Biofuels: Getting the Energy Without Losing the Food
Photo by Steve Jurvetson/CC BY 2.0
Article by Anna Gomes
In a time of exponential population growth, devastating biodiversity loss, and global temperatures rising faster than scientists had predicted, innovative thinking is crucial to continuing climate change mitigation efforts. When most people consider renewable energy sources, many overlook the possibility of using biomass to generate power, instead, thinking only of solar panels, wind turbines, and hydropower. However, this fuel source may hold more promise than it is given credit for. Contrary to popular belief, an increase of biofuels does not necessarily lead to an increase in food prices. Additionally, some claim that burning biofuels increases greenhouse gas levels, but in actuality, biofuels release the same amount of CO2 taken in by plants during photosynthesis, thus making it carbon neutral. As the world becomes increasingly globalized and transportation becomes the second largest source of greenhouse gas emissions (GHGs), directly behind electricity, over 90 percent of transportation fuel is dirty petroleum based.[1]
Biofuels have been around since cars started driving on roads. Even Henry Ford planned to fuel his Model T with ethanol![2] Once huge underground petroleum deposits were discovered, biofuels were simply left in the dust. However, now biofuels are beginning to regain the limelight they once had. According to Dr. Alison of the Department of Energy and based on 2016 Billion-Ton Report[3], biofuels can lead to energy security, independence of foreign sources, and greater environmental sustainability and are an overall cleaner energy source than traditional coal-based and petroleum-based fuel. Really, the only obstacle to the widespread use of biofuels is the large number the misconceptions that stand in their way.
Food vs. Fuel:
First, let’s confront the elephant in the room: is it really true, as many believe, that increasing use of biofuels would lead to an increase in the cost of food? The impression is partly due to the widespread belief that corn is the only option for producing biofuels, but many alternative efficient and environmentally friendly options have been and are being developed. Diverting corn to bioethanol can raise corn prices.[4] Nonetheless, further research and support for alternative biofuels, can lead to less dependence on corn. The shrinking dependence on human or animal crops for biofuels, the smaller the chances of biofuels altering the market structure of food prices.
The problem is not that food is diverted to produce fuel when many people are left starving. The problem is that our nation currently has a food waste issue. We do create enough food to be used for both biofuel feedstocks and fuel. According to Tristram Stuart’s fact-based novel, Waste: Uncovering the Global Food Scandal, [5] “There has been enormous attention paid to the ‘waste’ of food by US and European decision to use food grains and pulses to make biofuels. It is true that under current circumstances, and in some instances, the biofuel industry is… doing more harm than good to the climate[6]… But what about filling waste-bins in preference to feeding people? This is surely worse.” Stuart then states that the amount of food diverted to biofuels is less than half of the current amount of wasted food in the world.[7]
It becomes easier for the public to accept that ‘food to fuel’ is causing hunger and food shortages, when in reality, our treatment of food as a disposable commodity and our continuous waste from production to consumption, is the main issue here. Besides the upstream sources of food waste from farm to table, consumers generate a large volume of downstream waste in the form of kitchen byproducts and uneaten food. Left in the field or lost in food processing facilities, a large portion of grains, fruits, and vegetables produced never end up on the dinner table. Although oil and starch-rich substances are not consumable products within the food system, they can be used to create successful biofuels, without even changing the production systems. Americans could save two percent of all United States energy consumption if we ended our extensive food waste pattern. The Environmental and Energy Study Institute (EESI), analyzed data on food processing and crop waste to illustrate that unused agricultural production represents a potentially large resource. With current and future innovations in technology, we can turn some of this nutrient rich waste into usable energy in the form of biofuels and its byproducts.
The Process:
Recycling the waste mentioned in the previous section is only possible due to the specialized production processes and machines, which can turn plant material into flowing fuel. Biofuels come in multiple forms: bioethanol, biomethane, or biodiesel. Nonetheless, all of them are produced from living materials– the stored energy in which is generated through photosynthesis.
How is ethanol made? Once harvested, the feedstock crops are fermented into ethanol, an alcohol, with the addition of yeast. The combustion of ethanol creates chemical energy, water, and CO2 (ethanol + oxygen yields 4CO2 + water + ENERGY). The starch from the biomass is used to create the fuel; while the rest of the crop, known as distillers grains, is sent into the animal feed system as dry or wet mass. This leftover resource has high fiber content, containing the nutrients from the original crop as a result of only the starch being removed. Current research efforts are converting that leftover plant mass into energy as well, known as cellulosic ethanol, as this allows for almost zero waste of the entire crop. As the GHGs from biofuels come from side processes (transportation, fertilization, etc.), by using all parts of the crop, we can become less wasteful. More efficient utilization of the leftover biomass could help to further shrink the carbon footprint of producing ethanol.[8]
When consumers pull into a gas station, the most common fuel being pumped into a person’s car has about 10% ethanol. With flex-fuel vehicles, or vehicles with modifications to the fuel systems, they can use E85, a fuel with 85% ethanol and 15% petroleum, resulting in less particulate matter and lower GHG emissions. Bioethanol–meaning any biofuel produced by fermenting starch–can be produced from corn as well as many other products. The starch may from corn, wheat, potatoes, or even sugarcane. Most of the starch is produced in the Midwest, since most of the crops used for ethanol production are grown there.[9]
Another green source of energy, biomethane[10], or renewable natural gas (RNG), fits into the current Renewable Fuel Standards (RFS). Produced by anaerobic digestion of organic matter or a thermochemical process called gasification, biomethane production eliminates the release of large amounts of methane into the atmosphere, preventing the escape of harmful GHGs. The production process limits the exposure of decomposing organic matter to the air. Unlike natural gas, biomethane is produced from fresh organic matter.
The third form of biofuel is biodiesel. Biodiesel is produced through a process called transesterification, wherein glycerin is separated from the vegetable or fat oils. In addition to methyl esters (the biodiesel), transesterification produces glycerin, which is a valuable byproduct for pharmaceuticals or cosmetics. As a cleaner burning replacement for petroleum diesel fuel, biodiesel is a smarter way to fuel compression-ignition engines, as this form of fuel is an equally powerful environmentally friendly option. [11]
Not Just Corn:
Biofuels can be made from a variety of different organisms, crops, and substances. Non-edible crops, like fast growing trees and grasses, can be grown specifically for energy.[12] This has been done, for example, with switchgrass, a perennial grass native to North America, and sugarcane, a perennial grown in tropical environments. Switchgrass can grow in nutrient deficient soils without significant insect or disease problems. [13] As a high-yield feedstock alternative, once established, switchgrass can successfully produce biomass for 10-20 years. Switchgrass absorbs high rates of CO2 during growth, requires one third less nitrogen and water than corn, and is grown on land unsuitable for cultivation of edible crops. Farmers are hesitant to plant the perennial grass without a viable market, and since this form of biomass is not yet grown on a commercial scale, farmers face issues with seed availability, crop storage, and transport.
Sugarcane, currently occupying 10% of Brazil’s cropland, is a bioethanol crop with potential. Rarely discussed as a biomass crop, sugarcane grows year-round, produces more energy per hectare than corn, and contains nitrogen-fixing bacteria within its tissues, allowing it to maintain high levels of productivity with low inputs of fertilizer. The bioethanol is produced from the sucrose found in sugarcane juice and molasses, using up one-third of the energy potential of sugarcane. The other two-thirds is contained within the leftover sugarcane (bagasse) and straw, which scientists are working on converting this into fuel as well, cellulosic ethanol. A variety of feedstock are available and in progress.[14]
Show me the Money:
Biofuels can compete with traditional petroleum-based fuels when one considers the actual price of fossil fuels. ‘Actual price’ refers to the cost of GHG pollution to society, the environment, and personal health. However, petroleum-based fuels have a number of tax-related subsidies. Although there continues to be significant resistance to the idea in the US, some states and governments are already setting up carbon tax systems or subsidies for renewable fuel use. Research by the University of Illinois Extension Office concerns the difficulty of biofuels to compete financially, “It is difficult for solid biomass such as crop residue and wood chips used for heat and power to compete with coal at present prices. If pelletizing processes are used to make the biomass denser and easier to handle these add to the cost.” [15] In addition, biomass is expensive to transport, as it usually contains unprofitable dirt and water content, adding to the weight. Perhaps someone could design a special truck which could process the biomass, dehydrate it, and collect the water in a tank, recycling that water back to the farm. By reducing the distance the biomass travels from field to factory, this would not only reduce transportation costs, but would further reduce the small amount of carbon pollution the bioethanol produces.
Current large scale markets in the United States may not be ready for biofuels, but there are other opportunities, such as pellet stoves for home or small business heating systems that may offer profitable returns on biomass crops. Following the 2016 Billion-Ton Report by the Department of Energy’s Bioenergy Technologies Office (BETO), in order to market one billion tons of biomass, both a market pull and supply push will be critical. Market pull will source from higher demand, larger international markets, and more efficient conversion, while supply push will come from advancements such as precision agriculture and improved crops.
Do We Have Enough Biomass?
In the 2016 Billion Ton Report[16] released by the United States Department of Energy in July 2016, the authors conclude that the United States has the potential to produce one billion tons of biomass annually without interfering with its ability to meet its food, animal feed, and fiber needs, also. Furthermore, the report projects production of 1 billion to 1.2 billion tons of sustainable biomass by 2030, and 1.2 billion to 1.5 billion tons by 2040. An action plan following this informational document will be released in December 2016. That action plan will provide a practical layout for the opportunities biofuels have for our nation based on the work of multiple universities, scientists, and USDA datasets.
Current Efforts:
In order to incentivize switching to renewable fuels, Congress created the Renewable Fuel Standards program (RFS), which (as explained here) calls for an increase in advanced biofuels and increasingly strict standards raising over time, slowly creating a cleaner fuel system. The Climate Institute has been involved with one attempt to further this effort, working with Sustainable Solutions Technologies to develop and market an advanced biofuel from jatropha seeds grown in the Dominican Republic. This would be mainly biodiesel turned into a 50/50 jet fuel blend to be sold to military bases and airports in the southeastern region of the United States. [17]
Jatropha curcas is a small tree or large shrub found throughout the tropical regions of the world that is well-adapted to nutrient poor soils and rain-fed environments. As with many other biofuel products, there has not yet been much research on jatropha-derived biofuels. However, we do know that jatropha biodiesel can be an eco-friendly, biodegradable, and renewable fuel source. As a crop that can be grown by multiple small farmers, including using an intercropping system of energy stock and food crops, jatropha is a non-edible feedstock with a huge amount of potential. Recent studies found that the seeds contain 30-35% oil, which can be converted into fuel by transesterification.[18]
With the biojetfuel proposal in the works, our product could fill a niche market with the Department of Defense and the airline industry. Airplanes currently produce 11% of the transportation sector emissions in the United States. Since very few airplanes can run off of clean, renewable energy systems, airlines will need to begin adopting biodiesels if they want to get that number down.
The Challenges:
Why have biofuels not completely replaced traditional, dirty, polluting petroleum-based fuels? In short, science is full of trade-offs. Not one type of renewable energy source, new technological invention, or method of producing power will solve our current problems caused by climate change. It can be difficult to find a balance between economic and environmental sustainability.
One issue is that since the supply of biofuels is still at a low level, compared to petroleum-based fuels, it is difficult to make them cost competitive. Likewise, today’s extremely low oil prices are only hindering the switch to biofuels. By scaling up the United States bioeconomy, increasing the research and technology funds directed, and increasing policy support, we could lower fuel prices enough for biofuels to compete with fossil fuels.[19]
Despite biofuels’ carbon neutrality, most people tend to focus on the backstory. The majority of the GHGs produced from biofuels are linked to fertilizer application during biomass production. Due to the fluctuating growing conditions that most farmers face, nitrogen fertilizers become an essential piece to the puzzle of crop yields. The application of the fertilizers stimulates microbes, which then release N2O, a potent climate forcer, into the atmosphere. Besides the fertilizer treatment, manufacturing requires energy and distribution uses fuel.
Growing the food, plants, or stock for the biofuel uses sophisticated farm machinery, which burns fuel, introduces fertilizers which can leach into the ground water, pesticides which can harm beneficial insects, and uses tons of water, which can be scarce in certain regions of the United States. By picking location and crop combinations strategically, water efficiency can be maximized. When possible, selected crops should be grown in specific locations where rain fed irrigation is dominant.
Fortunately, researchers are working to find high yield strains of crops which need relatively little fertilizer and water. Precision agriculture, or highly specific and efficient treatment of crops, is helping to decrease fertilizer and water use. The University of Illinois is conducting studies to measure the age in soil nitrogen, giving precision agriculture another tool of knowledge in its toolbox. By selecting locations with a successful rain fed farming system, this method will prevent the extreme use of irrigation that causes salinization of the soils.[20]
Another drawback to biofuels is that the transportation of biomass to the processing facilities both is economically inefficient and itself produces GHG emissions. For since much of the biomass has a high percentage of water from growth, the feedstock is very heavy, and as a result it is expensive to move from place to place. And since the trucks that move it use gas or conventional diesel fuel, they add to our already excessive GHG emissions and undercut some of the emissions reductions that would otherwise be associated with biofuels. Fortunately, we may be able to solve both of these problems: the development of technology which dries biomass fast and affordable, would bring down costs. In addition, using biofuel to power the trucks would almost “cancel out” the challenge of transportation pollution.
The process of turning biomass into biofuel needs further research, as burning, fermentation, and distillation can be environmental enemies. Producing ethanol involves breaking down cellulose. Doing so is very difficult, requires a large amount of energy in the factory to break through that cellulose, and involves many steps with a high price tag. Research is being carried out to increase the efficiency of this process.
Forest-based residues from logging, timberland clearing, and fire control could also be another biomass source. Likewise those from agriculture. If wood as a bioenergy source is used in a sustainable manner, the biofuels it can produce can be successful. By not harvesting wood solely for energy purposes, and only removing forest leftovers, we would be burning only the waste with protection of national parks and continuous consciousness of the forest’s annual growth rate. By finding a home for this wood waste, we could give forestry companies and other companies alike a place for their production waste, one that might actually recycle its nutrients and potential.
Not only can wood residue and leftovers be converted into pellets for energy production, it can also be used to help mitigate fertilization runoff from biomass production. In a recent study, scientists created bioreactors, or woodchip filled trenches. The wood chips are not the superheroes, but simply the foundation for the bacteria that is neutralizing the nitrogen threat to downstream waters. Another study conducted by the American Society of Agronomy follows the precision agriculture approach to reduce nitrogen application as much as possible, saving nutrients and avoiding the extra costs for farmers.[21] By facing challenges with innovation, new and exciting mitigation strategies can be designed and implemented.
Our Innovative Future:
Working with the natural processes of life instead of against biology could lead to real solutions.
Microalgae are small, aquatic organisms that convert sunlight into energy. Some of these species can store energy in the form of oils that can be used as a natural biofuel. According to research by the US Department of Energy, algae could potentially produce sixty times more oil per acre than land-based plants. Besides the amount of sunlight the algae needs for photosynthesis, it can be grown almost anywhere, even as a resource to clean up wastewater. Since algae need CO2 to grow, it serves as a resource for temporary carbon sequestration, becoming a nearly carbon-neutral fuel source. We could make use of the waste products of energy production by placing an algae farm adjacent to a power plant emitting CO2. Genius. Even better though, would be eliminating CO2 -spewing power plants altogether. The USDA set up a program in 2011, which serves as an example of funding and support for this innovative fuel source, providing Sapphire Energy a $54.5 million loan guarantee to construct an algal oil commercial facility. Sapphire’s “Green Crude Farm”, is the one of the instances where USDA funding has assisted the development of biorefineries. [22]
Since cellulose in plant cell walls is so difficult and expensive to break down in order to produce biofuels, why not use an organism that does just that each and every day, naturally? Mushrooms could be one possible solution.[23] Lignocellulose is the primary building block of plant cell walls and is composed mainly of cellulose, hemicellulose, and lignin. Using microorganisms, such as fungi, to degrade the lignin could be a unique but highly efficient way to produce biofuels from non-traditional plant waste. Lignocellulosic biomass is a renewable, sustainable, and abundant source for producing low carbon emission fuels. Certain species of fungi can degrade lignin, leading to almost no loss of cellulose quality or energy potential.
Following the example of innovation concerning the production of biofuels by mushrooms, further research still needs to develop more efficient, more abundant, and higher quality fuel sources and production processes. In order to keep our current food prices stable, we need to develop drought tolerant, low maintenance, and non-food sources to produce sustainable biomass. Other management practices include utilizing intercropping systems, cover crops, and the use of rain fed irrigation. Agricultural practices can be adapted and improved to help both the farmers and the energy market. The National Renewable Energy Laboratory in Colorado is doing great work converting biomass into fuel. This is only one example of increased research efforts crucial to the success of biofuels. Recent innovations in biomass production include improved energy efficiency, reduction of water use, scaling down the complexity of the processing plants, and recovering more side products. [24]
According to research by the University of Illinois, “In addition to jobs and economic activity, benefits of a billion-ton bioeconomy[25] include an annual reduction of 400 million tons of CO2 and the potential to replace 25% of current petroleum transportation fuels”. Exciting opportunities lay buried in the depths of laboratory, field, and classroom research. Let’s get digging.[26]
Concluding Thoughts:
It is not likely that one type of crop and fuel combination executed throughout the world will be the ultimate solution to reaching our global action to limit the rise in global average temperature to 1.5 degrees Celsius above pre-industrial levels. Paralleling agriculture’s rich diversity in the United States, biomass production should be given an individualized approach. Each city, state, and region of the nation will need to reflect and analyze its own soil, climate, and clean energy availability–efficiently and sustainably producing biofuels while still growing food and feeding families. By a collaborative effort amongst farmers, researchers, scientists, environmentalists, engineers, and educational institutions, biofuels can serve as a critical tool and a unique opportunity for positive change.
Let’s face facts. We are out of land and out of space. We already have a food waste problem and landfills that are not only over capacity but physically producing GHGs and worsening the effects of climate change. We need to start recycling what we have already produced, and reuse what we have already wasted. Biofuels can and should be part of the solution.
References:
Argonne National Laboratory. (2016, July 13). Modeling predicts which counties could store more carbon in soil by growing bioenergy crops. Retrieved July 25, 2016, from http://www.sciencedaily.com/releases/2016/07/160713115218.htm
Biodiesel Fuel Basics. (n.d.). Retrieved August 10, 2016, from http://www.afdc.energy.gov/fuels/biodiesel_basics.html
Biofuel Facts, Biofuel Information – National Geographic. (n.d.). Retrieved August 15, 2016, from http://environment.nationalgeographic.com/environment/global-warming/biofuel-profile/
Biofuels | EESI. (n.d.). Retrieved August 08, 2016, from http://www.eesi.org/search/archive/f7012b4973bf5d50bfe455a22f117408/P10
Building a Billion-Ton Bioeconomy. (2016, July 19). Retrieved July 25, 2016, from http://www.eesi.org/briefings/view/071916billion
Chunzhong Yang, T. (2014). Chapter 5 – Biofuels and Bioproducts Produced through Microbial Conversion of Biomass. Retrieved August 16, 2016, from http://www.sciencedirect.com/science/article/pii/B978044459561400005X
Dugan, C. (2016, July 25). USDA Seeks Applications for Funding to Develop Advanced Biofuels and Plant-Based Products. Retrieved July 25, 2016, from https://content.govdelivery.com/accounts/USDAOC/bulletins/1589fc8
Energy 101: Biofuels. (n.d.). Retrieved August 15, 2016, from http://energy.gov/eere/videos/energy-101-biofuels
Energy Department Announces $11.3 Million for MEGA-BIO: Bioproducts to Enable Biofuels. (2016, August 2). Retrieved August 08, 2016, from http://energy.gov/eere/articles/energy-department-announces-113-million-mega-bio-bioproducts-enable-biofuels
Feldscher, K. (2016, July 21). Senators want more biodiesel in cars. Retrieved July 26, 2016, from http://www.washingtonexaminer.com/senators-want-more-biodiesel-in-cars/article/2597294
Global Climate Change, Professor Bloom, Professor Swisher, University of California, Davis
Measure of age in Soil Nitrogen Could Help Precision Agriculture. (2016, July 26). Retrieved August 11, 2016, from https://www.sciencedaily.com/releases/2016/07/160726094117.htm
Pandey, V. (2012, June). Jatropha curcas: A potential biofuel plant for sustainable environmental development. Retrieved August 16, 2016, from http://www.sciencedirect.com/science/article/pii/S1364032112000974
Renewable Natural Gas (Biomethane) Production. (n.d.). Retrieved August 2, 2016, from http://www.afdc.energy.gov/fuels/natural_gas_renewable.html
Shemfe, M. (2016, August 15). Comparative evaluation of GHG emissions from the use of Miscanthus for bio-hydrocarbon production via fast pyrolysis and bio-oil upgrading. Retrieved August 16, 2016, from http://www.sciencedirect.com/science/article/pii/S0306261916305827
Sources of Greenhouse Gas Emissions. (n.d.). Retrieved August 12, 2016, from https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions
Stuart, T. (2009). Waste: Uncovering the Global Food Scandal. New York: W.W. Norton, 2009. Print.
Tenenbaum, D. J. (2008). Food vs. Fuel: Diversion of Crops Could Cause More Hunger. Retrieved August 17, 2016, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430252/
University of Illinois Extension. (n.d.). Ethanol: What Is It? Retrieved August 05, 2016, from https://web.extension.illinois.edu/ethanol/
University of Nebraska. (n.d.). Soybeans. Retrieved August 16, 2016, from http://cropwatch.unl.edu/bioenergy/soybeans
Upstream Trenches, Downstream Nitrogen: Bioreactor trenches improve water quality. (2016, July 13). Retrieved August 14, 2016, from https://www.sciencedaily.com/releases/2016/07/160713143029.htm
[1] Sources of Greenhouse Gas Emissions. (n.d.). Retrieved August 12, 2016, from https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions
[2] Biofuel Facts, Biofuel Information – National Geographic. (n.d.). Retrieved August 15, 2016, from http://environment.nationalgeographic.com/environment/global-warming/biofuel-profile/
[3] Building a Billion-Ton Bioeconomy. (2016, July 19). Retrieved July 25, 2016, from http://www.eesi.org/briefings/view/071916billion
[4] Tenenbaum, D. J. (2008). Food vs. Fuel: Diversion of Crops Could Cause More Hunger. Retrieved August 17, 2016, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2430252/
[5] Stuart, T. (2009). Waste: Uncovering the Global Food Scandal. New York: W.W. Norton, 2009. Print.
[6] According to the authoritative International Food Policy Research Institute, maize ethanol produced in the US may cut GHG emissions by 10-30% compared to petroleum; but ethanol produced from cellulose or sugarcane (From Brazil, for example) could reduce emissions by 90%. But when either contributes to deforestation by increasing demand for agricultural land its impact is negative: IRIN (2008b: RFA (2008).
[7] Smil (2001) estimated that the equivalent of 100 million tons of cereals could be saved if rich nations reduced their waste to just 20% of supplies, and that 150 million tons are lost in post-harvest operations in developing world countries. Further in the novel, Stuart shows that the grand total throughout the world may be twice that.
[8] Biofuels | EESI. (n.d.). Retrieved August 08, 2016, from http://www.eesi.org/search/archive/f7012b4973bf5d50bfe455a22f117408/P10
[9] University of Illinois Extension. (n.d.). Ethanol: What Is It? Retrieved August 05, 2016, from https://web.extension.illinois.edu/ethanol/
[10] Renewable Natural Gas (Biomethane) Production. (n.d.). Retrieved August 2, 2016, from http://www.afdc.energy.gov/fuels/natural_gas_renewable.html
[11] Biodiesel Fuel Basics. (n.d.). Retrieved August 10, 2016, from http://www.afdc.energy.gov/fuels/biodiesel_basics.html
[12] Shemfe, M. (2016, August 15). Comparative evaluation of GHG emissions from the use of Miscanthus for bio-hydrocarbon production via fast pyrolysis and bio-oil upgrading. Retrieved August 16, 2016, from http://www.sciencedirect.com/science/article/pii/S0306261916305827
[13] Building a Billion-Ton Bioeconomy. (2016, July 19). Retrieved July 25, 2016, from http://www.eesi.org/briefings/view/071916billion
[14] Argonne National Laboratory. (2016, July 13). Modeling predicts which counties could store more carbon in soil by growing bioenergy crops. Retrieved July 25, 2016, from http://www.sciencedaily.com/releases/2016/07/160713115218.htm
[15] University of Illinois Extension. (n.d.). Ethanol: What Is It? Retrieved August 05, 2016, from https://web.extension.illinois.edu/ethanol/
[16] Building a Billion-Ton Bioeconomy. (2016, July 19). Retrieved July 25, 2016, from http://www.eesi.org/briefings/view/071916billion
[17] For more details regarding the current biofuel jatropa project, please visit our webiste: Climate.org and search under ‘Innovative Solutions Innitiatives’.
[18] Pandey, V. (2012, June). Jatropha curcas: A potential biofuel plant for sustainable environmental development. Retrieved August 16, 2016, from http://www.sciencedirect.com/science/article/pii/S1364032112000974
[19] Energy Department Announces $11.3 Million for MEGA-BIO: Bioproducts to Enable Biofuels. (2016, August 2). Retrieved August 08, 2016, from http://energy.gov/eere/articles/energy-department-announces-113-million-mega-bio-bioproducts-enable-biofuels
[20] Measure of age in Soil Nitrogen Could Help Precision Agriculture. (2016, July 26). Retrieved August 11, 2016, from https://www.sciencedaily.com/releases/2016/07/160726094117.htm
[21] Upstream Trenches, Downstream Nitrogen: Bioreactor trenches improve water quality. (2016, July 13). Retrieved August 14, 2016, from https://www.sciencedaily.com/releases/2016/07/160713143029.htm
[22] Dugan, C. (2016, July 25). USDA Seeks Applications for Funding to Develop Advanced Biofuels and Plant-Based Products. Retrieved July 25, 2016, from https://content.govdelivery.com/accounts/USDAOC/bulletins/1589fc8
[23] Chunzhong Yang, T. (2014). Chapter 5 – Biofuels and Bioproducts Produced through Microbial Conversion of Biomass. Retrieved August 16, 2016, from http://www.sciencedirect.com/science/article/pii/B978044459561400005X
[24] Energy 101: Biofuels. (n.d.). Retrieved August 15, 2016, from http://energy.gov/eere/videos/energy-101-biofuels
[25] Building a Billion-Ton Bioeconomy. (2016, July 19). Retrieved July 25, 2016, from http://www.eesi.org/briefings/view/071916billion
[26] University of Illinois Extension. (n.d.). Ethanol: What Is It? Retrieved August 05, 2016, from https://web.extension.illinois.edu/ethanol/