issues with electric Vehicles
“Will Electric Vehicles Finally Succeed?” (January/February 2011) ignores a key issue. Lithium-ion batteries exhibit a limited number of deep discharge cycles, and a car like the Chevy Volt can go roughly 35,000 to 40,000 miles before it needs a new set. Chevy will replace the batteries up to 100,000 miles, but that doesn’t come free. The cost runs up to 25 cents per mile, making electric cars far more expensive per mile than hybrids. New battery technology is coming along that may make electric-vehicle miles less expensive, but it is not available now, nor will it be in the near future.,
Eugene I. Gordon ,
Mountainside, New Jersey
Although very informative with regard to the automotive technology, “Will Electric Vehicles Finally Succeed?” did not address several issues that I believe will doom any effort by electric cars to make large-scale inroads into the automobile market.
The first issue is power demand. Utilities in the United States today can barely keep up with current domestic and industrial usage, let alone any projected increases. Should breakthroughs in battery technology be realized and electric-car sales soar, where will the electricity come from? We are building very few major power plants, and “alternative” sources aren’t even close to contributing significantly to the power supply.
The second issue is overall efficiency. Today’s gasoline-powered cars run at about 20 percent thermal efficiency; diesel models can approach 35 percent under ideal conditions. Even if electrics with new batteries can achieve, say, 80 percent efficiency, the electricity that powers them is generated at about 41 percent fuel efficiency (80 percent by fossil plants at 33 percent efficiency and the remainder by nuclear). Although state-of-the-art combined-cycle plants can achieve efficiencies of up to 50 percent, these make up just a small part of our national infrastructure. Add in transmission and distribution losses of about 5 percent, and only about 36 percent of the fuel burned ends up being delivered to the power outlet for the car. Include the car’s efficiency factor and the result is not much better than for gasoline, and not as good as the figure for diesel.
Electric cars thus reduce overall carbon dioxide emissions only minimally, but at significant cost not only for the cars themselves but for the utilities required to support them. ,
medicine’s age of engineers
The human genome represents the ultimate software puzzle that defines humanity (“The Human Genome, a Decade Later,” January/February 2011). Completion of the Human Genome Project brought medical science to a crossroads at which it began to require the support of engineers. Made up of three billion pairs of the nucleotides (or bases) adenine (A), cytosine (C), guanine (G), and thymine (T), the human genome is a computer program written in a language of which less than 6 percent has been deciphered. Analogous to the difficulty facing medical science would be an effort to decipher a string of three billion 1s and 0s without intimate knowledge of instruction code and how programs, reference tables, or data files are written.
We must aggressively apply what we know about computer programming and computer hardware design toward mapping out DNA, defining cellular operations, and interfacing with human brain function. Medicine will progress no further until we accomplish this task. The most prominent obstacle to developing meaningful medical therapies is the language-knowledge barrier that exists between medical science and engineers. Once it’s overcome, medical therapies will be limited only by the number of diseases in existence and the imagination of engineers. ,
Lane B. Scheiber,
Grosse Ile, Michigan,
New Model Needed for TV
Google does not address what I believe many people are looking for: an alternative to the traditional model of delivering video content (“Searching for the Future of Television,” January/February 2011). The cable and satellite-dish models deliver tens if not hundreds of channels that most people couldn’t care less about—“junk TV.” I would prefer an “à la carte” model where I get to pick and choose the content—not just accept what the cable companies choose to deliver. It might even save us some money. My cable bill just went up again, and the reason the cable company gave was “increased programming costs, new innovative features, and infrastructure maintenance.” I say it’s time to revolutionize the way video content is delivered and consumed.,
John Caporal ,
Norwich, New York,
Do Disregard Nuclear
On the letters page of the January/February 2011 Technology Review, responding to Matthew Wald’s story “Giant Holes in the Ground” (November/December 2010), James Hopf writes that “In any fair competition among non-emitting sources, nuclear would do very well.” It is my opinion that the nuclear industry has the ethics of the tobacco industry. It routinely lies and presents misleading information to the public. For the nuclear physicists in the audience: The industry says that nuclear waste will decay to unharmful levels in a few hundred years. While that may be true for products of nuclear fission, it is most definitely not true for the products of neutron capture. They take millions of years to decay back to the levels of the uranium they initially came from.
The industry claims that it can compete with renewable energy sources if only the government would refrain from subsidizing greener alternatives. Not true. Nuclear power receives a subsidy that is literally of incalculable value. It is the Price-Anderson Act, which caps industry liability from nuclear incidents at $10 billion. Anything higher would be covered by the federal government. Without this subsidy, the nuclear industry in the United States would go out of business tomorrow. ,
Frank J. Weigert,
Correction: In “Will Electric Vehicles Finally Succeed?” (January/February 2011), a caption incorrectly labeled a part in the Nissan Leaf as an inverter and said it converts AC power to DC. That conversion is performed by a rectifier; the part in question contains a rectifier and an inverter.
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