Bioenergy, Fuel & Food

Bioenergy is part of any energy solution, but it is not THE solution and the idea that bioenergy will soon make a large part of the American fuel mix probably violates the laws of physics and certainly is not justified by our levels of technology or economics.

Oil and gas are forms of bioenergy; they are just the fossil forms. Although when we say bioenergy, we almost never mean oil, gas or coal, remembering their ultimate origin helps understand the challenge of bioenergy today. Coal, gas & oil were once living organisms. For millions of growing seasons, ancient forests laid down these carbon-based energy riches. There is a geological period in deep time called the Carboniferous,because so many of our coal resources were laid down during it roughly sixty million. During this period, vast tropical rain forests expanded and then collapsed due to rapid climate change. This one period and there are many more millions of years.

When we are producing bioenergy today, we are using the product of one growing season, or at most that of dozens in the case of wood. You can see how our ephemeral efforts seem feeble in comparison to the millions of years and many trillions of life forms that produced the fossil fuels. Gasoline from fossil fuels is a superb liquid energy source that gives us more energy per gallon than almost anything else. A gallon of ethanol yields only around 80% of the energy of a gallon of gasoline. A pound of hydrogen contains much more energy than a pound of gasoline, but hydrogen weighs less than air and a pound of hydrogen takes up more than ten times as much space as a pound of gasoline. Even with its greater energy output, a gallon of hydrogen produces only a little more than 25% as much as a gallon of gasoline.

I digress into the geological and physical facts because I enjoy such things and also to explain the origins and weaknesses of biofuels that are often overlooked. To continue with the mainstream article …

There are many varieties of bioenergies. GMOs promise to deliver biodiesel & other forms of energy from many varieties of plants. We can already produce fuels from things like oil seeds and palm oil. Some of these things have significant ecological costs. For example, rain forests are sometimes removed to plant oil palm. These things can add more greenhouse gases than they remove.

In the profound understanding that yesterday’s solutions are today’s problems, we should be careful, understanding that some of today’s solutions will be tomorrow’s problems.

The most promising bioenergy that might replace petroleum is not really bioenergy at all, but rather is a byproduct. Much of our modern industrial society is petroleum based and much of that is not the stuff we burn. Plastics, drugs, fertilizers and many composites even the paving on our streets is petroleum based. We could replace liquid petroleum fuel a lot easier than we could do without many of these petroleum based products. But when we recall that petroleum is a biofuel, we can see that we could use bioenergy production to replace petroleum in many of these uses. In fact, Middle Eastern potentates feel more acutely threatened by developments in alternative materials than they do the development of alternative fuels. As long as we need the “byproducts” production of oil etc is assured.

The most famous liquid bioenergy is ethanol. Ethanol is criticized because its production can be inefficient (i.e. consume as fossil fuel as it replaces) and the feedstock is usually some form of food and/or the production of the crop for ethanol displaces a food crop.

The first criticism can be valid. You can make ethanol from almost anything that grows in the earth, but some are less efficient than others. You have to look at the precise circumstances. The idea that it displaces food production is one of those things that make intuitive sense, but it not true.

The displacement argument is based on a zero sum thinking that is rarely valid. A modern diversified agriculture produces a variety of crops in a variety of ways. These crops can complement each other and allow greater productivity. For example, some farmers plant sugarcane (a multiyear crop) followed by corn and then by soybeans. One crop enriches the soil for the others. It also can make sense to intersperse crops. In any case, the U.S. has produced more food and feed in the last five years than in the previous twenty while simultaneously producing a bumper crops for biofuels. It works on the small scale as well. Poor farmers in Tanzania, for example, have had success in producing cassava and sunflowers, used in bioenergy along with the crops they eat. Production in general has increased, while addressing the problem of persistent energy poverty.

Biofuel is not the same as bioenergy, which is a broader term. This is clear in the production of ethanol. Ethanol production from sugar cane is very efficient because of the energy potential of the feedstock itself, but also because of the usefulness of the “waste” i.e. the stalks called bagasse. Burning these residues produces enough energy to completely fuel the ethanol production plus surplus energy that can be fed into the national grids. (In 2010, the EPA designated Brazilian sugarcane ethanol as an advanced biofuel due to its 61% reduction of total life cycle greenhouse gas emissions, including direct indirect land use change emissions.)

All new Brazilian vehicles are flex fuel and Brazilians consumers have the choice of ethanol or gasoline at the pump. They make choices based on the relative prices. When the price of ethanol moves above 80% of the price of gas, they buy gas. Ethanol prices have been high in recent months and so Brazilian drivers have been opting more and more for gasoline, while Brazil, somewhat ironically, has been importing ethanol from the United States. The United States is both the world’s biggest consumer and producer of ethanol. Brazil is second and between our two countries we account for 87.8% of total world production. Brazil and the United States partnered to share techniques and technologies among themselves and with developing countries in the Caribbean and Africa.

The Holy Grail of ethanol production is ethanol from cellulous, i.e. wood chips, corn husks, switchgrass etc. President Bush mentioned this as a goal in his State of the Union speech in 2006. President Obama has reiterated this pledge to find a technology to do this. Presidents, BTW, have beWhen making similar pledges on various technologies since Richard Nixon. Anyway, they always think the technology will be available about 5-10 years from the time of the speech. It is a good round number that allows them to take credit but largely be out of the way when it doesn’t happen.

IMO, biofuels will never come close to replacing petroleum as a liquid fuel source. The science is still not available, but as importantly it lacks practical or economic sense. Cellulose is common in farm and forestry wastes and is “available” as a feed stock, but it also has other characteristics. Most notably, cellulose waste is bulking, heavy and it tends to burn well. It will never make practical sense to move all this stuff to factories to be turned into ethanol, a process which will produce relatively little energy in return for the massive input. The most useful alternative is what the Brazilians already do with bagasse and what many pulp, paper and wood mills do with their sawdust and scraps: burn them on site to produce electricity. This is a good use if we remember the more inclusive word bioenergy instead of the narrower biofuel.

This woody biomass is a vastly underutilized bioenergy source. If we use electric cars, it would be good if the electricity is produced from a carbon neutral source such as woody biomass. Why take the expensive and less effective extra step of turning it into ethanol?

Anyway, I see bioenergy as an important part of future energy portfolios, but never anything close to a really major solution. We just do not have enough land to produce enough biofuel for even a small percentage of our vehicles. On the other hand, bioenergy and byproducts can form an important part of materials we use and additives in other products. For example, using ethanol as an oxygenator in gasoline makes a lot of sense - burning the stuff in pure form, not so much.

In an uncertain world, you have to try all of the above with a wide portfolio of solutions … and be ready to be flexible when some of your favorites don’t work.

Posted by Christine & John at June 26, 2011 12:00 AM
Comment #325053

Once again I see that the quality of your articles and the comments they receive are often inversely proportional.

Posted by: Warped Reality at June 27, 2011 7:12 PM
Comment #325054

Once again I see that the quality of your articles and number of comments they receive are often inversely proportional.

Posted by: Warped Reality at June 27, 2011 7:13 PM
Comment #325056

Excellent observation. I would add the additional point that the number of comments are inversely proportional to the number of explicit political references within the article.

It is my opinion, that there would be much more agreement than disagreement between liberals and conservatives on many, if not most issues, if a discussion was limited to the facts and available options. However, once the labeling starts, the brain turns off and tribal instinct takes hold. Of course, it would not be much fun if we all started agreeing. It might be more productive though.

Posted by: Rich at June 27, 2011 7:56 PM
Comment #325058

Warped & Rich

I plan to be more partisan and provocative in the future. I just don’t feel as aggrieved as I might. Lots of the macro things are confusing me.

Right now I am literally on my way to Brazil and I have been thinking about those science related things instead of partisan politics. I plan to be wandering around there, taking pictures and writing on my other blog, but I don’t expect that those thought will be good WB material.

re lack of comments:

Recall the joke about the kid who is born normal and healthy but just doesn’t talk. His parents take him to all the doctors and specialists, who can find nothing wrong with the boy. He just doesn’t talk. The parents get used to it, so they are surprised one day when he is about four and he says, “This oatmeal is cold”. His parents are surprised and his mother exclaims, “You can talk!” The kid responds, “of course I can talk” Mother asks, “why didn’t you say anything before” The boy responds, “up until now, everything has been okay.”

Posted by: C&J at June 27, 2011 8:27 PM
Comment #325059
I plan to be more partisan and provocative in the future. I just don’t feel as aggrieved as I might. Lots of the macro things are confusing me.

No objections from me. Also, I think the more provocative & partisan posts are from Christine’s hand; or am I wrong? That joke about the child with a language delay applies even more to your other blog. I usually read it once every other week, but I never comment. In any case, I’m glad you are of a curious state of mind right now. Unfortunately, curiosity is in short supply these days. Hopefully you learn a great deal from you trip to Brazil.

Regarding the ethanol economy, I was wondering if you could do me a favor. As someone who is studying atmospheric pollution, I know that ethanol combustion leads to the production of peroxyacetyl nitrate (PAN), which is a component of photochemical smog. Gasoline combustion also produces photochemical smog by emitting NOx pollution that leads to elevated tropospheric ozone levels. I’ve read a few papers in the peer-reviewed literature that discuss the effects of the tradeoff between PAN and tropospheric ozone that is occurring in Brazil. The tradeoff between the two is debatable, but I have no idea how this issue is playing in the eyes of ordinary Brazilians or with Brazilian policymakers. Those sorts of questions are usually not answered in scientific literature, so I’m curious how things are going on there (given the fact I can’t afford to travel there myself). How many Brazilians are aware of this tradeoff? Have policymakers reviewed the evidence on both sides in order to make an informed decision or are they mostly ignorant of this issue? I hope this isn’t too imposing; feel free to decline my request because I know you like to keep your work stuff, your personal stuff and your political stuff separate so I understand if my questions remain unanswered. It’ll just motivate me to travel there myself someday.

Also, I actually found your proposal to burn cellulose en masse interesting. The research I’m conducting right now is actually related to cellulose combustion, but mostly from natural sources (AKA forest fires). Basically I’m looking at biomass burning aerosols (BBAs) and determining their interactions with anthropogenic pollutants (such as NOx) as well as naturally occurring substances. Personally, I have no idea whether increased biomass burning of the sort you propose would be a good thing or a bad thing. Although biomass burning can be construed to be beneficial from the respect of greenhouse gas emissions, it is much more likely to produce NOx pollution than gasoline production. Over the last few decades we’ve made gigantic strides in reducing NOx pollution (compare LA’s smog today with what it was 10 or 20 years ago). I wouldn’t want to ruin that progress without first investigating the implications.

Posted by: Warped Reality at June 27, 2011 9:46 PM
Comment #325060

“Lots of the macro things are confusing me.”

That’s a good thing. Certainty is the stock and trade of politicians and ideologues. It is frequently unjustified. Framing issues on partisan terms blinds us to weaknesses in our own arguments and to alternative options.

Posted by: Rich at June 28, 2011 7:40 AM
Comment #325074


Most people don’t care enough about those things to support a posting here. You know how to find me. Write me a note on the contact on my personal other blog. I will be making my business to find out such things in Brazil anyway. Your questions might help me sound more erudite to my interlocutors.

Posted by: C&J at June 28, 2011 7:40 PM
Comment #325110

Fair enough. I’ll send you an e-mail soon.

Posted by: Warped Reality at June 29, 2011 6:06 PM
Comment #325386

We won’t know until we invest on a level equal to its importance.

Posted by: Aldous at July 8, 2011 11:53 AM
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