To V2G, or not to V2G? That is the question!

Phil Carson | Feb 17, 2010


Funny how a topic can suddenly appear on your mental radar, break wide open (with help) and – at least in the smart grid’s case – instantly tie in to current events. Gets me up in the morning.

Yesterday one reader asked if anyone knew of a source for the size and electricity requirements of the U.S. fleet of cars and light trucks. Implied between the lines: what’s the potential load and what’s the potential to harness that much storage? 

Lo! a response came in that cracked open the vehicle-to-grid (V2G) space for me. And that setup a delicious dilemma: go through with my planned dinner with my girlfriend tomorrow night, or fly to San Diego for Friday morning’s V2G panel discussion, part of the American Association for the Advancement of Science’s annual meeting. 

(Decisions, decisions. Whether to maintain a once-in-a-lifetime romance or get up-to-date on V2G? But I digress.)

Should you be San Diego-bound, or looking for fresh sources on this topic, the panelists Friday provide a real roadmap for further enquiry. 

They include: Willett Kempton, a University of Delaware professor who has examined V2G’s potential for stabilizing the grid and providing load and storage for renewable energy; Kenneth Huber, with PJM Interconnection, who has looked at electric transportation’s implications for the grid; Jasna Tomic, with CALSTART, has weighed hurdles to implementation; Tina Kaarsberg, U.S. Department of Energy, has looked at alternative electric transportation (trucks, trains); Jeff Stein, University of Michigan, has worked on V2G’s interactive nature; and Ray Boeman, Oak Ridge National Laboratory, has looked at state-of-the-art technologies and that much-sought-after but often elusive route, “the path forward.”

That’s almost enough to make a man give up on love. (But not quite.) 

So, in taking a cannonball-like plunge into the deep end of the V2G pool, I came across several researchers whose work is worthy of note. I thought I’d begin with a column on the vision of V2G, based on one researcher’s calculations of their potential impact. The numbers are eye-opening and go a long way to explain why a lot of very smart people are expending a lot of calories and dollars to push the envelope in that direction. 

My enquiries yesterday included requests for interviews with top researchers, so I promise to bring you the fruits of those conversations soon in this space.

So, to the vision. Kempton, at the University of Delaware, has coupled the nation’s electric utility system and the light vehicle fleet as “two massive but separate energy conversion systems.” Nearly 10,000 utility generators produce more than 600 gigawatts (GW). More than 176 million cars and light trucks produce more than 19,500 GWm (m stands for mechanical energy). That’s 24 times the capacity of the electric generation system.

As the automotive world explores electric vehicles (EVs) and renewable energy sources are tied into the grid, in Kempton’s words, “the economics and management of energy and power in the light vehicle and electric systems make their convergence compelling in the early decades of the 21st century.”

EVs can provide electricity storage and quick-response generation to the grid, electricity will complement and displace gasoline in the fleet and automated controls will optimize the transfer of energy between the two giant systems, given their different but compatible needs based on time of day. 

In a paper titled, “Vehicle-to-grid power implementation,” in The Journal of Power Sources, Kempton calculated that one-fourth of the U.S. fleet produces mechanical energy equivalent to the entire output of the nation’s electricity generation. “Capital costs to tap vehicle electricity are one to two magnitudes lower than building power plants,” Kempton wrote. 

“The average per kWh cost of vehicle electricity is considerably higher and design lifetimes are one to two orders of magnitude lower,” Kempton wrote, “but the critical insight…is that vehicle electricity is competitive in specific electricity markets.”

Kempton examined the four relevant "markets," by which he means baseload, peak, spinning reserves and grid regulation. He found that V2G is not suitable for baseload, in some cases it may be suitable for peak power, it is competitive for spinning reserves and highly competitive for regulation -- the short but frequent requirements of the grid to keep frequency and voltage steady. 

In the future? Storage by V2G of intermittent renewable resources.

I’m speaking soon with a gentleman who has invented a charge controller that makes this future scenario possible today. 

So, we’ll leave it there for now. I just wanted to begin with the premise and the promise, quantified. Feel free to jump in, folks, the water's fine. And there are multiple paths of enquiry opened here.

Phil Carson
Intelligent Utility Daily

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To V2G! No longer a question...

Vehicle-to-grid development began with a hand-full of dedicated folks (some listed above) and the 'nay-sayers' were discouraging from the start.  For Dr. Kempton, his efforts began in the mid-1990s.  Today, V2G is on the verge of shaking up the electric and automotive industries like a tsunami.  Already some island states and countries are putting V2G plans in place to incorporate wind and other renewable generation with the battery storage available in electric vehicles.

Once the general public learns car owners with V2G are earning an income while the car is parked and plugged in, their inquiries will drive the O.E.M. to make V2G available in their PHEV and EV offerings.  In the near future, the O.E.M.'s mentality of V2G will wisely be, "No car left behind."  The Mini-E demonstration participants will be shocked to learn that their beloved EVs already have V2G 'inside' but no one to aggregate their potential power and pay them for the service!

When the 'bean counters' at the electric utilities realize that the needed grid storage can be provided by the utility at great cost, installation and maintenance fees, OR motivate their Customers to buy and use V2G cars, the decision will be simple.

V2G or waste a resourse

How could anyone not want V2G. Just a s abattery tickle to provide power REGULATION which costs the utilites a lot of money you would get paid to be plugged in and just povide a few seconds of charge or discharge energy.

You get opid for just for being connected. With almost no power being added or taken fron the battery. ACPROPULSION did a study and found it increased battery like. It's like like a deep discharge cycle.

When you charge off peak it costs pennies per mile. With an advanced battery that can go 300 miles on a charge like the new Tesla S family sedan it can pay for itself. If there is a power outage your vehicle could provide the power until the GRID is back. SMART metering, V2G and smarter drivers all adds up. Solar and wind make it amazing.

Or you could keep importing oil which we now do for 60% of the oil we burn each day that kills our economy, pollute the air and drive a 80% inefficient gas internal combustion Engine. It's all up to you.  

I would hope every new advanced battery vehicle has V2G built in. It's like many other standrd feature that are now standard. How can we not have it.


How could anyone not want V2G?..…

Because it will be an economic loss for the owner of the vehicle.

To analyze the economics of V2G you will need to begin by taking into account Total Cost of Ownership.  It also is necessary to use units of measure that have real meaning (Penny’s per Mile is not relevant to V2G economics since no miles are traveled).  When considering the energy portion of the equation, what is meaningful are the Kilowatt-Hours added and extracted from the batteries, the cost differential between charging at off-peak and discharging back to the grid at or near peak, and the inherent losses associated with the conversion and storage. Unless you are able to receive orders of magnitude more for the energy the system provides then your cost to charge it there is no way V2G can be viable.

Here’s a rough calculation that is very unrealistic and ignores system losses, but will use numbers that entirely favor V2G concept.

Battery storage Capacity – 20 kWH (more then twice the rated amount usable in the Chevy Volt at 8 kWh)

Charging rate is 5 cents / kWH … so a full charge cost would be $1.00

Discharging rate is 50 cents / kWH … so if you remained parked all day and completely sold back to the utility the entire 20 kW you’ll receive $10.00, a tidy $9 a day profit. (Of course no utility has a 10 times price differential between on and off peak, but let’s continue.)

Cost of Battery Replacement - $3000 and up depending on model

So how many days will you have to make your batteries stretch while being willing to travel nowhere so you can at least break even?  Almost a year (333 days). It is possible that the battery life will be reduced by less, but I doubt it.  I looked for your study online that claims extending battery “like” (I assume you meant “life”), but did not find it, perhaps you could provide a URL. I would be interested in reading how they have solved the problems inherent in the charge/discharge cycle.

Ultimately, the only electrical storage system that holds any economic viability remains to be pumped storage in my opinion.