Monday, October 1, 2007

Electric Cars

I haven’t seen “Who Killed the Electric Car?” a documentary directed by Chris Paine about the EV1, a General Motors electric automobile that was withdrawn from (limited) production in the late 1990s, after a California Air Resources Board rule mandating some “zero emission vehicles” was rescinded. That doesn't mean I don't have opinions about the matter, of course.

There’s been a fair amount written about the entire affair, and I’ll only add the point that I suspect that one major factor was never addressed by the filmmakers or anyone else. In every large organization, the major decisions at the top have more to do with personal infighting amongst the managers than anything external. There were people pushing the project, for a variety of reasons, including some who wanted it sabotaged from the beginning, and they got their way. To whatever extent it was a con job designed to demonstrate that there was no market for electric vehicles only underscores the point. The GM divisions that were making big bucks selling gas guzzlers were never going to let an alternative vision get a fair hearing; the eventual fate of the Saturn is a good demonstration of the phenomenon.

Nevertheless, we do have some electric cars on the road now, though they are called “hybrids” and they burn gasoline in a motor to generate electricity that then runs electric motors to power the drive train. Some versions of the hybrid have the gasoline engine connected directly to the drive train and use the electric motors to add power when needed, and to recharge the batteries when the drive demands are less than the gasoline engine output.

A major part of the deal with hybrids is to greatly narrow the operating conditions of the gasoline engine. Under constant, optimized load conditions, you can finely tune the engine performance to maximize fuel economy and minimize emissions of pollutants. The other secret of any electric engine is that it can use “regenerative braking,” i.e., when the car slows (or if you’re going downhill), the electric motors become electric generators and you can recapture and store a substantial amount of the vehicle’s kinetic energy back into the batteries.

Having the internal combustion (IC) motor available finesses the major drawback of electric vehicles, limited range. Typically, EVs only manage less than 100 miles on a full charge, and take substantial time to recharge (1-15 hrs). Hybrids have the full range of gasoline powered vehicles.

The next obvious step in the development pathway is the “pluggable” hybrid, which allows the vehicle to be brought up to full charge from an external electrical source (and there would be a larger battery pack, bringing the thing closer to the true electric vehicle in electric storage). For a substantial number of commuters, the IC engine would seldom need to be engaged; one fellow who has “hacked” his Japanese hybrid claims that his overall fuel efficiency is over 100 MPG, though that doesn’t take into account the fuel burned to produce the pluggable power. (Actually, I seem to recall that he has home solar power panels, so he’s just the greenest of the green, isn’t he?).

Some environmentalists (and some fake environmentalists who carry water for the energy industry status quo), argue that electric vehicles merely shift the power generation (and pollution) elsewhere. That ignores the fact that IC engines operate at a pretty low thermodynamic fuel efficiency (the efficiency of converting the heat of combustion of the fuel to motive force, ignoring losses in the drive train), generally around 25%, though highly optimized, high compression engines can exceed 30%. By contrast, ordinary steam turbines generally start at 40% efficiency, and combined cycle and other tricks make more modern large stationary plants as much as 55% efficient.

It’s also considerably easier to manage pollution control from a single, large point source (whether the regulatory process manages to accomplish this is another story), and there is some hope that such things as geological sequestration of combustion CO2 might reduce the greenhouse gas emission from such facilities as well. Such tricks are pretty well out of the question for mobile vehicles.

Then there is the matter of the impending changeover from fossil fuel driven electric power generation to renewable sources. Wind power is already economically competitive to fossil fuels in many circumstances, and will become more so as the greenhouse gas "externalities” (economist-speak for “beggar thy neighbor”), are rationalized. As a scientist and engineer, I’m also a fan of nuclear power; I just don’t trust our current industrial oligarchy to do it in anything like a safe and sane manner.

There is also the photovoltaic option. The overall field and the statistics behind it are pretty slippery, but it looks like the cost per peak watt for photovoltaics have been halving at something like 5-10 year intervals, while the install capacity has been going up more dramatically, as each price reduction opens up a larger market. Also, in contrast to the U.S., Europe and Japan have been using regulatory action, subsidies, and guaranteed market tactics to encourage alternative energy, rather than discourage them. (In the U.S., a giant game of “crack the whip” has some governmental entities attempting to encourage alternate energy sources, while other entities penalize them, which is a good way to generate paralysis and wasted development efforts).

If you put photovoltaic cells on an automobile, you don’t get a “solar car” in the sense of being able to run on sunlight alone, but (the last time I did the calcs anyway), you do get the equivalent of about 10-20 miles per day of solar driving in the sunbelt areas of the country. That’s not trivial in terms of oil consumption; on average, it could reduce the fuel consumption of a hybrid by around 15-25%. If you’re already driving to work on the charge you got the night before, you’re down to needing maybe a half-gallon of gasoline per day on your daily commute.

That looks like the natural channel for the technology to follow, but there are plenty of things that can screw up a lovely vision of the future, including those who just plain want to keep everything “under control.”


Anonymous said...

I did see the movie (on an airplane ... so was personally burning through the hydrocarbs at pretty good rate while watching ... but let's ignore that.), but do not have too much too add. It does make the case that things that were pretty hard to understand from the outside were going on. Real motivations - not sure? A lot of was the banality of indifferent bureaucratic "evil". I can see where I would have been personally infuriated - but not much beyond that.

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