Graphic - wild prairie grasses have roots very deep and provided 3 to 4 meters. (Source: United-States Department of Agriculture, the depth in meters was added by the author of this blog)
With petroleum fuels, it takes carbon that was underground, it burns constantly and thus increased the CO2 content of the atmosphere. The idea behind biofuels is to avoid emitting CO2 from carbon sequestered in geological formations ("géocarbone") and use instead of "bio-carbon" found in plants. It then enters what is called the carbon cycle, where the carbon we send into the atmosphere by burning biofuels is reabsorbed by the plants grown for producing biofuels. It it adds not constantly in the atmosphere, since it does not use fossil fuels to produce biofuels. In this case we say that biofuels are carbon neutral.
This ideal situation is not achieved in practice and gives a positive assessment of CO2 emissions, with greater or lesser reduction in emissions compared to fossil fuels. This reduction is only 20% for ethanol produced from corn kernels, and some say it is zero if we take into account greenhouse gas emissions it took to produce the machinery issue . Add to this the problems of soil degradation and pollution of water due to fertilizers and pesticides, and it is understandable why many environmentalists do not like biofuels.
However, the second-generation biofuels have the potential to reduce emissions of greenhouse gas emissions by 80% to 90%, using the entire plant instead of only grains and fruit, as is currently the case. But the problems of degradation and soil erosion by intensive monocultures must also be taken into account.
Nature would have it, the Researchers have been studying for decades the advantage of crop wild prairie grass, such as switchgrass (switchgrass in English). First, these herbs are perennials, they need not be replanted every year like corn or soybeans. In addition, these herbs have well-developed root systems and deep (picture at the beginning of the ticket). With these two features, wild prairie grasses protect soil from erosion, rather than amplifying it as do the intensive monocultures of annual crops in rows .
Furthermore, wild grassland herbs need not be watered because their roots are very efficient to retrieve soil moisture up to 3 or 4 feet deep . By comparison, corn requires coolants often several hundreds of liters of water per liter of ethanol produced. There
or growing grass prairie wildlife becomes particularly interesting when it is grown in a mixture, including plants that fix nitrogen . This was experienced researchers at the University of Minnesota for 10 years on degraded land. They grew 152 different parcels of land containing different mixtures of up to 16 different herbs in the same plot. The stunning results of their study were published in 2006 (Tilman, Hill and Lehman, Science, Vol. 314, 8 December 2006, page 1598-1600).
First, quantities of fertilizers and pesticides required are much reduced compared to corn and soybeans, as shown in the chart below , from their publication (color added by the author this blog).
The word "Biomass" in this graph represents the mixture at high diversity (16 different herbs).
Now the surprise is that second generation biofuels from such crops with high diversity have strongly negative carbon balances ! That is to say that in addition to avoiding the net emissions of CO2 in the atmosphere (carbon neutral), it literally removes CO2 from the atmosphere to reduce the concentration. The reason is simple, the carbon is stored underground in large quantities in the roots . It a bit like charcoal Terra preta, buried by the natives of the Amazon (see previous post).
However, to obtain carbon footprints strongly negative (-150% to -250%), it must grow several herbs together. For example, plots with a mixture of 16 herbs store 31 times more carbon in the soil than in monoculture plots!
No, definitely, biofuels of tomorrow will have nothing to do with those of today, hence the importance of not throwing out the baby with the bathwater. A sustainable development of biofuels is quite conceivable, if done intelligently and not to produce only small quantities.
In my last book Driving without oil, I show that f area of energy crops to produce biofuels equivalent to 5% of current petroleum fuels would no longer sufficient to consume oil in road transport. The electricity networks would, of course, the main "fuel". It would also use for biofuels, municipal waste, forest waste and recycling of oils and fats in the food industry, which can easily provide equivalent to 2.5% of current petroleum fuels, for a total of 7.5% biofuel (including dedicated energy crops).
With petroleum fuels, it takes carbon that was underground, it burns constantly and thus increased the CO2 content of the atmosphere. The idea behind biofuels is to avoid emitting CO2 from carbon sequestered in geological formations ("géocarbone") and use instead of "bio-carbon" found in plants. It then enters what is called the carbon cycle, where the carbon we send into the atmosphere by burning biofuels is reabsorbed by the plants grown for producing biofuels. It it adds not constantly in the atmosphere, since it does not use fossil fuels to produce biofuels. In this case we say that biofuels are carbon neutral.
This ideal situation is not achieved in practice and gives a positive assessment of CO2 emissions, with greater or lesser reduction in emissions compared to fossil fuels. This reduction is only 20% for ethanol produced from corn kernels, and some say it is zero if we take into account greenhouse gas emissions it took to produce the machinery issue . Add to this the problems of soil degradation and pollution of water due to fertilizers and pesticides, and it is understandable why many environmentalists do not like biofuels.
However, the second-generation biofuels have the potential to reduce emissions of greenhouse gas emissions by 80% to 90%, using the entire plant instead of only grains and fruit, as is currently the case. But the problems of degradation and soil erosion by intensive monocultures must also be taken into account.
Nature would have it, the Researchers have been studying for decades the advantage of crop wild prairie grass, such as switchgrass (switchgrass in English). First, these herbs are perennials, they need not be replanted every year like corn or soybeans. In addition, these herbs have well-developed root systems and deep (picture at the beginning of the ticket). With these two features, wild prairie grasses protect soil from erosion, rather than amplifying it as do the intensive monocultures of annual crops in rows .
Furthermore, wild grassland herbs need not be watered because their roots are very efficient to retrieve soil moisture up to 3 or 4 feet deep . By comparison, corn requires coolants often several hundreds of liters of water per liter of ethanol produced. There
or growing grass prairie wildlife becomes particularly interesting when it is grown in a mixture, including plants that fix nitrogen . This was experienced researchers at the University of Minnesota for 10 years on degraded land. They grew 152 different parcels of land containing different mixtures of up to 16 different herbs in the same plot. The stunning results of their study were published in 2006 (Tilman, Hill and Lehman, Science, Vol. 314, 8 December 2006, page 1598-1600).
First, quantities of fertilizers and pesticides required are much reduced compared to corn and soybeans, as shown in the chart below , from their publication (color added by the author this blog).
The word "Biomass" in this graph represents the mixture at high diversity (16 different herbs). Now the surprise is that second generation biofuels from such crops with high diversity have strongly negative carbon balances ! That is to say that in addition to avoiding the net emissions of CO2 in the atmosphere (carbon neutral), it literally removes CO2 from the atmosphere to reduce the concentration. The reason is simple, the carbon is stored underground in large quantities in the roots . It a bit like charcoal Terra preta, buried by the natives of the Amazon (see previous post).
However, to obtain carbon footprints strongly negative (-150% to -250%), it must grow several herbs together. For example, plots with a mixture of 16 herbs store 31 times more carbon in the soil than in monoculture plots!
No, definitely, biofuels of tomorrow will have nothing to do with those of today, hence the importance of not throwing out the baby with the bathwater. A sustainable development of biofuels is quite conceivable, if done intelligently and not to produce only small quantities.
In my last book Driving without oil, I show that f area of energy crops to produce biofuels equivalent to 5% of current petroleum fuels would no longer sufficient to consume oil in road transport. The electricity networks would, of course, the main "fuel". It would also use for biofuels, municipal waste, forest waste and recycling of oils and fats in the food industry, which can easily provide equivalent to 2.5% of current petroleum fuels, for a total of 7.5% biofuel (including dedicated energy crops).
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