What is your take on V2G for grid support and what is the value that V2G aggregators will get by providing ancillary services (voltage control) to the grid?
so-so. I am scoring it as marketing hype.
To go from the DC stored in the battery will require a Grid-Tie rated inverter.
That is not part of a standard vehicle battery charging station.
While DC to AC Grid Tie rated inverters exist in common practice as part of Solar PV and Small Wind Turbine set-ups -- during the day when the Grid could actually use and benefit from the added input -- those Solar PV inverters will be busy converting the Solar DC from their PV.
That makes it rough share that inverter. So an additional inverter is around US $1500 per each location, and likely the car would be out operating on the road during the day when the grid would want the power from the battery.
Really the larger problem to solve on the Grid and Power Distribution is "Time of Use."
Ideally Time of Use would closely align with Time of Production. The entire hope of the industry is that recharging the vehicles overnight would make for some use of the vastly surplus power available overnight.
The voltage control aspect is dubious, as well. Load Tap Changers on transformers already handle that fairly well.
so smart charging overnight can come to the rescue? But how viable is that
I think the idea is a great one, viability and feasibility on the other end are issues that need to be addressed. The most expensive part of the electric vehicle is the battery whose life is highly dependent on the charging and discharching cycles. Feeding from and to the grid in different intervals kills this battery not to mention how much power and over what time period this battery can deliver.
Using smart systems is a good idea but far from implementation until the issue of energy storage systems for EVs is sorted.
I mainly agree with what Phillip mentioned, except that it is very likely that most of the cars are actually available for ancillary services. First, to provide meaningful ancillary services an aggregation of the energy of many electric vehicles is necessary, as individual contributions are not significant. Since, a typical car is parked for more than 90% of the time it is very likely that a minimum amount of vehicles is at a charging station at all times. Of course, this requires that charging stations are installed in offices, malls, residences, etc and that a lot of vehicles operate with a battery. So V2G in the current state of the grid and transportation fleet is not very feasible, but the availability of cars would't be a problem.
Overnight charging is a different story. As Phillip mentioned there is an energy surplus at night mainly due to hydroelectric, nuclear, and wind power plants. These types of generation cannot be "turned off" during periods of low demand (e.g. midnight). So it is in the interest of utility companies to sell more energy during these periods. The only limitation, at this moment, is the capacity of residential connections and distribution networks. Because the load for charging a vehicle's battery is larger than a typical household total load, distribution lines and other equipment could be overwhelmed. A solution for this is to allow users to determine a deadline for their cars to be charged, then the utility company can control the charging of all vehicles and operate the grid within its limits. So not all vehicles are charged at the same time but before some specified time. This would require the deployment of smart meters capable of communicating with utility companies and controlling loads. So overnight charging requires additional infrastructure and therefore investments from system operators, but I think it can be done and become profitable.
Yes you are right aggregation is the key so that from the perspective of the grid, EV fleets will be a large MW battery storage.
And keep in mind, that for the long view -- things are rarely as they appear in the here-and-now.
If electric roadways (see link below) become a trend, the use of batteries may be greatly reduced.
http://www.electricroadway.com/
If the battery can be reduced to just meet the relatively small need to move in and out of a garage or parking lot . . . costs per vehicle can be significantly reduced, along with the energy->storage->energy loss.
Dear, my last paper in EEM 13 conference make the evaluation of your question for the french market. Have a look on it and if you have some questions, I will be happy to answer them!
ok I would have a look at it. Can you please send an e-copy to me?, or where can I download it
Although there is a disagreement about using EV battery to store excess energy through intermittent charge cycles, I strongly believe that the reactive power capability of the grid connecting inverter of future EVs could be utilized to provide voltage control at distribution level.
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