La comunità scientifica NON è divisa. E' noto qual è l'alternativa più ECO-sostenibile. Tuttavia, la sostenibilità non è fatta solo di ecologia ma anche di temi sociali ed economici, da qui può non convenire la trazione elettrica. In aggiunta, come dice Yuza, l'energia elettrica non è infinita. Tuttavia, a questo proposito è appena stato pubblicato un articolo su Environmental Science and Technology in cui si paragona l'utilizzo di bio-carburanti con la trazione elettrica generata da fotovoltaico, in un'applicazione sito-specifica negli Stati Uniti: il risultato è che, sebbene il FV abbia bassi rendimenti, si utilizzerebbe comunque meno suolo rispetto all'utilizzo di biocarburanti e in più si avrebbero gli ovvi vantaggi in termini di emissioni.
Allego l'abstract per chi è interessato e per DoppiaEffe.
Growth in biofuel production, which is meant
to reduce greenhouse gas (GHG) emissions and fossil energy
demand, is increasingly seen as a threat to food supply and
natural habitats. Using photovoltaics (PV) to directly convert
solar radiation into electricity for battery electric vehicles
(BEVs) is an alternative to photosynthesis, which suffers from
a very low energy conversion efficiency. Assessments need to
be spatially explicit, since solar insolation and crop yields vary
widely between locations. This paper therefore compares
direct land use, life cycle GHG emissions and fossil fuel
requirements of five different sun-to-wheels conversion
pathways for every county in the contiguous U.S.: Ethanol
from corn or switchgrass for internal combustion vehicles
(ICVs), electricity from corn or switchgrass for BEVs, and PV electricity for BEVs. Even the most land-use efficient biomassbased
pathway (i.e., switchgrass bioelectricity in U.S. counties with hypothetical crop yields of over 24 tonnes/ha) requires 29
times more land than the PV-based alternative in the same locations. PV BEV systems also have the lowest life cycle GHG
emissions throughout the U.S. and the lowest fossil fuel inputs, except for locations with hypothetical switchgrass yields of 16 or
more tonnes/ha. Including indirect land use effects further strengthens the case for PV.
Quindi non si può dire che la comunità scientifica sia DIVISA, non è assolutamente vero.
Allego l'abstract per chi è interessato e per DoppiaEffe.
Growth in biofuel production, which is meant
to reduce greenhouse gas (GHG) emissions and fossil energy
demand, is increasingly seen as a threat to food supply and
natural habitats. Using photovoltaics (PV) to directly convert
solar radiation into electricity for battery electric vehicles
(BEVs) is an alternative to photosynthesis, which suffers from
a very low energy conversion efficiency. Assessments need to
be spatially explicit, since solar insolation and crop yields vary
widely between locations. This paper therefore compares
direct land use, life cycle GHG emissions and fossil fuel
requirements of five different sun-to-wheels conversion
pathways for every county in the contiguous U.S.: Ethanol
from corn or switchgrass for internal combustion vehicles
(ICVs), electricity from corn or switchgrass for BEVs, and PV electricity for BEVs. Even the most land-use efficient biomassbased
pathway (i.e., switchgrass bioelectricity in U.S. counties with hypothetical crop yields of over 24 tonnes/ha) requires 29
times more land than the PV-based alternative in the same locations. PV BEV systems also have the lowest life cycle GHG
emissions throughout the U.S. and the lowest fossil fuel inputs, except for locations with hypothetical switchgrass yields of 16 or
more tonnes/ha. Including indirect land use effects further strengthens the case for PV.
Quindi non si può dire che la comunità scientifica sia DIVISA, non è assolutamente vero.