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ACEEE Blows Hot & Cold on PHEVs; Christian Science Monitor Reports
Sep 24, 2006 (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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The American Council for an Energy-Efficient Economy has just released a report on the benefits of PHEVs. In the accompanying press release, co-author Theresa Langer says, "Plug-ins represent a major step toward the electrification of the transportation sector, a transition that has tremendous potential to help solve some big problems."

Unlike most other reports, this one compares PHEVs not to internal combustion engine (ICE) cars, but to today's (part-of-the-way-there non-plug-in) hybrids. It finds benefits even in this comparison that analysts may see as significant or minor. We're expecting other reports this fall to go far in answering the remaining objections about how much better hybrids are than ICE cars and hybrids, but these findings of a 15% CO2 reduction compared to a hybrid on today's national (half-coal) grid, are already helpful. Significantly, this report comes from a group that has reserved judgment on PHEVs, and whose work has been cited by some analysts and organizations that remain skeptical about electric transportation. (Many are reluctant to factor in the likelihood that the power grid will get cleaner as renewable portfolio standards and other requirements emerge -- leading to the point that, while ICE cars get dirtier as they get older, electric cars get cleaner, because electricity gets cleaner.)

The report cautions against overselling PHEVs' benefits, especially the 100+MPG message. PHEV advocates make serious efforts to communicate whenever possible that it's "100+MPG of gasoline, plus electricity."). While it is not yet possible to predict the performance of production PHEVs, based on my own daily experience, it appears the report underestimates what's possible from driving at "mixed speeds" -- at both mid-range 35-55 MPH and highway speeds.

In contrast to co-author James Kliesch's comment that " 'electric-then-gasoline' depiction of plug-in operation is not realistic and has contributed to overstatements of the fuel savings potential of plug-ins in the popular media," here's what I've been getting in "mixed-mode" driving: Since filling my car 13 days ago, I've driven 538.86 miles on 4.158 gallons, achieving 129.5 MPG. And at­photos.html you can see a photograph taken September 1 showing I had driven 949.75 miles on 9.365 gallons, achieving 101.4 miles. (This even included a 175-mile round-trip from the Bay Area to Sacramento where I drove mostly as standard hybrid.) We'll have more data soon...

The chart cited in the Christian Science Monitor news story that follows the press release below includes ACEEE data showing a $3,500 long-term incremental cost for a 40-mile all-electric range battery, which matches up to statements by PHEV scientists, economists and advocates. (The ACEEE's press release contains a link to the full report in PDF format.)

Plug-Ins Promising -- But Better Batteries, Cleaner Power Plants Essential

Washington, D.C. (September 21, 2006): Plug-in hybrid vehicles could contribute greatly to reducing automobile oil consumption and emissions, but reaching those goals requires major progress in key areas. According to a report released today by the American Council for an Energy-Efficient Economy, the environmental and economic appeal of plug-in hybrid vehicles will depend heavily upon cleaner power sources and further battery advances. The report, "Plug-In Hybrids: An Environmental and Economic Outlook," examines the benefits of plug-ins relative to today's hybrids. It finds that greenhouse gas emissions reductions associated with a plug-in powered by today's electric grid would be about 15% on average across the nation, ranging from 32% using California electricity to zero using Upper Midwest electricity.

Plug-ins' oil savings could be quite large. Battery size and cost rise steeply with the amount of fuel savings, however, suggesting that plug-ins with modest electric-only range will appear first. According to report co-author James Kliesch, the "electric-then-gasoline" depiction of plug-in operation is not realistic and has contributed to overstatements of the fuel savings potential of plug-ins in the popular media. "Achieving adequate battery lifetimes and minimizing battery costs will require a vehicle control logic that turns on the internal combustion engine when extra power is needed, even within the 'electric-only' range of the vehicle," said Kliesch. The ACEEE report estimates fuel savings relative to today's hybrids of 30% for a plug-in with a 20-mile electric-only range and 50% for a 40-mile range.

With high volumes and a drop in nickel prices, the cost of the nickel-metal hydride batteries used in hybrids at present could fall quite dramatically. To reach an appropriate balance of size, weight, and power for a long-range plug-in, however, researchers' bets are on lithium-ion batteries, which still need technological breakthroughs to reach commercial production for plug-in applications. Projections of long-term costs for plug-in batteries imply that the incremental cost of a plug-in could match that of a hybrid today.

"Plug-ins represent a major step toward the electrification of the transportation sector, a transition that has tremendous potential to help solve some big problems," said report co-author Therese Langer. "But realizing this potential means maintaining an all-out effort on advanced batteries, cleaning up electric power generators, and adopting policies that drive efficiency technologies by requiring a sustained ramp-up of average fuel economy."

"Plug-In Hybrids: An Environmental and Economic Outlook" is available for free download at­pubs/­t061.pdf­pubs/­t061.pdf or a hard copy can be purchased for $16 plus $5 postage and handling from ACEEE Publications, 1001 Connecticut Avenue, N.W., Suite 801, Washington, D.C. 20036-5525, phone: 202-429-0063, fax: 202-429-0193, e-mail: aceee_publications@....

The American Council for an Energy-Efficient Economy is an independent, nonprofit organization dedicated to advancing energy efficiency as a means of promoting both economic prosperity and environmental protection. For information about ACEEE and its programs, publications, and conferences, visit http://aceee.org

Contact: Jim Kliesch, 202-429-8873, x721 Therese Langer, 202-429-8873, x724 Media Contact: Glee Murray, 202-429-0063

A reality check on plug-in hybrids
Vehicles that draw power from the electricity grid offer uneven
benefits, a new study finds.
By Mark Clayton | Staff writer of The Christian Science Monitor
from the September 25, 2006 edition­2006/­0925/­p03s02-usgn.html

There are hybrid vehicles, whose gasoline/electric engines get great mileage. And then there are "plug-in" hybrids, only about a dozen of them in the US, which have been modified to store more electricity in beefier batteries by plugging in at night to the electricity grid.

Felix Kramer's "plug-in" Toyota Prius gets about double the mileage of a conventional Prius - about 100 miles per gallon. To him, it is the holy grail of cars, zapping pollution, oil imports, and high pump prices all at once.

So, should the whole country jump on the band wagon?

A groundbreaking study released last week sounds a cautionary note to the consumer. Plug-ins do burn less gasoline than regular hybrids - and gobs less than gasoline-only vehicles - but the high cost of their bigger battery packs will probably neutralize even significant savings at the pump, according to a report by the American Council for an Energy-Efficient America (ACEEE).

The study is the first to compare the performance - and the costs - of two hybrid technologies: the conventional versus the plug-in. It comes even as President Bush, energy-security hawks, and many environmentalists are talking up plug-in hybrid-electric vehicles (PHEVs). Dozens of cities, too, have signed on to promote a new Plug-in Partners program, and Toyota and other automakers say they're working on the technology.

"We want government policy based on reality, not overstating what [plug-in technology] can achieve and when," says report coauthor Therese Langer, ACEEE's transportation program director. "We don't want what happened with the hydrogen hype to happen with plug-in hybrids, too," she adds, referring to optimistic assessments of a timetable for shifting to a hydrogen-powered vehicle fleet.

Cleaner skies, in some places

Environmental impacts of PHEV technology, for instance, would vary dramatically by region - benefiting some areas but not others, the report found.

For a plug-in owner in California, where most electricity on the grid is generated by low-pollution facilities, driving a PHEV might cut emissions of carbon dioxide by one-third compared with driving a regular hybrid.

But if the same PHEV were charged in the Midwest, where coal-fired power plants supply the electricity, reduction of CO2 emissions would be nil. Nitrous-oxide emissions (which form smog) would fall slightly, but sulfur-dioxide emissions (which contribute to acid rain) would quadruple.

Still, environmental gains are possible.

Plug-ins would chop CO2 emissions by 15 percent on a national average, compared with conventional hybrid cars, the ACEEE report found. At the same time, the plug-in would emit 157 percent more sulfur-dioxide pollution. The need, plug-in proponents say, is for policies that would clean up the electricity grid so that PHEV technology supplies cleaner skies along with energy independence.

Pricey batteries

The cost of nickel-metal hybrid batteries may also limit the appeal of plug-in hybrids - at least in the short run.

Today's conventional hybrids command a premium price - $2,000 to $4,000 more than their nonhybrid counterparts - and their owners will recover that extra cost in about three years, assuming $3-a-gallon gasoline and 12,000 miles a year of driving, the report found. (Graphic)

For the plug-in, the payback period is longer - 6.4 years for a vehicle that can travel 40 miles exclusively on stored electricity - even under the more optimistic scenario in which battery prices fall sharply, the ACEEE report estimates.

Others, however, say that PHEV technology is crucial for America's energy security and that mass production will bring battery prices down.

"This is an important technology from an energy-security standpoint," says Gal Luft, executive director of the Institute for the Analysis of Global Security, a Washington-based energy-security think tank.

Even so, he agrees that expectations have become a bit overheated. "It's true this technology isn't going to be suitable for everyone," he says,

Felix Kramer's souped-up Prius

As for Mr. Kramer, who is apparently the first of about a dozen people nationwide to have acquired a plug-in hybrid Toyota Prius, the ACEEE report gives him not a moment's pause. Cofounder of, a group promoting plug-in technology, he keeps close track of his mileage and now commutes to work powered almost solely by stored electricity. On a recent 450-mile run, at mixed speeds and terrain, he got 125 miles to the gallon.

Now he's installed solar panels on his car's roof to charge the battery and lower his costs even further.

"In the real world, battery reliability [will improve] and costs are going to come down fast," he says. "My real-world experience tells me they're understating the benefit. I'm doing a lot better than the report."

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