One blogger I admire is Robert Rapier who writes the R-Squared Blog who posted on Monday about the solar base of electricity needed to displace the equivalent of today’s gasoline use. It is an interesting concept that is rife with problems of equivalency.

The U.S. is reported to be going through 389 million gallons of gasoline per day. While useful for entertainment and to run calculations comparing gasoline use to solar sourced electricity isn’t realistic. But that gasoline is energizing seat miles. I admit that Mr. Rapier is trying hard to make a sensible case using verifiable numbers for the base assumptions. All well and good, it plays right into the audience that tracks Mr. Rapier’s commentary, which seems headed into the gloomy and doomed end of civilization.

So lets speculate, and up front, there isn’t any reason to be going to great lengths to use verifiable numbers for the assumptions. Any sensible set, if based in the personal and commercial reality of the day will do.

Assume that those 389 million gallons of gasoline are moving something 20 miles each for 7.78 billion miles. This assumption offers the reality that no one will be changing their lifestyle. The hole in the number is just what is the actual traveled miles per day of the U.S. gasoline powered fleet actually is. Of course, everyone will be above or below this number and the investment in the vehicle will vary hugely, too. So, lets just divide the gallon at say $3.50 by 20 for $0.175 per mile or $52.50 per 300 mile week. But the important number is the assumed and full of holes 7.78 billion daily miles.

One set of numbers for the electrical cost is the Tesla site on the well to wheel page. Tesla offers that the mileage for the Tesla Roadster is 110 Wh/km or 180 Wh/mile or 54,000 watthours in the 300-mile week. That would be 54-kilowatt hours and if the price is say $0.10 the weekly cost is $5.40.

But the Tesla might be highly efficient so let’s use instead of the 180 Wh/mile, let’s say about two fold or 360 Wh/mile, multiplied by the 7.78 billion miles. At 2.77 miles per kilowatt we get 2.81 billion kilowatt hours per day. Mr. Rapier is at 2.7 billion kilowatt hours per day. OK, you caught me, I doubled the Tesla numbers, but the point is that Mr. Rapier is about right, probably in the high side, he just went wildly astray trying to get to the point.

Mr. Rapier is also pretty much on the spot figuring the power generation needed and his conclusion of needing 444 gigawatts of generating capacity is well past what would be conceivably required to fully displace the gasoline fueled fleet. When you consider the assumptions here that double the Tesla Wh/mile the generation numbers are easily within the overnight charging capacity of the U.S. right now.

For us personally the difference between paying as low as $3 to maybe $10 per week to charge up against more than $50 per week in gasoline might free up about $150 per month for new investment. While many worry about the investment being lost from converting to electric drives or other alternatives, keep in mind the money invested in personal vehicles is going to be lost in any case, it’s really a matter of how fast. I spoke with a salesman who is driving a ¾ ton pickup and has been trying to trade it in for something much more fuel efficient only to find the trade in value is humiliating IF they will offer to trade at all.

Mr. Rapier’s conclusions are on point, particularly the part about not having a good way to store electrical potential. While he mentions an odd idea such as splitting water to get hydrogen, there is a better likelihood you could sell me a super capacitor and the necessary kit to have one at home that charges during the day and offloads to the car any time its needed or maybe feeds the grid when excess is available. Even a cheap lead acid battery set would be preferable to investing in the solar panels needed to split water and burn the hydrogen or feed a fuel cell that converts back to electricity.

The Wall Street Journal’s Environmental Capital blog picked up Mr. Rapier’s post. That’s a good thing. Even though most will miss the important reasons to be looking in the direction of electric drive vehicles as Mr. Rapier did, we’re lucky he and others who watch him get to see a number that while at the high range and loaded to show the amount of solar installation needed to get there does show the viability.

Regular readers will know that the stop mark is the storage issue both in vehicle and at small solar installations. One might think that the smart money, issue maker and policy maker might catch on someday. In any case, the weekly power or fuel cost numbers show those batteries and capacitors are two of the gold mines of the coming new energy and fuel era.


11 Comments so far

  1. tesla solar energy on May 15, 2008 5:10 AM

    […] of today??s gasoline use. It is an interesting concept that is rife with problems of equivalen…Senate OKs tight General Fund The Troy MessengerWith limited funds to work with, the Senate passed a […]

  2. Electric Cars. « Light, Sweet and Crude. on July 14, 2008 8:32 AM

    […] 312,500,000,000 Kilowatt hours of electricity to charge all those new cars on the road each year.  That translates to 312 Gigawatts of power production which is currently 10 times what we produce now and in addition that is ADDITIONAL to our current usage.  So we would need 444 gigawats of future electricity to generate the power used to fuel electric cars. […]

  3. Fred on July 14, 2008 2:02 PM

    I recently talked to someone who said he was associated with a solar power generating business. He told me that the present cost was $3 per installed watt, and that they were hoping to bring it down to $1/watt in the future. 312 gigawats at $3/installed watt equals about a trillion dollars. It’s a lot of money, but about the same as has been spent in recent months by the US gov’t to bail out failing financial institutions. Spending that on solar power would have powered our cars for perpetuity.

  4. Brian Westenhaus on July 14, 2008 5:18 PM

    Let’s be careful with the numbers. The U.S. can put up about a terawatt at any given time for a short while, but that isn’t watt hours. I see a lot of sites, bloggers and comments confusing capacity (watts) and production (watt/hours). Try to get clarity.

    On the money, if construction costs can be contained technology across many sources will be viable. Enough electrical power shouldn’t be an issue. The wider the sources of supply the better.

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