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Researchers Conclude Average Farm Cost of Switchgrass for Ethanol Is About $0.49/Gallon

A new study by the US Department of Agriculture (USDA) Agricultural Research Service and University of Nebraska-Lincoln has determined that the farm cost of producing switchgrass for cellulosic ethanol averages $65.86 per metric tonne (Mg) of biomass dry matter, with an annualized yield of 5.0 tonnes per hectare. The study will be published in this month’s BioEnergy Research.

The study contracted 10 farmers in Nebraska, North Dakota and South Dakota to commercially grow switchgrass for five years, starting in 2000 and 2001. Results showed a wide range of yields and costs across the five production years and ten sites, with an overall average cost of $65.86 Mg-1 of biomass dry matter, and annualized yield of 5.0 Mg ha-1.

The low-cost half of the producers were able to produce at an average cost of $51.95 Mg-1 over the 5-year period. When projected to a full 10-year rotation, their cost fell further to $46.26 Mg-1. The researchers concluded that substantial quantities of biomass feedstock could have been produced in this region at a cost of about $50 Mg-1 at the farm gate, which translates to about $0.13 per liter ($0.49 per gallon US) of ethanol. These results provide a more reliable benchmark for current commercial production costs as compared to other estimates, which range from $25 to $100 Mg-1, according to the researchers.

The same team of researchers published a paper in January in the Proceedings of the National Academy of Sciences that found that switchgrass produces 540% more renewable energy as a biomass energy crop for cellulosic ethanol than energy consumed in its production. Previous estimates, based on small scale research plots (<5m2 and estimated inputs) suggested switchgrass would yield a net energy production of about 343%. (Earlier post.)


  • Richard Perrin, Kenneth Vogel, Marty Schmer and Rob Mitchell, Farm-Scale Production Cost of Switchgrass for Biomass, Bioenerg. Res. DOI: 10.1007/s12155-008-9005-y


Jeff Baker

Biomass Logistics: Farm to Refinery

There are several other important costs to determine. The logistics of shipping and handling the biomass from the farm gate to the biorefinery. How big can the shipping radius be? The bigger the radius, the higher the cost. Would smaller plants with shorter shipping radii be more cost effective than shipping a longer distance to one large refinery? What type of fuel will be used? Will the trucks consume gasoline or diesel fuel, biodiesel or E-85, hydrous ethanol or bio-crude oil, or electric and solar? Could that fuel be produced locally? How far is it from the farm to the biorefinery? How far is it from the biorefinery to the nearest market for the finished fuel product? What is the most efficient method for storing and handling the biomass at the biorefinery? Can some of the biomass be used to produce combined heat and power (CHP) to power the plant? Could surplus electric power be produced as well? Could that surplus power be used to charge batteries to run electric trucks to ship the biomass? Would it be more efficient to use fast pyrolysis at the farm gate, and then ship and store liquid biocrude oil at the biorefinery, instead of shipping and handling bales of biomass?


You should rephrase that as
"The USDA concludes"


I heard that about a 20 mile radius from farm field to fuel plant is acceptable to keep transportation costs low enough. That is why I favor putting the fuel plants about every 10-20 miles in the Nebraska, Oklahoma, Kansas and other growing regions. You should be able to drive down roads in the Great Plains states of the U.S. where the biomass is grown and see a fuel plant every 10-20 miles. I would make SNG out of the biomass and pipe it, but that is the beauty of gasification, you can take several input and make several outputs. I have been telling everyone here about gasification for more than a year. I am glad to see that the message is catching on.


==the beauty of gasification, you can take several input and make several outputs.==

Yeah, but who's to say what those inputs are?


I do not understand the question and I do not think that you do either.


5 tonnes/ha is about 2.2 short tons per acre.  That's about the yield of excess corn stover on the average field, and there is no additional input required to grow it.

Faced with a choice between food and fuel, or food PLUS fuel, the latter is going to be increasingly attractive.

Healthy Breaze

@ E-Poet,
What about the concern that diverting the corn stover will deplete the soil's fertility?

@ G-Falcon, ,
Gasification requires pipelines. Pipelines cost.

$65/ton * 2.2 tons/acre = $143/acre. How many harvests per year?

Would that be of interest to a farmer who could grow corn instead?

What about the concern that diverting the corn stover will deplete the soil's fertility?
It's my understanding that stover above a certain amount has to be removed from the soil in spring anyway, otherwise the soil doesn't warm properly and allow new seeds to germinate on time.  If the excess stover (and cobs) was a paying product instead of just a problem, farmers would do even better.

The stover doesn't have to disappear.  I could see something like Carbon Diversion's scheme to make charcoal and gas, used in concert with Coskata's ethanol process to make ethanol from the gas.  This would yield:

  • All the non-volatiles as charcoal, suitable for addition to the soil.
  • A liquid fuel product, ready for sale.
I just tickled Carbon Diversion with this idea.


ok 5 Tonnes/hectares or dry matter ~ 1.5 Tonnes of ethanol/hectares ~ 350 gallons/hectares. The last bill of the congress targert 35 billions gallons of ethanol by 2020 right ? 100 millions hectare or 200 millions acres, hummm that is about 60% of arables land in US. Totaly irrealistic to dedicate 60% of arable land to switch grass.

I am not sure switch grass + cellulosic ethanol is going to fly. Wood forest + thermal conversion sounds a better solution


It seems that Elephant Grass can yield twice as much as switch grass, sounds a better horse, the problem with elephant grass is that there is no seeds only rizhome which makes it difficult to handle.


There are more than 500 million acres in production in the U.S. and all yield some kind of biomass, including the 90 million acres in corn. If you leave half the stalks and straw on the land it still yields more than 100 gallons per acre. That would be 50 billion gallons of fuel from agriculture and another 50 billion from forest product waste. That would be 2/3 of the fuel. Now if you use hybrids and eventually fuel cells you get twice the mileage, which gives you enough not to have to use oil for fuel for cars. Now you have to tackle trucks, planes and trains, but one step at a time. We still produce 1/3 of our oil needs domestically, so a REAL energy plan could give us a secure future. (I say real, because up until now it has been mostly tax breaks for oil companies that already make 10s of billions of dollars in profits annually....about 14 billion dollars worth of tax breaks so far.)


I still don't like the land crop for fuel solution as a large solution. What about our feedstores for those less fortunate? We supply the world right now, the poor in Africa to Asia and South America with feed grains.

How does this impact that area?


Treehugger:  Check your math.  1500 kg / 0.79 kg/liter / 3.7854 l/gal = ~500 gallons.

I've asked UIUC if Elephant Grass (Miscanthus Giganteus, to be more precise) has been tested in swales, stream borders and other areas where crops are not desirable.  It would be good if these areas could serve several purposes at once:  to retain soil, capture eroded soil and nutrients from elsewhere, and produce a useful product.  Unfortunately, it appears that nobody has researched these things yet.

One advantage of fuel grasses is that they are not bred to produce grains heavy in nitrogen and phosphorus.  The desired products are entirely carbon and hydrogen (with oxygen along for the ride), and those come from air and water alone.


Maybe we can do 100 billions gallon of ethanol including everything, but that is going to be a very tedious jobe to carry all this biomass from the field to the ethanol plant.


the question is: can the farmer make more money out of switchgrass or corn? The transportation costs have to be accounted for the bulky dry product.. but enventually fuel factories will spring up nearby if it is profitable.

The other thing to consider is that the genetic engineers have not had the same opportunity to meddle with switchgrass as they have with corn.


Am I correct in assuming that if you gassify biomass for SNG then you can recover the mineral nutrients for use in fertilizers?



I wonder the same thing and I also wonder how efficient biomass -> SNG is. E.g. for a given amount of biomass, how many MCF of SNG are produced by gasification and catalytic conversion.

If elephant grass were to be used, special machinery would have to be developed for harvest in order to avoid crushing the rhizome. While I'm not a fan of genetic engineering, it has done wonders for corn yields and I'm sure it can do the same for grass. I will add, however, that most genetic engineering in grass has been focused on developing dwarf grasses for golf courses and that these grasses are extremely frail.


You have more carbon than you can use with biomass. You could add H2 and make more fuel or return the carbon to the land. Since H2 costs to produce, just return it to the land. You are also only taking 1/2 of the biomass and leaving the rest for the land. Corn cobs right now produce little or no income for the farmer. These are great for gasified biofuels. Now the farmer gets more revenue from those as well.

The farmers might make $400 per acre at the present price of corn and another $100 for the biomass. That pays for a lot of fertilizer. I think farmers will make more on the food than the biomass and if you locate the gasifier plants within 20 miles of where it is grown, the transportation costs are low.

Now, if you can make SNG and just pipe it from the gasifier plant, then you eliminate the transportation of the biofuel by tanker truck. Once you bring available SNG at a stable price to the market, industries like chemicals and fertilizers may return to the U.S. They left after deregulation.



You are perfectly right and that is an important part of the all thing to recycle the ashes so that you don'ta have to rely on unsustainable external output of mineral.

GreenPlease, you are probably right that preserving the rizhome might be an issue, if you look at sugar cane now in Brazil, most of it is collected manually...that can be a limitation,

Gazeification is a nice solution since it is highly efficient, simple and therefore can be implemented at the farm level then avoiding to carry this biomass to the biofuel refinerie. But then you need to build an infrastructure of pipes and then the transportation of NG is relatively inefficient (it requires about 15% of its energy content to push it through the pipe over long distances, not to mention leaks that are unavoidable in practice).

In fact the ideal would be a conversion from biomass to a liquid fuel that can be higly efficient and simple enough to be implemented at the farm level. But I can't see what it could be...


As per the study, “using a conversion rate of 0.38 l kg−1”, or 380 liters per metric tonne, and “an annualized yield of 5.0 tonnes per hectare”, or 2.0 metric tonnes per acre, one gets 770 liters, or 203 gallons, per acre. Allowing for the lower energy in ethanol as compared to gasoline, the gallon of gas equivalent (GGE) yield is 136 gallons per acre.

Area of the US = 2.26 billion acres. In 2003, the annual US gasoline consumption was 127 billion gallons (433 gallons per capita). So, we would require 930 million acres (1,450,000 sq. miles) of arable or semi-arable land to grow enough switch grass to fuel the US transportation sector. This area represents over 60% of the contiguous US land area. Realistically, cellulosic ethanol can only play a minor role in fueling the economy.

However, solar energy requires a lot less area and low rainfall areas are preferred - deserts, are ideal. An acre of SW desert annually receives 7,600 MWh of solar energy. A 10% conversion efficiency with 50% ground cover (to allow for cleaning and servicing of the solar modules or mirrors) yields 380 MWh of electricity per acre which at 5 miles per kWh for an electric vehicle the size of a Prius would be equivalent to 1.9 million miles per acre. For an equivalent conventional vehicle at 50 miles per gallon of gasoline, 1.9 million miles of travel would require 38,000 gallons of gasoline. The land efficiency of solar is over 250 times that of cellulosic ethanol and probably 10,000 times that of corn-based ethanol. Yeah, solar requires storage and it is currently expensive but its land efficiency is so compelling even for the northern tier of states. Also, this storage can be used in conjunction with other non-dispatchable energy sources like wind power and the cost of solar has historically decreased at an 8% annual rate, whereas petroleum costs at the pumps has increased by a factor of 5 in the last ten years with no long term relief expected.


The coskata process transforms biomass to liquid fuels. It can be built in relatively small modules close to the farmer. It could probably even be made transportable, that way taking the transformer to the biomass instead of biomass to the transformer. that would increase the efficiency a lot, since many trucks of biomass can be transformed to one truck of fuel (ethanol).
As mentioned before, if (nuclear, solar, wind) hydrogen is added to the coskata (or other) process, the transformation of biomass-carbon to fuel-carbon can be increased dramatically.


If think you might get 100 gallons of mixed alcohols (mostly ethanol and methanol) out of a ton of biomass using the Syntec process mentioned on this site. I think that you can get 100 therms of SNG out of a ton of biomass and a therm is 100k btus, so the conversion is more efficient than alcohols.

The nice thing about this corn stalk/cob biomass is that the farmers are already planning a "one pass" harvest system. I have seen slide sets showing that with a super combine, they can put ears of corn in one bin and stalks in another in one pass. They leave the stubble and roots in the land. Once they process the corn, they have the cobs from that one pass harvest as well. Some machines can actually shuck the corn on the fly and put the grain in a bin and the cobs in another.



To put the reactor on a truck is quite an interesting idea that I also thought about, then you move the reactor instead of the biomass, I was just wondering if it is possible to fit a thermal reactor on a truck. The Kotsaka process is based on thermal decomposition --> syngas + bio reactor to produce ethanol. If it happens to be true that could quite an efficient approach then, because when you think of it : a one million tonnes ethanol plant would require one truck of 30 tonnes of biomass every 6mn night and day 365 days a years, hwo on heart is it possible to handle that ?


The above calculations for the area needed to grow energy crops like switchgrass have ignored net energy. Even the best estimates for corn ethanol are poor. Switch grass might be better, but even at 2:1 this would double the required crop area.

We need to get beyond liquid fuels for transportation and electrify the entire industry. We could start with railroads and mass transit which would have a substantial impact and then personal vehicles.



that might be the problem that could make the all biofuel stuff just a scam if they can't get beyond an EROI of 2, then the whole thing is just hopeless. They need at least 3 at a very minimum and 5 to be solution for the long term

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