To PHEV or Not To PHEV (At Least in the Near-Term)
17 February 2008
Two of the consistent threads in the discussions and presentations of the 2008 SAE Hybrid Vehicle Technology Symposium last week in San Diego were (a) explorations of the near- to -medium-term technical viability of plug-in hybrid electric vehicles (PHEVs)—which mainly (although not entirely) means the viability of the lithium-ion battery technology—and (b) the desirability of pursuing PHEVs now, versus alternatives such as focusing on broadening the conventional HEV market and treating PHEVs as a longer range solution.
Looming over both threads was the question of market demand and behavior: would a sufficient number of consumers buy PHEVs to make the effort required to develop and to produce them financially and environmentally worthwhile?
On the OEM side, the most forceful proponent of a plug-in approach was GM, as Pete Savagian, Engineering Director, Hybrid Powertrain Systems Organization, outlined some of the market rationale driving GM’s decision to push hard on the Volt Extended Range Electric Vehicle (E-REV), as well as describing some of the company’s recent analysis of real-world benefits. (Earlier post.)
Although both Chrysler and Ford have PHEV trial projects underway (the Sprinter PHEV for Chrysler and a plug-in version of the Escape hybrid for Ford), their presentations reflected the lower level of shorter-term commercialization commitment those companies currently have made to the plug-in platform, compared to GM.
In his presentation outlining Ford’s next-generation hybrids (earlier post), Sherif Marakby, Ford’s Chief Engineer for Sustainable Mobility Technologies, said that PHEVs represent a potential opportunity to reduce petroleum fuel consumption, essentially buying society time by closing the gap until more advanced technologies and renewable fuels become readily available.
Ford is collaborating with Southern California Edison a set of research Escape PHEVs. The Escape PHEV is based on a 10kWh Li-ion battery pack developed in partnership with Johnson Controls-Saft (earlier post), and are getting as much as 120 mpg in testing, according to Marakby. The Escape PHEV powertrain operates in three distinct modes: electric drive (ED) mode, blended mode (a combination of engine operation and charge-depleting electric drive), and conventional hybrid mode. Ford and SCE are also exploring V2G applications of the PHEV platform.
Chrysler’s Gary Oshnock, Environmental and Energy Planning, while spending more time describing his company’s upcoming two-mode hybrid, noted that the test fleet of Sprinter PHEVs will give Chrysler the opportunity to develop lithium-ion battery technology which will complement its future hybrid, fuel cell and pure electric systems.
In his presentation describing Nissan’s work with its next-generation lithium-ion batteries (earlier post), Toshio Hirota noted that the company sees plug-in hybrids as a potential mechanism to reduce CO2 output in the shorter term, but that it has concerns that include battery cost, market demand, and the CO2 intensity of electricity.
None of the three more engineering-oriented presentations from Honda or Toyota dealt with the PHEV topic. Toyota described the evolution of its motor design as implemented in the Lexus LS600h and LS600hL luxury hybrid transmission. Honda described its model-based approach to hybrid-electric vehicle design, as well as a concept Rankine-cycle system coupled with a hybrid drive. (Earlier post.)
However, John German, Manager of Environmental and Energy Analysis for Honda and one of the organizers of the SAE symposium, took an unscheduled opportunity to present a few slides calling into question the near-term benefit of plug-ins.
While acknowledging that “plug-ins are likely to be one of the alternatives to fossil fuels,” German said that given the projected near-term economics, a premature focus on plug-ins might deliver less benefit than focusing on expanding the market share of conventional hybrids. In his remarks, German referenced economic payback analysis from the American Council for an Energy Efficient Economy (ACEEE), as well as a detailed May 2007 study by Matthew Kromer and John B. Heywood at MIT on the prospects for electric powertrains in the US.
The plug-in hybrid offers a striking opportunity to reduce petroleum consumption to a level half of that offered by the hybrid vehicle. In addition, while the plug-in hybrid’s business-as-usual GHG emissions do not project a significant benefit, they offer a continuous path for incremental improvement through decreased carbonization of the power sector—an opportunity that does not exist for the hybrid vehicle.
...At the same time, the PHEV is a less cost-effective way to reduce petroleum and greenhouse gas emissions than the hybrid (particularly in the near-term); and, due to its higher upfront cost, it will have a harder time penetrating the market. The plug-in hybrid also faces greater technical and infrastructure risk than the HEV: while the hybrid has already enjoyed market success, the plug-in hybrid still requires significant improvements in battery technology to meet the rigors of an automotive duty cycle. And while the infrastructure for supporting hybrid vehicles is already mature, deploying the plug-in hybrid at scale will require regulation to ensure that off-peak generation capacity is used; depending on geography, it could also require capacity expansion. While the infrastructure issues represent a relatively low barrier to deployment, the technical challenges will delay the time-to-market for the plug-in hybrid.
Taken together, the long time to market penetration and the lower cost-effectiveness of the plug-in hybrid suggest that the HEV offers a higher leverage, lower-cost path to reducing petroleum and GHG emissions in the near-term. However, given the upper bound on the HEV’s effectiveness, the plug-in hybrid offers a mid- to long-term path to continued reductions.—Kromer and Heywood (2007)
At the conference, Menahem Anderman of Total Battery Consulting would develop aspects of that argument more fully in his presentation on prospects for the lithium-ion battery market.
Anderman, a consultant to the automotive energy storage industry who also organizes the annual Advanced Automotive Battery and Ultracapacitor Conference, publishes an annual report on the industry. The 2008 report will be published later this year, but Anderman presented some updated results on the 2007 report.
Based on his interviews with automakers, integrators and cell and battery pack developers, he anticipates the entire market for hybrids to hit about 1.1 million units in 2010, with about 750,000 of those being from Toyota. Those HEVs will predominantly use NiMH packs, with Panasonic EV being the dominant provider, and Sanyo in the number two position.
The lithium-ion battery market, by contrast, is much more volatile, and still faces a technology shake-out in terms of cathode and anode chemistries, cell design and packaging, manufacturing, safety and cost. There are more than 20 providers who say they expect to be in the market in 5 years, according to Anderman.
If I believed what everyone says about the viability of other cathodes [than their own], there would never be a lithium-ion automotive battery.—Menahem Anderman
Anderman projects that lithium-ion cells batteries will represent a market of about $300M by 2012, and begin their ramp-up in 2013. That means, he noted, a major shift to Li-ion for hybrid platforms around 2014. Lithium-ion will be the preferred technology for hybrids “at some point in the future,” he said.
However, a PHEV, he said, due to the requirements of battery size, drive system and vehicle design, is too expensive for the value. Anderman projected a cost of $600/kWh for the pack. (In an earlier presentation, Ric Fulop from A123Systems projected $500/kWh.) “I don’t like it, but it is. Not liking it will not solve the problem.”
The environmental and societal benefit in moving from HEVs to PHEVs is smaller than that of moving from conventional vehicles to HEVs, but there is a much larger negative impact on consumer value. In moving from a PHEV to fuel cell HEVs, there is no additional benefit—and maybe even less. But the negative impact on consumer value is much higher. With battery electric vehicles, there is more benefit, but also more negative impact. The PHEV may be a long term solution.—Menahem Anderman
Anderman’s current take is that PHEVs are unlikely to reach commercial volumes in the next seven years, and that while it is not ready for commercial introduction now, the business risk in pursuing the platform now is “tremendous”.
PHEVs are, however, he noted, considerably more realistic than fuel cell vehicles in the 10-20 year timeframe. In the longer term—assuming much higher cost of fuel or government policies—a PHEV in a blended control strategy could become attractive.
PHEVs are a detour and not a step forward, Anderman said, if:
For the sake of the PHEV, car and battery companies dilute their efforts to expand conventional HEVs and to introduce li-ion batteries into the market;
If governments miss the opportunity to provide incentives for conventional HEVs, “the only electrified vehicle technology that can make an impact on the environment in the next 10 years” and
If the PHEV is rushed to market by bypassing prudent automotive engineering design, verification, qualification and supplier management standards.
PHEVs are a step forward, he said, if fuel cell vehicle development resources are redirected toward PHEVS.
Anderman’s conclusions about the economic viability of PHEVs were vigorously questioned by Dr. Mark Duvall from EPRI (Electric Power Research Institute), who had just preceded Anderman on the dais with a presentation on the impact of PHEVs on emissions and on the utility industry.
I’m gratified to see $600/kWh cost figure. At $600/kWh there are many highly likely near-term scenarios where PHEVs can pay back. What I’m saying is that we did a cost study, we think it’s credible...and it disagrees dramatically with you...There is greater leeway to discuss this. We can’t assume the negative impact on consumer value. We have to look at entire value equation of the vehicle.—Mark Duvall
The transportation sector has to do much more than plug-ins, Duvall noted. His most optimistic projections show plug-ins pulling up to 500 million tons of GHG out of the sector. “The transportation sector has to do way more.” Noting that HEVs would only deliver a very small portion of the total reduction required, Duvall said that to say we should develop the HEV market fully and then pursue other avenues wasn’t viable.
In one of the opening presentations of the symposium, Tom Turrentine, an anthropologist with the PHEV Research Center at the University of California Davis presented his research that indicates that contrary to what some in the auto industry may think, consumers tend not to calculate paybacks.
Consumers don’t calculate paybacks, but they want better mpg. The dual fuel nature of the PHEV is a primary market feature for consumers...they can choose. It’s the meanings which motivate buyers. Motivation is driven by emotions.—Tom Turrentine
For its part, the California Air Resources Board (ARB) has a number of initiatives under way to support a more rapid development and deployment of PHEVs, as ARB’s Craig Childers described in his presentation:
In the more immediate term, the $1.6M Alternative Fuel Vehicle Incentive Program (AFVIP) provides grants of up to $5,000 to qualified individuals, businesses, public agencies and entities, and non-profit organizations that purchase or lease an eligible AFV. PHEV drivers will receive the full $5,000, although the PHEV must be ARB-certified and have at least a 10-mile equivalent all-electric range. PHEVs are the only flexible-fuel vehicle that qualify; conventional hybrids do not.
California’s AB 118, signed into law in October 2007, is a seven-year program funded by vehicle license fees that will provide around $205 million each year to be applied in clean air, fuel and vehicle technology.
And ARB staff has proposed amending the Zero Emission Vehicle (ZEV) regulations to create a “New Path” that would provide a strong incentive for the development and deployment of PHEVs in the period from 2012-2017). (Earlier post.)
After a presentation by Lee Slezak from the Department of Energy that outlined the breadth of the DOE support activities for the development of PHEVs—development research on power electronics and electric machines (PEEM), research on energy storage, modeling & simulation, and testing & validation—Michael Duoba from Argonne National Laboratory (ANL) provided a more detailed update on the development of revised SAE J1711 test procedures—used to measure the exhaust emissions and fuel economy of HEVs—to accommodate PHEVs.
Test procedures are not something you think about at the end of a development project. You need to think about it in the beginning. PHEVs are significantly different from the conventional and hybrid vehicles and thus require a new testing paradigm. Since OEMs have announced production PHEV plans, the need for a revised J1711 has become urgent.—Michael Duoba
ANL PHEV testing is supporting the J1711 development—and also helps the fine-tuning of PHEV systems development as well. A slide used by Ric Fulop in his presentation used data provided by Duoba and his lab showing the progression of three-generations of the Hymotion PHEV conversion pack as it went through successive tweaks to address successfully the emissions issue caused by the conversion. (Earlier post.)
Duoba also noted that ANL has made public basic data from the dynamometer testing of hybrids and PHEVs via the Downloadable Dynamometer Database “D3”.
Matthew A. Kromer and John B. Heywood (2007) Electric Powertrains: Opportunities and Challenges in the US Light-Duty Vehicle Fleet (LFEE 2007-03 RP)
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