Studies are important. They are crucial, often enough, to the decision making that must take place in any number of areas in life or business. Studies tell us whether we should consider changing our diet to live longer ... how living near high-power electrical lines or holding a cellphone to our head may, or may not, be a fairly bad idea. They illuminate in myriad ways the cause and effect of activities, products, or decisions that may have major impacts on our lives. Today they are no doubt influencing a new Administration and its policies that promise to have long lasting implications on our lives, including the type of vehicles we may drive.
The problem is, studies too often have an agenda or are based on perspectives or assumptions that are simply ... wrong. What makes this especially challenging is that credibility seems to have little to do with how studies can impact public opinion and government policy. Too many in the media see a press release regarding a new study and report on it as fact. It's then picked up by other sources, hits the Internet, and goes viral, finding an infinite and unending voice that may not be deserved.
So imagine my surprise when I read about the new Carnegie Mellon University study that determined Chevrolet's Volt would not be as effective an answer for drivers' needs as a Toyota Prius plug-in hybrid with much a more limited electric-only range. This plays well into the media frenzy that strives to position GM against Toyota, U.S. domestic automakers against import brands, and paint some automakers as lacking the vision of their rivals. But it doesn't serve to explain why the Volt is an important ... maybe critical ... step forward for the auto industry, and why in the long run it is a better and more meaningful idea than vehicles capable of much more limited electric-only driving range.
It is no small consequence that the Chevrolet Volt was recently named Green Car Journal's 2009 Green Car Vision Award winner at the 2009 Washington Auto Show. It was honored with this distinction precisely because of its attributes, among them a 40 mile all-electric range that suits most commuting needs and groundbreaking technology that will not only help spur mass production quantities of batteries and electric drive components, but lead to additional GM models in various classes with the same environmentally positive features.
The assumptions made by this latest Carnegie Mellon study, released at a time of national debate regarding which direction a new generation of automobiles should take, are counterproductive. Gasoline prices will certainly rise. Dependence on imported oil will continue. The desire for zero emission driving - whether to address fossil fuel use, greenhouse gas emissions, or energy diversity and security - will grow. And vehicles like the Prius, as outstanding as they may be for their market segment, are not a universal answer for all drivers ... nor is the more limited seven mile electric driving range that Toyota is said to be aiming at in a plug-in Prius variant. The diversity of the automotive market will exist regardless of the whims of those who would have everyone drive a smaller vehicle. Thus, the application of battery electric drive in plug-in hybrids - or range extended electric vehicles like the Volt - must by nature be scalable from small vehicles to large, reflecting the need to make all classes of vehicles much more energy efficient and environmentally positive than they are today.
It may be, as the Carnegie Mellon study points out, that almost half of all passenger vehicle miles traveled in this country are in vehicles driven less than 20 miles per day, thus "targeting drivers with the potential to charge frequently would not limit plug-ins to a boutique market." Presumably, frequent daytime charging could adequately expand the all-electric reach of a vehicle with seven miles of battery range to fill the need without resorting to the hybrid's internal combustion engine, if those 20 miles were not being driven in greater than seven mile increments and sufficient time is available for charging in between trips.
But is frequent charging a desirable thing? One of the serious challenges to commercializing massive numbers of battery electric vehicles is the need to encourage charging during off-peak nighttime hours when excess electrical capacity is readily available, rather than frequent charging during daytime periods of peak demand. The former extends the use of existing electrical grid capacity while the latter strains it, ultimately prompting the need for additional powerplants.
This isn't to diminish the importance of plug-in hybrid vehicles with limited all-electric range. There is a place for different types of hybrids, plug-in hybrids, and all-electric vehicles on our highways. It's simply disingenuous to conclude that vehicles with larger battery packs capable of 40 miles or greater range like the Chevy Volt or (unnamed in the study) the Fisker Karma are of lesser value or economic viability than more limited range plug-in hybrids.
Carnegie Mellon concludes that plug-ins with larger and more expensive battery packs capable of providing 40 or more miles of electric travel "are too expensive for fuel savings to compensate, even in optimistic scenarios." With fuel prices on the upswing again and likely headed toward levels that make everyone uncomfortable, the calculations are likely to change.
Plus, what the study researchers don't get is that it isn't all about penciling out short-term costs vs. return on investment. Early hybrid buyers happily paid the premium for more eco-friendly gasoline-hybrid propulsion because of a strong desire to drive green. New car buyers wishing greater levels of performance or luxury have historically paid more - often in the tens of thousands of dollars - for the attributes they desire. It will be no different for those buyers of the Volt and other range-extended electric cars or plug-in hybrids in the early years of their commercialization. And as the numbers grow, so too will battery costs diminish.
This latest Carnegie Mellon study - Impact of Battery Weight and Charging Patterns on the Economic and Environmental Benefits of Plug-In Hybrid Vehicles - immediately brought to mind an earlier study that Carnegie Mellon researchers released in the midst of heated public policy debates back in the summer of 1995. Then, it was California's Zero Emission Vehicle (ZEV) mandate that was taking center stage and Carnegie Mellon weighed in with what many considered to be a flawed study on the impact of large numbers of electric vehicles and their lead-acid batteries. That study - Environmental Impacts of Lead-Acid Batteries in Electric Vehicles - was widely assailed by many including the California Air Resources Board, the Electric Drive Transportation Association (then known as the Electric Vehicle Association of the Americas), and Battery Council International. In case you're interested, Green Car's report on that 1995 study follows verbatim as it was published in its June 1995 issue.
EV LEAD EMISSIONS: MYTH vs. REALITY
The environmental benefits of electric vehicles are questioned in a recently-released study from Carnegie Mellon University, striking at the very qualities which have traditionally been the EV's driving force.
Specifically, the now-controversial report examines increased lead emissions expected to occur as a result of the production, manufacturing, and recycling of the lead-acid batteries expected to be used in automakers' first-generation electric vehicles.
The study prompted a virtual call-to-arms by the EV industry when the New York Times made it front page news, and the journal Science published the study in its May 19, 1995 edition. Since then, it has been widely quoted in the media and used as political ammunition by those striving to kill California's 1998 zero emission vehicle mandate.
Insiders wonder about the timing of this study's release to the media, which coincided with the beginning of the California Air Resources Board workshops to discuss the mandate. They also question its scientific validity.
There are problems with the study, which many cite as rife with erroneous assumptions and calculations. Called "seriously flawed and misleading" by the Electric Vehicle Association of the Americas [editors note: now the Electric Drive Transportation Association] and plain "wrong" by Battery Council International, the study by Carnegie Mellon professors Chris T. Hendrickson, Francis C. McMichael, and Lester B. Lave is based on a hypothetical EV using "available" and "goal" technology.
Available battery technology is defined as 450 driving cycles per battery, 3035 pounds (1378 kg) per driving cycle, 70 percent lead by mass, and eight Watt-hours per pound (18 Watt-hours per kilogram). The study defines goal technology as 1000 cycles per battery, 975 pounds (443 kg) per driving cycle, 70 percent lead by mass, and 25 Watt-hours per pound (56 Watt-hours per kilogram). Three problem areas are given in the life of an EV battery where lead may be released: Primary lead processing, recycling, and battery manufacturing.
Based on these assumptions, the authors calculate total lead discharge rates of 2488 mg per mile (1876 mg per kilometer) for available technology batteries and 283 mg per mile (272 mg per kilometer) for goal battery technology. (Data presented in the Science article text differs from that in the chart, and are slightly lower.) These figures are compared to lead emissions presumed to be created by a subcompact Geo Metro if it were running on leaded gasoline (with 2.1 grams of lead per gallon).
The study's conclusion: Electric vehicles release "60 times the peak fraction released by combustion of leaded gasoline," if the batteries are made from "newly-mined lead." Recycled lead and goal technology batteries are said to reduce that number to five times the rate of leaded gasoline.
Citing U.S. EPA figures indicated that "17 percent of the total lead and 11 percent of the lead compounds released to the environment from on-site lead processing facilities is emitted into the air," the study's authors conclude that EVs "don't deliver the promised environmental benefits." They also imply that further research into EV batteries is futile: "Even with incremental improvements in lead-acid battery technology and tighter controls on smelters and lead reprocessors, producing and recycling these batteries would discharge large quantities of lead into the environment."
STUDY FLAWS
Responses to the study criticizing its assumptions, methodology, and conclusions followed immediately, but have not received the same widespread press attention of the study. For example, key technical specifications of the GM Impact, including battery weight and driving range, were erroneous. EVAA points out that since the Impact was the sole example of "available technology" used by the study, this misstep began "an alarming series of miscalculations and unsubstantiated 'guesstimating'."
The Advanced Lead-Acid Battery Consortium (ALABC) is critical of one of the study's principal points that lead emissions would leak into the air. ALABC counters that "most of the 'emissions' in the lead mining and smelting process is slag, a solid, inert material which poses no harm to the environment." GCJ editors point out it's important to note that about 90 percent of the lead used in the manufacture of automotive lead-acid batteries is derived from scrapped lead products and not newly-mined lead. This means that assumptions made regarding emissions during production are grossly inaccurate.
Putting the ZEV mandate into perspective, EVAA executive director Robert Hayden estimates that the total number of batteries needed for the 127,000 EVs expected to be sold under California, Massachusetts, and New York mandates is less than 20 percent of those already being used in the 188 million cars, trucks, and buses currently registered in the United States, assuming each EV uses 27 batteries like the now-benchmarked GM Impact. EVAA also disputes the study's assertion that current batteries have an energy density of 18 Watt-hours per kilogram, noting that 40 Watt-hours per kilogram batteries are available.
Several EV organizations have also emphasized that lead-acid batteries are only an interim technology, with more efficient and environmentally-designed energy storage technologies to come. For example, GM Ovonic expects to begin marketing nickel-metal-hydride batteries produced at partner Energy Conversion Devices' facility in Troy, Michigan later this year, with production increasing when its Dayton, Ohio battery manufacturing plant is completed.
On the study's assessment of increased lead emissions from battery production: Battery Council International (BCI) points out that extensive government regulations currently regulate lead facilities. Thus, "whether a plant processes two tons or 100,000 tons of batteries per year," says BCI, "the amount of lead allowed in the air is fixed by federal laws. It cannot be increased."
BCI adds that even under current U.S. Clean Air Act standards, a new plant built to produce vehicle batteries would produce less than .05 percent of the lead losses cited in the study. Edison Electric Institute further points out that EPA is expected to soon release a new rule requiring new and existing battery recyclers to reduce emissions by 70 percent over current standards.
Defending the recent history of battery manufacturers, lead mines, and smelters' safety records, the Lead Industries Association notes that studies have shown children's blood lead levels near current lead facilities are "well below" the 10 micrograms-per-deciliter standard of the U.S. Centers for Disease Control (CDC) and consistently with national averages. Additionally, average U.S. blood lead levels have declined over the past 30 years, a fact that CDC calls a "major public health success."
The battery recycling infrastructure should also have little trouble accepting the additional batteries that EVs will bring: It's currently operating at only 65 percent of capacity, according to the Los Angeles Department of Water and Power.
"The lead recycling infrastructure is the most mature of any recycling program in the country and ensures that the effects of lead on the environment are minimized," says Michael Semmens, CEO of Electrosource, manufacturer of the Horizon advanced lead-acid battery.
Many of the study's flaws are summarized in "Environmental Impacts of Lead-Acid Batteries in Electric Vehicles," a 13 page technical brief from EVAA (TB-1995-1).
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