New comprehensive estimates of consequences due to direct and indirect land use changes in the biofuel industry more accurately highlight necessary policy change.

With the new increases in biofuel production around the world, attention must turn to the potential negative environmental impacts due to altered land use.  Previous estimates of these consequences used models that were not geographically nor ecologically specific and led to gross miscalculations. This case study in Brazil projects the effects on the Amazon due to increased biofuel production using a spatially explicit model to project land-use changes caused by that expansion in 2020 (Lapola et al, 2009).  New estimates reveal that current methods of land use allocation may create a carbon debt that would take up to 250 years to be repaid, an amount which overcomes the carbon sequestering benefits of biofuels over fossil fuels. — Elena Davert
Lapola, D.M., Schaldach, R., Alcamo, J., Bondeau, A., Koch, J., Koelking, C., Priess, J.A.  Indirect land-use changes can overcome carbon savings from biofuels in Brazil.  Proceedings of the National Academy of Science 107, 3388–3393.

 Currently, Brazil’s government, in conjunction with the biofuel industry, is planning a large increase in the production of biofuels over the next 10 years. With the potential ethanol production increase of 35 (4) x 109 liters in the 2003-2020 period –which equates to a projected indirect deforestation of 121,970 km2 by 2020– there are clear concerns about measuring the consequences of the land-use changes (LUC) associated with this increase. Some of the previous studies focused on the direct land-use changes (DLUC) and the resulting “carbon debt” caused by replacing native habitats with biofuel crops, while others pointed to the probable indirect land-use changes (ILUC) in Brazil caused by future expansion of food and biofuel croplands in other countries such as the United States. Although these studies showed that potential LUC must be taken into account to assess the efficacy of a given biofuel, they were neither spatially explicit, nor did they specifically consider competition between different land uses in view of concurrent food and biofuel demands. Because of this, calculations of the effects of LUC in previous studies are mostly underestimated or incomplete.
In order to create as fully comprehensive estimate of effects due to LUC, Lapola et al used a new spatially explicit modeling framework to project the complete DLUC and ILUC resulting from Brazil’s biofuel production targets for 2020.  In addition to being spatially explicit, the new model is also concurrent with increasing food and livestock demands and their demands for land as well. The modeling framework comprises of 3 major components: (1) a land-use/land-cover change model for land-use suitability assessment and allocation; (2) a partial equilibrium model of the Brazilian economy of the agricultural sector for future food demands, livestock demands, and advancement of crop yields due to improved technology; and (3) a dynamic global vegetation model for varying crop and grassland potential productivity driven by climate changes. The competition among land uses –for land resources– is also incorporated into the model based on an evaluation of suitability, hierarchical dominance of major land-use activities (settlement, crop cultivation, livestock grazing), and a land allocation algorithm which looks for land-use pattern stability over multiple land use objectives.
According to the new model, 88% of the DLUC  (145,700 km2) due to sugarcane cropland increasing by 57,200 km2 and soybean cropland increasing by 108,100 km2 will take place in areas previously used as rangeland, and the amount of cropland area replaced by biofuels would reach 14,300 km2. The resulting deforestation amounts to only 1,800 km2 of forest and 2,000 km2 of woody savanna, the required payback time for sugarcane DLUC emissions would be 4 years, while the DLUC carbon emissions for soybean biodiesel would not be paid back for at least 35 years. While these numbers are not considerably daunting, the model revealed that ILUC could considerably compromise the GHG savings from growing biofuels, mainly by pushing rangeland frontier into the Amazon forest and Brazilian Cerrado savanna. With an expansion of 121,970 km2 of rangeland into forest areas, and 46,000 km2 into other native habitats due to the expansion of biofuel croplands, the required payback time for GHG emissions increases to 44 years for sugarcane crops and 246 years for soybean crops.
Ultimately, the dramatic costs of ILUC in this study raise the question of whether the common practice of reallocating all displaced rangeland should continue. Changes in current practices will be difficult because not only is animal acquisition currently heavily subsidized in Brazilian cattle ranching, especially in the Amazon region, but very few incentives are provided for the recovery of degraded pastures. Socioeconomic surveys also suggest that technological innovation or the intensification of livestock inside the Amazon region may increase the attractiveness of cattle ranching and thus further deforestation. The authors argue that in order to avoid the undesired ILUC caused by biofuels, strategies for increased cooperation between the cattle ranching and biofuel-growing sectors should be implemented by the biofuel sector, and institutional links between these two sectors should be strengthened by the Brazilian government.

Holistic approach to life-cycle analysis required for accurate appraisal of potential biofuel feedstocks

As the development and research processes for the biofuel industry continue to increase, so does the necessity for accurate comparisons and appraisals of the fuels themselves. Although second-generation biofuels hold great promise as a supplemental energy supply, the ecological and environmental consequences cannot be fully understood without enhancing and standardizing the computational tool of  “Life Cycle Analysis” (Davis et al 2009).  Because the currently incomplete datasets can cause significant variation in the estimates for both the energy yields and the greenhouse gasses (GHG) associated with biofuel production, increasing more inclusive ecological data and establishing uniform units of comparison are both key components of furthering the accuracy of comparable fuel analysis. — Elena Davert
Davis, S., Anderson-Teixeira, K., DeLucia, E. Life-cycle analysis and the ecology of biofuels. Trends in Plant Science 14 (3) (2009) 140-146.

 Life Cycle Analysis, or LCA, is an all-inclusive account of the inputs and outputs of a production system, likened to an ecological food web that traces the fluxes of energy throughout an entire system. In the case biofuel production, some example inputs and outputs are energy requirements and net yields, economic costs and surpluses, and ecological feedstocks and environmental consequences. More specifically, the life-cycle inventory is a list of components assessed within an LCA for each step of the production chain; for biofuel LCA, the life-cycle inventory could include components such as manufacture and transport of fertilizers, pesticides, herbicides and seeds, to represent the inputs for step of feedstock production.  However, not all life-cycle inventories include the same components even when the boundary for the analyzed system is same. The life-cycle inventory thereby influences the outcome of an LCA and can be manipulated in order to understand which components have the greatest effect on the calculation of GHG balances for various fuels. LCA results are also frequently used in political and economic applications such as cost-benefit analysis, so accurate and comprehensive scientific data is crucial to evaluating the ecological and economic sustainability of biofuel crops.
In the reported survey, the authors compared published biofuel studies that analyzed corn, switchgrass, miscanthus, and mixed temperate grasses using various methods LCA, and found a number of indicators that more specific ecological understanding should be incorporated into the analysis. For example, the net energy values (NEV) and fuel energy ratios (FER) had drastic ranges across all reports and species, highlighting the fact that many types of energy are not directly comparable because they inherently incur very different costs and benefits. The authors also realized that even within reports regarding the same species, inconsistencies developed due to conflicting initial data.  Not only did variation in life-cycle inventories produce discrepancies among the LCA reports, but only three studies included uncertainty estimates of inventory item values and many of the inventories were incomplete.
In addition, although topography, soil and climate variability within a region prevent the direct application of small-scale LCA data to larger areas, this was ignored in many of the reports and yielded inaccurate assessments. The authors also noted that many LCA analyses ignored the fact that fuel energy production is so closely influenced by economic and political interactions and failed to communicate in common terminology to the professionals (engineers, economists and policymakers) who work within other branches of the biofuel production system.
Second-generation biofuels have potential as alternate forms of energy, but the consequences of increasing the use of biofuels cannot be communicated without a transparent and standardized approach to LCA.  By increasing collaboration among ecologists, economists and engineers, a more holistic approach to constructing the inventories will lead to more accurate appraisals of biofuel potential.

New microbial biofuels could increase efficiency and commercial viability for renewable energy

Although bioethanol and plant oil-derived biodiesel have comprised the first generation of the biofuel industry, their relatively low energy content and incompatibility with existing fuel distribution and storage infrastructure limits their economic use in the future.  However, scientists and engineers are now able to develop more sustainable and economically feasible microbial biofuels through means of metabolic engineering and synthetic biology.  Exploiting the diverse metabolic pathways in organisms such as Saccharomyces cerevisiae and Escherichia coli produces biofuels that have physical properties closely resembling petroleum-derived fuels without requiring additional chemical conversion, which suggests that investigating these new microbial fuels may provide insight into more efficient and commercially viable renewable energy (Rude et al. 2009). Elena Davert 
Rude, A. M., Schirmer, A. New microbial fuels: a biotech perspective. Current Opinion in Microbiology 2009, 12: 274-281.

 All biofuel production involves accessing the energy of the sun stored as chemical energy in the bonds of biologically produced materials through photosynthesis.  Three major pathways to convert renewable resources into energy-rich fuel-like molecules currently exist: 1) direct production by photosynthetic organisms, such as plants or algae; 2) chemical conversion of biomass into fuels; and 3) the fermentative or non-fermentative production by heterotrophic microorganisms such as yeast, fungi, or bacteria. Although the first two options can rely on expensive feedstocks and timely processes, research on key biocatalysts responsible for converting metabolic intermediates into fuel-like molecules hope to increase the economic viability of the third option. 
Microbiologists have started this research process by investigating the metabolic pathways of microorganisms that produce all four types of microbial fuels, which are divided into classes depending on the biological pathway from which they are derived: non-fermentative alcohols, fermentative alcohols, isoprenoid-derived hydrocarbons, and fatty acid-derived hydrocarbons. As is the case with non-microbial biofuel production process, the organic feedstocks involved in microbial fuel production still represent the largest cost component. Because of this, the overall production cost is directly related to the efficiency of the metabolic pathway in converting sugar to fuels. 
In order to effectively examine these efficiencies, the metabolic mass yield, gallon of product per ton of glucose, enthalpy of combustion, and enthalpy of combustion yield was calculated and compared for each microbial fuel pathway and characteristic.  Although ethanol had the highest metabolic mass yield within the microbial gasoline fuels (ethanol, butanol, isobutanol, and 3-methyl-1-butanol), butanol had the highest enthalpy of combustion, making them equally efficient with enthalpy of combustion yields of 97% and 95%.  Although the microbial diesel fuels had slightly lower enthalpies of combustion yields ranging between 75 and 88%, the fatty acid-derived hydrocarbons have the advantage of low solubility in water.  This means that centrifugation can be used to separate these compounds from fermentation broth, as opposed to distillation, which requires much more energy.
Understanding these metabolic pathways will allow for the expansion of the renewable fuel industry as greater knowledge of biocatalysts leads to a greater variety of hydrocarbon product discoveries.  Because the specific metabolic efficiency of any given pathway has a significant impact on the economics of fuel production in a microbial host investing in further research is crucial. Because microbial biofuels are easy to recover and do not require additional chemical conversion, the biofuel production process has the potential to develop into a cost-effective and unsubsidized commercial processes. 

New Geographically-explicit Agricultural Dataset Provides Most Accurate Estimates of Potential Production of Biofuels Worldwide

Although aggressive renewable energy policies have allowed for the immense growth of the biofuel industry, they have also exhausted surplus agricultural feedstocks and subsequently contributed to rapid commodity price increases in crops such as corn, soybeans, and rapeseed.  However, simplistic yield tables frequently used to project the success of biofuel feedstocks fail to consider their geographic location and can overestimate yields by up to 100% (Johnston et. al, 2009).  With new spatially-explicit global agricultural datasets—M3 cropland datasets— as well as more accurate yield conversion methods, scientists are able to better describe total global biofuel production, and thus more accurately predict its potential as a sustainable energy source.—Elena Davert
Johnston, M., Foley, J.Al, Holloway, T., Kucharik, C. Monfreda, C., 2009.  Resetting global expectations from agricultural biofuels.  Environmental Research Letters, 4 014004 (1-9).

While some may address the vast potential of alternative biofuels, such as cellulosic-ethanol and algae-biodiesel, agricultural-based biofuels are the only profitable alternatives to liquid fossil fuels that can currently be produced in large enough volumes.  It is for this reason that the study of agricultural biofuel reliance has become so prevalent in the scientific community as well as in the media. In order to make the information about biofuels more accessible, yield tables have become crucial translating complex differences between chemical breakdowns of multiple crops into simplistic illustrations of their potential fuel volumes. However, it is often the case that single yield estimates for a unique location are applied to global models, and specific units are not always appropriate for comparing different crops. Unfortunately, despite these doubts, these yield figures are so heavily relied on in scientific journals, policy reports, and even media articles, that many assume that the frequency with which the values are cited corresponds to their accuracy.
This recent study combats these faults by producing the most comprehensive report to date of biofuel production potential by including crop area and yield statistics drawn from over 22,000 agricultural surveys, censuses, and statistical databases. Statistical datasets for ten ethanol crops (barley, cassava, maize, potato, rice, sorghum, sugarbeet, sugarcane, sweet potato, and wheat) and ten biodiesel crops (castor, coconut, cotton, mustard, oil palm, peanut, rapeseed, sesame, soybean, sunflower) were analyzed across 238 countries, territories and protectorates, then converted to standardized units of liters-per-hectare.  This standardization was achieved by multiplying current agricultural yields, percent oil content, and oil densities for each crop, as well as factoring in constant processing ratios and refining factors specific to different regions.
Compared to earlier biofuel yield tables, this detailed agricultural analysis can infer that  previous reports overestimated yields by 100% or more. Barley, cassava, castor, maize, rapeseed, and sunflower all show that previous global biofuel yields were overestimated by at least 100%, with wheat–ethanol and groundnut–biodiesel estimates having been overestimated by 150% or more. By confirming that previously accepted biofuel yield estimates are highly unrealistic, the study hopes to highlight the actual cost-benefit consequences of expanding cropland dedicated to its production. Resetting the expectations for global agricultural biofuel production and the required technology is important from en environmental standpoint because it will help more accurately frame the allocation of funding for alternative energy research.

Banana Biomass Proven to be a Feasible Source of Renewable Energy

Renewable energy is gaining popularity in Malaysia because of the country’s new environmental policy, and a greater understanding of the possibilities of green energy (Tock et al. 2009). Because Malaysia has many natural resources in agriculture and forestry, it has several sources for new carbon neutral biofuel feedstocks, such as banana biomass. Currently, research has calculated the theoretical potential power generation to reach more than half of the renewable energy requirement in the new national policy, making banana biomass a feasible source of renewable energy in Malaysia as well as in similar tropical countries in the world.— Elena Davert
     Tock, J.A., Lai, C.L., Lee, K.T., Tan, K.T., Bhatia, S., 2009. Banana biomass as potential renewable enrgy resource: A Malaysian case study. Renewable and Sustainable Energy Reviews 14, 798–805.
The nature of a banana plant’s cultivation and structure make it an excellent candidate for a source of green energy. Because it can only produces fruit once during its lifetime, it loses its agricultural value after one season and leaves farmers with large quantities of biomass waste.  Banana biomass is also ideal because of its widespread availability and high growth rates. Not only does its rapid growth and harvest rate of 10–12 months allow for a relatively constant supply of energy feedstock, but its sturdy, fibrous stalk structure— it’s pseudostem—and dense planting allow for a high yield of biomass per plant as well as per hectare. Currently, small percentages of banana pseudostems are either used as organic fertilizer, animal feed, or temporary plates and food storage because current methods of extracting banana fiber for textiles are far from economical. In addition to the banana pseudostems, rejected fruits make up about 30% of the total derived feedstock and are easy to both handle and store.  The fruit’s peels are also a feedstock consideration in countries in which bananas are a major food crop. When disposed of indiscriminately, rejected fruits and peels produce noxious gasses such as hydrogen sulphide and ammonia as they decompose, both of which are environmental hazards.   
     Currently there are two feasible methods for conversion of banana biomass into energy: thermal conversion (gasification), and biological converstion (anaerobic digestion).  Gasification, or supercritical water gasification (SCWG), utilizes water that supercedes its critical temperature (647 K) and pressure (22.1 Mpa), exhibiting density and viscosity charictaristics between water and steam, in order to create rapid reactions of organic compounds that are mixed within the water.  Although SCWG avoids high processing costs associated with drying processes by using wet biomass, it is still a relatively expensive technology. Instead, anaerobic digestion is preferrable because it can also directly process wet biomass, but at much lower temperatures and costs.  This is accomplished by the fermentation of chopped and ground banana residue and waste that yields CO2 (that has been fixed during the plant’s lifetime), and methane levels that are higher and more efficient than the fermentation of other fruits.   Using these technologies, Malaysia has been able to produce 4.6% its total energy needs, just short of it’s 5% goal.
     Because bananas produce a very clean form of biogas, and because the waste is normally dumped in landfills or nearby bodies of water, companies have access to virtually free feedstock for energy production.  As the current technologies become more widespread for commercial use, they should be able to meet the growing demand of energy from Malaysia as well as other developing tropical nations.Elena Davert

Banana Biomass Proven to be a Feasible Source of Renewable Energy

Renewable energy is gaining popularity in Malaysia because of the country’s new environmental policy, and a greater understanding of the possibilities of green energy (Tock et al. 2009). Because Malaysia has many natural resources in agriculture and forestry, it has several sources for new carbon neutral biofuel feedstocks, such as banana biomass. Currently, research has calculated the theoretical potential power generation to reach more than half of the renewable energy requirement in the new national policy, making banana biomass a feasible source of renewable energy in Malaysia as well as in similar tropical countries in the world.­—Elena Davert
Tock, J.A., Lai, C.L., Lee, K.T., Tan, K.T., Bhatia, S., 2009. Banana biomass as potential renewable enrgy resource: A Malaysian case study. Renewable and Sustainable Energy Reviews 14, 798–805.

The nature of a banana plant’s cultivation and structure make it an excellent candidate for a source of green energy. Because it can only produces fruit once during its lifetime, it loses its agricultural value after one season and leaves farmers with large quantities of biomass waste.  Banana biomass is also ideal because of its widespread availability and high growth rates. Not only does its rapid growth and harvest rate of 1012 months allow for a relatively constant supply of energy feedstock, but its sturdy, fibrous stalk structure— it’s pseudostem—and dense planting allow for a high yield of biomass per plant as well as per hectare. Currently, small percentages of banana pseudostems are either used as organic fertilizer, animal feed, or temporary plates and food storage because current methods of extracting banana fiber for textiles are far from economical. In addition to the banana pseudostems, rejected fruits make up about 30% of the total derived feedstock and are easy to both handle and store.  The fruit’s peels are also a feedstock consideration in countries in which bananas are a major food crop. When disposed of indiscriminately, rejected fruits and peels produce noxious gasses such as hydrogen sulphide and ammonia as they decompose, both of which are environmental hazards.   
Currently there are two feasible methods for conversion of banana biomass into energy: thermal conversion (gasification), and biological converstion (anaerobic digestion).  Gasification, or supercritical water gasification (SCWG), utilizes water that supercedes its critical temperature (647 K) and pressure (22.1 Mpa), exhibiting density and viscosity charictaristics between water and steam, in order to create rapid reactions of organic compounds that are mixed within the water.  Although SCWG avoids high processing costs associated with drying processes by using wet biomass, it is still a relatively expensive technology. Instead, anaerobic digestion is preferrable because it can also directly process wet biomass, but at much lower temperatures and costs.  This is accomplished by the fermentation of chopped and ground banana residue and waste that yields CO2 (that has been fixed during the plant’s lifetime), and methane levels that are higher and more efficient than the fermentation of other fruits.   Using these technologies, Malaysia has been able to produce 4.6% its total energy needs, just short of it’s 5% goal.
     Because bananas produce a very clean form of biogas, and because the waste is normally dumped in landfills or nearby bodies of water, companies have access to virtually free feedstock for energy production.  As the current technologies become more widespread for commercial use, they should be able to meet the growing demand of energy from Malaysia as well as other developing tropical nations.Elena Davert