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Toyota Engages w/PHEV Advocates on Vehicle-To-Grid (V2G)
Aug 3, 2007 (From the CalCars-News archive)
This posting originally appeared at CalCars-News, our newsletter of breaking CalCars and plug-in hybrid news. View the original posting here.
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Toyota has outdone itself -- this time, advancing the discussion within the auto industry on the future of V2G. The company's reservations are less significant than the fact that it is paying very serious attention to the subject.

Background: On July 26, Toyota's VP Irv Miller posted a video and description of Toyota's objectives for its pilot program -- see it at­2007/­07/­readers-of-this.html. We commented about Mr. Miller's favorable words about conversions at­calcars-news/­804.html. The other big news from that blog posting turns out to be an opening to the topic of V2G. Below is Toyota's latest post, followed by a joint response from CalCars and Prof. Willett Kempton, who is probaby more responsible than any other individual for gestating and developing the V2G concept. (We did not include several other comments that preceded ours that were interesting but off--topic.)

IRV'S SHEET: The Prius Plug-in as Energy Supplier ~ Contributed by Irv Miller, Group Vice President Corporate Communications July 27, 2007 Posted at 04:11 PM­2007/­07/­irvs-sheet-the-.html

We were very interested to read a question posted here by Jon Wellinghoff, a commissioner with the Federal Energy Regulatory Commission. Mr. Wellinghoff asks, basically, about plans to equip a production version of the Prius Plug-in Electric Hybrid Vehicle (PHEV), the topic of a previous blog posting here on Open Road, for what's called Vehicle-to-Grid (V2G) applications.

As you probably know, the V2G concept means that consumers would plug their PHEVs in overnight to get them fully charged, then drive to their destination for the day, plug them in again and allow the PHEV to feed its stored electrical power back into the energy grid.

First of all, we're very grateful for Mr. Wellinghoff's interest in Toyota's continuing development of our plug-in hybrid technology, and in the ways in which the Prius PHEV may fit into ideas about V2G applications.

However, we think it's important to keep in mind that Toyota's first priority is to continue developing its PHEV technology and then, when the technology is ready, get PHEVs into the hands of our customers. Secondly, our expertise is in building motor vehicles. It's not in power generation. That's something that we would prefer to leave to those best equipped to do it.

That said, as you're no doubt aware, Toyota is one of several auto makers who are developing PHEV technology. While our various approaches to solving the many challenges may differ, there is broad agreement on this: Before market-ready PHEVs can be developed, we need to develop advanced batteries that can meet the customer's expectations for performance, durability and cost. Prior to any meaningful exploration of V2G concepts, we must first resolve the very basic battery and product issues that we're addressing today.

Beyond the challenges of developing PHEV technology, electric-energy experts tell us that the hurdles for V2G concepts are significant:
- Battery performance must be 10 times higher than today's best batteries.
- PHEVs are intended to be charged from home, using existing circuitry. The grid contribution from a single car therefore is insignificant when compared to the massive size of regional grids. This means that meaningful V2G contributions will depend upon hundreds of thousands of vehicles plugged into an existing grid, all contributing grid services in some yet-to-be-defined coordinated method.
- We are unaware of any discussions concerning how to pay for the necessary infrastructure to collect the 120 VAC current from each PHEV and step it up to transmission and/or distribution voltage.
- We are also unaware of any concrete plan for insuring the safety of utility workers in light of such a massively distributed system.
- And while there are many concepts for vehicle and account identification and communication, none of these concepts are thoroughly developed.

There's another important question, as well: In light of the uncertainty of gas prices and perhaps even future gasoline availability, will motorists want to sacrifice overall MPG by trading away their PHEV's reserve battery power?

The automobile business is changing and will, we feel sure, require strategies, partnerships and alliances we might not even have thought of yet. We don't even know, for sure, if PHEVs will come to market in the way in which we think they will. Indeed, that's the point of at least some of the research now being done, using Prius PHEVs, at UC Irvine and UC Berkeley. UC Irvine, with its expertise in the technical side of these issues, is studying that, while researchers at Berkeley take a long, hard look at the human side of the equation from the point of view of the PHEV consumer.

Finally, when we discuss various pricing schemes to make the idea of V2G interesting to consumers, we must make every effort to avoid unintended consequences. We can all learn from the recent problems with the California solar roof program, where, in some cases, time-of-day rates actually increased the overall utility bills of participating customers. This had the consequence of severely reducing program participation by California consumers the very opposite of the program's intent.

So while the potential for V2G is another intriguing aspect of hybrid technology, we must not become sidetracked so that we lose sight of the immediate goal. That goal is to produce an affordable, reliable PHEV that can be sold in large quantities, that can be serviced at any dealership, and that will meet the needs of the American motorist.

I assure you, that's a big enough task.

RESPONSE BY WILLETT KEMPTON & FELIX KRAMER Posted by: Felix Kramer | August 03, 2007 at 12:32 PM:

After Toyota's decision to begin building PHEVs, motivated by what Irv Miller sums up as "that goal is to produce an affordable, reliable PHEV that can be sold in large quantities, that can be serviced at any dealership, and that will meet the needs of the American motorist," almost nothing could make us happier than to have Toyota begin to engage a Federal Energy Regulatory Commissioner who calls PHEVS "cash-back hybrids" on the potential and obstacles of vehicle-to-grid (V2G)!

As two people working every day to promote plug-in hybrids generally and the integration of the power generation and transportation sectors, we're thrilled that it took only 23 hours for Toyota's VP Irv Miller to respond to Commissioner Jon Wellinghoff's question. That tells us that the question didn't catch Toyota by surprise: people in the company are thinking deeply about this subject.

We'd like to respond on three levels to the issues raised, and point to some ways to move forward.

Just as it took a few years to persuade people that the grid had enough night-time power to charge cars, and that plugging in will provide significant greenhouse gas reduction even while the national power grid moves away from high-CO2, it's important to begin to communicate that:

  • Today's batteries can easily demonstrate the benefits of V2G, many of which don't require high energy transfers.
  • No car-owner will ever have to lose money making the battery available to the utility. On any day when a driver's battery is ever drained significantly, the payments will always substantially exceed the cost of driving home using gasoline.
  • The technology exists today to implement V2G. The big challenge is to carefully develop protocols and standards for safety, interconnections, data management and communication, control, aggregation and accounting.


  • Design, testing and evaluation programs involving a few hundred cars can provide a demonstration on a scale comparable to a full-sized power plant, providing important information for planning in terms of technology, integration and business models.
  • Here's the evolutionary path: Even a few thousand cars can provide significant benefits in improving the efficiency and reliability of a utility's power generation and distribution system. Then hundreds of thousands of cars can turn intermittent renewable energy sources like night-time wind power into reliable 24/7 energy sources. And further in the future, tens of millions of V2G cars can help provide homes, businesses and communities with affordable back-up power, reducing the consequences of power failures. None of this is dependent on a brand-new redesigned power grid: it can be added incrementally.

  • We respectfully disagree with Mr. Miller's suggestion that planning for V2G would sidetrack carmakers from the immediate goal of commercializing PHEVs. The stages we just described provide benefits at every point. And because V2G-capable cars (and batteries removed in the future from plug-in cars for stationery secondary use) can provide revenue streams, it makes sense to give business planners (especially in fleets) the information to take V2G into account in projecting lifetime total cost of ownership of PHEVs.
  • Because warranty and liability issues are so critical, it may be that smaller companies will pioneer in providing vehicles with high power transfer capabilities for demonstration projects. But it will be immensely beneficially for the large carmakers to watch and participate in discussions at every step along the way.
  • As Mr. Miller said so well, carmakers' expertise is in designing and building vehicles. That's why it's appropriate that the utility sector is taking the lead here. Meanwhile, other carmakers are announcing research partnerships with utilities. We encourage Toyota to do so as well, either with an individual utility or one or more of the organizations developing V2G technologies.
  • Ideally, we would have the federal government take the lead, so that all the intellectual property would be public and designs would be optimized for national security, electric reliability and CO2 reduction. However, we don't know when we'll get that level of commitment from Washington, DC,
  • Mr. Miller suggested we're all in unexplored territory that may bring us to "strategies, partnerships and alliances we might not even have thought of yet." Toyota would earn all our thanks if it took the lead in organizing a consortium of automobile companies, each contributing funds to sponsor a large-scale demonstration program once the first pilot programs are underway.
  • Once again, we thank the company and Mr. Miller for its responsiveness and openness to new ideas!

    -- Felix Kramer, Founder, The California Cars Initiative

    -- Prof. Willett Kempton, Senior Policy Scientist, V2G Research Group, University of Delaware

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