Comments on: Let them eat biofuels! http://climateprogress.org/2008/04/27/let-them-eat-biofuels/ The Latest on Climate Science, Solutions, and Politics Sun, 08 Nov 2009 12:18:00 -0500 http://wordpress.org/?v=2.8.5 hourly 1 By: Peter Foley http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11789 Peter Foley Tue, 29 Apr 2008 23:52:22 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11789 For years I heard how a oil tax would solve the world's energy problems, well you got your 4$ a gallon gas in the US and you are still whining. What was the error of your thinking when you though energy was too "cheap" if isn't fixing everything now? Untill meat animals start eating fossil fuels they're not a major source of new CO2. Meat animals have displaced 'wild' fauna in the oxygen-carbon cycle. Politically vegatarism is a death sentence for any "green" political goals. For years I heard how a oil tax would solve the world’s energy problems, well you got your 4$ a gallon gas in the US and you are still whining. What was the error of your thinking when you though energy was too “cheap” if isn’t fixing everything now?
Untill meat animals start eating fossil fuels they’re not a major source of new CO2. Meat animals have displaced ‘wild’ fauna in the oxygen-carbon cycle.
Politically vegatarism is a death sentence for any “green” political goals.

]]> By: David B. Benson http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11771 David B. Benson Tue, 29 Apr 2008 18:09:47 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11771 Forget to finish the prior post. However, out of the 800 exajoules of total energy usage by a population of 9 billion in 2050CE, 200--400 exajoules from bio-energy appears quite reasonable, at least at my current state of understanding. Forget to finish the prior post.

However, out of the 800 exajoules of total energy usage by a population of 9 billion in 2050CE, 200–400 exajoules from bio-energy appears quite reasonable, at least at my current state of understanding.

]]> By: David B. Benson http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11770 David B. Benson Tue, 29 Apr 2008 18:05:57 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11770 Earl Killian ---- Smeets et al. obtain much higher estimates than the (older) IEA report. Nor am I a fan of ethanol. I opine that much better efficiences can be obtained via biomass conversion to biodiesel. Nor I am promoting 100% bio-energy. That would be silly. Earl Killian —- Smeets et al. obtain much higher estimates than the (older) IEA report.

Nor am I a fan of ethanol. I opine that much better efficiences can be obtained via biomass conversion to biodiesel.

Nor I am promoting 100% bio-energy. That would be silly.

]]> By: Earl Killian http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11751 Earl Killian Tue, 29 Apr 2008 03:05:38 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11751 Paul K, I am not promoting, for example, 100% solar and 0% biofuel. Indeed, I would expect that biofuels may be 10% of transportation in a world that has solved its GHG emissions problem. I am simply trying to make sure that readers here understand that some of the claims made here for biofuel don't seem to as rosy as some would suggest. I think it is important to get reasonably accurate estimates, and so I do challenge numbers I consider to fail the squint test. Paul K, I am not promoting, for example, 100% solar and 0% biofuel. Indeed, I would expect that biofuels may be 10% of transportation in a world that has solved its GHG emissions problem. I am simply trying to make sure that readers here understand that some of the claims made here for biofuel don’t seem to as rosy as some would suggest. I think it is important to get reasonably accurate estimates, and so I do challenge numbers I consider to fail the squint test.

]]> By: Earl Killian http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11750 Earl Killian Tue, 29 Apr 2008 02:59:55 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11750 David Benson, if you don't like da Rosa's numbers, consider <a href="http://www.pnas.org/cgi/content/full/105/2/464" rel="nofollow">Schmer et al. in the 20080115 PNAS</a>. They report 60 GJ / hectare / year from switchgrass. That is 0.19 W / m^2. If one assumes an average insolation of 225 W / m^2, then the efficiency is 0.08%. If you don't like that, remember that Miscanthus is supposed to be 2-3x better than switchgrass, so consider the <a href="http://en.wikipedia.org/wiki/Ethanol_fuel" rel="nofollow">estimate on Wikipedia for Miscanthus</a>: 7300 L ethanol / hectare / year. Since ethanol has a LHV of 21.2 MJ/L, this gives 155 GJ / hectare / year, or 0.5 W / m^2. Using the same 225 W / m^2 calculate the efficiency to be 0.2%. Next question: have you actually read the IEA report at the link you cite, or just the graph? Strangely, 1545 EJ never occurs in the report. The text mentions 100-300 EJ from energy crop farming on Ag land, and possibly another 40-170 EJ from organic wastes and residues, and sums by saying "could amount to 400 EJ per year during this century." This is also before conversion to a convenient fuel, such as ethanol or biodiesel. This is the raw energy in the plants in the field. Elsewhere it lists the "Technical Potential" of biomass as 200-400 EJ. 1545 EJ is overstating this by a factor of 3.9 to 7.7. Moreover, there is still the usage efficiency, as I mentioned before. David Benson, if you don’t like da Rosa’s numbers, consider Schmer et al. in the 20080115 PNAS. They report 60 GJ / hectare / year from switchgrass. That is 0.19 W / m^2. If one assumes an average insolation of 225 W / m^2, then the efficiency is 0.08%.

If you don’t like that, remember that Miscanthus is supposed to be 2-3x better than switchgrass, so consider the estimate on Wikipedia for Miscanthus: 7300 L ethanol / hectare / year. Since ethanol has a LHV of 21.2 MJ/L, this gives 155 GJ / hectare / year, or 0.5 W / m^2. Using the same 225 W / m^2 calculate the efficiency to be 0.2%.

Next question: have you actually read the IEA report at the link you cite, or just the graph? Strangely, 1545 EJ never occurs in the report. The text mentions 100-300 EJ from energy crop farming on Ag land, and possibly another 40-170 EJ from organic wastes and residues, and sums by saying “could amount to 400 EJ per year during this century.” This is also before conversion to a convenient fuel, such as ethanol or biodiesel. This is the raw energy in the plants in the field. Elsewhere it lists the “Technical Potential” of biomass as 200-400 EJ. 1545 EJ is overstating this by a factor of 3.9 to 7.7.

Moreover, there is still the usage efficiency, as I mentioned before.

]]> By: Paul K http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11748 Paul K Tue, 29 Apr 2008 02:45:29 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11748 False either/or keeps popping up. Which is better bio-fuel or solar is irrelevant. Both are necessary. It was interesting last week how commenters touted their own particular wedge or solution while disparaging others. Yes/and has to replace no/but. It is also good to remember the longest journey begins with a single step and don't put the cart before the horse. Replacing fossil fuel is an extremely incremental process. Venture capital is the engine of deployment. False either/or keeps popping up. Which is better bio-fuel or solar is irrelevant. Both are necessary. It was interesting last week how commenters touted their own particular wedge or solution while disparaging others. Yes/and has to replace no/but. It is also good to remember the longest journey begins with a single step and don’t put the cart before the horse. Replacing fossil fuel is an extremely incremental process.

Venture capital is the engine of deployment.

]]> By: David B. Benson http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11747 David B. Benson Tue, 29 Apr 2008 01:12:02 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11747 Earl Killian --- I'm not recommending using just bio-energy to meet the projected need. I just point out it is possible. I suspect your numbers are off by quite a bit, however, The papers linked in here http://jcwinnie.biz/wordpress/?p=2815 claim 1545 exajoules after leaving enough for food, fiber and forestry needs for a world population of 9 billion. The goup in The Netherlands has studied the matter for several years, so probably have thought through all the details. By all means use the most efficient systems possible. Dish/Stirling might well prove highly suitable in locations with enough sunlight. Earl Killian — I’m not recommending using just bio-energy to meet the projected need. I just point out it is possible.

I suspect your numbers are off by quite a bit, however, The papers linked in here

http://jcwinnie.biz/wordpress/?p=2815

claim 1545 exajoules after leaving enough for food, fiber and forestry needs for a world population of 9 billion. The goup in The Netherlands has studied the matter for several years, so probably have thought through all the details.

By all means use the most efficient systems possible. Dish/Stirling might well prove highly suitable in locations with enough sunlight.

]]> By: Earl Killian http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11745 Earl Killian Tue, 29 Apr 2008 00:19:11 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11745 David Benson, the Earth receives 1,100,000 EJ of sunlight on its land masses each year. The conversion of sunlight into biofuels is generally very inefficient. For example, da Rosa estimates sunlight to sugarcane ethanol as 0.13%. If most biofuel production were that inefficient, then you're down to just 1,430 EJ of biofuels, <i>if</i> you use all of Earth's land for fuel feedstock. 800 EJ would require 56% of the Earth's land area. That seems terribly wasteful. One of the attractions of algae is that it might reach a couple of percent efficiency at storing solar energy (out of an approximate maximum of about 7.8%). This is still rather small compared to 30% for Stirling dishes. That is the production side, but the story is bad on the use side too. Feeding hydrocarbons and alcohols into an internal combustion engine wastes something like 80% of the energy in the ethanol; only 20% ends up turning the wheels. In contrast, 70% of the energy from a Stirling dish would end up as wheel motion with only 30% wasted. David Benson, the Earth receives 1,100,000 EJ of sunlight on its land masses each year. The conversion of sunlight into biofuels is generally very inefficient. For example, da Rosa estimates sunlight to sugarcane ethanol as 0.13%. If most biofuel production were that inefficient, then you’re down to just 1,430 EJ of biofuels, if you use all of Earth’s land for fuel feedstock. 800 EJ would require 56% of the Earth’s land area. That seems terribly wasteful.

One of the attractions of algae is that it might reach a couple of percent efficiency at storing solar energy (out of an approximate maximum of about 7.8%). This is still rather small compared to 30% for Stirling dishes.

That is the production side, but the story is bad on the use side too. Feeding hydrocarbons and alcohols into an internal combustion engine wastes something like 80% of the energy in the ethanol; only 20% ends up turning the wheels. In contrast, 70% of the energy from a Stirling dish would end up as wheel motion with only 30% wasted.

]]> By: Earl Killian http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11743 Earl Killian Tue, 29 Apr 2008 00:03:04 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11743 One problem I see with algae: companies like <a href="http://www.greenfuelonline.com/" rel="nofollow">Green Fuel</a> are targeting fossil power plant flue gas as a CO2 source (which might be 209,000 ppm CO2 instead of 385 ppm CO2). That means the fossil CO2 is only delayed in its release into the atmosphere. True, it substitutes for crude oil CO2, but if we shut down our coal plants, where does this leave algae biodiesel if it is optimized for high CO2? One problem I see with algae: companies like Green Fuel are targeting fossil power plant flue gas as a CO2 source (which might be 209,000 ppm CO2 instead of 385 ppm CO2). That means the fossil CO2 is only delayed in its release into the atmosphere. True, it substitutes for crude oil CO2, but if we shut down our coal plants, where does this leave algae biodiesel if it is optimized for high CO2?

]]> By: Joe http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11739 Joe Mon, 28 Apr 2008 22:16:30 +0000 http://climateprogress.org/2008/04/27/let-them-eat-biofuels/#comment-11739 Paul -- with the VC $$$ going into algae, I'd consider it an in-the-pipeline technology. That said, if I had one MMBD for every such "breakthrough" I've seen announced in the past two decades, I could fuel the world. Paul — with the VC $$$ going into algae, I’d consider it an in-the-pipeline technology. That said, if I had one MMBD for every such “breakthrough” I’ve seen announced in the past two decades, I could fuel the world.

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