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Researchers Caution on Potential of Energy Crops as Invasive Species

Miscanthus
A research plot of Miscanthus.

A University of Arkansas researcher and his colleagues are calling for caution in developing dedicated energy crops, citing the possibility of some of those biofuel crops becoming invasive species.

Robert N. Wiedenmann, professor of entomology, and his colleagues S. Raghu, Roger C. Anderson, Curt C. Daehler, Adam S. Davis, Dan Simberloff and Richard N. Mack put forth their argument for ecological studies of biofuel crops in the policy forum in the 22 September issue of Science.

Most of the traits that are touted as great for biofuel crops—no known pests or diseases, rapid growth, high water-use efficiency—are red flags for invasion biologists. We want to start a dialog and approach the question of biofuels systematically.

—Robert N. Wiedenmann

The authors of the article in Science call for an examination of potential invasiveness as crops are examined for their biofuel potential and before putting such crops into large-scale production.

Seemingly benign crops that have become invasive species have already occurred in the United States. Wiedenmann and his colleagues cite the case of Sorghum halepense, otherwise known as Johnson grass. Johnson grass was introduced as a forage grass and now has become an invasive weed in many states, causing up to $30 million annually in losses for cotton and soybean crops in just three states.

One proposed biofuel crop, Miscanthus, can grow up to eight feet in six weeks. Wiedenmann describes it as “Johnson grass on steroids.”

Plants like these, particularly grasses, have great potential from an energy standpoint, but the benefits need to be balanced with the costs.

—Prof. Wiedenmann

Although invasive species are traditionally thought of as introduced species, a native species also can become invasive through alterations to the environment, Wiedenmann said. One example: the removal of oak and chestnut trees along much of the east coast has led to sugar maples becoming invasive in some areas.

Invasive species alter ecosystems in ways that can cause both ecological and economic harm. Since 1999, the U.S. government has had an invasive species council, which develops invasive species management plans.

Researchers investigating the potential for biofuels tend to be engineering or agricultural specialists who are looking at maximizing energetic conversion or crop size. Wiedenmann and his colleagues want to see ecologists at the table with engineering and agricultural researchers addressing the potential for invasiveness.

Resources:

  • Adding Biofuels to the Invasive Species Fire?”; S. Raghu, R. C. Anderson, C. C. Daehler, A. S. Davis, R. N. Wiedenmann, D. Simberloff, R. N. Mack; Science 22 September 2006: Vol. 313. no. 5794, p. 1742 DOI: 10.1126/science.1129313

Comments

Andrey

Rafael:
Radioactivity and half-life of particular isotope are rigidly connected, just because of definition of half-life. Longer half-life - lower radioactivity, shorter half-life – higher radioactivity. And no way around.

Engineer-Poet

RJ needs to use real figures; the EIA says that 2005 generation was 4038 billion kWh.

Van

Renewable biofuels certainly provides something to burn. But power from nuclear energy also provides a path to energy independence. However, unless Yucca mountain is opened and the existing spend fuel is transferred there, I believe no one will build more nuclear plants in the USA.

Yes, with today's technology, lauch of significant quantities of nuclear waste would be an unaccectable risk. However long term underground storage in a monitored and retrievable configuration is not. And who knows, perhaps in 2 or 3 hundred years, we will have the technology to safely launch significant quanties of nuclear waste.

Currently we have about 100 plants, providing close to 20% of our electricity. Thus, an additional 300 plants could replace our coal burners, and significantly reduce our emmision of air polution, regardless of whether or not the coal plants significantly contribute to the increase in global CO2 levels.

And then our PHEVs would shift our consumption from foreign oil to domestic energy sources. It would be a lot easier to replace 40% of our current petroleum consumption with biofuels, and in effect replace the other 60% with nuclear power, than to try to replace the whole thing.

Rafael Seidl

Andrey -

reporcessed waste contains higher concentrations of plutonium than the primary waste does. So per kg of *waste* that needs to be stored underground, the intensity of the radiation is higher. In addition, a higher concentration of plutonium means the radiation levels stay high for much longer.

Your logic applies to equal quantities of pure radioactive substances, but waste always contains significant amounts of inert material as well.

Freedom_First

Rafael -- Reprocessing removes 97% high-level waste including plutonium which makes this waste a lot easier to store because there is much less of it. Reprocessing does not create higher levels of radioactivity isotopes as you stated.

Freedom_First

Sorry about my double posts. Maybe it is my old version of the Opera browser.

Freedom_First

"the EIA says that 2005 generation was 4038 billion kWh."

This is the number, 4 x 10^12 Wh , that I used to deduce the 28% increase in electrical energy which would be required to fuel the electric fleet under discussion.

Of course, this increased demand does not necessarily require a similar increase is power generating capacity because cars can be charged off-peak. Just run the existing plants at full throttle 24/7. This illustrates one of the great advantages of switching to electric fuel. The infra-structure is all in place.

Engineer-Poet

You can't run the existing plants at full throttle 24/7 because, aside from the base-load plants, they usually are neither designed to do so nor do they have enough energy supply.  I expect that we would have to divert perhaps 1/3 of the saved petroleum to combined-cycle turbines to make up the difference.

rj

The numbers I grabbbed are in mega watts NOT mega watt hrs, the numbers I used are "real" but not the same units as the numbers you grabbed... we even grabed them from the same source.

That is what is causing the confusion and what I missed earlier.

Take the 4038 billiion Kwh and divide by the number of hrs per yr.


(4038 x 10^3) x 10^9 = 4.038 x 10^15 watt hrs/ yr

1 yr = 8765 hrs

SO watt hrs / number of hrs per yr gies us ave demand in watts.

from the same table the number for 2004 was 3.97 x 10^15 watt hrs

3.97 x 10 ^15 / 8765

compair this with the capacity numbers on the link from earlier ... nameplate capacity of us generators (in 2004) (that is the latest data they have out ...why they can list how much we generated in 05 before they can list capacity we had in 05 is beyond me but hey its the government)

1,049,615 mega watts (2004) (1.049 x 10 ^12 watts)

3.97 x 10^15 / 8765 = 452 x 10^9 watts
That is the ave power that was being generated at any given instant in 04 note that it is a fraction of generating capacity.

But poet says we can't run at 100% all the time anyway and just because we can generate that much power that does not mean that we can move it to where it is needed.

Boy we got off on a tangent.

Lets try not to suggest "the answer to everything is _______" solutions without checking (and double checking) some numbers.

I think we should all just ride horses. They run directly off of renewable biofule.
(thats a joke guys)

Freedom_First

"You can't run the existing plants at full throttle 24/7 because, aside from the base-load plants, they usually are neither designed to do so nor do they have enough energy supply."

Poet, you are being gratuitus and irrelevant. Obviously, no physical mechanism can run 24/7 without breaking down.
My argument was stated clearly. An increase in electrical demand does not necessarily require an equal increase in generating capacity if that demand is off peak. Many power plants routinely throttle down at night, not because they run out of fuel but beacuse of decreased demand. Existing power plants could charge many EV's during low-demand hours. And, of course, they would need to use more fuel to generate more power. sheesh.

Freedom_First

rj -- your original statement

"(200x10^6)*15000 mi per yr * 370 Wh/ mi = watt hrs / yr= 1.11 penta watt hrs (1.11 * 10^15) +/- as I didn't check if that is the power that needs to be generated, more likely that is the power required from your wall outlet before transmission losses." ... "So not only do we have an order of magnitude difference between capacity and would be use...."

was not clear to me because it seems to be mixing energy with power. The 28% increase in electrical energy required to run your electic fleet is not an order of magnitude difference. It is a modest difference. Order of magnitude usually means an intergral power of ten.

Likewise, the number for power generation, 452 x 10^9 watts is about 45% of the total capacity for power generation which is ~ 10^12 watts. Nothing strange there. No order of magnitude difference.

Cheryl Ho

There are developments in DME in China:
DME is an LPG-like synthetic fuel can be produced through gasification of Biomass. The synthetic gas is then catalyzed to produce DME. A gas under normal pressure and temperature, DME can be compressed into a liquid and used as an alternative to diesel. Its low emissions make it relatively environmentally friendly. In fact, Shandong University completed Pilot plant in Jinan and will be sharing their experience at upcoming North Asia DME / Methanol conference in Beijing, 27-28 June 2007, St Regis Hotel. The conference covers key areas which include:


DME productivity can be much higher especially if
country energy policies makes an effort comparable to
that invested in increasing supply.
By:
National Development Reform Commission NDRC
Ministry of Energy for Mongolia

Production of DME/ Methanol through biomass
gasification could potentially be commercialized
By:
Shandong University completed Pilot plant in Jinan and
will be sharing their experience.

Advances in conversion technologies are readily
available and offer exciting potential of DME as a
chemical feedstock
By: Kogas, Lurgi and Haldor Topsoe

Available project finance supports the investments
that DME/ Methanol can play a large energy supply role
By: International Finance Corporation

For more information: www.iceorganiser.com

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