would get extra power that you didn’t pay for nor were taxed for. The utilities get help with peak demand and pay it back when they have surplus capacity. A computer on the car could keep track of all the credits and debits. Likely the utilties would only pay back during off peak hours.
Sep 3rd, 2007 (12:59 pm)I would not like the idea of using my Volt to feed power the the AC company, Like most of the reasons stated above.
Also the extra equipment to feed back to the AC company would cost more then you would get back. Not to include the safety reason if the lines where down and some of the Volts where feeding it when the line crews came to do a repair.
But I like the idea of supply my house or Camp site when the need would arise.
The Volt uses a rectifier to convert the AC in to DC for the battery, you would need a converter to take the DC and make AC to run your stuff
They are already on the market
Tom
Sep 3rd, 2007 (1:23 pm)Would the electric company pay you back when your battery dies after 5 years instead of 10 because of the extra cycling?
Sep 3rd, 2007 (2:19 pm)I think this could be a good idea, but only if the power company pays a premium on the power that is pulled from the vehicles and if its optional. For instance, I commute 2 miles to a train station and use mass transit for the remaining 35 miles of my trip. If I could plug in at the train station and sell vehicle power to the grid at peak utility rates, plus a little extra “convenience” fee, I could charge up at night and make more than enough to offset the cost of having the generator kick in.
That being said. I don’t see anything like this happening in the next 5-10 years. It’ll take that long to have enough EVs on the road to make something like this feasible and another 5-10 years to work out the kinks and line up the political support to get it done.
Sep 3rd, 2007 (3:24 pm)In my opinion this is pie in the sky that will never come to fruition! People are going to plug in the volt in a regular wall socket and that is going to be the end of that.
How many people have the ability to measure the power they send back to the grid? Very few.
How long is it going to take for a single car to pay for that meter? Too long for you are the power company want to invest the money.
Who wants extra cycles put on their battery? Very Few.
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While we are on the subject, just for curiosity sake, how will the grid tell the car to power the grid. I have power supply 24/7 how will electic demand change the direction of the current flow?
Are we too be prevented from chargeing during peak hours?
Sep 3rd, 2007 (3:52 pm)I don’t know the exact design for the Volt, but most battery chargers only work one way – AC to DC. I would be surprised if the Volt’s charging circuit would allow DC from the battery to flow back to AC for the grid, as this would lead to extra design complexity and cost.
But let’s imagine that the Volt’s battery charger is designed to work both ways. Then you have the issue of the home wiring. The circuit breaker is probably limited to 15 amps of a single phase in the breaker box. If you have a blackout, you won’t be able to power the whole house with the same wire that charges the battery.
I think a more likely scenario is to use various sized Inverters for different AC power generating applications. Inverters convert DC to AC. Here’s one of many sites that sell them:
http://www.donrowe.com/inverters/inverters.html
The only problem is the battery voltage. The Li/Ion battery pack used in the Volt will have a much higher voltage than the standard 12 volt car battery. Designing an Inverter with this higher input voltage is no big deal, it’s just that someone will have to design, build, and sell this – so it might take a while. Then there’s the issue of accessing the Li/Ion battery terminals, especially considering that they are relatively high voltage.
Also, what happens if GM designs an E-flex crossover SUV, and the Li/Ion battery for that has a higher voltage to support more horsepower in the electric motors.
My proposal is for the Volt to offer:
1) factory 110 volt AC convenience outlets standard. These would go up to 15 amps total.
2) larger inverters as factory options.
By the way, most of this has been discussed before here:
http://www.gm-volt.com/volt-discussion?forum=1&topic=50&page=1
Sep 3rd, 2007 (4:13 pm)Mike G – Actually most people already have the ability to measure how much power they send back to the grid. In other words, most electric utility meters already spin in both directions. This is what makes Grid-Tie solar system viable.
http://www.affordable-solar.com/grid.tie.htm
If your meter consistently runs backwards more than it runs forwards, then the power company actually owes you money and you get a check once a year. Unfortunately, the rate they pay you is usually much lower than the rate they charge you. Given that solar systems aren’t cheap, it usually pays to just have the system simply lower your average grid usage by 2/3 or so. But the meter will sometimes spin backwards.
Sep 4th, 2007 (2:33 am)I could see this catching on if the utility companies offered an incentive. I am also basing this opinion on two assumptions
1. one that it could safely be done in regards to battery life.
2. There are sufficient number of people willing to participate within a given area.
For example, they could give plug in owners a discount on their monthly usage by agreeing to sell back during peak hours. I would think if the discount where high enough people would go for it.
Given the above assumptions I would think the utility companies could avoid expanding capacity if peak demand could be buffered. This could allow them to give the discounts and still be ahead if the savings for them were high enough.
Sep 4th, 2007 (9:10 am)I was wondering, what about vehicle to home use? Rather than sell back the power to the grid, supplement your own home power during peak usage periods. You juice up your car at night, then drain your battery during the day when the AC is cranked. Eliminate the power company as a middleman in a scheme to save yourself money on power. Granted, there is a cost benefit analysis to be done in terms of wear and tear on the battery, but this could be the most direct way to benefit from having a large battery pack sitting in your garage. If you lease the vehicle and/or the batteries, the number of cycles is less of an issue.
Sep 4th, 2007 (10:05 am)What does v2g give us?
More stable grid means less downtime and less strain on the grid which means fewer repairs and less maintenance. More available standby power at peak means less run up/run down at the peaks means fewer more efficient plants which use less fuel. Less fuel means lower power costs & fewer emissions.
V2G = Efficiency, lower costs, fewer plants, less fuel burned and lower emissions. Hello, are you in there McFly?
Sep 4th, 2007 (12:04 pm)Sorry, McFly is busy replacing his Volt battery (prematurely) due to excessive V2G charge cycles…
Sep 4th, 2007 (12:55 pm)As long as it’s in the “sweet spot” there should be little degradation. Perhaps those who sign up for V2G can receive a FREE extended battery warranty from the power utilities. They can pay for the warranties with some of the $Billions they are saving by not having to build more plants, upgrade the grid or waste expensive fuel by spinning turbines while waiting for spikes.
The devil is always in the details and there are many to yet work out.
Sep 4th, 2007 (2:15 pm)“The Volt uses a rectifier to convert the AC in to DC for the battery, you would need a converter to take the DC and make AC to run your stuff”
I know this is a bit of a tangent, but is the Volt’s electric motor itself going to be AC (like the EV1) or a brushless DC?
Sep 4th, 2007 (2:58 pm)AC Motor!
Sep 4th, 2007 (8:58 pm)Transfer switch and/or subpanel (subpanel limits the circuits – e.g., no A/C compressor, no electric range)
The guy at http://priups.com/riddle/answer-1.htm
matched the UPS in his house to the battery in his Prius (DC to DC)
I don’t see any real incentive for V2G at my cost (max rate The circuit breaker is probably limited to 15 amps of a single phase in the breaker box
Sep 4th, 2007 (8:58 pm)Transfer switch and/or subpanel (subpanel limits the circuits – e.g., no A/C compressor, no electric range)
The guy at http://priups.com/riddle/answer-1.htm
matched the UPS in his house to the battery in his Prius (DC to DC)
I don’t see any real incentive for V2G at my cost (max rate under 8 cents/kWh)
I’d never let power be sucked back out of my charged battery pack for grid use, even if they paid me 2x retail.
I’d want that power for the vehicle or as an emergency backup to run household loads in the event of a power failure.
>The circuit breaker is probably limited to 15 amps of a single phase in the breaker box
Sep 4th, 2007 (10:08 pm)AES – The generator (alternator) is DC for practical purposes.
Mike G – The generator/alternator is mechanically AC, but uses diodes to convert AC to a choppy DC. Connecting the alternator to the battery smoothes out this chop significantly. So it’s basically DC.
There is a good picture of this here:
http://www.bcae1.com/charging.htm
about 1/2 way down the page.
Even if you could get some sort of AC tap off the alternator, there’s no way it would exactly line up with the 60 hz phase on the grid.
Bottom line: You will need to convert the DC of the battery-generator bus back to AC using an Inverter.
Sep 5th, 2007 (11:02 am)A couple of things to point out here: V2G technology has an extremely strong potential to modernize our electrical grid (which is actually very, very outdated in some places) and allow us to maximize wind power at lower costs than coal power (due to managing intermittency), also we live in free market and people (both users and utilities) will be free to do whatever they want, so the prices paid for V2G services will meet or exceed that demanded by providers. And one last thing, V2G services are not base load services with the same prices as power plants. What V2G services are called are ‘ancillary services’ and they are used to maintain high quality electricity to the grid. It is extremely expensive, and while a fleet of vehicles using V2G technology will bring the costs down, we as EV owners and service providers will not be cut out of the savings.
We are actually liable to make money by doing this, and it’s conceivable that the power companies may even take over our battery leases for us and guarantee replacement if we accept contracts. Also, it’s not inconceivable that we will be able to set the parameters ourselves for charging and uploading to the grid, including our own prices where if we’re not paid what is demanded then we will simply be charging our cars at regular prices and nothing else. This is a market opportunity for all involved, and a significant one at that. Money, both savings and income, will be available for everyone involved. I support this, and if the terms will be favorable for me to provide services, then I will volunteer them at the proper cost.
Sep 5th, 2007 (12:43 pm)I really want to see this as an option.
I would like to use a Volt for power backup more than for helping the utility on a regular basis.
However, if there are enough controls on how it is used, I’d be happy to supply grid at peak demand.
I will pay plenty for the ability to use as a standby / backup generator, because then I don’t need to buy a generator.
This would also need to be available in 240v rather than 120v for me to be interested.
This also complicates things if the battery is leased, because V2G will tax the battery a little more. Possibly putting it through 2 cycles per day rather than 1.