Mercedes-Benz Details Product Roll-Out and Timeline for 6 Hybrids and Fuel Cell Vehicle
Report: Mitsubishi Heavy, Shell and ExxonMobil To Develop Coal-to-Liquids Facilities

PG&E and Tesla to Research Smart Recharging Vehicle-to-Grid Technology

Pacific Gas and Electric Company is partnering with Tesla Motors to further evolve vehicle-to-grid (V2G) technology by researching smart charging—a form of V2G designed to allow remote control charging of electric vehicles connected to the power grid.

V2G is conventionally considered as the delivery of power from a vehicle back to the power grid. However, vehicles can also provide short-term ancillary services to the grid even without delivering power back to the grid. By allowing the vehicle charging rate to be ramped up and down remotely through smart metering, a vehicle can perform a grid ancillary service called regulation. Regulation is currently performed 24/7 by power plants in order to fine tune the balance between generation and load.

Of the four power markets that are relevant to V2G—baseload power, peak power, spinning reserves and regulation—regulation is a highly competitive market opening for V2G, according to an earlier analysis by Willet Kempton and Jasna Tomić.

But electric drive vehicles, with their fast response and low capital costs, appear to be a better match for the quick-response, short-duration, electric services, such as spinning reserves and regulation. These constitute, for example, in the US, 5–10% of electric generation costs, or about US$ 10 billion/year.

—Kempton and Tomić

The project partnership will combine Tesla Motors’ electric vehicle expertise with PG&E’s electric infrastructure experience to explore the ancillary grid benefits of remote charging.

We are focusing our initial V2G implementation on smart charging. Smart charging is a form of V2G in which the vehicle does not provide power back to the grid. Instead, the vehicle charging rate is controlled remotely in order to support the operation of the grid or to best match load to the availability of intermittent renewable energy resources such as wind and solar. Tesla Motors' goal in developing V2G is to eventually provide our customers with an option that could reduce their cost of electricity for vehicle charging while supporting greater penetration of renewable energy on the grid.

—JB Straubel, Chief Technology Officer, Tesla Motors

Tesla Motors will work with PG&E to equip a demonstration all-electric Tesla Roadster with the communications technology that enables intelligent charging. PG&E will also install monitoring equipment at the auto manufacturer’s San Carlos location for testing purposes.

If this demonstration project is successful, and smart charging is deployed on a wider scale, it is expected to be interfaced with PG&E’s SmartMeter technology, which continually reads circuits and electric meter usage and has the ability to provide financial incentives to customers who voluntarily shift electricity usage away from critical peaks.

In addition to partnering with Tesla on V2G research, PG&E is working with the auto manufacturer to support the installation of Tesla Motors’ charging stations into their customers’ homes or businesses. PG&E is working with Tesla Motors to ensure proper connection in its customers’ homes within the utility’s northern and central California service territory and advising the auto manufacturer on its collaboration with utilities nationwide.

PG&E became the first utility in the nation to publicly demonstrate the possibility of electric vehicles to supply homes and business with electricity at a Silicon Valley Leadership Group event in April 2007. (Earlier post.) More recently, PG&E shared this technical expertise with Google in June 2007 to upgrade a number of company-owned Toyota Prius PHEVs to be V2G capable for a demonstration at the company’s Mountain View campus.




Good stuff. Bring on the smart grid.


This appears to be a good move for Tesla to certify their charge station installations and further the third party charge station infrastructure. I see issues arising from grid operators wanting to control vehicle charge rates for reasons other than renewable efficiencies. While the leveling concept appears valid there should be concerns with regard to single source energy suppliers such as PG&E - a bottom line driven utility. Consider this future scenario: PG&E buys wind, solar from a variety of resources at rates below its coal/diesel/hydro generating costs. It buffers the lower cost energy into offline storage systems then instructs the smart V2G fleet to charge at it's regular off-peak rates (claiming the wind isn't blowing tonight.) The PG&E incentive is to resell it's low cost renewable energy at the higher daytime rates for greater profits.

Putting too much control of energy production distribution and billing into the hands of single source utilities is, like any monopoly a recipe for trouble. I would prefer to see the smart component rest in the vehicle/owner's hands. By tracking via third party software, the available grid energy and rate structures - the vehicle makes smart charging choices - putting the cost and usage where it belongs, in the hands of the consumers.

Further, for the lowest cost renewable structures we should encourage small grid concepts. Community, municipal PV/wind storage (via LiI banks) installations supplying localized (virtual) grids with supplemental energy. Single source grid monopolies should have competitors - like phone, cable, wireless services. De-centralizing the grid is the best method of mitigating losses from outages, shortages, equipment failures and security risks.

The oncoming BEV revolution should not engender another monopolistic industry like we have seen with petroleum. It should encourage the diversification of energy production, distribution and resale. The more people literally empowered by these new energy resources - the better for the community, environment and planet as a whole. IMHO...

Max Reid

Its grid to vehicle and not the other way round.
Oil has hit $80 / barrel and it will be expensive for vehicle to power the home.


The oncoming BEV revolution should not engender another monopolistic industry like we have seen with petroleum. It should encourage the diversification of energy production, distribution and resale. The more people literally empowered by these new energy resources - the better for the community, environment and planet as a whole. IMHO...

Great point.

Some Jerk

Getting V2G made an industry standard will be beneficial to small scale solar and wind production. Being able to provide backup power from a hybrid instead of a bank of deep cycle batteries will make grid-tie solar even more attractive to homeowners.


If the charging rate fluctuates depending on grid electicity demand, how does this affect the longevity of the batteries? I would expect that a constant charging rate is better for batteries than one that varies. Does any one know if this is the case?

Bob Bastard

gr, I agree with everything you said, but I'm curious as to what you had in mind with the sentence: "It buffers the lower cost energy into offline storage system..."


The thing of it is, these batteries are designed for rapid charging/discharging. Think about slamming on the brakes or the accelerator. I don't think the ramping up or down from the grid operator would be much different.

My understanding of the V2G techonology is that batteries would be used to provide ancillary grid services like regulation (tiny up or down changes in the amount of power on the grid) not as an ultimate power source.


I don't think Tesla batteries are capable of very rapid charging.

Since BEVs will (hopefully) have their own charging cables with standard 115V or 230V plug they can be charged from home or a charging station, trying to monopolize that might be hard.


Are BEV batteries the best ones for load balancing ?
They have to be light and have to be more robust than stationary batteries could be.

I would be inclined to separate the two, unless the utilities start to pay big bucks for power at peak times.

A smart charger makes a lot of sense - charge when there is excess power: wind and night time coal/nuke.

The key to renewables is energy storage - but getting it to scale to match (say) wind, at the right price is a major challenge - anyone who succeeds will become very rich.

Harvey D

Based on

(1) 100+ million PHEVs and BEVs each equipped with a quick charge discharge 20KWh (average) battery pack.

(2) Up to 100% pluged in during night hours.

(3) Upt to 50 % pluged in during the rest of the day.

those vehicles would certainly represent a major energy source to and from the power grids if managed efficiently.

Of course, this could not be done without adequate laws and regulations to ensure that everybody's interests are adequately protected.

Since electric power flows between States and Provinces and even between countries (example: USA and Canada), V2G or G2V regulations would almost have to be international or bilateral.

This is not impossible to do but it may be time to get started.


Considering an average commuter is moving about 1-2hours per day in a car, that means 23-22hours potentially available at a charging station.



If I owned such a vehicle, what would really matter to me is if my car had a full charge when I needed it. I'd be really upset if the power company had ended up using so much energy during the day that they didn't leave me enough to drive home.


There are many advantages to Tesla and PG&E to move early in this area and to attempt to set the de facto standards, i.e., the plug, the interface and the interface control. In other words, set the protocols to favor their requirements and devices.

In keeping with the cautionary advice from gr: The standards agreed upon should also consider the requirements that it is compatible with home generated power and that any rules or specifications must be approved by a third party watching out for the welfare of the consumer. There are many companies that fully understand the concept that he who controls the distribution, sets the prices and controls the product. For a long time that has been the Oil Companies and they are still in the cat bird seat as long as fuel is pumped at stations. However, it could very well become the utilities as we move from oil to electrons. Let's get off to a better start this time.


If I owned such a vehicle, what would really matter to me is if my car had a full charge when I needed it. I'd be really upset if the power company had ended up using so much energy during the day that they didn't leave me enough to drive home.

That's not going to happen.


Prof. Andy Frank (UC Davis) gave lecture here last spring on the topic of PHEVs and V2G. His proposals only included using a small fraction of the batteries total capacity mostly for regulation and replacement of spinning capacity (with application to peak power once enough storage potential was on the grid). The beauty of using only a small part of the battery was that it has almost no wear and tear on the battery (which are capable of millions of such shallow cycles) and virtually removes the chance that someone will be inconvenienced by driving off on a depleted battery.



The power companies could charge you less if you allow them to V2G, or pay you a higher premium for the discharge back. And if used in PHEV then you would not be stranded because you do have engine backup. To avoid complaints I think the power companies would use V2G sparingly, that and I don't think V2G will be mandatory.


Vehicle-to-grid power implementation: From stabilizing the
grid to supporting large-scale renewable energy


Gr et al.
In a renewable electron economy... there is a significant risk that an electric utility can exert more monopolistic style power. But, on the other hand, because the electric system is already structurally so prone to monopoly, our governments have already put a boat-load of regulations on private companies that operate parts of the electric system.

Implementing a complex, smart-grid technology like V2G which is to the benefit of almost everybody, is not without costs or risk for the electric utility. There are a lot of gadgets to buy, software to program, and new operating procedures to implement in order to operate a grid/network with so many intelligent agents on it. I would caution against the attitude (that some demonstrate on this board and others having to do with distributed energy topics) that somehow the utility is going to foot the bill and then we are going to be able to "run away" with the goods without paying the utility back for the services that they have rendered. Managing a grid is hard work and capital intensive, something that most distributed energy advocates have not yet had experience. A smart grid be a local one or a national one, is a big capital expense which we will all (and should) pay for through our electric bills or some other means.

I am in agreement that metering and billing with V2G adds an additional area for regulatory oversight and perhaps third-party monitoring of controls and metering standards.

hampden wireless

As someone else said this is not V2G but G2V. Our local power company already does this with central AC units. They will pay you $100 a year for control over your AC compressor. They claim to turn it off for less then a few hours a season at the worst peak times and not for long stretches for any one person. The control is actually radio control not a signal through the power line.

Considering an electric car is a larger load I suspect they would pay more for that control.

A more complex system would be to allow for varying electric rates and have a charger that YOU THE CUSTOMER can control to pick the rates and times of charging.


The example of remote control of home air conditioning by utility companies shows this approach must grow. Note the utilities pay for it. Does that mean they will contribute to the cost of daytime charging stations?

Maybe the car owner could specify whether their battery is available for shallow cycle voltage regulation and/or deep cycle storage like brownout avoidance.



I am using a digital term to refer to offline storage of electrical power, e.g. supercap banks, flywheels, or high end batteries like the ANanos. A single source distributor (PG&E) can purchase renewables at a discount, store the electrons, then sell them to customers at peak rates. Not a bad thing in a market economy but a problematic thing if it is a monopoly. I am arguing that we provide opportunities to diverse energy suppliers via the grid, rather than a single utility. Diversity encourages innovation and deflates monopolistic entropy.


my point exactly. The intelligence i.e. "smart" capability is given to the consumer (vehicle). Energy is offered at varying rates by a diversity of suppliers. The "smart" car is then empowered to select which supplier at what rate and in what volume. The logics of this are not difficult - essentially the technology is currently off the shelf. We need critical mass demand to create new small energy suppliers who have a realistic chance of winning customers - sort of like the equalizing effect of the internet on corporate media. Diversity = empowerment = growth.



Why do you think that the market can support a large number of small suppliers vs. larger suppliers who have the advantage of economies of scale? There are a limited number of places suitable for power plants, be they renewable or otherwise. Micheal above raises some very pertinent issues as well.

hampden wireless

One other thing. Its MUCH smarter to have G2V under control on many vehicles then V2G on fewer. The batteries are not negatively effected on G2V control schemes but V2G can degrade a customers batteries. The financial equation becomes much more complex at that point. Of course the electronics of V2G are also far more complex then G2V control. Yes, I think V2G is sexy and neat but G2V should give the utilities most of what they need and the best benefit to the consumer.


Why do you think that the market can support a large number of small suppliers vs. larger suppliers who have the advantage of economies of scale? There are a limited number of places suitable for power plants, be they renewable or otherwise.

The entire US could be powered with a fraction of the roof space. Solar is already affordable and gets cheaper all the time. The relative scale advantages of utility-grade power production really don't measure up so clearly anymore.

The comments to this entry are closed.