Electric car batteries can do more than power electric cars. They can send current to homes and buildings, or send it back to the grid when demand is high. Some experts even believe EV batteries might one day boost the prominence of renewables by storing the energy from wind and solar farms.
The idea of so-called “vehicle-to-grid” schemes inevitably stirs debate among engineers. But make no mistake: The concept has a huge following. Googling the term “vehicle-to-grid” yields an astounding 526 million hits. That’s one reason electric utilities, auto manufacturers, and university researchers are all studying the concept.
We collected photos and diagrams from ongoing vehicle-to-grid programs. From pure EVs to plug-in hybrids to wild-looking concept cars, we offer a peek at some of the vehicles that could one day power your home.
Click on the image of Willett Kempton to start the slideshow.
Willett Kempton of the University of Delaware has been a driving force behind the idea of vehicle-to-grid (V2G) technology. In 2013, Delaware teamed with NRG Energy to launch the world’s first revenue-generating V2G project. Here, Kempton is shown with a Honda Accord Plug-In Hybrid that’s being used as part of a demonstration project by the university. (Source: Honda)
FM, Your use case happens in many major thunderstorms - Power outages. Typically, power would be out for a day or two, and a fully charged car battery can run the important things in your house for that duration (e.g the refrigerator, the oil furnace, and the well, as well as a few lights).
Here in the northeast, we can typically expect one or two days without power every year. Right now, we have a gas generator ($1000) in the garage that we have to wheel out and plug into the external outlet ($1000 to install). We have to maintain that gas engine as well.
If we can just plug our car into the house, that would have saved the costs of the generator and the associated effort to keep it available for use.
I'm not a big fan of the battery only electric car anyway, you always risk getting stuck. I think that the plug in, multi fuel hybrids will dominate. The articles I have read say the owner could pay for their batteries just doing 3% spinning reserve and frequency stabilization for the utilities. We will have emergency generators on BEV's the size of a shoo box, always ready to go, at the very least. Till the market for batteries is saturated, we can't afford to waste batteries on all electric cars anyway.
Distributed grid stabilization and generation reduce grid losses. Locally generated electricity is mostly locally consumed. Centrally generated electricity must traverse the entire path on the grid. The grid is inherently bi directional at the local levels. The other huge advantage of personally owned backup power is the security and effect on attempts by gov and private companies to gouge the people as is happening with gas on the east coast right now.
The big problem is the whole business model for private utilities is obsolete. The utilities view the grid, spinning reserves, frequency stabilization and reserve capacity to be sunk costs. They are not profit centers without gov help. Let's skip the private utilities and have the gov directly provide all those services and part of the national electrical grid freeways. Private companies cut corners till things break. Private companies are notorious for the failure to spend the money on rare contingencies. Gov on the hand is good at this.
Great points about spinning reserve, trenth. I do wonder, though, how many consumers will be willing to sell their battery charge back to the utility, especially if the EV is a BEV and is their primary form of transportation. If I own a BEV, and it's my primary means of getting to work, and it takes five hours to recharge, how often will I be willing to sell my power back to the grid?
One would hope that the PPA (Power Purchase Agreement) that enables this bi-di power sharing would factor in lost battery life and standby converter power in the $$ paid to the EV-owner for this service. Sort of the same kind of thing as a mileage allowance for cars driven for business purposes - the 51.5 cents per mile is far greater than just the cost of the gas, and factors in auto maintenance and depreciation. Same principle here.
Having someplace for the semi-exhausted batteries to go after their utility in cars has diminished sounds like a secondary market to me. Maybe one would develop around battery salvage!
Correct! That's the point I tried to make in my last post. As far as reducing the overall usuable life of the vehicle's battery pack, there needs to be some structure in place whereby the packs are traded in for fresh packs - this could be financed by the same power companies. These same power companies could then take the used vehicle packs and utilize them for stationary peaking facilities.
Of course there is some energy usage by the in-home or publically installed Bi-Di unit in standby mode. I bet that all of the little vampires that are always plugged into duplex outlets throughout one's home gobble much more power than a single charging station. If one is that concerned about wasted energy, then you just have to disconnect your home's mains feed at night or every time you leave to go to work - cool!
OK, so i'm not that smart. If you search on "Vehicle to Grid", you'll find concepts similar to what i've posted. The utility doesn't get your EV for free; they're proposing to pay for the service where you hook up wherever (home or elsewhere) & they can use a certain user-defined percentage of your battery for either siphoning or storing extra. You would be essentially renting some of your EV range for a fee. You gain a little rental income and the utility gains by not having to build out and maintain as much infrastructure.
Just thought of another loss left out of their calculation. To do this now you need to leave the controller on your car & wall charger in some form of wait/ready state. This state will drawn power even if the power company is not needing power from your PEV at the time yes it is only 2*15w(30W) of power but this is far more than the 5W or less drawn while off. And this power adds up even when no grid update is needed. to be able to source at a moments notice you need the controller in some semi awake state to respond.
Their goes another few percent out the window that nobody mentions. so now if you are in this program you loss money even if they draw no power. Good Idea????
Good point; i wasn't considering wire losses in this mix. There's so many other downsides to this even without considering that.
Wire losses and power in/out finances notwithstanding, consider too that the utility would also get to use some expensive load-leveling equipment that their customers pay for. They don't have to pay a dime; such a deal for them!
On the other hand...
I can see the transient peak load leveling provided by a bunch of PEVs as being valuable to the utilities (and all of us) - ok, that's reasonable. Short-term use with a minimal energy drain, and energy replacement within minutes. That would be acceptable to me. BUT only if the utility kicked in some coin for it. They'd be getting a benefit from this at my expense. If they would want this, they need to be prepared to pay me for providing that service. A lease agreement, if you will, with limits on siphoned power and guaranteed time-limited replacement! How 'bout that?
Yes, Davek3gau, I think it wouldn't work if someone had to deal with an electricity or power provider. I think the Army's scenario works because it is based on a microgrid the Army set up itself. Now if someone has their own home electricity grid based on, say, solar or wind power (this is possible in the countryside), then they could charge their car on their grids and also power the grid with the car battery in case of an emergency or something (provided they don't need to drive the car at that moment).
I love when people do effeciecy calculations they always make assumptions so they can leave out losses they do not want to accept or deal with.
The report inverter effeciencies of 97% each way. But they always leave facts out when calculating these effeciencys. They assume power is right their from you meter. Well in most case the charger it is 0-50 ft of 10AWG wire for a 30-40A circuit. Assume the mid point here as average and you loose 44W (30Sq *25ft *10AWG(R/ft) * 2) (1.2% just to wire resistance from breaker box to charger) of power when charging and 44W of power when selling back to the grid just in heat loss of cable If you ise 12AWG legal in some areas for a 30A circuit that goes to 66W. And that is just one of the losses ignored their are coupling resistances, contact resistances, control circuit power used, (yes most eff calculation leave out the power used by the controllers they just calc the high voltage power eff. Even a 20W system is another 1% of loss, *2 because you have the charger Controller and the onboard controller both operating at this time)
All of these 1% losses add up to an overall loss of 7-8% each way. That is 15% overall loss once you buy - sell. How does that make any sense, you buy 1KW and then of that 1KW you sell 0.85KW??
Twenty months after news leaked about Apple Inc.’s secretive automotive project, the high-tech giant has apparently decided it will not go toe-to-toe with Detroit, leaving few in the Motor City surprised.
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