Two researchers working at the Department of Mechanical Engineering at Iowa State University set out to compare the capital and operating costs of generating fuel from starch and cellulose-containing materials.
They showed that the capital costs for 150 million gallon gasoline equivalent capacity range from around $111 million for a conventional grain ethanol plant to $854 million for an advanced (Fischer Tropsch) plant. The difference in the final cost of the fuel, however, was less severe, being $1.74 for grain ethanol when corn costs $3.00 per bushel and $1.80 for cellulosic biofuel when biomass costs $50 per ton.
The authors compared biochemical and thermochemical approaches to biofuels. They showed that both have much higher capital costs than conventional grain ethanol plants, but that neither had a significant cost advantage over the other.
The assumption of $3 for a bushel of corn seems low given that a bushel of corn for December 2007 delivery is above $3.50 at the time of this writing. However, $50 as the price of a ton of biomass material seems realistic:
Biomass Program analysts estimate that 512 million dry tons of biomass equivalent to 8.09 quads of primary energy could initially be available at less than $50/dry ton delivered (Walsh et al. 2000, 2003, Ugarte et al. 2003). Of this, 36.8 million dry tons (0.63 Quads) of urban wood wastes were available in 1999. In the wood, paper, and forestry industrial sectors, they estimate that 90.5 million dry tons (1.5 Quads) of primary mill residues were available in 1999 and 45 million dry tons (0.76 Quads) of forest residues were available at a delivered price of less than $50/dry ton. An estimated 150.7 million dry tons (2.3 Quads) of agricultural residues (corn stover and wheat straw) would be available annually. A joint U.S. Department of Agriculture and Department of Energy evaluation of the potential to produce biomass energy crops (Ugarte et al. 2003) estimated 188 million dry tons (2.9 Quads) of biomass could be available annually at delivered prices of less than $50/dry ton by the year 2008. A county-level database of potential energy crop resources is available at Oak Ridge National Laboratory and a county-level database of multiple resources will be available soon. State-level information can also be obtained at the EERE website.
Once cellulosic technologies mature to the point that costs drop then the demand for biomass ethanol will rise. What I wonder: Will this increase or decrease the demand for land to make ethanol? On the one hand ethanol yield per acre will rise. On the other hand, lower prices will cause demand for ethanol to displace more gasoline. That might boost the demand for ethanol so much that land usage for biomass ethanol will rise. The ability to use more types of land to grow various biomass ethanol feedstock plants could allow biomass ethanol agriculture to grow far beyond the lands currently used to grow corn.
I do not want to see more habitats shifted into biomass energy production. I'd rather we develop better battery technologies so we can switch from gasoline to electric power rather than to ethanol.
|Share |||Randall Parker, 2007 August 09 10:26 PM Energy Biomass|