Global Warming Reduction by Switching to Healthy Diets

by Shelby Long

The consumption of food and beverages accounts for 22–31% of total private consumption greenhouse gas (GHG) emissions in the EU (Tukker et al. 2009). More specifically, the production of meat and dairy products tend to produce greater GHG emissions (Audsley et al. 2009). Saxe et al. (2012) examine how different diets, which are composed of different foods, are associated with varying potential GHG emissions. They use consequential Life Cycle Assessment to compare the emissions, or global warming potential (GWP), from food production for an Average Danish Diet (ADD), the Nordic Nutritional Recommendations (NNR), and a New Nordic Diet (NND), which was developed by the OPUS Project. They determined that the GHG emissions association with NNR and NND were lower than those associated with ADD, by 8% and 7%, respectively. When taking into account the transport of food, NND emissions are 12% less than ADD emissions. With regard to organic versus conventional food production, GHG emissions are 6% less for NND than for the ADD. Saxe et al. adjusted NND to include less beef and more organic produce, and they substituted meat with legumes, dairy products, and eggs, which made the diet more climate-friendly. As a result of this adjustment, the GHG emissions associated with NDD was 27% less than emissions for ADD. Continue reading

The Effect of Climate Change on Prawn Fishing in Bangladesh

by Shelby Long

Nearly 400,000 Bangladeshi people are financially dependent on the fresh water prawn market. Bangladesh offers the natural resources and ideal climate to support prawn farming from wild postlarvae. In 2002, a ban was placed on the fishing of wild postlarvae by the Department of Fisheries in Bangladesh. However, this ban is not strongly enforced, so many locals who rely on the market to make a living continue to fish. Ahmed et al. (2013) examines the effect of climate change on prawn fishing in the Pasur River through variables, including cyclones, salinity, sea level rise, water temperature, flood, rainfall, and drought. The Pasur River ecosystem, more specifically the prawn postlarvae, is highly vulnerable to climate changes because it is only one meter above sea level. Researchers surveyed and interviewed local fishermen, government fisheries officers, policymakers, and non-governmental organization workers. They also conducted focus group discussions with fishers and local community members regarding the various climate-affected variables under study. Ahmed et al. determined that prawn postlarvae catch has gradually decreased by approximately 15% over the past five years, with cyclones being the most significant climatic variable affecting the catch. Decreases in postlarvae prawn catch impact the health and socioeconomic well-being of local fishermen, many of which are women and children. Continue reading

Effect of Climate Change on Australian and Global Food Production

by Shelby Long

Recent droughts associated with climate change have had immense negative effects on food production in Australia. Australia is an important producer and exporter of livestock, dairy, and wheat. Much of the wheat produced is exported to Indonesia, Japan, South Korea, Yemen, Vietnam, and China. The Murray-Darling Basin is one of the main agricultural areas in the country, contributing 40% of Australia’s gross value of agricultural production. Water scarcity is accompanied by a high demand for water for both agricultural irrigation and non-agricultural uses (Quiggin and Chambers 2004). Therefore, it is necessary for crop producers to adopt new strategies to mitigate the impacts of drought. Some of these strategies include land use changes and introducing drought tolerant crop varieties. Qureshi et al. (2013) aim to use the Australian Bureau of Statistics (ABS) data and modeling to explore the possible future effects of Australian water Continue reading

Climate Change Increasing Water Scarcity

by Shelby  Long

The production of food and economic prosperity are highly dependent on a sufficient water supply. Both the demand and supply for water are affected by climate change-induced adjustments of precipitation patterns, temperature, other climate variables, and shifts in population. Much uncertainty remains among climate change models regarding how precipitation levels and patterns, as well as temperature, will change (Meehl et al. 2007). Also, precipitation changes affect other hydrological variables, such as surface or subsurface runoff and river discharge, and, therefore, effective hydrological and climate change modeling takes these variables into account. Schewe et al. (2013) use multiple global hydrological models (GHMs) and greenhouse-gas concentration scenarios to examine how climate change impacts global water resources. They determined that climate change is likely to intensify regional and global water scarcity. They project that a 2°C increase in global temperature will result in approximately 15% more of the global population experiencing a severe decrease in water resources. They also project this 2°C rise in temperature to increase the number of people living under absolute water scarcity by at least 40%, while some models predict a 100% increase. Along with climate change, they expect future population growth to Continue reading

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
418.

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.

Increase in Efficiency of Cattle Manure Biogas Production Due to the Addition of Palm Oil Effluent

Fifty-eight million tons of palm oil mill effluent (POME) is produced each year in Malaysian palm oil mills.  This effluent can be used for biogas production, an especially viable renewable energy source in India, China, Malaysia, Thailand, Indonesia and the Philippines where palm residue is in high abundance (Renewable Cogen Asia).  Typically, biogas is produced from industrial, municipal, and agricultural waste, such as cow manure.  Raw palm oil contains high levels of fatty acids and oil, and, therefore, a high oxygen demand, which makes it necessary to treat in oxidation ponds where it can also be used to support bacterial growth (Alias and Tan 2005, Zakaria et al. 2008).  This form of anaerobic digestion not only is a form of waste treatment, but it is also used for the production of biogas in the absence of oxygen (Santibanez 2011).  Therefore, scientists expect that palm oil effluent can also be used as a beneficial additive in the treatment of cattle manure for biogas production (Nasir et al. 2012).  Shelby Long
Nasir, L.M., 2012.  Palm oil mill effluent as an additive with cattle manure in biogas
production. Procedia Engineering 50, 904912

Nasir et al. investigated the benefits of using palm oil effluent as an additive in cattle manure biogas production.  Researchers created an anaerobic environment in a jacketed fermenter from which they sampled the products of the cattle manure and palm oil effluent digestion daily.  They used a 10 L fermenter to conduct two treatments.  In the first treatment they placed 500g of fresh cattle manure and 1.5L of POME in the fermenter.  In the second treatment they only added 500g of cattle manure and added distilled water in order to achieve a solid content of 9%.  For both treatments, they carried out a batch mode for the first ten days and a semi-continuous mode for the remainder of the experiment.  In batch mode they added the contents to the fermenter and allowed it to digest for ten days.  In semi-continuous mode they removed digested cattle manure daily and replaced it with the same volume of fresh cattle manure.  For both treatments, they maintained a temperature of 53˚C in the digester, and they controlled the pH by adding 1 N HCl and 1 N NaOH as needed.  The contents were stirred at a constant speed of about 150 rpm.  In order to maintain the anaerobic environment in the sealed digester nitrogen gas was added to purge the oxygen.  Researchers removed samples on a daily basis and analyzed the total solids (TS), volatile solids (VS), biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonia nitrogen content, and methane content.  They used a gas chromatograph to analyze the methane content and a spectrophotometer to measure the methane content.  In order to measure the biogas produced in the digester, researchers used the water displacement method.  
            Nasir et al. observed that biogas production in the first treatment, with cattle manure and POME, was continuous in the batch operation but declined after the sixth day.  However, the production increased at a constant rate during the semi-continuous mode.  The biogas production was more rapid for the first half of the digestion period and the methane content fluctuated between 5255% through the course of the experiment.  In the second treatment, with no POME, biogas production began on day 2 and peaked after four days.  The biogas production only achieved a methane content of 20%.  The level of biogas production in the first treatment (0.346 m3kg-1VS) was almost three times greater than the biogas production in the second treatment.  Researchers determined that the increase in biogas potential of the cattle manure is most likely caused by microbial degradation of organic matter because of anaerobic bacteria in the POME additive (Zakaria 2007).  
The ammonia nitrogen NH3-N content observed in the cattle manure and POME treatment seemed to stabilize throughout the experiment, only fluctuating between 400 and 600 mg/L, while the NH3-N content in the cattle manure treatment fluctuated in large amounts, between 400 and 800 mg/L.  The stabilization of ammonia nitrogen content within the cattle manure and POME treatment suggests that the nitrogen ammonia did not inhibit the digestion process with POME present, which ultimately led to a higher biogas and methane production.  Conversely, the high fluctuations in NH3-N in the cattle manure treatment suggest that the accumulation of ammonia nitrogen led to a lower amount of biogas production because of an inhibition on microorganisms.  After three days, the volatile solids content in both treatments began to decrease more rapidly, which was most likely due to the ideal pH and temperature and adaptation of the microorganisms present (Dubrovskis et al. 2009).  Overall, more VS were removed from both treatments during the semi-continuous period than in the batch period. 
The chemical oxygen demand concentration decreased most rapidly for both treatments within the first ten days, which is most likely due to hydrolysis of the cattle waste.  The fluctuations in the COD during the semi-continuous operation was likely due to the continuous adaptation of the microbial population to the changing environment within the digester (Muhammad 2011).  The substrate concentrations sampled from both treatments throughout the experiment suggest that the reduction in TS, VS, and COD can be significantly improved by two-fold using POME additive during cattle manure biogas production.  Nasir et al. recommend the use of POME as an effective additive in the biogas production from cattle manure through anaerobic digestion.  They suggest that not only would the POME considerably improve the removal of TS, VS, COD, and ammonia nitrogen in cattle manure digestion, but the process would also create a use for the palm oil waste from mills.          
Other Sources
         
        Alias Z. and Tan, I.K.P., 2005.  Isolation of palm oil-utilising, polyhydroxyalkanoate (PHA)-producing bacteria by an enrichment technique.  BioresourceTechnology 96, 1229–1234.
         
Dubrovskis V. et al., 2009.  Investigation of biogas production from mink and cow
manure. In Proceedings of the 8th International Scientific Conference, Engineering for rural development.
Muhammad, N.I., 2011. Anaerobic digestion of cattle manure with Palm Oil Mill
Effluent as inoculum for biogas production.  Department of Chemical and Environmental Engineering Universiti Putra Malaysia.
               
Renewable Cogen Asia. Biogas Power Asia.  http://www.rcogenasia.com/biogas-
power-cogen/biogas-power-asia/Accessed on: 13th June, 2012.
Santibanez, C. et al., 2011.  Residual glycerol from biodiesel manufacturing, waste or
potential source of bioenergy: A review.  Chilean Journal of Agricultural Research 71, 469–475.
Zakaria, M.R., 2007. Biogas production and determination of methanogens from
digester-treated palm oil mill effluent. Master Thesis 2007; Department of Biological Sciences, Universiti Putra Malaysia.
         
Zakaria M.R. et al., 2008.  Comamonassp. EB 172 isolated from digester treating
palm oil mill effluent as potential polyhydroxyalkanoate (PHA) producer.  African Journal of Biotechnology 7, 4118–4121.

Renewable Energy for Marine Vessels

Marine transportation remains one of the most important sources of cargo transportation on Earth; however, it has been estimated that 60,000 premature deaths each year can be attributed to ship emissions (Hiricko 2008).  Marine vessels, which run on petroleum-derived diesel, are one of the largest contributors to air pollution, global warming, and premature deaths.  In order to reduce the high amount of greenhouse gas contribution and premature deaths Lin (2013) emphasizes the need to replace marine fuels, which contain sulfur, asphalt, and other environmentally harmful components, with a more environmentally friendly fuel (Lin and Lin 2006).  As a renewable and clean fuel, biodiesel has the potential to become the new leading energy source in the marine transportation sector; however, without large steps being taken to formulate marine biodiesel blends, reduce manufacturing costs, increase subsidies, and improve marine biofuel technology this potential will not be met. —Shelby Long
Lin, C.Y., 2013.  Strategies for promoting biodiesel use in marine vessels.  Marine
Policy 40, 8490.

Cherng-Yuan Lin of the National Taiwan Ocean University investigated the necessary development of biodiesel for the marine transportation sector.  He analyzed current emission limit requirements for marine vessels, environmental impacts of biodiesel, the biodiesel life cycle, obstacles for biofuel use in marine vessels, and strategies to overcome the obstacles.  Current and proposed emission limits for sulfur oxide and nitrogen oxide have been set by the International Convention for the Prevention of Pollution from Ships (MARPOL).  Biodiesel contains fatty acids and other contents that do not produce harmful emissions like petroleum diesels do when combusted, such as sulfur oxides.  Research shows that as the proportion of biodiesel blended into liquid fuel increases, the nitrogen oxide emissions decrease (Qi et al. 2011).  When analyzing the life cycle of biodiesel there are five stages that are taken into account:  feedstock production, transportation of feedstock, production of the fuel, distribution, and use of the fuel (National Biodiesel Board 2005).  Past studies have shown conflicting results over whether the total production of biodiesel requires more energy than it produces.  More specifically, a study by Pimentel and Patzek suggests that 118% and 27% more fossil fuel energy was used to produce sunflower and soybean oil biodiesel than total biodiesel oil was produced (Pimentel and Patzek 2005).  However, a more recent study by the National Renewable Energy Laboratory found that 320% of biodiesel energy is produced for every unit of fossil energy input during soybean biodiesel production (Sheehan et al. 1998).  These conflicting results can be accounted for by the lack of a precise definition for energy input and varying methods for calculating energy use within the biodiesel life cycle (National Biodiesel Board 2005).  An obstacle that remains for biodiesel use in marine vessels is the lack of a marine-grade biodiesel specification.  There are specifications for biodiesel use in land vehicles; however, marine vessels are very different in that they contain copper and other metal components which are susceptible to deterioration by biodiesel (Nayyar 2010).  Another obstacle is the large amount of farmland needed to grow the vast amount of feedstock required for the production of the biodiesel.  Lastly, Lin examines the low-temperature fluidity of biodiesel, which is a problem for marine vessels operating in colder climates.  As the surrounding temperatures decrease, crystals form in the biodiesel, which can plug the fuel lines.  
Lin suggests strategies to combat the various obstacles inhibiting the use of biodiesel in marine vessels.  In order to establish a marine biodiesel specification, he recommends that field tests must be conducted to determine the optimal mix of biodiesel and marine fuel using current ASTM biodiesel specifications and marine heavy fuel oil standards for density, viscosity, flash point, etc.  He recommends government subsidies, tax cuts, tax exemption, and fuel tariffs be made for marine-grade biodiesel to make it more price-competitive and to promote the long-term development of renewable marine biodiesels.  Previous studies have shown that an increase in the proportion of biodiesel to marine diesel results in decreased emissions from fishing boats (Lin and Huang 2012).  Therefore, if the amount of biodiesel were to be increased it would not only result in the decrease in the price of biodiesel due to economies of scale, but it would also reduce overall emissions.  Also, Lin suggests that storage tanks that are susceptible to deterioration from oxides reacting with biodiesel must be substituted with carbon steel, aluminum, fiberglass, or stainless steel tanks. 
In order to improve the fluidity of biodiesel in colder temperatures various combinations of biodiesel feedstocks must be tested.  Certain biodiesel types have a higher saturated fatty acid content, which creates a higher temperature at which crystals form and clog fuel lines; therefore, different feedstocks can be mixed in varying proportions to create an optimal blend that can withstand a desired temperature.  Lastly, Lin suggests that glycerol, a byproduct of the transesterification process of biodiesel production, can be purified and sold to the pharmaceutical, cosmetic, and other lucrative industries.  The selling of this glycerol surplus can be used to lower the price of biodiesel production and to decrease the environmental harm untreated glycerol can cause.  Although there are various obstacles that must be overcome in order to create a widely-used marine-grade biodiesel, these obstacles have feasible solutions.  Lin maintains that if these solutions are achieved and the renewable and clean biodiesel energy is used in the marine transportation sector, worldwide emissions will be reduced, thereby decreasing global warming and protecting people’s well-being.
Other Sources
        Hiricko, A. 2008.  Global trade comes home: community impacts of goods movement. Environmental Health Perspective 116, A78–A81.
         
        Lin, B. and Lin, C.Y. 2006.  Compliance with international emission regulations: reducing the air pollution from merchant vessels. Marine Policy, 30, 220–225.
        Lin, C.Y. and Huang, T.H. 2012. Cost–benefit evaluation of using biodiesel as an alternative fuel for fishing boats in Taiwan. Marine Policy 36, 103–107.
National Biodiesel Board. 2005. Response to David Pimentel biodiesel life cycle
analysis.
Nayyar, P. 2010. The use of biodiesel fuels in the U.S. marine. Report for the U.S.
Maritime Administration (MARAD).
        Pimentel, D. and Patzek, T.W. 2005. Ethanol production using corn, switchgrass, and wood; biodiesel production using soybean and sunflower. Natural Resources Research, 14, 65–76.
        Qi, D. et al. 2011. Effect of EGR and injection timing on combustion and emission characteristics of split injection strategy DI-diesel engine fueled with biodiesel. Fuel 90, 1884–1891.
Sheehan J. et al. 1998. Life cycle inventory of biodiesel and petroleum diesel for use
in an urban bus, final report. National Renewable Energy Laboratory, NREL/SR-580-24089 UC Category 1503.