The new administration has made alternative “green” energy and motor-vehicle fuel efficiency a priority for infrastructure and research spending. It would appear from what has been written in this magazine that we of the U of C and Chicago communities have a vested interest in the president’s success, so I hope to shed some light on his apparent blind spot. Here is what you and he need to know.

It will take at least 40 kilowatt-hours (kWh) of electricity to motivate an electric automobile as far down the road as it would have traveled on a gallon of gasoline (professors, check it out). In my neck of the woods, that will cost $12. Technology for the cars exists. For cheap electricity, it does not. Solar and wind are simply not and can never be competitive without perpetual federal subsidy. U.S. consumption of gasoline in cars and light trucks is approximately 400 million gallons per day to go a distance of about 6 billion miles or an average of 15 miles per gallon. To replace petrol with electricity just for private vehicles would require 16 trillion kWh per day.

Using annually averaged solar power generation for the Sunbelt of 0.1 KWh/day per 14 square feet of panel, it would take 80,000 square miles of solar panel to produce that much electricity. Add 32,000 for diesel trucks and buses, and you need over 3 trillion square feet. That would blanket most of Southern California and Arizona. In less commodious climes like Chicago, the required area goes up by a factor of 2 to 3. Current installation costs in Southern California are about $40 per square foot with an expected lifetime of 10 years not counting maintenance. Even if that cost could be reduced by a factor of 1/10, it would still take $1.25 trillion every year or so to produce the required energy.

Except for tornadoes and hurricanes, wind power is an even less concentrated alleged power resource. It is not merely installation costs and the acquisition of so much real estate; it is the maintenance and durability of expansive installations that, of necessity, must remain open to the elements. Numbers are very stubborn things, and the purpose of these calculations and estimates is to get people and politicians to pay closer attention to them. Eventually it will be realized that nuclear is the only realistic option. I hope before it is too late.

Halbert Fischel, SB’59
Santa Barbara, California

This will probably be one of a number of letters on the same subject, but here goes.
Halbert Fischel, SB’59, states in his Mar–Apr/09 letter (“The Energy Problem Solved”) that “it will take at least 40 kilowatt-hours (kWh) of electricity to motivate an electric automobile as far down the road as it would have traveled on a gallon of gasoline.” I’m no professor, but I can get that number if I use the 1 hp = 746 watt conversion and assume that a 30 mpg car will go that far in half an hour using 107.2 hp.

But once a car gets going, it doesn’t need or use all that horsepower. Wikipedia’s entry on the General Motors EV1 (electric vehicle) lists a range of 55–75 miles for battery units between 18.7 and 26.4 kWh. If one assumes the battery unit still has 10 percent of its energy left after a full-range trip, that’s about 3.21 miles/kWh, or 9.35 kWh for the 30 miles. This turns Fischel’s $12 for electricity into $2.80, comparable to the price for a gallon of gas we’ll be seeing again real soon. Electric cars—if we can live with limited range—are a good thing.

Although I disagree with Fischel on the economy of electric cars, I totally agree with him on the main solution to the energy problem. Nuclear is the only realistic option. Nuclear waste can be stored safely, and power-plant sites can be made secure.

Harold Finn, SB’57
Pleasanton, California

Halbert Fischel provides incorrect information regarding electric vehicles (EVs). The first error is in claiming it takes 40 kWh to move an EV the same distance as one gallon of gasoline. A gallon of gas does represent about as much energy as 35 kWh of electricity. But Fischel’s assertion is true only if EVs and gasoline-powered cars have the same energy efficiency. EVs, however, are far more efficient.

Real-world examples illustrate the point. In 1996 General Motors’ EV1 went 34–62 miles per charge with an 18.7 kWh battery pack, or about 2–3 miles/kWh. EVs today can achieve 3–6 miles/kWh. This is an order of magnitude better than Fischel’s number.
(Note a misstatement in the letter: Fischel’s figures yield an electricity requirement of 16 billion, not trillion, kWh per day.)

Secondly, driving 15 miles in an EV will cost less than 40 cents, not $12. In the past two years, electricity in the United States ranged from less than 5 to rarely more than 15 cents/kWh.

As for solar photovoltaic systems, they have no moving parts and require almost no maintenance. Panels do not need replacing after ten years; they carry warranties of 20–30 years. They can function long beyond that but might lose some efficiency.

If all U.S. vehicles were electric and powered only by solar electricity, the required area of solar panels is nowhere near the claim of “most of Southern California or Arizona,” even using Fischel’s inaccurate result of 11,200 square miles. The areas of California and Arizona are, respectively, 163,700 and 114,000 square miles. The Mojave Desert is 25,000 square miles. Using realistic values for the kWh needed to power EVs and using Fischel’s low-end estimate of photovoltaic power generation, the total needed area of solar panels would be 700–1,400 square miles.

Of course, not all the electricity would come from photovoltaics, nor are solar panels concentrated in one spot. Many EV owners can rely at least in part on their own rooftop panels to charge their cars. And wind, geothermal, hydroelectric, and concentrated solar thermal power can contribute substantially to the electric grid.

Yes, wind and solar currently rely on federal subsidies. But coal, natural gas, and nuclear plants have been receiving billions of annual subsidy dollars for years.

I agree these kinds of calculations are critical and sometimes overlooked, and I’m glad Fischel inspired me to take a closer look at the feasibility of cleanly powering EVs. When the numbers are accurately represented and empirically based, the prospects are not so dire at all.

Gillian Zaharias Miller, AB’98
DeWitt, Iowa

If General Motors had been able to deliver its promises, it would not be going bankrupt. As for the randomly reedited Wikipedia, well enough said for ‘reliable sources’ (Letters, May–June/09). Here are some real facts. Actual measured brake-horsepower data from manufacturers like Toyota and Honda, which sell cars people buy, operate at 2,500 rpm and 120 to 160 ft-lbs of engine torque while getting 31 and 23 mpg for compact and standard cars, respectively, traveling at 60 mph on a level highway. That translates into 57 and 76 horsepower, respectively, for these models. Opel's NeCar5, DaimlerChrysler, Mercedes A-Class, and Jeep Commander all use a 75 kW fuel-cell power source to motivate a subcompact size/weight automobile after finding that 50 kW was not enough to do a credible job. To deliver sufficient horsepower, a battery or fuel cell must provide 40 or 53 kW of electrical power, respectively, for the cited examples. That assumes 80 percent of the power goes to the drive shaft because an electric motor can operate at 90 percent, but 10 percent is reserved for creature comforts, support systems, and entertainment in back for the kids. Because a computer-controlled electric car or hybrid can recover some braking and idling power and is more efficient at start-up, i.e., acceleration, I also allowed the commonly accepted improvement of 30 to 33 percent over petrol.

The respondents, Harold Finn and Gillian Zaharias Miller, would have us believe GM's claims of 18.7 kW power based upon 9.35 kWh to go 30 miles or twice that to go 60 miles at 60 mph. My real-world power estimate is about twice that value; not a factor of 10. Now here's the rub no one considered. If you want to get 1 kWh out of the battery or fuel cell, you have to buy at least 2 kWh from the electric company because of the basic thermodynamics I learned at U of C. The power you buy goes into enthalpy of chemical formation; the power you get comes from a voltage-loss fraction of the Gibbs free energy, which—according to "Fuel Cell Systems Explained" by James Larminie, et al, 2nd ed. (2003), which I highly recommend to the respondents—is very difficult to get much more than 50 percent. You will also find a discussion of the cars I cited in that excellent book. So, net net, to go 60 miles at 60 mph to keep it simple, the compact petrol car uses 1.94 gallons, and the same size electric car uses 40 kWh or 20.6 kWh/gallon. However, you have to buy twice that from papa Edison, so it's about 40 kWh/gallon like I said. Do this exercise for the standard car and—what do you know!—you get just about the same result.

As for solar, no one in my sunny neighborhood buys it because a) they can't afford it and b) they don't want to be perpetually climbing on the roof to clean bird presents. Read the manufacturer's fine print about lifetime guarantees. Bruce Power Co. of Canada operates an 8-reactor nuclear facility at 6.4 gigawatts and is building a new facility with four 1.0 gigawatt reactors. France reprocesses nuclear fuel, which reduces the volume of waste to 1/25 of what we have to put up with and with less and shorter-lived radioactivity. If only the purveyors of energy mythology would get their facts straight, we might climb out of the economic morass into which the United States seems to be inexorably sinking. I did make a mistake in print where 16 trillion should have read billion. My apologies to the editor and readers.

Halbert Fischel, SB’59
Santa Barbara, California