This seems like predominately an argument against biofuels for electricity production, noting that land usage of alternative renewable sources are orders of magnitude better.
Aside from the reference of carbon intensity vs ethanol, it’s not obvious to me that this is an argument against biofuels for situations where electrification faces other challenges. For example, jet fuels. Do you have similar arguments against using biofuels for aviation? The metric for comparison there certainly isn’t hectares per TWh/yr.
Another area I’ve seen dedicated biomass discussed is as feedstock for carbon dioxide removal or BECSS, where the predominate benefit isn’t electricity production, but permanent removal of carbon dioxide from the atmosphere.
You're correct, these figures specifically apply to biofuels for electricity production. Thanks for highlighting that there are other potential uses of biomass.
I haven't analyzed biofuels for aviation. Given how much land is needed to produce crops, and the amount of processing needed to then transform them into usable fuel, my guess would be that electrofuels (e.g. https://terraformindustries.wordpress.com/2022/07/24/terraform-industries-whitepaper) are a better path. But that's just a guess.
BECSS is something I really have no idea about. I'd love to dig into the numbers on this, and probably will at some point. If you have any sources on this that you found especially valuable, please let me know.
The post "misrepresents" imho if you just edit the last section. It's certainly worthwhile to discuss biofuels for high energy density / weight scenarios like heavier than air aircraft and rocketry.
25 years from now, once the impacts of CO2 are universal and severe enough that we have properly rolled the external costs of CO2 into "all the things", that calculation of "biofuels are 25% less CO2 efficient than pumped oil" will have changed dramatically (e.g. add the costs of carbon recapture to the costs of burning "already captured" oil carbon).
And I'll posit that 25 years from now I'm still going to want to be able to travel coast to coast in the US in one day and to ship/receive business product coast to coast in less than 3-5 days and transatlantic in less than 1-2 weeks. In "Ministry of the Future", Kim Stanley Robinson makes a good story around wind/kite hydrofoils and lighter than air (e.g. dirigible) shipping reemerging, but I'm not convinced that either of these is going to win out over a 737-ish burning carbon neutral biofuel.
So the core message of your post -- that biofuels don't have a meaningful role in the future and that all interest and investment in their development should be redirected towards more fruitful energy alternatives -- well, I think it's likely to be just straight up wrong. Unless you think that you can make the argument that solar/wind farm -> NH3 is a more efficient path? Maybe? But you didn't prove that point out, and until you do, the main thesis is invalid.
You're correct, I inadvertently conflated "dedicated biomass for electricity" with "dedicated biomass for energy source of any sort" in more than just the final section of the post; including the title. I'm making further edits now to clarify that.
I do think that solar/wind farm -> chemical fuel (not necessarily NH3) is likely a more efficient path. I also think that even if biomass -> chemical fuel does turn out to be an economically viable solution for residual applications of chemical fuel, those applications (plausibly aviation, shipping; perhaps long-term storage; conceivably high-temperature industrial heat) might not be sufficiently large volume to exceed the supply of waste biomass and thus call for dedicated biomass. Dedicating arable land to production of biomass has huge costs, economic and otherwise: displacing food crops, driving water and fertilizer usage, contributing to deforestation, etc. I'd like to explore the numbers on all of this. But you're correct that I have not yet done so.
Fair enough. I did a quick investigation of dirigibles and the current top speed is 71 mph vs. 560 mph for a typical passenger/cargo jet, so it looks like we're going to be using some form of biofuel in a carbon neural future that includes air travel.
Your point about 2% energy capture for photosynthesis vs. 20% for photovoltaic is an excellent one. However my counter argument would be that we're quite good at farming and we don't really need new technology or infrastructure to make biofuels today. And we're going to need very large investments of both resources and technology to achieve carbon neutrality or net negative recapture over the next 25 years.
So perhaps it's not a smart move to throw away or de-invest any tool we have right now, especially something familiar and well proven like growing calories in a field. We might need all of them, even the 'inefficient' ones...
Now, water capture for farming, that's another topic entirely. Also something we need more of and also know how to do. And with more/better water capture technology at hand, making arid land productive is something we've shown (through California at least) we're quite good at today. So adding biomass doesn't necessarily need to displace food production or forests, it needs currently unused land (lots of that in the US alone) and water.
You might consider a hybrid, where the biomass is there mostly as a way to fix carbon from CO2, and then separate energy input is added so that all the carbon there ends up in the fuel. Converting cellulosic biomass to hydrocarbons by itself would release half the carbon as CO2, since the extra oxygen has to go somewhere. If one were to add a separate input stream of hydrogen then all the carbon could be used.
The reason biofuel crops need land is because they need sunlight to fix carbon through photosynthesis. Algae fix carbon the same way, so they will need lots of sunlight too.
You may be able to grow algae vertically using artificial light, but artificial light is more expensive than sunlight. Electricity -> light -> biomass -> mechanical energy -> electricity is an incredibly uneconomical pipeline.
You forget the evolution bias! If the whole world is covered in agricultural areas; there wont be any industry, cities, or in general big power consumers either. By itself, that would not be a problem, but can you picture yourself eating corn for the rest of your days? Me neither.
I view biomass as a useful source of feedstock, not an energy source. Biofuels have very poor biomass carbon -> usable product carbon. Oxy fire gasify to make CO/CO2 the. Upgrade the syngas with clean H2, and can get on the order of 3-4x the product.
Gasified biomass is not picky about the source either, so scraps and waste is fine. And the same synthetic routes could use DAC CO2, so less lock in risk and/or feedstock source switch ability is inherent.
No, just on the utilization end.from what I have seen biofuels tend to only end out with at best 1 in 4 carbons that were in the biomass. With this approach you would use essentially all the carbon in it to make product, so roughly 4x the use out of it...
Agree that growing crops on land and processing into fuel is insane. Best case - grow algae, dry, and burn directly in thermal power plant for electricity. I believe this is the concept of one of the finalists in Musk’s carbon X-prize. Haven’t checked the numbers myself - probably should.
Ok i get this in general, but I'm curious about biofuel for jet fuel. Given that we have no good options on the table, how does this compare with our other bad options? Wondering if you guys found any of this in your research. Lufthansa tries to upsell all their customers the option to contribute to using biofuel for jets.
This seems like predominately an argument against biofuels for electricity production, noting that land usage of alternative renewable sources are orders of magnitude better.
Aside from the reference of carbon intensity vs ethanol, it’s not obvious to me that this is an argument against biofuels for situations where electrification faces other challenges. For example, jet fuels. Do you have similar arguments against using biofuels for aviation? The metric for comparison there certainly isn’t hectares per TWh/yr.
Another area I’ve seen dedicated biomass discussed is as feedstock for carbon dioxide removal or BECSS, where the predominate benefit isn’t electricity production, but permanent removal of carbon dioxide from the atmosphere.
You're correct, these figures specifically apply to biofuels for electricity production. Thanks for highlighting that there are other potential uses of biomass.
I haven't analyzed biofuels for aviation. Given how much land is needed to produce crops, and the amount of processing needed to then transform them into usable fuel, my guess would be that electrofuels (e.g. https://terraformindustries.wordpress.com/2022/07/24/terraform-industries-whitepaper) are a better path. But that's just a guess.
BECSS is something I really have no idea about. I'd love to dig into the numbers on this, and probably will at some point. If you have any sources on this that you found especially valuable, please let me know.
(I'm editing the final section of the post to clarify that I am specifically referring to electricity production)
The post "misrepresents" imho if you just edit the last section. It's certainly worthwhile to discuss biofuels for high energy density / weight scenarios like heavier than air aircraft and rocketry.
25 years from now, once the impacts of CO2 are universal and severe enough that we have properly rolled the external costs of CO2 into "all the things", that calculation of "biofuels are 25% less CO2 efficient than pumped oil" will have changed dramatically (e.g. add the costs of carbon recapture to the costs of burning "already captured" oil carbon).
And I'll posit that 25 years from now I'm still going to want to be able to travel coast to coast in the US in one day and to ship/receive business product coast to coast in less than 3-5 days and transatlantic in less than 1-2 weeks. In "Ministry of the Future", Kim Stanley Robinson makes a good story around wind/kite hydrofoils and lighter than air (e.g. dirigible) shipping reemerging, but I'm not convinced that either of these is going to win out over a 737-ish burning carbon neutral biofuel.
So the core message of your post -- that biofuels don't have a meaningful role in the future and that all interest and investment in their development should be redirected towards more fruitful energy alternatives -- well, I think it's likely to be just straight up wrong. Unless you think that you can make the argument that solar/wind farm -> NH3 is a more efficient path? Maybe? But you didn't prove that point out, and until you do, the main thesis is invalid.
You're correct, I inadvertently conflated "dedicated biomass for electricity" with "dedicated biomass for energy source of any sort" in more than just the final section of the post; including the title. I'm making further edits now to clarify that.
I do think that solar/wind farm -> chemical fuel (not necessarily NH3) is likely a more efficient path. I also think that even if biomass -> chemical fuel does turn out to be an economically viable solution for residual applications of chemical fuel, those applications (plausibly aviation, shipping; perhaps long-term storage; conceivably high-temperature industrial heat) might not be sufficiently large volume to exceed the supply of waste biomass and thus call for dedicated biomass. Dedicating arable land to production of biomass has huge costs, economic and otherwise: displacing food crops, driving water and fertilizer usage, contributing to deforestation, etc. I'd like to explore the numbers on all of this. But you're correct that I have not yet done so.
Fair enough. I did a quick investigation of dirigibles and the current top speed is 71 mph vs. 560 mph for a typical passenger/cargo jet, so it looks like we're going to be using some form of biofuel in a carbon neural future that includes air travel.
Your point about 2% energy capture for photosynthesis vs. 20% for photovoltaic is an excellent one. However my counter argument would be that we're quite good at farming and we don't really need new technology or infrastructure to make biofuels today. And we're going to need very large investments of both resources and technology to achieve carbon neutrality or net negative recapture over the next 25 years.
So perhaps it's not a smart move to throw away or de-invest any tool we have right now, especially something familiar and well proven like growing calories in a field. We might need all of them, even the 'inefficient' ones...
Now, water capture for farming, that's another topic entirely. Also something we need more of and also know how to do. And with more/better water capture technology at hand, making arid land productive is something we've shown (through California at least) we're quite good at today. So adding biomass doesn't necessarily need to displace food production or forests, it needs currently unused land (lots of that in the US alone) and water.
You might consider a hybrid, where the biomass is there mostly as a way to fix carbon from CO2, and then separate energy input is added so that all the carbon there ends up in the fuel. Converting cellulosic biomass to hydrocarbons by itself would release half the carbon as CO2, since the extra oxygen has to go somewhere. If one were to add a separate input stream of hydrogen then all the carbon could be used.
"In some cou"
I think you've got an editing error there.
Indeed! Fixed, thanks.
I'd point out that biofuels can have zero land use. Arguably one of the densest biofuel sources is neochloris oleoabundans, which is an algae.
The reason biofuel crops need land is because they need sunlight to fix carbon through photosynthesis. Algae fix carbon the same way, so they will need lots of sunlight too.
You may be able to grow algae vertically using artificial light, but artificial light is more expensive than sunlight. Electricity -> light -> biomass -> mechanical energy -> electricity is an incredibly uneconomical pipeline.
You forget the evolution bias! If the whole world is covered in agricultural areas; there wont be any industry, cities, or in general big power consumers either. By itself, that would not be a problem, but can you picture yourself eating corn for the rest of your days? Me neither.
I view biomass as a useful source of feedstock, not an energy source. Biofuels have very poor biomass carbon -> usable product carbon. Oxy fire gasify to make CO/CO2 the. Upgrade the syngas with clean H2, and can get on the order of 3-4x the product.
Gasified biomass is not picky about the source either, so scraps and waste is fine. And the same synthetic routes could use DAC CO2, so less lock in risk and/or feedstock source switch ability is inherent.
Have you seen a good analysis of this approach? (E.g. potential productivity per acre; resulting net carbon impact.)
No, just on the utilization end.from what I have seen biofuels tend to only end out with at best 1 in 4 carbons that were in the biomass. With this approach you would use essentially all the carbon in it to make product, so roughly 4x the use out of it...
Agree that growing crops on land and processing into fuel is insane. Best case - grow algae, dry, and burn directly in thermal power plant for electricity. I believe this is the concept of one of the finalists in Musk’s carbon X-prize. Haven’t checked the numbers myself - probably should.
Ok i get this in general, but I'm curious about biofuel for jet fuel. Given that we have no good options on the table, how does this compare with our other bad options? Wondering if you guys found any of this in your research. Lufthansa tries to upsell all their customers the option to contribute to using biofuel for jets.
This is a question I'd love to dig into, but haven't yet done so. If you find (or undertake) any good analysis here, let me know!