Reply |Mark Delucchi to energy-discuss.
show details 21:34 (12 hours ago)

I tend to agree with Mark B. here.
FWIW, the IEA report mentions algae but doesn’t feature it in its analysis. I’ve seen a few LCAs of algae fuel, and and the results are not particularly impressive. The IEA report includes algae in one of its GHG-LCA graphs.
For a couple of reasons, I find biofuels to be inferior to WWS power. First — and this point has been made by others in this group — it is not clear that the environmentally best options are commercializable. For example, in the US the best option is something like high-diversity, low-input, unmanaged, mixed native grasses grown on degraded lands. (This is like the biofuels version of wild urban eating, where you go around the city picking wild greens for your salad.) But it is not clear that it will be economical for anyone to do this, or for government to compel people to avoid intensively managed monocultures with high inputs on prime ag. land.
Second — and this point for me is decisive, and also woefully under-appreciated — in these biofuels study (including the IEA study) the counterfactual is wrong. Typically, people imagine growing some nice tidy biomass on some terribly ravaged land, and then say that the improvement in the environmental quality of the formerly ravaged land counts as a benefit. But this is the wrong comparison. If we are in a world where we care so much about land use, habitat, diversity, environmental quality, water quality, and climate change that we are considering programs to promote the lowest-impact biofuels, then the correct counterfactual is with another alternative in the same basic world, with the same concerns, not with a different world with different concerns. So, if our goal is to minimize climate and land-use impacts, then we should compare low-impact biomass with, say, WWS power plus habitat restoration. Thus, all so-called “degraded” land that is a candidate for  low-impact biomass in the biofuel case is a candidate for full restoration to best native habitat in the WWS case.
And then there are the technical/environmental-impact issues that Mark B. brings up. Plus the fact that biofuel combustion always produces some pollutants, whereas use of WWS power in electric motors does not.
Since full restoration to native habitat always is preferable to even low-impact biofuel feedstock, and since WWS provides better climate and air-quality benefits than do biofuels, at the same or lower cost, biofuels are an unnecessary and inferior option.
Mark Delucchi, Stanford Universtiy