|Current and emerging liquid biofuels technologies. Click to enlarge. Source: Nexant.|
A newly published study by energy consultant Nexant, Inc. concludes that the current generation of commercialized biofuels—biodiesel and bioethanol produced from grains and sugars—are likely transitional technologies.
The study—Liquid Biofuels: Substituting for Petroleum—concludes that fatty acid methyl ester biodiesel will be capable of substituting for only a small fraction of global diesel demand. However, as a biodegradable, low-toxicity product, it will likely hold market share far into the future.
Bioethanol from grains and sugar, though an excellent high-octane gasoline blendstock, has many practical problems and is also likely to be transitional over the long term, according to the study.
Nexant projects that the next phase of development is likely to be ethanol made by fermentation of sugars obtained through biomass hydrolysis. Nexant also concludes that, perhaps sooner than some may believe, integrated thermochemical platforms will take the lead in producing both gasoline and diesel range biofuels (biomass-to-liquids [BTL], similar to coal-to-liquids and gas-to-liquids), most likely in conjunction with electric power and chemicals. This alternative should be—and probably will be—pursued contemporaneously with developing biomass-based ethanol, according to Nexant.
Regardless of which substrate is used to produce it, ethanol will eventually need to be dehydrated to hydrocarbon gasoline fractions that are more compatible with the existing fuel distribution and vehicle infrastructure.
In adopting ethanol dehydration, higher alcohols, and biofuels from syngas, society will make tradeoffs between two options: (1) the current renewable, sustainable biofuels that are biodegradable and have low toxicity, but have limited supply potential, and (2) other biofuels that are equally renewable and have small carbon footprints but are less biodegradable or more noxious—yet are more attractive in other ways.
While crop biotechnology may provide a more productive, varied, and stable feedstock platform for a biofuels industry, the potential for early conflict with food is probably underestimated, according to Nexant.
The role of byproducts such as DDGS, and possibly biodiesel glycerine, in balancing animal nutrition supplies is conversely underrated or even missed by many analysts. Nonetheless, the market’s mere perception of competition of biofuels for sugar and grains with the food, feed, and fibers sectors seems to be enough to cause dislocations. This is already evident in the markedly higher late 2006 prices for US corn, Brazilian sugarcane, and European rapeseed—each the primary biofuel feedstock in its venue.
The study outlines a number of attractive “paths of least resistance” for developing the global biofuels industry based on leveraging current or co-developing technologies, such as coal gasification and gas-to-liquids catalysis. For the interim strategy of fermenting sugars from biomass, a number of preparation options are available, and thermal utilization of fermentation process residues needs to be carefully considered.
For the thermochemical platform of the future, more work must be done to develop in-field pyrolysis of biomass to help overcome logistics challenges, as well as biomass gasification and system optimization.
The study profiles a broad range of agricultural and biotechnology platforms and issues, and its geographic coverage includes the countries playing significant roles in biofuel feeds, production, and/or technology development over the next decade, including:
The Americas—primarily, the US, Brazil, and Canada, and also other countries in the hemisphere with activities in liquid biofuels.
Europe—Western, Central, and Eastern, and Russia.
Asia—primarily, China, Japan, India, Thailand, and Malaysia, and also other countries in Asia with activities in liquid biofuels.
Africa (primarily South Africa) and Australia.
Prospectus for Liquid Biofuels: Substituting for Petroleum