Archive for the ‘biofuels’ Category
Water is a major factor in large-scale agriculture so when questions arose about jatropha’s water utility, various investors such as BP began to reconsider their investment.
The success of these outsourcing contracts will depend more on political than agricultural considerations.
Inherent problems associated with corn-based ethanol in the United states had led to the proclamation by a strident opposition that bioethanol technology, especially for use in the liquid fuels transportation industry was a failure. On the contrary, Brazil with a sugarcane-based program has been a model of excellence and even with recent crude oil discoveries which rival the North Sea in size and importance, has vowed to retain her ethanol program.
The production economics for various cellulosic ethanol feedstock need to be evaluated. For example, production from a feedstock of agricultural residues has the advantage of utilizing already existing infrastructure (crop, acreage, etc) but the yield may be less than that from lignocellulosic feedstock, for which infrastructure is currently less well developed.
Palm oil, from the oil palm (Elaeis guineensis) for example, yields about four times as much biodiesel per hectare of cultivated land than jatropha and that does not include the added yield from the palm kernel. A crop of oil palm trees also has the advantage of extended productivity sometimes for decades.
A note or two just before celebrating battery-powered automobiles. Only a tiny fraction of vehicles in the United States for example are battery-powered. The infrastructure (recharging stations etc) is not well established. Forecasts for the proportion of hybrid electric vehicles by the year 2015 are in the 10% range with an even smaller value for battery-powered ones. Appropriate pricing for these may also not have been settled. The process of substituting current internal combustion-engine vehicles with electric ones will therefore be slow and protracted if indeed plausible.
There is however a measure which will utilize the synergies between bioelectricity and bioethanol in a lignocellulosic energy program.
The process of ethanol production from biomass such as miscanthus or switchgrass involves fermentation to produce the solution which is then distilled to obtain ethanol. In Brazil, widely acclaimed as the model of ethanol excellence, ethanol is produced from sugarcane. The milling residue known as bagasse is burnt to produce auxiliary power just like in the afore-mentioned report. For most of these ethanol milling plants, the power so-generated is sufficient to power the whole production process with a lot to spare. The excess power is sold to utilities with proceeds in the millions of United States dollars. Two points are worthy of note here. The first is that the power is generated from the residue of the ethanol production process, that means after ethanol milling. The second is that even then, the said power is in excess of production requirements. In Brazil, synergies between ethanol and sugar (both products of the sugarcane feedstock) have sustained the milling plants.
The same crop of switchgrass for example can therefore be used for production of both ethanol (for blending with gasoline in traditional internal combustion engines) and electricity (for charging battery-powered vehicles). The inherent synergies would deliver on two key pillars of current energy policy thrust, more efficient and reliable energy source as well as greater greenhouse gas offsets. That the electricity-powered engine is more efficient than its internal combustion counterpart is not in doubt but due to the current impassioned and implacably polarized ethanol-gasoline arguments it would be necessary to add that the United States Department of Agriculture has determined that ethanol has 81% greater energy efficiency than gasoline.
When other countries’ automobile companies were improving on fuel efficiency and emissions standards, those of the United States, with brazen state support skimped. Today, the same US automobile companies are teetering on the brink of collapse while the Toyotas and Hondas even with the current recession are better off. There is no current evidence that bioelectricity or bioethanol will replace gasoline any time soon, as the fuel for automobile transportation. However, in the current energy quest, this process will provide for a much-desired, cleaner, efficient and more reliable addition to the transportation energy mix.
Feedstock is a critical factor in any bioethanol program; the US corn-based ethanol program was ipso facto doomed from onset. The other factors are production process and land.
Corn is a principal staple in food and agricultural processes and the US is the largest producer. Figure 1 shows the global utilization of cereals for ethanol production for the years 2004 to 2009. In the case of the US, corn constituted more than 95% by weight of cereals (corn and sorghum) used.
Clearly, more than three quarters of all cereals utilized for ethanol production was by the US. A 2008 report by the World Bank blamed in the main, the diversion of these grains to ethanol production for the large drawdown in global grain inventories and the associated price increases. The rising corn prices only served to increase the cost of ethanol production much like, to use Jean-Joseph Rabearivelo’s allusion to a waning moon, a moribund lapidiary on his own unnoticed grave. The necessary process of converting corn starch to sugar before fermentation also added to the already high cost of corn ethanol production; and with the precipitous fall in oil prices corn-based ethanol production became largely uneconomical. Some production plants became bankrupt. One such case is the much-bandied purchase by the oil refiner Valero, of eight of the failed VeraSun’s plants. This may well be more of a consolidation by Valero. The company was active in recent refining consolidation. But there is more. Corn has poor ethanol productivity compared to, for example miscanthus, the tall woody grass. Table 1 shows the ethanol productivity values for selected crops. Miscanthus has almost five times the productivity of corn. This means that on a given parcel of land, one can obtain
about 5 times more ethanol using miscanthus as crop than if corn were used. Perhaps the lack of infrastructure for miscanthus informed the initial use of corn for feedstock, a decision that has proved uninformed.
And then there is the issue of energy balance, the ratio of energy yield to energy input. Sugarcane for example has almost eight times the energy balance of corn and this is quite significant.
The significance of a proper choice of feedstock is evident in the Brazilian ethanol program. With sugarcane as feedstock the program has become a model of excellence. First, sugarcane is not a food crop per se and as such does not bear those fuel-food conflicts associated with corn. It also has great market synergies in its products, sugar and ethanol. Sugarcane milling plants also use the milling residue known as bagasse to generate power which for many plants is in excess of production requirements. The excess power is sold to utilities with proceeds in the millions of dollars.
Table 2 compares key features on Brazilian and US ethanol programs. In just about all the categories Brazil is superior.
Brazil shows a lower cost of production, much higher energy balance, greater ethanol penetration, zero subsidy from Government, higher greenhouse gas reduction among others. Gasoline blend ratios in Brazil now range from E25 to E100 (0% gasoline) and all service stations are ethanol stations.
It is estimated that using corn ethanol to offset 20% of gasoline use in the US will require 25% of current US cropland, while using miscanthus will require only 9%. Brazil has surpassed that mark using only 1% of arable land and that is due mainly to the choice of feedstock, sugarcane.