Power Transmission lines
Unlike today's hybrid-electric cars from Honda and Toyota, grid-connected hybrids would derive some portion of their range from electricity transported over the nation's vast power grid.

Making the Case for Grid-Connected Hybrids

An interview with Robert Graham, Electric Vehicle Program manager, EPRI

By Bill Moore

Here is how a grid-connected hybrid would work.

Like a battery electric car, you would plug it in at night and recharge it, presumably at cheaper off-peak rates. You would then unplug it in the morning and drive to work or school on battery power alone, producing zero tailpipe emissions. If the car's zero emission range is 20 miles and you worked 15 miles from home, you would use the gasoline engine to provide you with the last 10 miles of your commute. If the ZEV range where 50 miles you could commute daily generating no pollution, and when you wanted to take that trip to a nearby city, you could make the trip on hybrid-drive with fuel economies rivaling that of the industry's best PNGV prototypes.

Sounds like a great idea. So why isn't anyone doing it? (Actually, EV World hears that one major carmaker is, in fact working on a hybrid with ZEV-only range, but we have been asked to keep this "under our hat").

Part of the reason has to do with a lack of knowledge as to whether or not the concept is economically feasible. It is the age-old question of "Is there a market for it"? That is what Robert Graham and a team of researchers set out to uncover two years ago. Now the results of their efforts have been made public in a massive 268 page report entitled "Comparing the Benefits and Impacts of Hybrid Electric Vehicle Options."

EV World asked Graham, who was in Washington, D.C. at the time of the terrorist attack on the Pentagon, to explain the objectives of the study.

"It's primary object," he replied, " was to do a proof of concept to determine whether or not we can, in fact, build a plug-in hybrid-electric automobile. And when that vehicle is compared against a conventional vehicle, would that vehicle add value, and if the value is added would it be able to attract consumers?

"Therefore the object is to understand the technical issues, the cost issues and the marketing issues that would be required to introduce into the marketplace a vehicle... that has the efficiencies of an electric drive system as well as the range with an internal combustion engine.

"So, in theory, we could give the customer the best of both worlds. They could be all-electric, quiet and emissions free for a period of time during their daily operation, but if they wanted to go to the mountains on the weekend, they could accomplish that."

In addition to extended ZEV range that is more than the current Toyota Prius and less than the GM EV1, there is a fundamental difference in the type of batteries used in the plug-in hybrid. Graham pointed out that the Prius and the Honda Insight both use high power batteries to improve the performance of their internal combustion. By contrast, a grid-connected hybrid would use a high energy storage battery to provide the car with electric drive-only capabilities.

EPRI undertook the study beginning two years ago with the support of its member utilities. Other participants included the California Air Resources Board, the South Coast Air Quality Management District, the Department of Energy, Argonne National Laboratory and the National Renewable Energy Laboratory, plus a number of professional consultants with expertise in various aspects of the study. Graham stated that GM also participated by providing valuable technical and cost analysis assistant.

"It was a pretty diverse group with both the political view, industrial view and utility power view."

So Why Is No One Buying the Concept?

Up until now, no major automakers -- with one possible exception -- have taken the notion of a grid-hybrid seriously. EV World asked Graham his view on why this is so.

"It's my opinion that the reasons that they're not, and they are accurate reasons, (are) one, there is some cost and complexity to a plug-in hybrid vehicle that does not exist in a conventional vehicle. But there is also some cost and complexity issues in the currently hybrid vehicles made by Toyota and Honda, as well. But the incremental difference in complexity is not as great.

"I think the primary difference is the cost of the battery and the cost of the electric drive system, which they perceive at the moment is greater than what the market would bear.

"The second reason is because there is such a strong emphasis now on the hybrid vehicle, the zero all-electric range hybrid vehicle, that most of the auto manufacturers are spending their intellectual capital and engineering talent to build and develop those hybrid vehicles where they can bring them to market as quickly as possible.

"A plug-in hybrid vehicle would require (their) engineering core to begin to look at two different types of configuration and that might stretch their resources.

"So, we need to build a very strong business case and an engineering case and a cost and technical analysis case that makes the argument that this is a viable product and it will add value and it will attract market attention and will create market pull, in order to cause the auto manufacturers to be willing to invest the millions of dollars that they would be required to invest to introduce this product along with the other hybrid vehicles they are developing."

EPRI's study considered and compared three types of hybrids, HEV 0 with no electric-only range, HEV 20 with 20 miles of all-electric range and HEV 60 with 60 miles of electric-only range. Graham explained that his team picked these numbers to give them a range for their study. Going higher, he said, would have put them in the pure battery electric vehicle arena.

" I don't think it's been determined yet, which is why we have phase two, as to which of those configurations or something in the middle might be ideal. Nor have we determined which vehicle platform would be ideal. My instructions to our team is to determine which of those configurations would generate maximum market pull and create maximum market demand so that we could create a path of market commercialization. The jury is still out as to which of those make the most sense," he stated.

While EPRI's study indicates that there could, indeed, be a market for a grid-connected hybrid, a number of significant outstanding questions need yet to be answered.

"Somewhere in those numbers, you have to determine which range gives you maximum appeal. Which range causes you to have a certain size battery, which may increase the cost. Which battery gives you the most headaches when it comes to packaging the battery internally in the vehicle. And you have to do tradeoffs on all of those," Graham said. "Out of that is going to come a vehicle that makes sense."

"What I can tell you is that it will not be a niche car vehicle. What it will be will be a vehicle that is more like what you and I recognize today as a standard passenger car that you're used to buying, that you're used to operating, that already has a strong market appeal. It could be an SUV. It could be the new, small SUVs. It could be a van. It could be the new station wagons, or it could be a five or six passenger, mid-sized (Toyota) Camry or (Ford) Taurus. To be determine. But it will not be a little, sleek, two-seater that is truly a niche product."

What About Well-To-Wheel Efficiency?

Some skeptics contend that by the time you include generation losses, transmissions losses, charging system, battery storage losses, and drive system losses, a battery electric vehicle may not, ultimately, be that much more efficient than a good, modern gasoline-powered or diesel-powered engine. If this is the case, and we asked Graham this question, do grid-connected hybrids make sense form a well-to-wheels efficiency point of view?

Graham responded, "The actual study shows the opposite. That from a well-to-wheels approach that electric-drive vehicles make significant sense." He pointed out that electric power can be generated by a variety of different fuels, some of them clean, renewable fuels like hydro power and wind energy. He also observed that "inherently, I would think that you could move electric through the grid a lot easier and faster than trucking fuel around. Plus at the end of the day, the efficiencies of electric motors far exceed the efficiencies of an internal combustion engine."

Graham further contends that his grid-connected vehicle concept would work equally well outside the state of California. He points out that there is just as much of an interest by Alabama utilities, which derives most of its electric power from coal-fired generators, in electric vehicles as there is in California. The reason is, it would allow the utility to improve its operating efficiency by selling off-peak power. Consumers would benefit because they could run their grid-hybrids on this cheaper electricity.

He noted that one of his chief requirements during the study was this hypothetical vehicle should perform identical to a conventional vehicle from the driver's perspective. "There is no market for a vehicle that does not perform the same."

"Now that does not mean there might not be some subtle differences in performance, just like there are subtle differences in performance between my wife's Explorer and my V-8 Camero. But in general, the vehicle must have the same performance requirements and meet the same performance issues that you would have in a conventional vehicle, including towing, including luggage space, including zero to sixty miles per hour. All of those performance issues must be met, otherwise you do not have a product.

"You do have a difference in that you do have an option," he continued " of plugging the vehicle in and you would most likely, based on current electric vehicle owners, will want to plug that vehicle in because you have determined the fuel economy savings, you'll live driving it as a noiseless vehicle. So the study shows and the surveys that we've done show that people would prefer plugging in the vehicle, especially when they understand the benefits."

He added that this is at odds with carmaker contentions that people don't want to plug in their cars. "That is just not borne up by when you do interviews with folks who are driving things like the EV1."

Graham contends that when people understand that they can drive an all-electric vehicle without any fear of every running out of range, as long as there is a gas station handy, they will accept this concept.


Times Article Viewed: 19702
Published: 23-Sep-2001


blog comments powered by Disqus