« Wednesday Gumpagraph | Main | Today's Bush Joke »

March 08, 2006

Switchgrass To Ethanol Energy  Peak Oil

In his State of the Union speech, President Bush made a point of mentioning switchgrass as a promising biomass input for ethanol production. The Oil Drum yesterday carried an illuminating post that looked at the hype vs. the reality regarding switchgrass. Excerpts:

Switchgrass is a perennial grass native to the great plains, suitable for marginal lands because it grows well with relatively moderate inputs and can effectively protect soil against erosion. So far so good - one of the major attractions to switchgrass is that it is more environmentally friendly than corn....Best [yield] estimates [from switchgrass are] roughly 1000 gallons of ethanol per acre. Corn, by comparison, offers about...350 gallons per acre. This is why so many folks are beating their drums over switchgrass - in theory, it can be grown on marginal lands with ethanol yields 3 times that of corn with "minimal inputs." From this description, one gets the sense of legends in the making. Let's take a critical look at some of them.

Legend 1: Switchgrass does not require fertilizer or irrigation...

Fact: Switchgrass is a perennial grass, just like the grass in people's lawns. If you bag all your lawn clippings from your lawn, very quickly you will notice that your lawn will start to become yellow, and your "yield" (the number of times you have to mow) will decrease. This is because of the lack of fertilizer. Each time you remove biomass from an environment, you remove nutrients, and future yields will suffer. Switchgrass is exactly the same - if you harvest switchgrass for biomass, fertilizer must be applied in levels very similar to those applied if corn is the primary crop....In addition, phosphorous and potassium (potash) must be applied in amounts consistent to the amount of biomass removed, which actually exceed that necessary for corn.

Regarding irrigation, it is true that you don't need to irrigate switchgrass, just like you never "need" to water your lawn. However, just like your lawn, switchgrass won't yield nearly as well if it doesn't have adequate moisture....Switchgrass yields vary strongly with precipitation - planting the dry plains, New Mexico, or Arizona with switchgrass will not yield much biomass.

Legend 2: It is estimated that 15 percent of the North American continent consists of land that is unsuitable for food farming but workable for switchgrass cultivation. If all that land was planted with switchgrass, we could replace every single gallon of gas consumed in the United States with ethanol.

Fact: There certainly is a significant amount of land that is non-productive for agriculture but could be planted with switchgrass....Switchgrass would certainly grow on [non-agricultural] land, but yields would not approach the 6-8 tons/acre on good agricultural land.

Legend 3: Switchgrass yields a certain amount now, but in the future, with selective breeding, etc., it will yield much more.

Fact: Switchgrass is a perennial, and needs to be seeded only once every decade. Is it reasonable to think that Monsanto is going to spend much research effort on seeds that they will only sell to farmers once a decade? Certainly one can select varieties of switchgrass that are more prolific..., but it is difficult to see that there will be much yield improvement beyond that, certainly not on timescales of a decade or so. For a wide variety of annually varying weather conditions, soil quality, etc., it is hard to argue that switchgrass yields will exceed the 6-8 ton/acre range. We've been growing alfalfa for many years for biomass with a very high incentive to increase yields per acre, without much success. Switchgrass probably won't be much different.

Legend 4: Switchgrass is substantially cheaper as a feedstock than corn for producing ethanol.

Fact: This is the big one. [...] Switchgrass must be cut, allowed to dry, raked, and then bailed for transport. For large, round bales of switchgrass (the cheapest method), estimated costs are $74/ton for 4 tons/acre yield, and $66/ton for 6 tons/acre yield. Presumably, that can be extended to $58/ton for 8 tons/acre yield, and so on. Note that these costs will generally be higher for smaller fields, another black mark against the use of [non-agricultural] land for growing switchgrass.

On top of those costs, there will be transportation, which currently is about $0.25/ton per mile. How far will the switchgrass have to be transported? That's a bit more involved. A reasonable sized bioreactor facility would be 10,000 bbl/d, as 200 such facilities in the US would produce about 15% of the daily gasoline usage. Such a facility would use roughly 2 million tons of biomass feedstock per year, which is the output of 250,000 acres at 8 tons/acre. That is an area of roughly 400 square miles, or about 20 miles on a side. Given that rural roads don't run straight, that 20 miles is a fair figure for the average load to travel, leaving travel costs of $5/ton. So, we are talking something in the $60-70/ton range delivered to the bio-reactor. However, that is assuming 100% of the land around the bioreactor is switchgrass. If we instead only plant marginal land, the transportation distance would go up by a factor of 3 (due to the sparseness of the switchgrass fields) to $15/ton, leaving the total cost $70-80/ton. At 70 gallons of ethanol per ton of biomass, this suggests a minimum cost of $1/gallon ethanol simply to get the switchgrass to the facility. Yields less than 8 tons/acre will lead to proportionally higher costs.

How does that compare to corn? That's a bit more dicey, as corn is heavily subsidized. Wholesale corn currently costs about $1.90/bushel, while the Iowa 2006 Crop Production Cost is $3.40 per bushel (if the difference between those numbers seems incredible, remember that you, the US taxpayer, are picking up the tab). Corn is much more dense than switchgrass biomass in terms of energy per unit mass, so transportation costs are much less, certainly under $0.10/bushel. At retail, this suggests a cost of $0.80 per gallon to get the corn to the ethanol facility based upon wholesale, and $1.40/gallon based upon the Iowa Crop Production cost of $3.40/bushel.

Given that the switchgrass costs more to make into ethanol once at the bioreactor due to need for enzymes ($5-10/barrel or $0.20-$0.40/gallon plus extra energy used), there doesn't appear to be any advantage to switchgrass over corn for ethanol. [...]

As a final note, there is sensitivity to energy prices in this analysis. However, it appears to go the wrong way for switchgrass....This suggests that corn may become more competitive with switchgrass as time moves forward and energy costs rise, exactly the opposite interpretation most people would have anticipated. [...]

What's the moral in all of this? If corn ethanol is marginal on an energy returned on energy invested (EROEI) basis, it is very difficult to argue that biomass grown to make ethanol will be any better. To be blunt, if there are concentrated stocks of waste biomass in place, such as at lumber mills, then biomass ethanol probably makes sense. Otherwise, it appears to be more or less equivalent to corn based ethanol - in other words, a wash. [Emphasis added]

The analysis seems plausible, and it appears to make the case that if switchgrass is better than corn for making ethanol, it's not by much. Which means that ethanol from switchgrass won't be a net energy winner any more than corn is. Ouch.

One caveat: this analysis may be applicable in the near term only. Before long, currently unanticipated developments in bioengineering and nanotechnology may lead to entirely new ways of processing biomass, for example. The pace of technological change in bioengineering and nanotechnology (as in computer technology) is currently exponential, so we are likely to be fooled if we simply extrapolate the current pace of change linearly into the future — thinking, for example, that the next twenty years will lead to about as much change as the last twenty years. In fact, barring a catastrophic disruption in world systems, the amount of technological change over the next twenty years is likely to be orders of magnitude greater (possibly many orders of magnitude greater) than over the last twenty years.

That's the (potentially) good news. The bad news is that we are faced with a near term problem right now — assuming world oil production is already peaking, as it appears to be. Technology may provide answers in time, but there is likely to be significant turmoil and hardship in the interim.

Posted by Jonathan at March 8, 2006 11:14 PM  del.icio.us digg NewsVine Reddit YahooMyWeb


Ohhh Jonathan, did I just hear you say technology might save the day?

(stickly in fun :)

Posted by: Jeff at March 9, 2006 08:20 PM

I know you're kidding, Jeff, but let me say that this isn't a new position for me. See, for example: http://www.pastpeak.com/archives/2005/11/fuel_from_desig.htm

Let me quote from what I said in that post:

"Energy pessimists like James Kunstler think nothing will ever really replace oil, so we're headed into a 'long emergency'. Energy pollyannas think new technologies will automatically come online as rapidly as they are needed, making for a smooth and relatively painless transition. The pessimists make the mistake of assuming future technology won't be qualitatively different from current technology. The pollyannas make the mistake of failing to grasp the colossal scale and urgency of the transition that has to occur.

"My own view is somewhere in between: fossil fuel production is indeed peaking and we are in for a difficult, turbulent couple of decades as we transition out of our current way of doing things. But if we make it through the needle's eye (without, for example, blowing ourselves up in a world war over oil) genetic engineering and nanotechnology will almost certainly open up new sources of energy — or, rather, new ways of capturing the energy of the sun. The world isn't going to go dark. Genetic engineering and/or nanotechnology on the scale required to satisfy the world's energy appetite are likely to introduce dangerous new problems, but one way or the other we are likely to find ways to capture the sun's energy and make it available for human use. It's just not going to happen overnight, so there's rough sledding ahead in the near term, and success is far from guaranteed.

"Unfortunately, current US policy seems to combine the worst extremes of the positions of the pessimists and the pollyannas. On the pessimistic side, the administration appears to assume that the nations of the world teeter on the brink of a grim and deadly struggle for the oil that remains, so the solution is the military occupation of the world's oil-producing regions. Hence, Iraq. On the pollyanna side, the administration seems to assume that it has no responsibility to raise public awareness and foster the development of alternative energy sources and increased efficiency: the market will provide, all by itself. But the price signals that move the market will arrive too late. If we wait for a crisis, we will have waited too long.

"Better to take the middle path: cooperate with other nations in equitably distributing the fossil fuels that remain, while putting public resources to work in a crash program to develop solutions for tomorrow. Like grownups."

I couldn't have said it better myself. ;-)

Posted by: Jonathan at March 11, 2006 11:30 PM

Good forum, very intellegent contributions from all involved.

Pessimists and pollyannas eh, very amusing.

You mentioned in passing that market forces don't often respond as quickly as desired.

One of the problems in market based solutions is meddling from sources removed from market forces. Examples would be government or power-brokers like cartels.

I live in an oil-producing region. I worked briefly in the oil industry when we moved here. I found out that many proven high performance wells are currently capped off.

The low price of foreign oil was the reason they were closed. Obviously those days are gone. Unfortunately, not many new refineries were built during that period.

With the current sky high gas prices, we now have too few refineries to process any additional volume of crude. And thanks to EPA paperwork piled as high as Mt. McKinley to build a new refinery, opening wells wouldn't do a bit of good anyway! We need refineries!

So in the short-term, increased domestic production of fuel isn't going to help us.

More economic cars would help. A local fellow hereabouts came up with a great idea. He modified a deisel engine such that when a cylinder began to exceed operating temperature, a temperature sensor switched from diesel to water. When injected, the water turned instantly to steam and pushed the piston down just like the fuel would.

Before the cylinder cooled down to a temperature where this process couldn't be maintained, the temperature sensor switched the diesel back on.

The engine had no need for a radiator, burned 50% less fuel and worked seamlessly.

When he revealed his invention to the world he was litigated into bankrupcy then prosecuted into prison where he now lives.

If cars didn't have radiators there would be 67% fewer breakdowns! Bad bad bad for the auto industry who count on revenue from repairs when your car's value supports it, and from new car sales when it doesn't.

See how well GM is doing as a result of this ruthless marketing strategy? Warms your heart, doesn't it?

And 50% less fuel! How can we have a crisis if we use less fuel! You're just not with the program. Gotta have crisis. Without crisis how are we going to keep taxes high? If all the problems were actually solved by the government, who would we give those trillions of tax dollars to? We NEED crisis in order to keep government busy! Busy hands, you know.

I could go on, but you folks are good people and I'm poisoning you so I'll stop. No, I changed my mind. This could benefit you individually and our nation collectively.

I just wish you folks were in charge. Because you're good natured trusting folks. You actually assume everybody wants a solution and you pose very intellegent and viable solutions to difficult problems.

You never sought power. People in power are not good natured, but they know good natured people are very trusting. Trust can be very profitable. I wish trust were like gasoline, once burned, can't be burned again. Unfortunately trust is burned over and over and over again.

Did you know the dollar has lost 94% of its value since 1913? Where did the value go? The farmer got it. Not the guy with the tractor, the guys who planted the seed of legislation called the Federal Reserve Act. The same guys who watered it with money paid to corrupt politicians to vote for it. Those farmers!

You trustingly use dollars every day. They get smaller as you carry them in your wallet, as they sit in your 401k, as you earn them week after week after week.

Did you know EVERY single crisis we have was farmed? Including terrorism? Yup, true. Crisis are planted, watered, grown and farmed just like potatoes or corn. The yeild is higher taxes. Yup, filthy lucre.

Did you know the federal government is a corporation? Yup, true. Did you know the States are subsidiaries of that corporation? Yup, true. Their sole purpose is to earn profit. What's their product? Deception. Your trust is the fertile field in which seeds of speaches and campaign promises are planted. Then comes the betrayal and the harvest.

The equasion hasn't changed since the players were called carnies and rubes, but the game is the same. P.T. Barnum observed that a sucker is born every minute. That was the foundation of his enterprise, carnies and rubes.

I guess the moral of the story is; don't be a rube. But everybody stopped reading this spiteful monologue a long time ago anyway. Nobody likes to discover they've been duped.

Hitler's Germany was also a crop grown from seed. Go back into the history books and see how many industrialists and power merchants financed the Third Reich. Hitler had this bad habit of not keeping his promises. He bit the hand that fed him, and changed alot of friends into enemies. He just played his hand wrong, he had all the right cards.

Extremist Islam is another example. Slobodon Milosovic was a bulwark against radical Islam, but Clinton took him out! Was Milosovic an angel? NO! Harps don't clobber terrorists effectively! Saddam was another who kept radical shiit muslims at bay. Was he an angel? NO, but weakening him forced him into a compromise position relative to radical Islam. He had to curry their favor to stay in power.

So now we've farmed a big green monster to replace the big red monster we lost because of that bad ole' Ronald Reagan. Islam is such a nice crisis, complete with built-in photo ops to convince people that we need more taxes. Lots of blood and kids killed and stuff. Sells well.

So, if you're convinced the world pivots on money and power corrupting key players to change free men into chattle, what now?

Ask for a totally free copy of my ebook. I'll even dump your email address and you'll never hear from me again. I just want you to know what I've found out by studying the Bible. Yup, the Bible. God is real. I was surprised too. If you look at it deeply you discover some very disturbing things . . . disturbing for farmers that is, no, not the ones with tractors.

So, am I a Pollyanna? You bet I am.

Alfred Eugene, Pearl
alfredepearl at hotmail dot com

Posted by: Alfred Eugene, Pearl at March 17, 2006 07:23 PM

Ok, let's get this back on track a little...

The whole analysis above about "switchgrass" versus "corn", while interesting and usefl, seems to ignore some of the other costs involved in bringing these feedstocks to the refinery.

First and foremost, how sustainable is the tilling of topsoil requird for corn? what energy is required per year to plant switchgrass (presumably 1/10th the energy needed to sow corn?). Is that energy use included in your statement about energy output per galloon of ethanol.

Similarly, you need to factor the irrigation costs of switchgrass and corn production. stating that switchgrass needs water is not wholly useful without quantifying the water required for both and the cost models of present and projected increased future costs of irrigation.

Lastly, this analysis of inputs/outputs and ignoring the system impacts are what us got into the terrible hidden costs of the petroleum world that we live in. What environmental costs are you building into your corn versus switchgrass models. e.g. nitrogen and phosphorus surplus in rivers and lakes. Soil erosion. Detrimental effects of herbicides, fungicides, insecticides, and other biocides. Risks to environment of consolidation of diverse biomass into a few species (monocultures). Soil salination. Are these free for the farmer, and sustainable?


Posted by: jstevens at April 14, 2006 05:42 PM