<DrumBeat: August 9, 2006The Oil DrumDrumBeat: August 10, 2006>

329 comments on Khosla Responds: "Imagining the Future of Gasoline: Reality or Blue-sky Dreaming?"

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FossilFool on August 9, 2006 - 5:01pm Permalink | Subthread | Parent | Comments top
What I have read is that if all the crop acreage in America was devoted to corn for ethanol, then it still wouldn't be enough to fuel America's truck fleet.  
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Jack on August 9, 2006 - 8:26pm Permalink | Subthread | Parent | Comments top
Can you do better than "What I have read"? Otherwise it is meaningless.

On the one hand, it is fairly clear that we can not replace every drop of oil we use from corn. On the other hand it seems equally obvious that ethanol, particularly if you are willing to consider cellulosic (I tend to agree with Odogragh here however), could play a very important role in offsetting declining oil supply.

I read somewhere that if you wanted to replace all global electricity consumption with solar technology, you would ahve to cover the entire earth with panels - so solar is worthless, right?

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Prof. Goose on August 9, 2006 - 9:13pm Permalink | Subthread | Parent | Comments top
well done Jack.
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Will on August 9, 2006 - 10:43pm Permalink | Subthread | Parent | Comments top
Why does this response merit an editorial: "Well done"?

I see no facts criticised with no facts. Save the atta-boys for something worth reading not put-downs.

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Prof. Goose on August 10, 2006 - 2:04am Permalink | Subthread | Parent | Comments top
I was merely responding to Jack's call for evidence.  
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Prof. Goose on August 10, 2006 - 2:05am Permalink | Subthread | Parent | Comments top
and as you will read below, led to a productive discussion.  
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solarfan on August 9, 2006 - 11:07pm Permalink | Subthread | Parent | Comments top
Can you do better than "I read somewhere"?  Otherwise it is meaningless.

I believe your solar assertion, while I realize that you were using it to make a point, is erroneous.

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solarfan on August 9, 2006 - 11:41pm Permalink | Subthread | Parent | Comments top
A Google search revealed a published number of 4000 terawatts per year of electricity consumption in the US.  

http://www.quaker.org/tqe/2006/TQE145-EN-Hybrid-Details.html

OK, it's one source and who knows how close it is, but let's see what happens...

Assume 4 sun hours per day (4 hrs at 1000 watts/sq.m), a 12% efficient panel will produce 1000x0.12x4x365=175,200 Whr per year.  Take 4000 TW (4E15 Watts) divided by 175,200 = 22.8E9 square meters, = 22831 sq. km = 8800 sq. mi.  for a square area that equates to 93 miles x 93 miles.  To cover the electrical use for the entire country.

So unless the 4000TW number is off by orders of magnitude, we are nowhere near having to cover the US with solar panels to provide our current consumption (which BTW could be easily reduced substantially, but that's another topic).  Does the rest of the world consume orders of magnitude more electricity per surface area than the US?  I'd bet dinner not, and I only bet dinner when I know I'm going to win.

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Robert Rapier on August 9, 2006 - 11:59pm Permalink | Subthread | Parent | Comments top
Take 4000 TW (4E15 Watts) divided by 175,200 = 22.8E9 square meters, = 22831 sq. km = 8800 sq. mi.  for a square area that equates to 93 miles x 93 miles.  To cover the electrical use for the entire country.

I wonder how much demand you could satisfy by covering a substantial fraction of all the roofs with solar panels? I realize currently that is cost-prohibitive, but I hope we see this happen someday.

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louGrinzo on August 10, 2006 - 12:11am Permalink | Subthread | Parent | Comments top
Bingo!  Every time I hear someone talk about how you need to cover a sizable portion of Nevada with solar panels, it drives me nuts because that's not where cheap, thin-film panels will be installed--they'll go on rooftops of homes, businesses, municipal buildings, schools, etc.

The NanoSolar plant being built in/near silicon valley will produce 430MW of panels per year, supposedly at much cheaper prices than anything currently available.  That's enough panels for one heck of a lot of rooftops, and from just one plant.  It's a safe bet that if they come close to their price points and production volumes after they ramp-up that we'll see them getting tons of additional funding and building more plants.

I think it would be downright funny if all this talk about ethanol, hydrogen, CTL, etc. was largely derailed by one of the "old school" renewables, solar, that finally had the major price breakthrough we've all been hoping for since the 1970's.

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Jack on August 10, 2006 - 7:46am Permalink | Subthread | Parent | Comments top
Sorry Lou. Just trying to make a point. These blanket statements - about ethanol, solar, etc. - are inaccurate and don't help us to look at and compare solutions.
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ggg71 on August 10, 2006 - 9:17am Permalink | Subthread | Parent | Comments top

Why would you put all the solar panels in one 93 square mile area?  For one it would become a huge terrorist target.  Second it would be vulnurable to natural disasters (tornados, earthquakes, etc..)

I think a distributed solution of using business and household rooftops makes way more sense.  Supplement that with wind and tidal power, and it could go a long way towards getting households and small business into a more sustainable model.

It doesn't solve the liquid fuel problem though.

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solarfan on August 10, 2006 - 12:41pm Permalink | Subthread | Parent | Comments top
I wasn't saying that all of the panels should go in one area, I was just computing the total area required, since it was asserted above that we would have to cover the planet to meet our current consumption.  One of the beautiful features of grid-tied solar systems is that the power source is distributed, not centralized, which is much more robust and secure.  Also, you are generating the power close to where it is consumed, so transmission losses are minimized.

Rooftops are the perfect place for panels, and there's way more than enough existing roof space to cover that 8800 square miles.  The only down side today is the high up-front cost, and the low supply of panels due to heavy solarization in Europe and Germany in particular.  

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Wharf Rat on August 10, 2006 - 10:35pm Permalink | Subthread | Parent | Comments top
National Geograpic, 8/05, said we need 10K square miles of solar panels, bigger than the area of Vermont, or roughly the size of Mendocino County, Ca, to satisfy all our electrical needs. Says all those panels could fit on less than  quarter of the roof and pavement  space in  cities and suburbs.

  Also, in California, at least, they figure 5 hours of sun/day; some are now starting to use 6 hours. Right now, I'm expected to be putting out 5.6KW/day; I'm actually at 9 +/- 0.3. Remains to be see what happens during 35 or 40 staight days of rain.

Rat

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Johnny Buffalkill on August 10, 2006 - 12:21am Permalink | Subthread | Parent | Comments top
Your figure for electricity use is pretty similar to the one found here https://www.cia.gov/cia/publications/factbook/geos/us.html

I think at some point it will become apparant that we can live pretty comfortably with alot less electricity than that though, so we really won't need even as much generation as you calculated.  

There is alot of energy in wind and solar, you just can't put them in your gas tank.  Oh well.  

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solarfan on August 10, 2006 - 12:45pm Permalink | Subthread | Parent | Comments top
There is alot of energy in wind and solar, you just can't put them in your gas tank.  Oh well.

You can if we had electric vehicles.  Has everyone seen this?

http://www.teslamotors.com

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Johnny Buffalkill on August 10, 2006 - 12:05am Permalink | Subthread | Parent | Comments top
Can you do better than "What I have read"? Otherwise it is meaningless.

I can.  Here are the raw numbers I will start with:

Total land are in the U.S. = 3,718,711 sq mi. http://en.wikipedia.org/wiki/United_states

Percent arable land in the U.S. = 18.01% https://www.cia.gov/cia/publications/factbook/geos/us.html

Average corn yield per acre (2005) = 148.4 bushels http://www.usda.gov/nass/aggraphs/cornyld.htm

So, 18.01% of 3,718,711 is 669,740 sq mi arable land, times 640 acres per square mile is 428633504.7 acres of arable land, times an average yield of 148.4 bushels times 3 gallons ethanol per bushel is about 190 billion gallons of ethanol.  The U.S. uses about 150 billion gallons of gasoline per year.  I don't have the exact energy conversion between ethanol and gasoline, but the amounts of energy are in the same ballpark.  So we could theoretically not only fuel our trucking fleet but all of our automobiles, and an be energy independent without sacrifice if we just grow corn of every arable acre in the country.  Fortunately, Canada is obligated by NAFTA to supply us with natural gas, so we can still make fertilizer to keep the corn yields up, and we can still eat if we can find an optimal deer population that will feed us but without eating so much corn to have an significant impact on yields.

This is looking easy.  On an unrelated topic, I think I can run a marathon in about an hour and twenty minutes based on my time in the 100m when I was in high school.

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Robert Rapier on August 10, 2006 - 12:16am Permalink | Subthread | Parent | Comments top
So we could theoretically not only fuel our trucking fleet...

Ah, but the trucking fleet runs mainly on diesel, which is not included in the gasoline number. Diesel has an even higher energy content than gasoline, and diesel engines are far more efficient. So, to replace the 50 billion or so gallons of diesel we use each year would take around 100 billion more gallons of ethanol.

Regarding the energy content of gasoline versus ethanol, ethanol has about 65% of the BTUs of gasoline.

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Johnny Buffalkill on August 10, 2006 - 12:25am Permalink | Subthread | Parent | Comments top
I need to be careful with sarcasm, I know it doesn't always work in writing as well as in speech, or with strangers.  I hope you got that my commentary was tongue in cheek.
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Robert Rapier on August 10, 2006 - 12:31am Permalink | Subthread | Parent | Comments top
Don't worry, I got the sarcasm. Just thought I would take it just a bit farther. :-)
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Johnny Buffalkill on August 10, 2006 - 12:48pm Permalink | Subthread | Parent | Comments top
Good.  In that case, all we need to do is develop a winter variety of soybean and double harvest all that land . . .
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sofistek on August 10, 2006 - 4:56am Permalink | Subthread | Parent | Comments top
ethanol has about 65% of the BTUs of gasoline.
Did you read that somewhere, Robert? :)
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Jack on August 10, 2006 - 1:42am Permalink | Subthread | Parent | Comments top
Actually this is useful. Firstly, I am happy to acknowledge that ethanol can not possibly, even in the wildest dreams of ADM, replace 100% of U.S. fuel consumption.

However, using your numbers, it does seem that it could make a difference. I have argued before that 10% of consumption on a BTU basis would make ethanol a huge contributer to replacing declining oil reserves. Even 10% of gasoline use would mean a lot, both in terms of its contribution as a fuel and as a replacement for the lightest refinery products - freeing up much needed capacity.

So, 10% of 150 billion gallons times 1.3 (to convert from volume to BTU) equals about 20 billion gallons. This is about 10.5% of the 190 billion gallons figure you cite for all US agricultural land.

Now, I also acknowledge that taking a mid-range EROEI figure of of 1.25, the net contribution to energy is only about 2% of gasoline use with the remainder being converted from other fuel sources.

My point is not that it is a good thing to do. It may not be. However, this analysis reveals a lot more about the actual tradeoffs than dismissing it because it can't solve all of our energy problems single handedly.

 

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Johnny Buffalkill on August 10, 2006 - 12:55pm Permalink | Subthread | Parent | Comments top
For the record, my sarcasm wasn't directed at you.  I was taking to opportunity to do the overly optimistic "anything is possible" tone of cornucopianism (if that's a real word).
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Jack on August 10, 2006 - 9:32pm Permalink | Subthread | Parent | Comments top
Thanks for this and the information in the above post. You are welcome to direct sarcasm at me any time you want.
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raymond on August 10, 2006 - 8:34am Permalink | Subthread | Parent | Comments top
There is plenty of arable land in Florida but it's quite poorly suited for corn.

The average yields cited per acre are in places that have 8-10 feet of rich soil and sufficient water.

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energydeveloper on August 11, 2006 - 3:39am Permalink | Subthread | Parent | Comments top
I would like to note that Mr. Khosla must agree with your assessment of there not being enough land for corn ethanol, which only provides 150 bushels per acre, as he states the following in his essay.

"Ethanol, butanol and any liquid fuel that has a shot at replacing our gasoline needs has to scale up to 2,000-3,000 gallons per acre."

Using your own calculations if cellulose ethanol is scalable to 2,000 bushels per acre as Mr. Khosla seems to believe, then it would require less then 10% of the U.S. arable land to completely replace our gasoline consumption with cellulose based ethanol.  10% seems like a much more reasonable number and something that may be achievable.

However this changes the main question to, "What is the evidence that Cellulose Ethanol can be scaled to 2,000 bushels per acre, given current methods."  I think this question deserves much consideration, because it is at the heart of the debate.

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Oil CEO on August 10, 2006 - 12:22am Permalink | Subthread | Parent | Comments top
If Mr. Khosla is still reading, I would recommend that he consider hiring Jack and Sailorman as consultants to his project. They would help greatly with efforts to win over the skeptical. And their style and methods are superb. There are others, but they are the only ones whose work on ethanol I am familiar with.
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zoglmannk on August 10, 2006 - 10:12am Permalink | Subthread | Parent | Comments top
This is my first post. I want to make a small correction to Jack's post.

No! You do not need to cover the entire earth with panels to replace the entire electricity demand with solar. For rough calculations... The earth is receiving an average of 1,000 watts/m2 with half the earth's surface lit at any given time, 5x10^14 m2. This yields 2.5x10^17 average watts at any moment. With 8760 hours available per year, this yields 2.2x10^21 watt/hr or 2.2x10^12 GW/hrs!! Solar cells vary in their efficiency from 6% to 30%. Most solar cells have around 14% effeciency. Thus using 14% effeciency that gives 3.1x10^11 GW/hrs per year.

In 2003, the world used 14,781 billion killowatt/hrs or 1.4x10^7 GW/hrs for easy comparison above. That is 4 orders of magnitude lower.

Maybe you meant only on available land mass? The oceans make up 71% of the earth's surface. Thus that reduces available energy to 9x10^10 GW/hrs per year. Obviously, it is still orders of magnitude more than needed.

So what percentage of land mass would be needed? .02%!!

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Jack on August 10, 2006 - 9:48pm Permalink | Subthread | Parent | Comments top
Welcome to TOD and thanks for the post. I was trying to be sarcastic or rhetorical, which can be hard in writing. Your post and others have added nicely to this discussion.

- Jack

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PeakOilPete on August 10, 2006 - 3:54pm Permalink | Subthread | Parent | Comments top
my understanding is that it would only take a PV panel array the size of, say, arizona to power the usa.  extrapolating and recognizing that the usa is the big gran electricity consumer du monde, it would probably only take an array the size of all of the world's deserts to power the world.  and i understand that there is pretty good sunlight in the desert....  perhaps not enough facts, but that (backing up WAGs with fact) is not my role in this forum.
-PoP
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