NASA scientist thinks salt-tolerant crops have large biofuel potential
Dennis Bushnell, chief scientist at NASA's Langley Research Center, where scientists test emerging technologies, is confident that within five years commercial aircraft could be powered using a type of biofuel derived from saltwater plants, or halophytes, grown in desert areas and irrigated using sea water. While the concept may sound far-fetched, engine manufacturer General Electric says it is following developments in this area "with interest". The chief scientist claims that an area smaller than the Sahara desert could yield enough biomass to replace the world's total fossil fuel requirements.
Bushnell says 22 countries are carrying out small experimental activities into the cultivation of halophytes for use in food production, although he admits "nobody is doing this type of biomass for aircraft" at this time. Nevertheless, Bushnell sees "no stoppers" to augmenting halophyte-derived biomass to produce biofuels capable of powering aircraft.
"This is far from evolutionary, it's just outside people's radar screens and the usual human reaction to this is to say that it's impossible," says Bushnell. "What's nice about biofuel is that it can use the existing infrastructure used by the oil companies and can be available much sooner than hydrogen, which would require changes to infrastructure and is, therefore, much further into the future."
Plant-based fuels such as biodiesel, ethanol or biogas can be produced from biomass ranging from cow manure and grass to wood chips and root crops. The advantage of developing biofuel from halophytes as opposed to other types of biomass is that saltwater plants are not dependent on fresh water, which is in increasingly short supply, and can instead be irrigated using plentiful sea water supplies. Bushnell notes that, following irrigation, the salt from the sea water "should leach back into the ocean" without causing problems to agriculture. Other scientists have found there to be a definite potential for 'saline agriculture' in the developing world.
Suitable areas around the world for cultivating halophytes include the Sahara desert and the Sahel, Western Australia, south-west USA, parts of the Middle East and parts of Peru. Scientists claim that an area smaller than the Sahara desert could yield enough biomass to replace the world's fossil fuel requirements.
Wetter deserts
Furthering the case for halophyte production, Bushnell says that, as these plants are grown in the desert, they will produce a cooler, wetter land surface, which could lead to rainfall in areas of the world where rainwater is in short supply:
biomass :: bioenergy :: biofuels :: energy :: sustainability :: salt-tolerant crops :: halophytes :: aviation biofuels :: Sahel ::
GE Aviation manager of advanced combustor engineering Timothy Held believes some progress can be made within five years on testing biofuels derived from halophytes for use in commercial aircraft engines, but he says that the entire process of developing and producing the fuel will take longer. "It seems plausible that some amount of suitable fuel could be made available for testing purposes in the five-year timeframe," he says.
"However, the steps of establishing suitability for use in flight gas turbines, obtaining approval from the engine manufacturers, incorporation of the new fuel into a specification and developing large-scale production capacity are quite time-consuming," Held says. While biodiesel has been used by GE to operate marine gas turbines, it is not suitable for aircraft engines because of its poor low-temperature properties, but he believes a fuel derived from bio-oil by conversion to a paraffin-based product has a significant chance of becoming a viable aviation fuel.
NASA's Bushnell believes the argument in favour of biofuels for aviation is being reinvigorated by "the incipient demise of cheap oil" and increasing evidence of global warming due to the burning of fossil fuels. "This is the only easy solution I know of, both in terms of economics and timescale, and we do not need major capital investments to do this. It is definitely worth a serious look," he says.
Bushnell brainstorms
We found an interesting (and very enthusiastic) stream of thoughts of the chief scientist on salt-tolerant crops and their biofuels potential. In the process of researching future technology/future warfare for the Military and Intelligence Communities, he ran across the following:
:: "The 'Bio Revolution' is developing plant life which is not only tolerant of brackish water but even thrives on seawater. I [Bushnell] understand that seawater-irrigated tomatoes are quite tasty."
:: "The Department of Energy (DOE) has the enzymes to convert such bio mass into petro-chemical feed stock, enabling biomass energy, including hydrogen, production on a MASSIVE SCALE. And this is in previously underdeveloped areas, in essentially a CLOSED [overall] CO2 cycle, using non-fresh water."
:: "Such an approach changes, on a global scale, nearly everything, including much of energy-related economics. [What would happen] should we no longer need to use fossil fuels for energy or conventional agriculture? And, such biomass also could be used for food and plastics, etc.. The resultant evaporation of seawater on these land masses could also produce terraforming, putting rainfall back into the Middle East, and reversing the desertification of the sub-Sahara and similar areas."
:: "Such an approach, enabled by the "Bio Revolution", could enable MASSIVE changes in agriculture, land use, and global economics and potentially aleviate the fresh water, global warming, land and food shortage problems while providing a CLEAN (closed CO2 cycle) energy source (with MANY ways to distribute the energy,including H20."
:: "In addition, the resultant mineral layer after evaporation is rich in MANY useful materials. Its use could obviate several currently polluting "mining" activities. Also,the Scientific American article argues that the soils in these areas are such that much of the salt would leach back into the ocean."
:: "The Indians (on the Indian sub-continent) utilize, and have utilized, existing plant stocks/species which were naturally adapted to brackish/salt water." Bushnell notes that he has several such growing in his backyard, on the York River in Virginia, a tidal estuary. The National Academy report mentioned above documents all this: some food utilization, much animal feed, etc. The key, evidently, would be to increase yet more the salt tolerance/processing bits and, for energy biomass, to increase the growth rate.
:: The Scientific American article notes that "Yields of salt-tolerant crops grown using seawater agriculture are comparable to freshwater-grown alfalfa". And this is BEFORE anybody might muck about with the genomics, etc.
:: MSNBC ran an article on 7/31/01 entitled "GM Tomato is the first to grow in salty water and soil" - indicating a beginning of the genomic "Salt-Transformation", albeit on a "back-burner" basis.
:: People are seriously looking into CO2/Carbon sequestration, and all sorts of expensive projects/approaches just for attacking global warming. According to Bushnell, the seawater cost approach "mitigates most of the major current human/species/planet ills" and it has tremendous potential geo-political impacts. "Simplistically, the oilmen become "farmers", but still stay in the Chemical Engineering business. The winners are the Australians, the North Africans, the Navaho and Hopi Indians in the American southwest, the Saudis and other desert-near-ocean owning groups, although pumping seawater inland is not that much of an issue."
:: Could this approach mitigate global warming (plants take up the CO2), provide a new source of Energy (just the Sahara may be enough to produce current energy requirements), and provide unlimited sources of fresh water?
:: Although there are alternatives for the energy and global warming isuees, says Bushnell, including "the wastly less expensive than current silicon Nano-PhotoVoltaics and H-B11 aneutronic fusion. An additional "gleam-in-the-eye" is Tapping Zero Point Energy, which some are seriously working on, has largely passed the giggle-factor stage. However,the seawater agriculture is doable NOW, is INEXPENSIVE, and has a large number of anciliary benefits. Conventional wisdom has it that Biomass is limited by conventional/arable land and fresh water limitations/scarcity. Seawater Agriculture removes these limitations. This is, of course, SOLAR!"
More information:
Edward Glenn, Jed Brown, and James O'Leary, "Irrigating Crops with Seawater",[*.pdf], Scientific American, August 1998.
"Saline Agriculture: Salt-Tolerant Plants for Developing Countries", U.S. National Academies of Science Press, 1990.
Stanford Solar Center: Ideas on the Use of Seawater Irrigation/Agriculture for Energy, Global Warming, Land, Fresh Water, Food & Minerals.
Flight Global: Making the desert bloom - with fuel-yielding plants, Jan. 16, 2007.
Article continues
Bushnell says 22 countries are carrying out small experimental activities into the cultivation of halophytes for use in food production, although he admits "nobody is doing this type of biomass for aircraft" at this time. Nevertheless, Bushnell sees "no stoppers" to augmenting halophyte-derived biomass to produce biofuels capable of powering aircraft.
"This is far from evolutionary, it's just outside people's radar screens and the usual human reaction to this is to say that it's impossible," says Bushnell. "What's nice about biofuel is that it can use the existing infrastructure used by the oil companies and can be available much sooner than hydrogen, which would require changes to infrastructure and is, therefore, much further into the future."
Plant-based fuels such as biodiesel, ethanol or biogas can be produced from biomass ranging from cow manure and grass to wood chips and root crops. The advantage of developing biofuel from halophytes as opposed to other types of biomass is that saltwater plants are not dependent on fresh water, which is in increasingly short supply, and can instead be irrigated using plentiful sea water supplies. Bushnell notes that, following irrigation, the salt from the sea water "should leach back into the ocean" without causing problems to agriculture. Other scientists have found there to be a definite potential for 'saline agriculture' in the developing world.
Suitable areas around the world for cultivating halophytes include the Sahara desert and the Sahel, Western Australia, south-west USA, parts of the Middle East and parts of Peru. Scientists claim that an area smaller than the Sahara desert could yield enough biomass to replace the world's fossil fuel requirements.
Wetter deserts
Furthering the case for halophyte production, Bushnell says that, as these plants are grown in the desert, they will produce a cooler, wetter land surface, which could lead to rainfall in areas of the world where rainwater is in short supply:
biomass :: bioenergy :: biofuels :: energy :: sustainability :: salt-tolerant crops :: halophytes :: aviation biofuels :: Sahel ::
GE Aviation manager of advanced combustor engineering Timothy Held believes some progress can be made within five years on testing biofuels derived from halophytes for use in commercial aircraft engines, but he says that the entire process of developing and producing the fuel will take longer. "It seems plausible that some amount of suitable fuel could be made available for testing purposes in the five-year timeframe," he says.
"However, the steps of establishing suitability for use in flight gas turbines, obtaining approval from the engine manufacturers, incorporation of the new fuel into a specification and developing large-scale production capacity are quite time-consuming," Held says. While biodiesel has been used by GE to operate marine gas turbines, it is not suitable for aircraft engines because of its poor low-temperature properties, but he believes a fuel derived from bio-oil by conversion to a paraffin-based product has a significant chance of becoming a viable aviation fuel.
NASA's Bushnell believes the argument in favour of biofuels for aviation is being reinvigorated by "the incipient demise of cheap oil" and increasing evidence of global warming due to the burning of fossil fuels. "This is the only easy solution I know of, both in terms of economics and timescale, and we do not need major capital investments to do this. It is definitely worth a serious look," he says.
Bushnell brainstorms
We found an interesting (and very enthusiastic) stream of thoughts of the chief scientist on salt-tolerant crops and their biofuels potential. In the process of researching future technology/future warfare for the Military and Intelligence Communities, he ran across the following:
:: "The 'Bio Revolution' is developing plant life which is not only tolerant of brackish water but even thrives on seawater. I [Bushnell] understand that seawater-irrigated tomatoes are quite tasty."
:: "The Department of Energy (DOE) has the enzymes to convert such bio mass into petro-chemical feed stock, enabling biomass energy, including hydrogen, production on a MASSIVE SCALE. And this is in previously underdeveloped areas, in essentially a CLOSED [overall] CO2 cycle, using non-fresh water."
:: "Such an approach changes, on a global scale, nearly everything, including much of energy-related economics. [What would happen] should we no longer need to use fossil fuels for energy or conventional agriculture? And, such biomass also could be used for food and plastics, etc.. The resultant evaporation of seawater on these land masses could also produce terraforming, putting rainfall back into the Middle East, and reversing the desertification of the sub-Sahara and similar areas."
:: "Such an approach, enabled by the "Bio Revolution", could enable MASSIVE changes in agriculture, land use, and global economics and potentially aleviate the fresh water, global warming, land and food shortage problems while providing a CLEAN (closed CO2 cycle) energy source (with MANY ways to distribute the energy,including H20."
:: "In addition, the resultant mineral layer after evaporation is rich in MANY useful materials. Its use could obviate several currently polluting "mining" activities. Also,the Scientific American article argues that the soils in these areas are such that much of the salt would leach back into the ocean."
:: "The Indians (on the Indian sub-continent) utilize, and have utilized, existing plant stocks/species which were naturally adapted to brackish/salt water." Bushnell notes that he has several such growing in his backyard, on the York River in Virginia, a tidal estuary. The National Academy report mentioned above documents all this: some food utilization, much animal feed, etc. The key, evidently, would be to increase yet more the salt tolerance/processing bits and, for energy biomass, to increase the growth rate.
:: The Scientific American article notes that "Yields of salt-tolerant crops grown using seawater agriculture are comparable to freshwater-grown alfalfa". And this is BEFORE anybody might muck about with the genomics, etc.
:: MSNBC ran an article on 7/31/01 entitled "GM Tomato is the first to grow in salty water and soil" - indicating a beginning of the genomic "Salt-Transformation", albeit on a "back-burner" basis.
:: People are seriously looking into CO2/Carbon sequestration, and all sorts of expensive projects/approaches just for attacking global warming. According to Bushnell, the seawater cost approach "mitigates most of the major current human/species/planet ills" and it has tremendous potential geo-political impacts. "Simplistically, the oilmen become "farmers", but still stay in the Chemical Engineering business. The winners are the Australians, the North Africans, the Navaho and Hopi Indians in the American southwest, the Saudis and other desert-near-ocean owning groups, although pumping seawater inland is not that much of an issue."
:: Could this approach mitigate global warming (plants take up the CO2), provide a new source of Energy (just the Sahara may be enough to produce current energy requirements), and provide unlimited sources of fresh water?
:: Although there are alternatives for the energy and global warming isuees, says Bushnell, including "the wastly less expensive than current silicon Nano-PhotoVoltaics and H-B11 aneutronic fusion. An additional "gleam-in-the-eye" is Tapping Zero Point Energy, which some are seriously working on, has largely passed the giggle-factor stage. However,the seawater agriculture is doable NOW, is INEXPENSIVE, and has a large number of anciliary benefits. Conventional wisdom has it that Biomass is limited by conventional/arable land and fresh water limitations/scarcity. Seawater Agriculture removes these limitations. This is, of course, SOLAR!"
More information:
Edward Glenn, Jed Brown, and James O'Leary, "Irrigating Crops with Seawater",[*.pdf], Scientific American, August 1998.
"Saline Agriculture: Salt-Tolerant Plants for Developing Countries", U.S. National Academies of Science Press, 1990.
Stanford Solar Center: Ideas on the Use of Seawater Irrigation/Agriculture for Energy, Global Warming, Land, Fresh Water, Food & Minerals.
Flight Global: Making the desert bloom - with fuel-yielding plants, Jan. 16, 2007.
Article continues
Tuesday, January 16, 2007
C4 plants do respond to atmospheric CO2 enrichment
But Tang et al. carried out an experiment - conducted under conditions of low soil phosphorus (P) content - and grew a group of three C4 grasses and three C3 grasses. They found the C4 species to respond better than their counterparts.
'C3' and 'C4' refer to different strategies with which plants fix carbon (binding the gaseous molecules to dissolved compounds inside the plant) for sugar production through photosynthesis. Evolutionary speaking, the C3 photosynthetic pathway is the oldest and covers approximately 95% of the world's plant biomass. Most grass species in temperate climates belong to this group.
The C4 strategy is younger and more efficient, resulting in higher biomass productivity (see image, click to enlarge). Many promising (tropical) energy crops follow this pathway. They include sugarcane, sorghum, and switchgrass (Panicum virgatum).
The three researchers from China's Zhejiang University grew the three C3 grasses (Poa annua L., Lolium perenne L., Avena fatua L.) and the three C4 grasses (Echinochloa crusgalli var. mitis (L.) Beauv., Eleusine indica (L.), Setaria glauca (L.) P. Beauv.) from seed to maturity under well watered conditions within controlled-environment chambers (maintained at a mean atmospheric CO2 concentration of either 350 or 700 ppm) in pots containing 2.5 kg of soil that was low in extractable P content. Under these conditions, total aboveground plus belowground plant biomass was enhanced by an average of 9.92% due to the doubling of the air's CO2 concentration in the group of C3 grasses, but by an average of 12.27% by the doubling of the air's CO2 concentration in the group of C4 grasses.
So how did it happen that the CO2-induced growth response of the C4 grasses was nearly 25% greater than that of the C3 grasses:
biomass :: bioenergy :: biofuels :: energy :: sustainability :: climate change :: CO2 :: plant biology :: photosynthesis :: energy crops :: sugarcane :: sorghum :: switchgrass ::
Tang et al. report that the C3 grasses they studied had low mycorrhizal colonization and that atmospheric CO2 enrichment did not significantly enhance this beneficial symbiosis, whereas injecting extra CO2 into the air did enhance mycorrhizal colonization in the C4 grasses. (Mycorrhizae are the result of the colonisation of the roots of the plants by a fungus, in a mutually beneficial relationship (either inside or outside of the root cells); the fungus survives by tapping energy (sugars) from the roots, but in exchange it allows the plant to make use of the fungus' tremendous surface area to absorb mineral nutrients from the soil.)
In addition, they say they observed "a positive correlation between mycorrhizal colonization rate and shoot P concentration, and between the increase in mycorrhizal colonization rate and the increase in total P uptake under elevated CO2," which findings they interpreted as suggesting that "mycorrhizae might enlarge P uptake for plants that have high mycorrhizal colonization and then promote host-plant growth response to elevated CO2." Or as they describe the situation in another place in their paper, "the C4 grasses ... used in our experiment were also significant mycorrhizal hosts and their mycorrhizal colonization was significantly stimulated by elevated CO2," which suggested to them that this situation may "promote the total P uptake of the C4 grass in low P soil and enhance the C4 grasses' response to CO2 enrichment."
As an added "bonus," so to speak, Tang et al. had also included three C3 forbs (Veronica didyma Ten., Plantago virginica L., Gnaphalium affine D.Don.) in their study, as well as three legumes (Vicia cracca L., Medicago lupulina L., Kummerowia striata (Thunb.) Schindl.), both of which plant groups responded better to the researchers' enriching of the air about them with CO2 than did the two groups of grasses. The C3 forbs, for example, exhibited a mean biomass increase of 35.61%, while the legumes exhibited a mean biomass increase of 41.48%. Of these latter champion responders, the researchers wrote that they too "had high levels of mycorrhizae, and their mycorrhizal symbionts were stimulated greatly by CO2." And they again noted that the "higher enhanced total P uptake of legumes under elevated CO2 concentrations implies that mycorrhizae may facilitate P uptake and enhance legume response to elevated CO2."
More information:
Tang, J., Chen, J. and Chen, X. Response of 12 weedy species to elevated CO2 in low-phosphorus-availability soil. Ecological Research 21: 664-670.
Article continues
posted by Biopact team at 4:16 PM 0 comments links to this post