minguinhirigue wrote: Where do you get the 0,5% photosynthetic yield values?
http://www.ecologie.gouv.fr/IMG/pdf/Agr ... nement.pdf
(report Agrofuels and Environment, December 2008, Ministry of Ecology)
113 page: "With solar photosynthetic conversion yields of less than 0,5%, the energy power of biomass is between 0,01 W / m2 and 1,2 W / m2 (Smil, 2003 *)."
* Smil, V. 2003, Energy at the Crossroads, MIT Press, Cambridge, Ma.
It is very easily verifiable by calculation.
Such a goal of 20% would lead to catastrophic environmental and social consequences: huge consumption of water, massive chemical pollution (pesticides, fertilizers), impact on biodiversity, health, food prices, etc.minguinhirigue wrote: the demand for biofuels can be limited to 20% of current consumption for long trips only
And remember that the liter of agro-biofuel, excluding subsidies, is very expensive.
minguinhirigue wrote: ] Micro-algae are around 4 at 6% in good conditions and with a theoretical maximum of 11% ... and recent bioreactors type 3DMS give results in the order of 200 tep / ha / year (in Arizona, but still ...;)) !?
Thank you for the link to Greenfuel, I know, they have also published one of my papers on microalgae on their website (paper translated into English):
http://www.greenfuelonline.com/gf_files/algaefuel.pdf
In the report Agrofuels and Environment, December 2008, Ministry of Ecology, you can read this:
"Third-generation agrofuels, ACG3, based on algae (...) would be around 3 W / m2, ie at run-of-river hydropower level. Wind energy has power. energy nearly ten times higher, between 5 and 20 W / m2, and mountain hydropower is between 10 and 50 W / m2. "
http://www.ecologie.gouv.fr/IMG/pdf/Agr ... nement.pdf (page 113)
Conclusion:
- even the best-performing photosynthetic organisms (some microalgae species) have a lower conversion efficiency than solar PV or CSP. [If we continue the study of the energy chain to the car, we have an additional correction factor of 4, related to the difference in efficiency between the electric motor and the thermal motor.]
- To note that cultivating the microalgae is very complex and very expensive and is strongly consumer, in water, in fertilizer, in antibiotics. Finally, the risks of environmental contamination by microalgal GMOs (+ other environmental impacts of crops) used have not been evaluated.
1 liter biodiesel microalgal = 10 euros according to the team Shamash, France = 1590 euros the barrel = 2270 dollars a barrel.
"Agrofuels are located in the lowest yield zone; they are in fact limited by the photosynthetic yield which is very low (<1%). The third generation, using algae, will remain much less efficient than any “electric” solutions, especially the use of solar energy."
http://www.ecologie.gouv.fr/IMG/pdf/Agr ... nement.pdf (8 page)
NB - For serious figures on the oil production of different photosynthetic organisms, see the 1 Table and the 2 table 296 page of this document:
http://www.agric.wa.gov.au/content/SUST ... oalgae.pdf