Wednesday, August 8, 2007

Plug-in hybrid vehicles

In "Plug-in Hybrids" (New Society, 2006), Sherry Boschert has written an engaging report on a timely topic: electric vehicles, charged from commercial power lines, with gasoline engine backup. A helpful background for Boschert's book has been provided by Michael Schiffer in "Taking Charge" (Smithsonian Books, 1994), recounting the early history of electric vehicles, including hybrids, from about 1880 through 1930.

Although invented more than 100 years ago, hybrid automobiles drawing much of their energy from the electrical grid have become more versatile because of recent improvements in power technology and control systems. They may reduce costs of automobile transport and help limit both petroleum use and air pollutant emissions. Such a technology can be viewed from many perspectives. Boschert's and Schiffer's books address consumer, conservation and environmental concerns.

Boschert does a fine job of recalling the many starts and slips of the past fifteen years or so. Although her presentation focuses on charismatic individuals, she also presents a variety of performance information about the vehicles they worked on. Schiffer reports both marketing and technical aspects of early electric vehicles. He shows, contrary to common perceptions, that they were notably successful in urban, commercial uses and that the endless quest for an ideal battery was driven more by competition than economics.

Consumer interests are the easiest to report: vehicle prices, operating costs, reliability and performance. Both Boschert and Schiffer largely concern themselves with those issues. Environmental and conservation issues are more complex and controversial. Boschert makes a few attempts to unfold the issues, but both she and Schiffer often assume rather than demonstrate that electric vehicles have favorable impacts.

Schiffer consistently emphasizes conflicts between driving performance and range with which potential customers for early electric automobiles became familiar. Boschert's elisions of speed and range will be irritating to a knowledgeable reader. After asserting, as though for the record, that higher speeds mean shorter ranges, Boschert subsequently ignores the issue, quoting range competitions (Boschert, page 89) while saying nothing about speed, after dwelling on speed demonstrations (Boschert, page 41) while saying nothing about range.

When it comes to organization and details, the limits of Boschert's background as a medical news reporter begin to show. She does not provide readers with historical perspectives for any of the several measures of progress. She makes a number of careless statements. For example (Boschert, page 40), "[Semiconductor] IGBTs didn't exist until about ten years ago," that is, until 1996. In fact, the insulated gate bipolar transistor was patented by engineers at Hitachi in 1985 and was soon successful in power applications such as strobe light controls.

Also (Boschert, page 43), "By the late 1990s, a much better battery technology than lead-acid...NiMH batteries...." In fact, Matsushita (Panasonic) introduced a nickel-metal hydride battery in the late 1980s, based on technology from Ovonic Battery (now Energy Conversion Devices) invented in the early 1980s, over which ensued legal battles.

The NiMH alkaline chemistry was a descendant of the nickel-iron battery that Thomas Edison began to develop for electric vehicles in 1901, inspired in part by the 1899 patent for the nickel-cadmium battery by Ernest Waldemar Jungner of Sweden. Starting in 1903, as Schiffer documents, the Edison battery was manufactured and sold for use in electric vehicles, storing more energy per unit weight than the lead-acid battery and providing extra durability but also costing substantially more.

Overall energy efficiency and pollution emissions from plug-in hybrids involve several factors, including power-plant technology, distribution losses, battery performance and driving conditions. Schiffer does not try to develop the topic. Boschert gives a quick pass at "well-to-wheels" analysis (Boschert, page 27), commenting that it is "very complex."

Comparing current, conventionally powered, high efficiency automobiles with their nearest equivalents in totally electric vehicles shows little change in carbon dioxide emissions when the electrical energy is being generated by current, coal-fired power plants. If plug-in hybrids, when powered by electricity, are to reduce carbon dioxide emissions, then added demands for commercial electricity must be met without stimulating new coal-fired power plants. Such an outcome cannot be assured by vehicle manufacturers.

Petroleum conservation concerns face a similar conundrum. If plug-in hybrids, when powered by electricity, are to reduce petroleum consumption, then added demands for commercial electricity must be met without stimulating new oil-fired or gas-fired power plants. Again, such an outcome cannot be assured by vehicle manufacturers. From a public policy viewpoint, the options remaining are nuclear power and renewable resources.

Current nuclear power plants already run near maximum outputs in order to help absorb high capital costs. Major, unsolved problems with waste disposal stand in the way of substantial growth of nuclear power. High capital costs and political interests, often masquerading as environmental, have held down development of wind and solar power. How to generate more electricity cleanly and at reasonable cost is a thus a critical issue for vehicles to be fed from commercial power lines, but neither Boschert nor Schiffer seems willing to address it.

If consumer, conservation and environmental concerns can be addressed, there will soon be a secondary but potent issue: what convinces people to purchase plug-in hybrids. While Boschert focuses on the enthusiasts and seems oblivious, Schiffer is helpful with historical patterns: that urban automobile owners often lack space for more than one vehicle; that purchasers tend to satisfy what they see as extremes of their uses rather than daily uses.

Boschert is helpful in deconstructing myths of hydrogen-powered transportation (Boschert, pages 57-61). It might seem obvious that if hydrogen is to be successful as an energy intermediate, it must surely succeed first in nonmoving applications, where its storage is far easier. Yet that seems to have escaped most other technology writers, as it did former Vice-President Gore and President Bush, in his 2003 State of the Union address.

Readers hoping for some analysis of the many particulars in these books will get little satisfaction. Schiffer's book expresses hope that electric vehicles will emerge again but does not explain why they would be beneficial. The back of Boschert's book gives way to a miscellany of enthusiasms and political speculation. In the end, the lasting value of the books is to identify some key players and events in the development and re-emergence of commercial electricity as a potential competitor with gasoline, at least in part, to power on-the-road vehicles.