Just Released! “Energy, Biology, Climate Change”

FrontCover6x9 white border 72dpi EBCC2015

Our newest book, published on May 6, 2015 and available at Amazon.com for $19.95.

The focus of this book is the interactions between energy, ecology, and climate change, as well as a few of the responses of humanity to these interactions. It is not a textbook, but a series of chapters discussing subtopics in which the authors were interested and wished to write about. The basic material is cutting-edge science; technical journal articles published within the last year, selected for their relevance and interest. Each author selected eight or so technical papers representing his or her view of the most interesting current research in the field, and wrote summaries of them in a journalistic style that is free of scientific jargon and understandable by lay readers. This is the sort of science writing that you might encounter in the New York Times, but concentrated in a way intended to give as broad an overview of the chapter topics as possible. None of this research will appear in textbooks for a few years, so there are not many ways that readers without access to a university library can get access to this information.

This book is intended be browsed—choose a chapter topic you like and read the individual sections in any order; each is intended to be largely stand-alone. Reading all of them will give you considerable insight into what climate scientists concerned with energy, ecology, and human effects are up to, and the challenges they face in understanding one of the most disruptive—if not very rapid—event in human history; anthropogenic climate change. The Table of Contents follows: Continue reading

Potential of Wastewater Grown Algae for Biodiesel Production and CO2 Sequestration

In response to a growing fear surrounding increasing levels of CO2 in the atmosphere and rapidly dwindling supplies of traditional oil as a source of energy, A. Fulke et al. investigated the CO2 sequestration rate (as a source of CO2 mitigation), the biomass creation (as a source of biofuel), and lipid composition of algae used in the wastewater stabilization ponds of industrial wastewater treatment plants. The green algae species of the algae they found naturally occurring in the wastewater stabilization ponds have a lipid structure equivalent to vegetable oil currently used to produce biodiesel. In the two most dominant algal classes Chlorophyceae and Cyanophyceae, they found four distinct species (Scenedesmus dimorphus, Scenedesmus incrassatulus, Chroococcus sp. and Chlorella sp.) currently being globally explored as sources of biodiesel. They isolated and cultured samples of these four species and examined the biomass concentration, lipid content, and CO2 fixation rates, finding that the samples where all four of these species were present (as opposed to each species cultured alone) had a biomass concentration (g L-1) and lipid content (g g-1) nearly twice as high as any alone, and a CO2 fixation rate (g L-1d-1) at least double individual species cultivations. They concluded that industrial wastewater could support a diverse culture of algal species capable of being used as a source of biodiesel. —Allison Kerley

Fulke, A., Chambhare, K., Sangolkar, L., Giripunje, M., Krishnamurthi, K., Juwarkar, A., Chakrabarti, T., 2013. Potential of wastewater grown algae for biodiesel production and CO2 sequestration. African Journal of Biotechnology 12, 2939–2948.

                  Fulke et al. collected samples of water from ten different locations in the wastewater stabilization pond at a currently active vehicle manufacturing plant in the western Maharashtra region in India. They found 27 species of Chlorophyceae, 16 species of Cyanophycea, 14 species of Bacillariophyceae, 4 species of Euglenophyceae and 4 species of Chrysophyceae in the wastewater, with a Shannon-Wiener Diversity Index range from 2.91 to 3.66. They used the Nile Red staining method to determine the lipid content and to identify the intracellular lipid content (used in the creation of biodiesel). Four of the algae species found (Scenedesmus dimorphus, Scenedesmus incrassatulus, Chroococcus sp. and Chlorella sp). are currently being globally explored as potential sources of biodiesel, so Fulke et al. chose to further investigate the lipid content and biomass creation during stress and no-stress scenarios. They cultivated each of the species individually in the lab over 14 days, each in a culture with abundant nutrients and in a culture with limited nutrients. They found that upon nutrient depletion, the algae produce more lipids which get trapped within the cell. Cells with a higher lipid concentration are more favorable for biodiesel creation.

Saving Land and Water by Cultivating Miscanthus

Due to government mandates in repsponse to climate change, ethanol production has steeply increased since 2009, and there are now for 79 billion liters of cellulosic biofuels yearly by 2022.  Cellulosic crops such as maize, switch grass, and Miscanthus have been determined to be viable biofuel sources. In order to meet the biofuel target in 2022, cellulosic crop cultivation needs to be expanded and intensified. The impact on land and water use needs to be considered as well. Zhuang et al. (2013) present a data-model assimilation analysis assuming that maize, switchgrass, and Miscanthus can be grown on available U.S. croplands.—Christina Whalen

Zhuang, Q. Qin, Z. Chen, M. 2013. Biofuel, land, and water: maize, switchgrass, or Miscanthus. Environ. Res. Lett. 8, 015020.

                  The current production levels of maize are not enough to be simultaneously used as biofuels and as a food source. The cellulosic crops switchgrass and Miscanthus have been identified as viable alternatives to maize in producing second-generation biofuel. This is staged to work especially well in temperate regions because of their higher biomass productivity and available crop-producing land. Other studies have shown that bioenergy crops have higher land and water efficiencies than food crops do, but the increasing demand of land and water to cultivate these crops hasn’t been researched using ecosystem models.  The study uses the terrestrial ecosystem model (TEM) to predict the demand of land and water for growing various biofuel crops so that enough ethanol can be produced to hit the 2022 target. The goal of the study is to analyze the demand for resources rather than to analyze the environmental impact of growing biofuel crops.
                  The TEM ecosystem model uses gross primary production (GPP) as the core algorithm, which describes the rate at which a plant produces usable chemical energy. The Net primary production (NPP) is the difference between GPP and plant respiration. In order to analyze the productivity of feedstocks and biofuels, the researchers estimated the biomass and biofuel production in terms of harvestable biomass (HBIO) and bioethanol yield. Current and future biofuel production was estimated using conversion efficiencies and currently available and potentially advanced technologies.  TEM was run several times at each site in order to achieve model equilibrium. Analyses were conducted on biomass and biofuel yield, water balance, and water use efficiency and were estimated based on simulations.
                  The results of the model demonstrate that in order to produce 79 billion liters of ethanol from maize grain, there would be a need for 190 million tons of conventional grain and 26.5 million hectares of land, which is equivalent to 20% of total US cropland. The water loss of this production would be 92 km3, but if the maize stover were also used, water would be saved. Because switchgrass has lower conversion efficiency, using this crop would result in a higher demand of biomass. More land and water would need to be used to produce the same amount of ethanol than using maize. Alternatively, Miscanthuswould only require half the amount of land and two-thirds the amount of water used for maize grain in order to produce the same amount of ethanol. Furthermore, with the advanced technologies predicted for future years, even less water and land will need to be used in converting biomass to biofuel. The model experiments demonstrate that switching from maize to Miscanthus will save land and water, but that switching from maize to switchgrass will require more land and water.

                  This study only predicts ethanol production using available croplands, but recent studies have illustrated that marginal lands could also be a source for cultivating cellulosic crops. Experiments have also shown that switchgrass may be more productive on marginal lands than on traditional croplands. The model may produce some bias because it does not consider the effects of fertilization, irrigation, rotation, and tillage. To strengthen the study, analysis of economic viability, food security, nutritional and ethical concerns, and other environmental consequences and benefits need to be conducted.

Improving Biofuel Cells

Biofuel cells transforming biological fuels such as ethanol or sugar into electricity are safe and ecofriendly source of power. However, biofuel cells are often limited to low voltage and are insufficient to provide necessary power for daily use. Like other traditional electrolyte batteries, stacking up the biofuel cells may boost their single cell voltage to an applicable level. Miyake et al. (2013) performed experiments on multiple ways to improve the voltage of biofuel cells utilizing fructose as the energy source. When stacking cells, each cell has to be isolated with proper wrapping to prevent short-circuits. The authors layered the biofuel cells with enzyme-modified carbon fabric strips and hydrogel sheets to ensure the ion-conduction between the anode and cathode fabric layers; the hydrogel sheet also served as a fuel tank. The modification effectively improved the performance of both bioanodes and biocathodes and maximizes cell power to 0.64 mW at 1.21V.  Chieh-Hsin Chen
Miyake, T., Haneda, K., Yoshino, S., Nishizawa, M., 2013. Flexible, layered biofuel cells. Biosensors and Bioelectronics 40, 45-49.

                  To increase the efficiency and the power of biofuel cells, the authors made three modifications to the cells; to prevent short-circuits due to ion-conduction. The first modification was the preparation carbon fabric anodes, where are multi-walled with carbon nanotubes to increase the reaction surface area; they are heated in 400 °C and immersed in multiple solutions such as D-fructose dehydrogenase to increase the efficiencies. The result of this modification is significant: it almost doubles the current density. In the first modification, the authors also found that the performance of cells is significantly affected by buffer concentration; buffer is added to stabilize the local pH level change caused by the oxidation process. With a stabilized pH level, enzymes in the carbon fabrics perform with the highest efficiency with a 0.5M buffer with maximum current produced at 0.6V of 15.8 mA.
                  The second modification is the gas-diffusion of carbon fabric cathodes. This process followed the process used for Biliruben oxidase (BOD) cathodes. BOD can catalyze the reaction of O2 to H2O without election transfer mediators. The cathode is also treated with heat and multiple solutions including BOD and a surface coat of carbon nanotube solution to make it hydrophobic. To test the effect, the electrode strip was put in an oxygenic pH 5 buffer testing the electric potential versus the current capacity. The performance of a BOD-modified strip reaches to about 1.9 mA cm-2; the additional carbon nanotube coating onto the BOD-modified cathode strip was enhanced to 2.9mA cm-2. The hydrophobic carbon nanotube coating controls the penetration of excess solution into the carbon fabric electrodes allowing the conduction to optimize. The authors also conclude that control of the buffer concentration may optimize the performance with maximum current of 4.6 mA cm-2 at 0V using a .25M buffer solution utilizing an oxygen supply from the ambient air through the carbon fiber.

                  The third modification is through double-network hydrogel films that contain fructose. This modification is prepared through a three-step process: first, the formation of one layer hydrogel film, then another layer of film, lastly with loading of 500 mM fructose. The hydrogel film is later treated with three stock solutions to secure the fructose solution in the film. Both cathodes and anodes went through the process of lamination with double-network hydrogel sheet; the lamination provides the cells with moisture, fuel sources, and buffering for the reaction. The cells are tested with 0.74V, which is about the electric potential difference between fructose oxidation and oxygen reduction. The performance of the biofuel cell is fairly good; it reached a maximum power density of 0.95 mW cm-2 at 0.36 V. However, the stability of the cell decreases drastically after a few hours due to drying of the hydrogel. More importantly, the authors found that bending the cell sheet into a cylinder effectively increases the performance of the cell. The laminated bent cell produced a maximum power of 0.64 mW at 1.21V, which is sufficient to light an LED unit. With these types of modification, we may expect a more powerful biofuel cell in the future.

Setbacks of Using Agricultural Crops and Natural Ecosystems as Energy Sources

The currently growing concerns around the world about foreign oil dependency and growing climate change, have contributed to an increasing interest in using bio-fuels as an alternative to fossil fuels such as coal, gas, and oil. The study conducted by Graeme I. Pearman (2013) demonstrates that bio-fuels and bio-sequestration can only make a minor contribution to lowering carbon levels and minimizing net emissions of carbon into the atmosphere. This is done through examining available solar radiation and observing how efficient natural and agricultural ecosystems are in converting that energy to usable biomass. The 11 countries compared in the study are Australia, Brazil, China, Japan, Republic of Korea, New Zealand, Papua New Guinea, Singapore, Sweden, United Kingdom, and United States, with a main focus on the researcher’s homeland, Australia. The objective of the study is to answer the following question: from a biophysical perspective, can using bio-fuels or bio-sequestration of carbon significantly contribute to the future of energy and the reduction of greenhouse-gas  (GHG) emissions?—Christina Whalen

                  Pearman, G. 2013. Limits to the potential of bio-fuels and bio-sequestration of carbon. Energy Policy 59, 523-535.

                  The first part of the study focuses on comparing annual rates of solar radiation and respective energy consumption for each country. The results group countries into 3 groups. Group 1, Japan, Korea, and Singapore had energy consumption around 1 en dash 10% of incident (surface) radiation. Group 2, China, U.K., and U.S. had energy consumption around 0.1% and Group 3, Australia, Brazil, New Zealand, Papua New Guinea, and Sweden had energy consumption around 0.1 en dash 0.001% of incident radiation. These comparisons demonstrate the limits that deriving energy from the sun has on meeting national expectations for energy consumption. We can consume much more energy than the sun could ever provide us.
                  Photosynthetic efficiency is another limit to the use of bio-fuels or bio-sequestration. The pigments in the chloroplast are only activated by certain parts of the solar spectrum, leaving much of the solar radiation unutilized. In addition, more than 50% of photosynthetic products (sugars) are lost through photorespiration. The whole process is only 3.3% efficient in C3 plants and 6.7% in C4 plants.
 The study then continues to examine the limitations of bio-fuels regarding energy efficiency captured from natural vegetation and from global crops. Net primary production (NPP) is how much carbon (or energy in this case) remains after the photosynthetic organism has used it for growth and other metabolic functions. In natural environments, a large portion of captured solar energy is used within the community and is vital for a functioning and healthy ecosystem. Thus, human use of this energy will no doubt have negative impacts on preexisting ecosystems. Agricultural ecosystems are constructed for the purpose of providing biomass for human consumption. The main difference between the two types of ecosystems is that a cultivated system inputs fossil fuels, which needs to be considered when accounting for the net production of energy. Comparisons within each of the countries were then made between energy captured annually as net primary production and the national solar radiation and energy consumption rates. The comparison demonstrates the inefficiency of the biochemistry involved in photosynthesis and is also influenced by temperature and water availability. The comparisons also conclude that modifying the NPP of the biosphere could be possible when global scale changes occur to temperature, rainfall, and carbon dioxide concentrations.
Photosynthesis can be more efficient in agricultural crops when there is plenty of water and fertilizer and crop management is most favorable during the peak growth rates. In the study, multiple samples were taken from various countries and locations in order to accurately compare the relative efficiencies of different cropping systems. This is called “tradable production” because the net production is calculated after discarding the roots, leaves, and stems of plants. Sugar cane and wheat crops have the potential to contribute significantly the nation’s energy demand, but have some economic and political setbacks that are not discussed in detail in the paper.
Though natural and agricultural biomass have the potential to provide energy for human use and to offset carbon emissions from fossil fuels, this study demonstrates that there are major limiting factors to this solution including the availability of solar radiation and the efficiency of photosynthesis needed to convert the energy into feedstock. Another limitation is how efficiently biomass can be converted into fuels that are appropriate for existing feedstocks, conversion systems, and applications. Solar radiation on land accounts for 1700 times the amount of energy consumed by humans, but the radiation and the energy demands are not evenly distributed geographically, so this process depends on the redistribution of energy. It also depends on how efficiently solar energy can be converted to meet the demands of humans, which is where photosynthesis becomes a limiting factor. In comparison, agricultural crops may be more efficient at converting solar radiation to a more usable form of energy, but the study demonstrates that wheat, rice, and corn crops have low efficiency rates that are similar to those of natural ecosystems. The only crop that shows a decent amount of efficiency is sugar cane.
                  The analysis conducted in this study is not meant to completely reject the idea of using crops and natural ecosystems as bio-fuel and bio-sequestration of carbon, but  is meant to illustrate that this would require a huge amount of increase in land utilization and/or altering existing crops. Investors in these types of activities and governments seeking policy implementation need to be aware of these so-called “attractive” energy efficiency solutions.
                  The paper summarizes 12 criteria of assessments of issues raised by the possibility of using bio-fuels as a future energy source and for the bio-sequestration of carbon. The first issue that needs to be examined is the potential for agricultural and forestry capacity to deliver to energy demands and emissions reduction. Another one is evaluating the co-benefits or dis-benefits of developing policies about bio-fuels such as soil productivity, job creation, economic opportunities, international balance of trade, security of energy supply and so on. There also has to be enough net energy to cultivate crops for fuels, to produce fertilizer, transform the energy into chemical energy, and for transporting the subsequent fuel.  Another issue to keep in mind is the continuously changing climate and its affect on which bio-fuels are appropriate. Other issues include timing, production location, strategic carbon & nitrogen budgeting, human capacity to convert the energy, competing use of land, costs of production, and social and political realities.
                  The conclusion of the paper does little to provide the answers to the various questions raised throughout the study, but rather implies that “we” have the knowledge to develop a system to produce bio-fuels and bio-sequestration of carbon from agricultural crops and natural ecosystems, but now we need more efficient biomass that will provide us with the tools we need to power that process.

Tracking Reusable Biofuel From Crops: Carbon and Solar Energy

Technology for production of biofuels has been a popular research area for many biochemists in the past ten years because finding alternatives to the use of fossil fuels can have important effects on the future of human life. Although the technology is not able to produce low cost, efficient biofuels yet, Borak et al. (2013) promote the possibilities and efficiency of biofuel production through crops. Their “PETRO approach” is used to evaluate the new crops, not only on the capture of solar energy but also the capture of carbon in atmosphere. The reverse of the carbon combustion cycle naturally occurs within plants, which use photosynthesis to convert carbon dioxide from the air to usable fuels. The energy source products from various crops are similar, but the efficiency of conversion of sunlight into energy varies. The authors summed up the total loss of energy during each process and organized data on the final energy content for each crop. They showed that using the PETRO approach for evaluating potential crops as biofuels can lead to more detail-based discussion in the scientific community.  Chieh-Hsin Chen
Borak, B., Ort, DR., Barbaum, JJ., 2013. Energy and carbon accounting to compare bioenergy crops. Current opinion in biotechnology 24, 369-375.

                  Because of the depletion of fossil fuels and the atmospheric increase of atmospheric carbon dioxide from combusting the fossil fuels, scientists are eager to find alternative fuels. The two main barriers to production of alternative fuels are the costs and shortage of potential stocks; thus the production of liquid fuels from crops has become one of the top environmental goals for future research. On a fundamental level, the concept of biofuel is replacing the process of mining with the process of agriculture; the process shift is significant because biomass has significantly higher carbon oxidation state than fossil fuels. The approach of biofuel essentially reversed the combustion of carbon-based fuels capturing the byproduct CO2 converting and storing as usable energy via carbon fixation utilizing plants and other terrestrial plant matter.
                  To further enhance the ability of the biofuel production, a detailed evaluation of efficiency of the crops and productivity of conversion of energy will be useful; however a systematic methodology for evaluation is currently lacking in the field. Different research groups studying in different geographical areas use a variety of non-comparative assumptions and approaches to calculation yields. The data consistency became one of the difficulties for further biofuel research. The authors introduced the Plants Engineered To Replace Oil (PETRO) approach that included the input of raw materials (sunlight, carbon dioxide and water), trace process of conversion by plants, and the output of liquid fuels. Photosynthesis reverses the combustion of fuels and stores the carbon energy along with solar energy in the plant; the production of biofuel extracts and concentrates carbon energy from plants, usually as ethanol, converting it into usable fuel.
                  Although plants have evolved effective photosynthetic pathway to capture light, they are not as efficient as we would like; the result of evolution does not aim for maximizing the benefits of wither for producing food or fuels. That C3 plants only utilize 4.6% of the solar energy and C4 plants utilize 6.0% suggests substantial room for improvement but even with these low capture levels of photons much of the captured energy is subsequently lost.
                  The authors looked into the difference in loss of carbon energy between C3and C4 plants in four levels: captured, harvested, purified, and processed. C3 plants lose half of their usable carbon energy in photorespiration and more in respiration. C4 plants lose less in respiration, but C4 plants lose more than half seasonally. Overall the final usable carbon energy in C3 plants is about 0.69% and 3.0% in C4 plants. But there are also some losses of carbon energy in the processing steps.

                  Although energy loss in the processing steps is small compared to the loss from photorespiration or seasonality, it is the first step that can be improved through conventional engineering. With careful genetic selection and engineering of crops, we will be ale to control the seasonality and other growth process of crops. The authors introduce data that show the differences in final fuel product of four common crops used in biofuels: maize, soybean, sugarcane, and switchgrass. The final energy content of the four different crops is very similar, but they have significant differences in overall fuel yield. Sugarcane contains the most overall fuel yield and soybean the least. 

Biofuel Production Using Charcoal and CO2 to Transform Animal Fats

The need for renewable fuels is increasing as the fossil fuel crisis becomes more severe.  Animal fats, an inexpensive source of triglyceride, are a potential cost-effective feedstock for biodiesel production (Kwon et al. 2012).  However, animal fats, which contain up to 6 wt% of free fatty acids (FFA’s), must be pre-treated before undergoing conventional catalytic processes (Crabbe et al. 2001; Naik et al. 2008).  Without pretreatment steps, impurities in the feedstock will react with the catalysts and limit the biofuel yield by producing soap.  Kwon et al. aim to prove that an efficient non-catalytic biodiesel conversion using only charcoal and CO2is possible.  They determined the optimal conditions for this conversion, including temperature, pressure, and feeding ratio of raw materials.  Previous studies on non-catalytic conversion suggest an optimal temperature of 250 °C, a pressure of 10MPa or higher, and a methanol-to-oil molar ratio of 6:1.  In the present study, Kwon et al. determined optimal operating conditions for the conversion of animal fats to biodiesel to be at a temperature of 350500 °C under ambient pressure, and volumetric flow rates of extracted lipid and methanol (MeOH) to be 10 and 3 ml min1, respectively. Shelby Long
Kwon, E. et al., 2012. Transforming animal fats into biodiesel using charcoal and
CO2. Green Chemistry 14, 1799–1804.

                  Kwon et al. analyzed the production process of biodiesel by transforming animal fat into biodiesel using charcoal and CO2.  They obtained cooking oil from a local restaurant, beef tallow and lard from the local slaughterhouse, charcoal from the local market, and MgOCaO/Al2O3 that was generated from magnesium slag from a magnesium-smelting factory.  They determined the acid value (AV), an indicator of oil quality, with the following equation: AV = A x c x 56.11/m (A = volume of KOH solution use to titrate sample; c = concentrations of KOH solution; m = sample mass).  They first examined the non-catalytic biodiesel conversion of used cooking oil to biodiesel using a pressure reactor.  For this experiment they used MgOCaO/Al2O3 as a catalyst.  Kwon et al. carried out the experiment at a temperature of 130–250 °C and maintained pressure by filling the reactor with nitrogen (N2) and CO2.  To further examine the effect of temperature on the conversion process they replicated the previous experiment but varied the temperature from 250–500 °C.  Kwon et al. replicated the same experiment a third time, but added a virgin catalyst, activated Al2O3, in order to examine the catalytic element effect of MgO–CaO on the transesterification reaction.  For their main experiment, Kwon et al. tested the conversion of beef tallow and lard into biodiesel using charcoal.  They packed charcoal into an airtight reactor and maintained the temperature at 250–500 °C while oil feedstock, MeOH, and CO2 reaction medium were continuously added into the reactor.  The mixture was allowed to settle for 2 hours after the reaction before the contents were analyzed.
Kwon et al. achieved an approximately 98% biodiesel conversion rate of used cooking oil after 30 minutes.  This high conversion rate suggests that CO2 can enhance transesterification.  CO2 is believed to enhance the efficiency of the transesterification process by accelerating bond dissociations, also known as thermal cracking (Kwon et al. 2009).  By examining the biodiesel conversion of used cooking oil, Kwon et al. determined that the conversion rate is more responsive to changes in temperature than to pressure.  They also found that non-catalytic biodiesel conversion can be completed using porous materials. The pores, such as those in charcoal, act as small reactors, while the high temperature drives the transesterification reaction.  One of the main findings Kwon et al. observed was that under atmospheric pressure and a relatively high temperature, the conversion cost can be decreased by almost 70%, compared to standard commercial processes.
                  The researchers suggest that the mass decay of lard they observed at the comparatively low temperatures of 120–140 °C may be due to low molecular lipids and moisture in the lard.  Also, the thermal decomposition of lard was observed to be lower than that of beef tallow, which may be attributed to its lower amount of saturated fat.  In addition, they also found that the thermal degradation pattern for animal fats is similar to that of vegetable oil.  The biodiesel conversion efficiency of lard and beef tallow was almost identical at 400 °C.  There was no evidence of thermal cracking taking place in the experiment.
                  Kwon et al. achieved a conversion efficiency of beef tallow and lard into biodiesel of 98.5 (+ 0.5) % under ambient pressure and at temperatures higher than 350 °C.  They determined these to be the optimal operating conditions.  Based on their observations, the researchers assert that the production of biodiesel using charcoal and CO2 has the potential to be a highly cost-effective biofuel conversion process.
Other Sources
Crabbe, E., et al., 2001. Biodiesel production from crude palm oil and evaluation of butanol extraction and fuel properties. Process Biochemistry 37, 65–71.
Naik, M., et al., 2008. Production of biodiesel from high free fatty acid Karanja (Pongamia pinnata) oil. Biomass Bioenergy 32, 354–357.
Kwon, E., et al., 2009.  ASME Conference Proceedings, 231–236. 

The Use of Coffee Grounds for the Production of Biodiesel

In recent decades, the production and consumption of coffee has increased.  As a result of the increased consumption of coffee there is a need for waste management of the spent coffee grounds (SCG).  Spent coffee grounds have a very complex chemical composition, which makes them useful for a variety of applications.  SCG have a 1020 wt% of oil content, and, therefore, they are viable feedstocks for the production of biofuels.  The high amount of sugars in SCG can be used to produce bioethanol through fermentation.  In addition, bioethanol can be used along with lipid fraction extracted from SCG to produce biodiesel through transesterification (Caetano, 2011).  Caetano et al. aims to investigate the use of SCG for the production of biofuels, as well as characterize SCG, the oil they contain, and the biofuels they produce.  They also identify the optimal operating conditions in order to extract oil from SCG, to perform oil transesterification to biodiesel, and to assess the biodiesel quality (Caetano et al. 2012).  Shelby Long
Caetano, N. et al., 2012. Valorization of Coffee Grounds for Biodiesel Production. Chemical Engineering Transactions 26.

Caetano et al. examined the use of SCG for the production of biofuels.  They obtained spent coffee grounds from a local coffee shop and allowed them to air dry for several days.  The SCG then underwent repeated cycles of oven drying at 105 + 5 °C followed by cooling in a desiccator.  The grounds were then weighed, and levels of total carbon (TC), total nitrogen (TN), protein content, ash content, cellulose content, and insoluble and soluble lignin content were taken.  In order to characterize and extract oil from the SCG researchers tested different solvents to determine which would be most effective for the extraction process.  For each treatment, 10 g of oven dried SCG and 200 mL of solvent were placed in a Soxhlet extractor for 2.5 to 9.5 hours.  When three consecutive measurements of the solvent refraction index were constant and close to the pure solvent’s value the extraction process was stopped.  The oil extraction rate was determined.  The oil extracted from the SCG were measured for solvent recoverability for hexane, isopropanol, heptane, octane, ethanol.  In order to recover the oil from the extracting solvent researchers used a rotary evaporator and a vacuum pump.  The extracted oil was characterized and assessed based on its quality.  The iodine number, acid value, water content, kinematic viscosity, density, and higher heating value (HHV) were measured.  In order to produce biodiesel, several esterification steps were performed in an orbital acclimatized shaker.  Researchers monitored the acid value of the product throughout the process and at specific steps added 40% methanol and H2SO4to perform the esterification process.  1% NaOH was used as a catalyst.  The biodiesel was then separated from the glycerol phase and washed with distilled water to achieve a neutral pH.  In order to characterize the biodiesel Caetano et al. accounted for the importance of compliance with standards for the use of biodiesel in vehicles engines.  Therefore, they assessed the biofuel density at 15 ˚C, the kinematic viscosity at 40 ˚C, the acid value, the iodine value, and the methyl esters content, which should all be in accordance with EN biofuel standards.
                  The results of Caetano et al.’s study somewhat differ from what previous studies report.  The moisture content is substantially higher, the higher heating value is lower, and the cellulose content differs from what other studies have indicated (Lago et al. 2001; Bizzo 2003; Mussatto et al. 2011b).  The present study suggests these differences may be due to different coffee extraction procedures, different storage conditions of the grounds, and the use of different types of coffee for the experiment.  The solvent that allowed for the highest oil recovery was octane.  Ethanol and hexane allowed for lower oil recovery.  Hexane had one of the higher recover rates, while ethanol exhibited a lower recovery rate.  Isopropanol had a strong capacity of oil extraction and solvent recovery.  The mixture of hexane and isopropanol at a ratio of 50:50 allowed for high oil extraction, but lower solvent recovery.
                  The extracted coffee oil had iodine values that were too low, too high viscosity to be used in direct combustion engines, and too high acidity to be directly converted into biodiesel without undergoing pre-treatment.  However, the high HHV indicates that the oil extracted may be used for direct combustion.  The biodiesel produced was also characterized, and researchers found that the acid value and viscosity were too high to comply with biofuel EN standards.  They suggest that the high water content in the oil and the high acid value may have hindered the completion of the reaction.  Caetano et al. indicate that more improvements in the SCG biofuel production process must be made in order to improve the quality of biodiesel to meet the EN standards.  Some of these improvements include obtaining a higher methyl ester content by drying the oil, removing water between esterifications, neutralizing excess acid before transesterification, and using different methanol-to-oil molar ratios. 

Effect of Increased Corn Ethanol Production on Food Export and Land Use Changes

The global production of biofuel has greatly increased due to energy security concerns.  Over the past two decades, ethanol production in the United States has grown 15–20% per year to meet the increased demand for renewable fuels (U.S. Energy Information Administration 2011).  The majority of ethanol produced within the United States comes from corn sugars.  Approximately 3% of the corn harvest was needed to meet ethanol demand in 1990, but this percentage grew to 37% by 2010.  Due to the increased demand for more renewable energy sources to replace environmentally harmful fossil fuels, policies have been enacted to promote the increased production of biofuel.  One of these policies is the U.S. Renewable Fuel Standard, which aims to increase biofuel production to 36 billion gallons by 2022.  It has been suggested that not only direct effects, but also indirect effects, of biofuel production should be taken into account (Melillo et al. 2009).  The direct effects of biofuel production include greenhouse gas (GHG) emission reductions, while indirect effects may be evident in land use changes.  It has also been argued that an increase in corn ethanol production will lead to a reduction in food exports and deforestation in other nations (Searchinger et al. 2008).  Due to the increase in the availability of U.S. agricultural data, researchers no longer have to rely on theoretical evidence; rather, now researchers can use real agricultural data to determine the effects of increases in ethanol production.  However, these data may not be sufficient enough to fully assess indirect land use changes in the United States (Wallington et al. 2012).  Shelby Long
Wallington, T. et al., 2012. Corn Ethanol Production, Food Exports, and Indirect Land
Use Change. Environmental Science and Technology 46, 6379–6384.

Wallington et al. analyzed the direct and indirect effects of the United States’ recent increase in biofuel production using available agricultural data through 2010.  They examined data on the global production, import, and export of agricultural commodities published by the United States Department of Agriculture Foreign Agricultural Service (USDA-FAS).  They also analyzed monthly data on energy statistics and production of fuel ethanol published by the United States Energy Information Administration (EIA).  Both sources of information were used by Wallington et al. to gain insight on the history of ethanol production and agriculture exports dating as far back as 1960.  Researchers examined agricultural productivity, corn ethanol production, and agricultural exports of the Unites States.  They acknowledge that between 2000 and 2010 the increase in use of corn for ethanol was accompanied by an increase in corn harvest.  However, researchers do not suggest that the increase in harvest was necessarily due to the increase in corn ethanol production. 
Wallington et al. recommend that future models need to account for increased yields in the United States and other countries due to agriculture technology improvements.  They suggest that these improvements are the result of increased biofuel production in the United States.  If this is the case, then researchers suggest decreases in land use outside of the U.S. would result, therefore, translating into a negative, favorable land use change burden.  In the long term, increases in demand for ethanol could lead to lower costs and higher yields.  In the short run, more intensive land use, investment in new production equipment, weather variability, movement of corn onto the better land, and increases in rotation of higher yielding crops (soy and corn) may take place. 
                  Wallington et al. determined that where there was an increase in ethanol production there were no obvious changes in corn and wheat exports in the past decade.  On the other hand, soybean, chicken, and pork exports have increased significantly over the past decade.  Annual corn exports showed no changes, as they remained at approximately 50 million tonnes.  There has also been a large increase in production and exports of distiller’s dry grains (DDG) over the past 10–15 years.  DDG is a co-product of ethanol production and is used as an animal feed.  Therefore, a reduction in demand for animal feed produced outside of the U.S. could be the result of increased biofuel demand in the U.S.  This reduction in demand for animal feed would lead to a negative indirect land use change.  The corn harvest has exhibited an upward trend over the past 50 years, increasing by about 2% per year.  Along with other factors taking place, the increase in harvest over the past 10 years was accompanied by an increase in use of corn ethanol.  There is no trend in the total harvested area of crops such as corn, soy, wheat, oats, and barley.  This may also indicate that there was no increase in the land devoted to the cultivation of these crops.  There is no significant correlation between U.S. ethanol production and corn exports in the past two decades.  Even if there was a correlation it could not be determined for certain whether one was the cause of the other.  Similarly, data on exports of meat and grains do not support the idea that corn ethanol production affects food exports. 
                  A past study predicted that a 56 billion liter increase in corn ethanol production would lead to a decline in corn, wheat, soybean, pork, and chicken exports by 62%, 31%, 28%, 18%, and 12% (5).  However, these levels of decline in exports were not seen as a result of the 43 billion liter increase in production over the past decade.  Another recent study proposed a model on indirect land use changes associated with an increase in corn ethanol production (Hertel et al. 2010).   The modeled increases in ethanol production were very close to the increase that took place between 2000 and 2010.  The model also predicted a net increase of 0.41% in coarse grain yield and a 17% decrease in coarse grain exports due to increases in ethanol production.  However, the historical 15% increase in ethanol production was 40x greater than the predicted 0.41% increase in yield of corn. 
                  The increases in ethanol production over the past decade have been accompanied by increases in harvest.  These increases in harvest are largely the result of improved yield per acre, increased acreage use, genetic improvements/hybrid plant breeding, and improved crop management (22).  There are two main arguments related to the effect of increased biofuel production on agricultural yields.  The first argument is that the increased market for corn ethanol production has not led to increases in agricultural yields.  This argument may be somewhat supported by the historical trend of corn yields over the past decade, which shows no change.  However, there are many other factors, such as population growth, dietary trends, economic growth, energy price fluctuation, and international export/import policy changes that may have been the cause of any changes in corn yields and demand.  Any changes are not necessarily due to the increases in ethanol production.  The other argument is that increases in demand for corn for ethanol production has made some contribution to changes in agricultural yields.  This argument is plausible because increases in demand and supply for corn, and interest in research and development of hybrid plants and improved agricultural practices are likely to lead to increases in corn yields.  Approximately 12 billion gallons of ethanol are made annually, which requires approximately 100 million tonnes of corn.  Approximately 30 million tonnes of DDG are produced as a result, and 1 tonne of DDG displaces approximately 1.2 tonnes of corn as animal feed (Arora et al. 2010).  If biofuel production does not contribute to increased corn yields, then there would be an indirect land use change due to increased corn ethanol production in the United States.  On the other hand, if biofuel production is responsible for all of the increased corn yields in the U.S., but none of the increased yields observed in the rest of the world, then there would be a small indirect land use change.  If biofuel production was responsible for all of the increases in U.S. corn yields and some of the increased yields in the rest of the world, then there would be negative indirect land use change due to corn ethanol production in the U.S.
                  Such large differences in corn yields of the U.S. and the rest of the world indicate that improved agricultural practices should be adopted by other countries, such as improved soil management, irrigation, fertilizer use, and farm machinery.  Due to the detailed agricultural data now available to researchers, new perspectives can be gained about crop yield changes and their effects.  However, further investigation must be conducted in order to gain a better understanding of the land use changes that may take place as a result of increased ethanol production.  In order to decrease the indirect land use changes in other countries as a result of higher biofuel production in the U.S., intensification of agricultural activities outside of the U.S. should be promoted.  Wallington et al. maintains that further investigation must take place concerning indirect land use changes resulting from ethanol production in order to determine what steps must be taken to decrease the impacts.         
Other Sources
U.S. Energy Information Administration, Monthly Energy Review, 2011.
Melillo, J. et al., 2009.  Science 326, 13971399.
Searchinger, T. et al., 2008.  Use of U.S. croplands for biofuels increases greenhouse
gases through emissions from land-use change.  Science 319, 1238–1240.
Hertel, T. et al., 2010.  Bioscience 60, 223–231.
Arora, S. et al., 2010. Estimated displaced products and ratios of distillers’ co-
products from corn ethanol plants and the implications of lifecycle analysis..  Biofuels 1, 911–922.

Economic Benefits of Biofuel Production in Thailand

Biofuel production requires approximately 100 times more workers per joule of energy produced than fossil fuel production (Worldwatch Institute 2007).  Biofuel is not only a viable option in the renewable fuel industry due to its lack of harmful emissions, but the production process also creates vast amounts of new jobs within developing countries.  Ultimately, this increase in demand for workers leads to an increase in overall economic activity and serves as an income generator for the workers who fill these jobs.  Increases in ethanol production are estimated to increase employment by 238,700382,400 people, and GDP by 150 million dollars by year 2022.  Biofuel policies aimed to promote production in Thailand are likely to improve the country’s agricultural sector, develop rural areas, and enhance energy security (Silalertruksa 2012).  In the United States, it is estimated that every 3.785 cubic hecta-meters of ethanol production create 10,00020,000 jobs (Kammen 2011).  Similarly, in South Africa, it has been determined that 350,000 jobs would be created if 15% of gasoline and biodiesel demand were replaced by ethanol and biodiesel production.  However, other aspects of the industry must be investigated, such as work conditions and labor laws.  The demand for biofuels in Thailand is expected to increase, and, therefore, the costs and benefits of increased production need to be taken into consideration.  Researchers expect the increase in biofuel production to have a strong effect on employment rates, GDP, trade balance, and overall socio-economic development (Silalertruksa 2012). Shelby Long
Silalertruksa, T. et al., 2012.  Biofuels and employment effects:  Implications for
socioeconomic development in Thailand.  Biomass and Bioenergy 46, 409

Silalertruksa et al. assessed the benefits of biofuel production increases on the socio-economic development of Thailand.  They examined palm biodiesel as well as ethanol production from cassava, molasses, and sugarcane.  Researchers analyzed the employment effects of biofuel production in Thailand using a “hybrid method” with an analytical approach at the micro level and an input-output model at the macro level.  In order to determine the effect on direct employment due to increases in production they used a production process analysis of the expenditures for labor in land preparation, feedstock plantation, treatment, and harvesting, along with annual wage data (Duer and Christensen 2010).  The following equation was used to estimate the potential direct employment that can be achieved based on labor costs and average annual working hours in Thailand’s agricultural sector: Employmentagr =(PCfeedstock x Laborshare)/AWGagr (Employmentagris agricultural employment in agriculture; PCfeedstockis the production costs of feedstock; Laborshare is the share of labor cost in feedstock production costs; and AWGagr is the average annual wage per employed person in Thailand’s agricultural sector).  Data on the number of employees and production capacity were obtained from 5 sugar mills, 5 dried-chip floors, 10 ethanol plants, 4 palm biodiesel plants, and 17 palm oil mills.  This information was used to determine the effect increases in biofuel production would have on direct employment in the feedstock processing sector.  The impact of increased biofuel production on indirect employment was also examined.  Indirect employment includes the sectors that process intermediate goods that are delivered to the biofuel processing sector.  Researchers used economic input-output tables from 2005 that were compiled and published in an 180 x 180 format, which they then formatted into 50 x 50 input-output table.  They then categorized the final demand for molasses ethanol, cassava ethanol, sugarcane ethanol, and palm biodiesel by organizing their production costs.  These production costs were then assigned to sectors in the input-output table in order to determine indirect employment. 
                  It was determined that the largest amount of employment based on volume of biofuel produced would be created by an increase in palm biodiesel production.  The second, third, and fourth largest amount of employment increases were from sugarcane ethanol, cassava ethanol, and molasses ethanol.  However, based on energy content produced, the greatest effects were in ethanol production, with biodiesel production from palm oil being the lowest.  Researchers determined that significant increases in employment due to direct and indirect employment opportunities would lead to rural development in Thailand.  However, those employed in the biofuel industry are likely to work on a temporary basis, and, therefore, those who work in these industries are not as well-protected by laws for working conditions or other policies. Silalertruksa et al. suggest that policies and laws for working conditions, fair wages, and other labor rights must be considered in order to help small scale farmers, biofuel industry workers, and unpaid family workers secure more rights.  With improved standards for safety risks, safety procedures, child labor, working conditions, and other worker rights the biofuel industry and production can be improved for the future. 
Researchers suggest that further survey and analysis practices need to be adopted in order to determine the overall need for changes in policy because current indicators, such as the Global Bioenergy Partnership (GBEP), cannot be used as a representative of the whole country.  Researchers examined four scenarios for increasing feedstock production.  Scenario 1 would expand the cultivation areas for cassava and sugarcane, Scenario 2 would include machines to help cultivate cassava and sugarcane, Scenario 3 requires a 50% increase in labor for the production of feedstock, and Scenario 4 requires labor that increases at the same rate as yield production.  In order to produce 9 cubic decimeters per day of ethanol by 2022, it was calculated that a range of 238,700–382,360 persons would be needed.  The lowest number of workers would be required in Scenario 2 because many of the workers would be replaced by mechanization. 
Increases in the biofuel sector would spark national development through increases in GDP due to increases in investment in the biofuel sector and improvement in the trade balance and energy security.  Researchers calculated the total impact of different types of biofuels in Thailand on GDP.  They determined that producing 1 million liters of cassava, molasses, and sugarcane ethanol and palm biodiesel would contribute to GDP by 499, 411, 604 and 632 k$.  Feedstock, the most costly aspect of biofuel production, affects GDP by approximately 62–73% directly or 29–55% in total impacts.  However, an increase in the production of biofuel will also lead to a decrease in the production of petroleum, and, therefore, a decrease in GDP by around 90%.  The decrease in GDP due to reduced petroleum fuel production offsets some, but not all, of the increase in GDP due to increases in biofuel production.   This rise in GDP also implies a rise in the incomes of workers.  Also, an increase in production by 1 TJ of cassava ethanol, molasses ethanol, sugarcane ethanol, and palm biodiesel will result in an increase in total imports by approximately 29, 18, 49, and 15 k$.  However, by replacing petroleum fuels with biofuels imports could decrease by 10–41 k$ TJ—1 of ethanol and 46 k$ TJ—1 of biodiesel.  The indirect impact of chemicals used in the biofuels conversion stage and from energy consumed contribute largely to imports.  The total imports of chemicals for biofuel production account for approximately 25–68% of total imports; therefore, if ethanol production reaches a level of 9 cubic decimeters per day by 2022 then ethanol production could help reduce imports by 2547 M$ per year.  Researchers determined that in order to improve security of feedstock supply for long-term ethanol production, cassava and sugarcane yields must be improved to 50 t and 125 t ha—1 by 2022 (Silalertruksa and Gheewala 2010).  In order to achieve these levels, Silalertruksa et al. recommend that more research be done to develop high yield varieties of cassava and sugarcane and to promote good agricultural practices (GAP) to improve yields.  Increased biofuel production could also have adverse effects, such as decreased access to food for poor families, permanent farm labor of young workers, and the loss of small-scale farmers’ access to land.  Therefore, policies must be formed in order to alleviate these potential problems.
Silalertruksa et al. assert that biofuel production results in many positive externalities to the Thai economy.  It is estimated that 1720 more workers are needed for biofuel production than gasoline production, and biodiesel production would produce 10 times more workers than diesel production.  They suggest that not only does biofuel production increase the need for workers, but it also leads to a decrease in ethanol and biodiesel imports and an increase in GDP by up to $60 k per dam3 of biofuels produced.  These socio-economic benefits could make biofuels more price competitive in comparison with petroleum fuels as well.  Also, increases in biofuel production through community-based plans are also expected to help raise the living standards of rural communities as people learn to derive biodiesel from cooking oil or other oil plants from their land.  This could make energy cheaper and more available to rural communities.  
Other Sources
Duer, H. and Christensen, P.O., 2010.  Socio-economic aspects of different biofuel
development pathways.  Biomass Bioenergy 34, 237243.
Kammen, D.M., 2011.  Hearing on: green jobs created by global warming initiatives. 
United States senate committee on environment and public works.
Silalertruksa, T. and Gheewala, S.H., 2010. Security of feedstocks supply for future
bio-ethanol production in Thailand. Energy Policy 38, 74767486.
Worldwatch Institute, 2007. Biofuels for transport: global protential and
implications for sustainable energy and agriculture.