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Large Field Trial Shows Miscanthus Could Meet US Biofuels Goals With Less Land
31 July 2008
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| In field trials in Illinois, researchers grew Miscanthus x giganteus and switchgrass in adjoining plots. Click to enlarge. Credit: University of Illinois |
Researchers at the University of Illinois have concluded that the perennial grass Miscanthus×giganteus could produce enough ethanol to offset 20% of current US gasoline use, while requiring 9.3% of current agricultural acreage. By contrast, using corn or switchgrass to produce the same amount would require 25% of current US cropland.
The findings come from side-by-side trials of Miscanthus and switchgrass established for the first time along a latitudinal gradient in Illinois. The results of the trials appear this month in the journal Global Change Biology.
Over 3 years of trials, Miscanthus×giganteus achieved average annual conversion efficiencies into harvestable biomass of 1.0% (30 t ha-1) and a maximum of 2.0% (61 t ha-1), with minimal agricultural inputs. The regionally adapted switchgrass variety Cave-in-Rock achieved somewhat lower yields, averaging 10 t ha-1. Given that there has been little attempt to improve the agronomy and genetics of these grasses compared with the major grain crops, these efficiencies are the minimum of what may be achieved. At this 1.0% efficiency, 12 million hectares, or 9.3% of current US cropland, would be sufficient to provide 133 × 109 L of ethanol, enough to offset one-fifth of the current US gasoline use. In contrast, maize grain from the same area of land would only provide 49 × 109 L, while requiring much higher nitrogen and fossil energy inputs in its cultivation.
In 2007, University of Illinois researchers presented the first direct comparisons of the biomass productivity of the two C4 perennial grasses switchgrass (Panicum virgatum) and Miscanthus. Results given at Plant Biology and Botany 2007 showed that Miscanthus is more than twice as productive as switchgrass. Its efficiency of conversion of sunlight into biomass is amongst the highest ever recorded. (Earlier post.)
(C4 refers to the type of photosynthesis used by the plant: in C4 photosynthesis, the CO2 is first incorporated into a four-carbon compound, as compared to the more common C3 photosynthesis and its three-carbon compound. Among their differences, C4 plants photosynthesize faster than C3 plants under high light intensity and high temperatures, and have better water use efficiency. Corn is also a C4 plant.)
The Miscanthus/switchgrass field trials study was led by U. of I. crop sciences professor Stephen P. Long. Long is the deputy director of the BP-sponsored Energy Biosciences Institute, a multi-year, multi-institutional initiative aimed at finding low-carbon or carbon-neutral alternatives to petroleum-based fuels. He also is the editor of Global Change Biology.
What we’ve found with Miscanthus is that the amount of biomass generated each year would allow us to produce about 2 1/2 times the amount of ethanol we can produce per acre of corn.
—Stephen Long
In trials across Illinois, switchgrass produced only about as much ethanol feedstock per acre as corn, Long said. The yields for switchgrass were equal to the best yields that had been obtained elsewhere with switchgrass, Long said. The Miscanthus proved to be at least twice as productive as switchgrass. Miscanthus is also tolerant of poor soil quality.
Miscanthus begins producing green leaves about six weeks earlier than corn in the growing season and stays green until late October in Illinois while corn leaves wither at the end of August. The growing season for switchgrass is comparable to that of Miscanthus, but it is not nearly as efficient at converting sunlight to biomass as Miscanthus, Frank Dohleman, a graduate student and co-author on the study, found.
One of the criticisms of using any biomass as a biofuel source is it has been claimed that plants are not very efficient—about 0.1 percent efficiency of conversion of sunlight into biomass. What we show here is on average Miscanthus is in fact about 1 percent efficient, so about 1 percent of sunlight ends up as biomass.
Keep in mind that when we consider our energy use, a few hours of solar energy falling on the earth are equal to all the energy that people use over a whole year, so you don’t really need that high an efficiency to be able to capture that in plant material and make use of it as a biofuel source.
—Stephen Long
Because Miscanthus is a perennial grass, it also accumulates much more carbon in the soil than an annual crop such as corn or soybeans.
Miscanthus is a sterile hybrid, and must be propagated by planting rhizomes. Mechanization allows the team to plant about 15 acres a day. In Europe, where Miscanthus has been grown for more than a decade, patented farm equipment can plant about 50 acres of Miscanthus rhizomes a day, Long said.
Once established, Miscanthus returns annually without need for replanting. If harvested in December or January, after nutrients have returned to the soil, it requires little fertilizer.
Keep in mind that this Miscanthus is completely unimproved, so if we were to do the sorts of things that we’ve managed to do with corn, where we’ve increased its yield threefold over the last 50 years, then it’s not unreal to think that we could use even less than 10 percent of the available agricultural land. And if you can actually grow it on non-cropland that would be even better.
Resources
Emily A. Heaton, Frank G. Dohleman, Stephen P. Long (2008) Meeting US biofuel goals with less land: the potential of Miscanthus. Global Change Biology doi: 10.1111/j.1365-2486.2008.01662.x
July 31, 2008 in Cellulosic ethanol | Permalink | Comments (42) | TrackBack (0)
Comments
Posted by: | August 02, 2008 at 09:48 AM
Wow, gaspower, so many leaps of logic in one post. So what do you think the heat rate will be for a the actual source of electricity, and the efficiency actual transmission lines, the actual batteries, and the motors that you use in your EV?
….wait for it…
Posted by: Kit P | August 02, 2008 at 11:12 AM
Combined cycle power plants do exist and GE sells them. Apparently utilities have surprisingly figured out how to connect them to the grid.
And as I said: This scenario will require plug-in hybrids to become popular.
GM and Toyota work on it. Does this mean that there might be a potential market or does this mean that they just waste R&D money for fun. Nobody knows.
Posted by: gaspower | August 02, 2008 at 12:06 PM
@gaspower
Yes, CCGT are used to make electricity. What makes you think they will supply PHEV?
Posted by: Kit P | August 02, 2008 at 05:25 PM
let the market determine what lands are used for miscanthus and wich ones for corn.. the market is very efficient at that.
Growing miscanthus is good for the land, it is a prairie grass right?.. and we leave the roots intact when we harvest it.
Posted by: Herm | August 02, 2008 at 05:39 PM
Kit_P,
Electricity goes where demand is.
If there's more demand, there is a need for more supply.
Here you can learn more about electricity:
http://en.wikipedia.org/wiki/Electricity
Posted by: gaspower | August 03, 2008 at 01:38 AM
@gaspower
It is where the electricity comes from stupid. Caveat wike.
Posted by: Kit P | August 03, 2008 at 01:57 PM
I would like to see most of the coal fired power plants in the east replaced with natural gas combined cycle power plants and the natural gas power plant expansion replaced with solar and wind in the west. Then we can make methane with biomass gasification and make that fuel more CO2 neutral.
Combined cycle natural gas plants would provide a good base load at night to charge PHEVs. During the day when building lights and AC are on, wind and solar can provide peak. There was a natural gas find recently in Louisiana that could power all the cars on the U.S. for 40 years. It could reduce imported oil, provided that we have enough dual fuel cars.
Posted by: sjc | August 03, 2008 at 04:51 PM
@sjc
Where was that, “There was a natural gas find recently in Louisiana” ? At the LNG terminal?
Sjc should become a rough neck so he can get his dreams to come true. I guarantee that the electricity generating industry can burn it faster than the gas industry can produce it.
Posted by: Kit P | August 03, 2008 at 09:30 PM
All,
Has anybody looked into the potential effects of planting huge quantities of a non native species throughout the US? Potential questions:
1) Does it hybridize with local grasses, if so, it would taint the current genetic pool.
2) Is it considered to be invasive? If Miscanthus G. spread beyond the farm, will it displace native species.
3) What are the effects on native wildlife? Will it displace current species that survive in grasslands, or will it bee a boon to wildlife?
These are just a few questions that need to be answered before we take a risk at effecting the local environments where Miscanthus will be planted.
Also, several people have mentioned that 50% of arable land planted with Miscanthus could supply our total transportation energy needs. I don't think a single source of fuel is the answer to our future engery needs. Indeed, there will need to be local solutions that may vary greatly across the nation and the world. Currently, we are used to single sources for our energy , such as ONLY using petroleum for transportation fuel. The 21st century energy economy will be much more diverse.
Peace,
Cosmo
Posted by: Cosmo | August 04, 2008 at 08:49 AM
Cosmo
A wise man among the children.
Posted by: | August 04, 2008 at 11:38 AM
Biofuels already failed to produce enough energy to start the Industrial Revolution in the UK two hundred years ago and has led to the deforestation of much of the world including the US. If ecology is what existed before humans came, Biofuels are the most anti-ecological activity on the face of the planet.
At one time the petroleum industry was researching feeding oil products to bacterial to make food. Natural gas was made into Pruteen in the UK. Animal feeds have been made in Norway from natural gas. The current high price of crude oil and gas is due mostly to the US government allowing the limiting of production while at the same time allowing speculation.
The US government has stopped the building of nuclear electric plants by imposing far more stringent safety requirements than on the coal electric industry, the auto industry, the farm industry, the chemical industry and the highway system among others.
The US government and its elected representatives have failed to effectively inform the public that all people and all life forms must always be radioactive to exist because every cell of the body needs potassium which is always and forever radioactive.
All life forms have also always been exposed to radio-activity from space and from the uranium and other radio-active materials in the earth. Every general fertilizer, organic or non organic is more radio-active than would be allowed to be disposed of by a nuclear power plant in an ordinary landfill. Many of them contain, now profitably, extractable amounts of uranium but for the almost non existant state of the US uranium industry. The "waste" from nuclear power plants contain many fewer radio-active atoms than those from conventional power plants. Even natural gas fired powerplants put more radio-activity into the air. The amount of radio-activity from nuclear and conventional power plants is less than that which is naturally in our bodies.
Also it has failed to get the nuclear fuel rod repository opened. The US government made the decision not to use the remaining 98% of the energy in used US fuel rods while France, England and Japan get much more. This misuse of uranium is excused by the fact that there is enough uranium in the ocean for hundreds of thousands of years of fission power and can be extracted at less than ten times the present price. This does not even consider the known uranium and thorium in the minerals of the earth. Nor does it consider the many thousands of tons of uranium in stockpiles left over from making concentrated uranium fuels that can also be used in operating and proposed reactors.
Chernobly killed less than 50 people in the first month after the accident ther may be fifty more people who have died from causes know to be related to the accident. Hiroshima combined with Nagasaki had fewer fatalities than Tokyo. There can never be a nuclear powerplant failure in the US as deadly as Chernobyl, and there have been far more deadly dam failures in the US as well as industrial accidents in the US and elesewhere. A ship exploded in Texas City that killed about 600 people and injured thosands. The same chemical is shipped as a liquid, in a slighly different form, daily on many highways and railroads and was used in the Oklahoma explosion. The failure of a shipment of used nuclear fuel rods could not kill anyone due to radioactivity. The gasoline in your automobile is more dangerous. ..HG..
Posted by: Henry Gibson | August 04, 2008 at 05:13 PM
@HG
“The US government has stopped the building of nuclear electric plants by imposing far more stringent safety requirements than ..”
Construction of nukes in the US stopped because we were built too many and coal cleaned up its act. Now that we need more baselaod power plants and the cost of coal is increasing, we are building nukes.
Furthermore, all large energy projects are regulated and include public comment periods.
“has led to the deforestation of much of the world including the US”
Actually, I think it was to clear land to grow food and to harvest lumber for construction. In any case it is not a reason to not properly mange land to grow biofuels.
Posted by: Kit | August 05, 2008 at 08:12 PM
Kit P
The natural gas find in Louisiana was found by an energy company in the North West part of the state. Look it up yourself, it will keep you busy so that you do not make stupid snide insulting comments about people here.
Posted by: sjc | August 06, 2008 at 10:44 PM
@sjc
Somehow a natural gas find that would increase a factor of six our available supply of natural gas does not seem too credible. I suspect sjc read something he did not understand but if I am wrong it should not be too hard post a link.
The US has huge reserves of natural gas. My comment was too subtle for idiots like sjc. So stupid, what is your plant to get out of the ground and get it too market? Why would your plan be better than making electricity with coal? How soon before we can shut down the LNG tankers, how soon before we do not need coal miners?
If sjc does not like snide remarks, he should stop making Pollyanna remarks.
Posted by: Kit P. | August 07, 2008 at 11:02 AM
Insulting people is indeed a very convincing argument against electricity production from miscanthus.
Anyway, go ahead spend all your private savings on nuclear power, but please, please stop asking for tax dollars.
http://www.npr.org/templates/story/story.php?storyId=15545418
http://www.npr.org/templates/story/story.php?storyId=89169837
After 60 years of massive public funding, it's time for nuclear to learn to walk on its own feet.
Posted by: gaspower | August 08, 2008 at 06:25 AM
“Insulting people is indeed a very convincing argument against electricity production from miscanthus.”
Of course, I made no such argument. Particularly since I think making electricity with biomass is a good idea. I did suggest that gaspower is using poor logic.
Now, wants to change the debate to nuclear power by repeating the same post over and over.
Posted by: Kit | August 08, 2008 at 03:56 PM
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