Will biofuels always be hopeless?
Posted by Stuart Staniford on May 26, 2006 - 12:04pm
Topic: Environment/Sustainability
Tags: biofuel, carbon cycle, climate change, global warming, hubbert peak, kyoto, oil prices, peak oil [list all tags]
Fair enough. I buy all that.
But, I think it's very important to ask: do biofuels suck for deep fundamental unchangeable reasons? Or for contingent reasons that might be amenable to change over time with technological innovation? And I'm starting to think the answer might not be so obvious.
Flows of carbon in biomass products entering the global economy. Source: FAO.
To get a sense of the relative scales of things, let's remind ourselves again of the basics of the carbon cycle:
Earth's carbon cycle with stocks in Gt (Gigatonnes), and flows in Gigatonnes/year. Click to enlarge. Source: Wikipedia. Click to enlarge.
The Wikipedia's numbers are a little out of date. As I discussed some time back, by 2004, fossil fuel emissions were up to about 8Gt/year and climbing fast.
Still it's of considerable interest that the amount of carbon moving through the biosphere is an order of magnitude larger than the flux of fossil fuels. To repeat myself:
Plants absorb about 120 Gt of carbon/year and turn it into sugars via photosynthesis (and then onto other materials). This is the gross primary production of photosynthesis in the biosphere. Of this, the plants themselves burn about 60 Gt of carbon (in the form of sugars) to power their own operations, so that is released out into the atmosphere again immediately. The remaining 60Gt or so is called the net primary production. Almost all of the net primary production ends up going into the soil (a small amount passing through some animal on the way), but humans use and burn some of it. The soil releases back pretty much all of the carbon influx through the action of decay organisms.Obviously, the energy density of biomass is not as high as that of coal or oil, but still, the ratio of energy flows is not going to be completely different than the 60/8 ratio of net primary carbon fixation to fossil fuel carbon usage (especially if we grant solar drying of the biomass). It's not obvious to me that there's no combination of technology, policy, and economics that could divert a sizeable fraction of that 60Gt into biofuels. It's also not obvious that there isn't scope for innovations to increase that 120Gt top line over time (especially in a world with more CO2 in the air to start with).
Here's a picture of the geographical distribution of primary producers:
Geographical distribution of plant density. Source: Wikipedia.
If we overlay that with human population density:
Estimated population density of the Earth in 1994. Source: NASA.
you can see why Brazil is the home of biofuel: the ratio of plants to people is probably as high there as anywhere. Thus the scope for using the plants to transport the people, as well as feed and clothe them, is exceptionally good.
But the US looks pretty good too. Europe, India, China, not so good.
How much of that 60Gt of global net primary productivity makes it into the economy now? I did some digging around at the United Nations Food and Agriculture Organization. It turns out that the major flows are wood and food (textiles and liquid biofuels are fairly neglible by comparison at present).
Let's take food for a moment, and just reassure those of you worried about peak food; we don't seem to be there yet (at least as of 2002). Here's calories/capita. Although cereal calories per person have peaked, total calories per person have not.
Global calories/capita 1960-2002. Source: FAO.
For a quick feel of what's involved in wood products, here are the major flows:
Global production of forestry products. Source: FAO.
Of course, these statistics should be taken as only rough indications. Adding up national statistics for wood production from a bunch of developing countries probably does not give a precision result.
Anyway, if we convert the FAO statistics into approximate carbon flows, we get:
Flows of carbon in biomass products entering the global economy. Source: FAO.
As you can see, only about 2.5Gt out of about 60Gt of net primary productivity makes it into the global economy.
Now I don't know enough to say how much that flow could be increased, nor how bad the resulting environmental impacts would be. But I think it's rather hard to make the case that getting to the order of magnitude of 8 Gt/year is impossible in principle.
But I do know that we've reached the point where defending our right to emit carbon on the scale we're doing it is several steps down the moral ladder from defending tobacco companies as innocent of causing cancer.
On the contrary, I believe we are committing evil in emitting so much carbon, and we need to change. We are heading for disaster after disaster.
And I think that's an important point when considering the subsidies for ethanol. Whenever the US, China, etc decide to leave the dark ages on these issues it's pretty obvious what needs to happen at an economic policy level. There needs to be big costs for anyone that emits carbon, and big payments to anyone who can prove they are sucking it out of the atmosphere and stashing it somewhere for a reasonable period of time. That would give everybody the right incentives and make possible business models for innovations that move us in the right direction.
Now, the ethanol subsidies are not what is needed. But they do at least have the right sign: they prefer biofuels to fossil fuels.
The closing price for carbon emissions today on the European exchange was €19.10/ton (about $24.40). Given about 2.4kg of carbon per US gallon of gas, that corresponds to about 6 cents/gallon. That's pathetic. In my opinion, it should be set on a ramp to go from the present value of nearly nothing to many dollars/gallon over the course of coming decades. And then the ethanol subsidies in 2006 might not look so big.
Our problem is that we are going to need more and more fuel, even counting with a reduction in car use in the west and all the mpg efficiency you can throw at it. We just need to stop this stupid car culture, starting from the ones who act as an example for the undeveloped world (that in turn would mean solving our urbanising problem, did you know that in Europe we are sprawling too!!?? at least in Spain)
We can throw and throw solutions, alternative fuels, efficiency, but I have my doubts about our chance to win over the Growth for Growth Sake Culture. Growth seems to keep ahead of us...
The best way to produce any bio based fuel is to start with the immense amounts of waste in all sectors of the economy.
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In other news, Earlier this week flash floods in northern Thailand destroyed a number of villages, combining both climate change and deforestation as probable factors.
The "non-grain" food production is still growing healthily.
Your thesis is based on a rather narrow definition of biofuel feedstock as being agricultural.
Add waste biomass to the definition and you start opening up possibilities. Waste has concentrations where people are in urban, agricultural, and forest environments. Convert waste biomass into ethanol - which new, clean bioconversion technologies are accomplishing in pilot programs - and you turn liabilities (corn stover, MSW, rice straw, infected trees, sewage, switchgrass, sulfurous coal, tires, auto fluff, etc.) into energy assets (ethanol and co-generated green electricity) without toxic emissions. Not to mention the positive environmental impact of ridding yourself of the waste.
Don't get hung up on "subsidies." Subsidies are spurring overdue investments that are going to get us from fossil fuel crisis to renewable fuel solutions. Biofuel subsidies are a pittance compared to fossil fuel subsidies with a much greater rate of environmental return.
One man's 'waste' is another man's compost for soil fertility.
To destroy weed seeds in your field in a biological way, you can use fungus to 'eat' the weed seeds. But you need carbon to get the fungus to 'bloom'. Putting 6 ton of finished compost PER acre (thats alot of compost bob!)
The boys over at magic soil show a way how excessive electrical energy from renewable generation can be fixed into compost management.
http://www.magicsoil.com/
Better make sure your 'plan' isn't destroying the soil food web just so you can keep the lights on and drive the SUV for a bit longer.
turn liabilities (corn stover, MSW, rice straw, infected trees, sewage
Corn stalks are fixed into animal protein in many opweations. Rice straw and cornstalks can be made into tasty or medicinal mushrooms. Sewage - Ha! When one looks at what is dumped down the drainpipes by most people, the seperation of the toxic materials from the non-toxic is problematic. The toxic crap effects the bio-process based fuel conversion, and random addition of metals like platinum make sewage an explosive depolymarization methods.
Being optimistic is fine, but just looking at the energy side is a recipe for just adding TO the disaster.
Soil health is very important. The biomass in the soil requires carbon to be recycled into it. If you take away that carbon, by converting it to fuels, you may have a recipe for a high rate of desertification.
Don't get me wrong - if we have waste that we can use - we should do it by all means. But in the end it may turn out a marginal source, limited by our agriculture capacity.
(think "Soylient Green")
In a totally natural system, NOTHING is wasted.
It may seem like waste to humans, but it serves a purpose.
The more natural-like a system is, the better it operates, because it operates more in harmony with natural laws and processes.
Natural wastes from artificial systems (like agriculture) also serves a useful purpose. Any divergance from this is simply asking for trouble further down the road.
An example might be co-locating a smallish coal-fired powerplant, an algal biodiesel facility, a pig farm, a biodigester and a mushroom-growing facility. The "waste" stream works like this:
The power plant produces CO2 that is bubbled into the algae ponds. The pigs produce manure that is passed through a biodigester to produce methane, and the remaining manure waste material is also added to the algae ponds as fertilizer. The oil is extracted from the algae, and the remaining cell-wall waste is used as a substrate for growing mushrooms. Following mushroom production, the substrate that has been "cracked" by the mushrooms is used as pig feed.
Out of this cluster you get electricity, biodiesel, natural gas, pork and mushrooms. All significant wastes get used within the cluster. Now the devil is in the details as always, but the theory is to mimic natural systems insofar as waste re-use is concerned.
The main problem is the capital cost of the electrolysis cells. Figuring out how to produce them in a more efficient way using less material would be a major win.
Add the energy/costs needed for their research, manufacturing, infrastructure, electricity storage etc.etc. and it becomes obvious why biodiesel is a preferrer way (well, at least for now).
There are problems with this appoach but I think it is far from certain that thin film silicon is the only appoach with a chance of large scale use'
In the end it comes down to costs (both financial and energetical) - obviously $1 invested in biofuels would yield much more energy in a suitable form than $1 in PV, despite the seemingly higher efficiency.
Paradoxically population growth is related to wealth anyway. If you look at growth in the wealthy westernised nations it's fairly low, at zero or even in decline in some places (I believe the UK population is currently kept stable via immigration).
The places with the biggest population growth are the poorer areas where a child is insurance, a pension and a hedge against risk all rolled into one. As life gets more stable people have fewer children ....
Stuart,
Excellent post and a great start for a thread. Unfortunately, I am not a good enough chemist to dispute any of your major points, which all seem pretty straight forward, and within the normally accepted framework on carbon exchange.
My area is much more in the design side of the physical environment, and mechanical techology side. If you and others concerned about carbon release (including me, so that should be "those of us concerned") seem to agree on any major accepted points, then the broadly accepted view would be (a) burn less fossil fuel and (b) keep more live plants. I know that's a great simplification but it gives us a great place to start.
I will not for this moment go into burning less fossil fuel, since volumes have been written about this right here on TOD, and in books and articles around the world. Since we know burning less FF is a good thing, all debate becomes how we can best achieve that humanely and effectively, leaving people able to heat their homes, cook their food, and move about to some degree greater than walking/bicycling, which are laudable but do have their limits (time, weather, safety, health,etc.) We have of course discussed a multitude of methods to reduce fossil fuel consumption and of course, more will be forthcoming.
Right now, I want to turn to the other point, that being (a) Plants, and how to retain them in quantity, quality, and variety, and (b) soil, the place from which plants are born, live, and die.
Having already given myself away as a non-chemist with no real expertise in soil chemistry (only the rudimentary basics) what could a "technical type" possibly have to say about soil/plant conservation?
Don't underestimate the contribution the designer/technicians can make in this area, especially those that are willing to read a bit broadly and outside their own normal field.
I have read here on TOD references to the great environmental/ecological writings of my fellow Kentuckian Wendell Barry, who has made the eloquent case for topsoil preservation, actually more, he means "respect" of the extremely valuable and prolific medium that topsoil is. I will not go deeply into this in this post, for sake of brevity, but if you put "Wendell Barry on topsoil" in a google search bar, it should give you an idea of the variety of thought, and depth of feeling Mr. Berry brings to this subject.
Think for a moment. Counting from about 6 inches above the ground, to about 18 inches below it (roughly) you have an 2 foot thick medium of extreme biological variety, chemical complexity, and the most extreme value in supporting life, and in fact, acting as the womb of life that can extend hudreds of feet into the air, and dozen (s) of feet below the ground. It is this thin layer that must be treated with the respect it earns by way of it's contribution to feeding animal and plant life, and feeding and purifying the atmosphere. If you go much over a couple of feet off the ground, or much more than a few feet below ground, you get essentially "free space" to use, if you take proper care of that 2 foot blanket. Digging below that blanket (topsoil) gets us resources, such as coal, oil and natural gas, plus the metals, iron, nickel, copper etc. We can dig hundreds of feet, thousands, but we must be careful about that "blanket" of topsoil at the surface. Likewise, we can build towers upward thousands of feet, and encase in them the equal of hundreds of city blocks, while only occupying the one block or so the building sits upon in terms of topsoil space.
The secret is verticalization, both upward and downward.
In the 1970's, when the energy crisis was at it's worst, and the "green" movement was being born, there were many plans laid for underground cities. Underground homes were built. Certain industrial and storage facilities found it to be the perfect solution. Humans can easily survive at 58 degree tempeture, whch is approximate tempeture throughout most of the populated world at only a few beet below ground. It is much easier and less fuel consuming to heat or cool from a point of 58 degrees to a comfy 68 or 70 degrees than it is to heat from a point below 0 (in northern states like Wisconsin or Michigan) or to cool from a point above 100 in California or Texas. Climate control solutions from going underground for many buildings and even city secttions make it worth it on energy savings and greenhouse gas reduction alone, but it gets better.
If I design sections of a city to exist underground, I can use the topsoil land surface for....yep, you got it, soil preservation and plant diversity. It's a win/win propositon, except....of course, the capital cost of excavation and building underground.
But with good architectural design, and creative construction techniques, it can be done, and in fact, if people could understand what the saving of plant life and the retention of the treasured layer of topsoil were worth in real terms, for the survival of the planet and the humans on it, it would be done now. It will be done in the future. The better thinkers have always known this.
In his legendary Public TV series "Cosmos", the late Dr. Carl Sagan was speaking of how an "advanced" civilization could be identified from long distance in space, either by telescopic view, or by passing space probes.
Sagan postulated (this in the 1970's) that beside our radio and television signal, going in a wave out into space at the speed of light, we would also be visible by our lights on the surface. The surface of the earth shows the population of a technical civilization by it's lit cities, lights visible to a spacecraft, and giving a pattern of rich/poor, technological/non-technological. This along with the television/radio wave makes an advanced civilization visible, and for Earth, it has only been true this last century.
Unless....Sagan speculated, if the civilization is MUCH more advanced than we are....then, it would move below surface to conserve bio-diversity, resources, and topsoil, and be more protected from weather, or enemy attack by bomb/missile. Underground cities of millions would be networked by high speed tunnel transport, and networks of fiber optic cable, one to another, to dispatch information at the speed of light....thus, the surface would again go dark, natural as it had been for millions of years, and the television and radio signal would go more and more silent, as more information was dispatched to the fiber optic intercity network....we would become essentially invisable (or very low visible at close range only) again, and the surface of the earth would host plants (including our cultivated ones, play areas, recreation, and one thing that would be visible once a passerby was close enough.....the giant solar and wind arrays in deserts and on the plains, now able to provide a great percentage of power to the extremely energy frugal underground cities.....
In such an arrangement, could bio-fuels make sense? Possibly, but they would not be anything like the current image of giant, square fields being combed over by fossil fueled machines, and sprinkled with massive herbicide/pesticide.
Instead, it would be much closer to "detritus" hunter gathering, with the dead fallen growth, and decayed plant matter collected for methanol or methane production, combined with plant and animal waste including human waste....a unique "natural gas" by dying plants and animals and their byproduct.
I will leave it at this, and let you folks look at the side of verticalization I did not address, the more controversial one. Allow me to give you a starting place:
A well designed, ecologically planned skyscraper is the environment and topsoil's best friend.
If we verticalize upward correctly, and downward correctly, the surface of the Earth with it's treasured layer of topsoil and plant diversity can be our protector from greenhouse gas and global warming. The stable climate of the Earth below ground would reduce our heating/air conditioning cost to a fraction of what it is today.
It's all in the design. We have thousand of feet, miles in fact, of earth and sky to use without harm, if we do it right....and we would never be far from trees, plants, gardens, waters, and life mixed right into our verticalized cities and homes.
The point that I don't think people understand correctly is this:
Humans are NOT having an energy/carbon/food/space crisis because we are "too advanced".
We are having these problems because we, and our technology, are still so unbelievably primitive.
Roger Conner known to you as ThatsItImout