Agricultural Wastes in the Middle East

Agriculture plays an important role in the economies of most of the countries in the Middle East.  The contribution of the agricultural sector to the overall economy varies significantly among countries in the region, ranging, for example, from about 3.2 percent in Saudi Arabia to 13.4 percent in Egypt.  Large scale irrigation is expanding, enabling intensive production of high value cash and export crops, including fruits, vegetables, cereals, and sugar.

The term ‘crop residues’ covers the whole range of biomass produced as by-products from growing and processing crops. Crop residues encompasses all agricultural wastes such as bagasse, straw, stem, stalk, leaves, husk, shell, peel, pulp, stubble, etc. Wheat and barley are the major staple crops grown in the Middle East region. In addition, significant quantities of rice, maize, lentils, chickpeas, vegetables and fruits are produced throughout the region, mainly in Egypt, Syria, Saudi Arabia and Jordan.

Date palm is one of the principal agricultural products in the arid and semi-arid region of the world, especially Middle East and North Africa (MENA) region. The Arab world has more than 84 million date palm trees with the majority in Egypt, Iraq, Saudi Arabia, Iran, Algeria, Morocco, Tunisia and United Arab Emirates. Date palm trees produce huge amount of agricultural wastes in the form of dry leaves, stems, pits, seeds etc. A typical date tree can generate as much as 20 kilograms of dry leaves per annum while date pits account for almost 10 percent of date fruits. Some studies have reported that Saudi Arabia alone generates more than 200,000 tons of date palm biomass each year.

In Egypt, crop residues are considered to be the most important and traditional source of domestic fuel in rural areas. These crop residues are by-products of common crops such as cotton, wheat, maize and rice. The total amount of residues reaches about 16 million tons of dry matter per year. Cotton residues represent about 9% of the total amount of residues. These are materials comprising mainly cotton stalks, which present a disposal problem. The area of cotton crop cultivation accounts for about 5% of the cultivated area in Egypt.

A cotton field in Egypt

Large quantities of crop residues are produced annually in the Middle East, and are vastly underutilised. Current farming practice is usually to plough these residues back into the soil, or they are burnt, left to decompose, or grazed by cattle. These residues could be processed into liquid fuels or thermochemical processed to produce electricity and heat in rural areas. Energy crops, such as Jatropha, can be successfully grown in arid regions for biodiesel production. Infact, Jatropha is already grown at limited scale in some Middle East countries and tremendous potential exists for its commercial exploitation.

A wide range of thermal and biochemical technologies exists to convert the energy stored in agricultural wastes into useful forms of energy. Thermochemical conversion technologies like combustion, gasification and pyrolysis can yield steam, syngas, bio oil etc. On the other hand, the high volatile solids content in agro wastes can be transformed into biogas in anaerobic digestion plants, possibly by codigestion with MSW, sewage sludge, animal wastes and/and food wastes. The cellulosic content in agricultural residues can be transformed into biofuel (bioethanol) by making use of the fermentation process. In addition, the highly organic nature of agricultural wastes makes it highly suitable for compost production which can be used to replace chemical fertilizers in agricultural farms. Thus, abundance of agro residues in the Middle East can catalyze the development of biomass energy sector in the region.

Date Palm as Biomass Resource

date-wastesDate palm is one of the principal agricultural products in the arid and semi-arid region of the world, especially Middle East and North Africa (MENA) region. There are more than 120 million date palm trees worldwide yielding several million tons of dates per year, apart from secondary products including palm midribs, leaves, stems, fronds and coir. The Arab world has more than 84 million date palm trees with the majority in Egypt, Iraq, Saudi Arabia, Iran, Algeria, Morocco, Tunisia and United Arab Emirates.

Egypt is the world’s largest date producer with annual production of 1.47 million tons of dates in 2012 which accounted for almost one-fifth of global production. Saudi Arabia has more than 23 millions date palm trees, which produce about 1 million tons of dates per year. Date palm trees produce huge amount of agricultural wastes in the form of dry leaves, stems, pits, seeds etc. A typical date tree can generate as much as 20 kilograms of dry leaves per annum while date pits account for almost 10 percent of date fruits. Some studies have reported that Saudi Arabia alone generates more than 200,000 tons of date palm biomass each year.

Date palm is considered a renewable natural resource because it can be replaced in a relatively short period of time. It takes 4 to 8 years for date palms to bear fruit after planting, and 7 to 10 years to produce viable yields for commercial harvest. Usually date palm wastes are burned in farms or disposed in landfills which cause environmental pollution in dates-producing nations. In countries like Iraq and Egypt, a small portion of palm biomass in used in making animal feed.

The major constituents of date palm biomass are cellulose, hemicelluloses and lignin. In addition, date palm has high volatile solids content and low moisture content. These factors make date biomass an excellent waste-to-energy resource in the MENA region. A wide range of thermal and biochemical technologies exists to convert the energy stored in date palm biomass to useful forms of energy. The low moisture content in palm wastes makes it well-suited to thermochemical conversion technologies like combustion, gasification and pyrolysis which may yield steam, syngas, bio oil etc. On the other hand, the high volatile solids content in date palm biomass indicates its potential towards biogas production in anaerobic digestion plants, possibly by codigestion with sewage sludge, animal wastes and/and food wastes. The cellulosic content in date palm wastes can be transformed into biofuel (bioethanol) by making use of the fermentation process. The highly organic nature of date palm biomass makes it highly suitable for compost production which can be used to replace chemical fertilizers in date palm plantations. Thus, abundance of date palm trees in the MENA and the Mediterranean region, can catalyze the development of biomass and biofuels sector in the region.

Biochemical Conversion of Biomass

Biochemical conversion of biomass involves use of bacteria, microorganisms and enzymes to breakdown biomass into gaseous or liquid fuels, such as biogas or bioethanol. The most popular biochemical technologies are anaerobic digestion (or biomethanation) and fermentation. Anaerobic digestion is a series of chemical reactions during which organic material is decomposed through the metabolic pathways of naturally occurring microorganisms in an oxygen depleted environment. Biomass wastes can also yield liquid fuels, such as cellulosic ethanol, which can be used to replace petroleum-based fuels.

Anaerobic Digestion

Anaerobic digestion is the natural biological process which stabilizes organic waste in the absence of air and transforms it into biofertilizer and biogas. Anaerobic digestion is a reliable technology for the treatment of wet, organic waste.  Organic waste from various sources is biochemically degraded in highly controlled, oxygen-free conditions circumstances resulting in the production of biogas which can be used to produce both electricity and heat. Almost any organic material can be processed with anaerobic digestion. This includes biodegradable waste materials such as municipal solid waste, animal manure, poultry litter, food wastes, sewage and industrial wastes.

An anaerobic digestion plant produces two outputs, biogas and digestate, both can be further processed or utilized to produce secondary outputs. Biogas can be used for producing electricity and heat, as a natural gas substitute and also a transportation fuel. A combined heat and power plant system (CHP) not only generates power but also produces heat for in-house requirements to maintain desired temperature level in the digester during cold season. In Sweden, the compressed biogas is used as a transportation fuel for cars and buses. Biogas can also be upgraded and used in gas supply networks.

Working of Anaerobic Digestion Process

Digestate can be further processed to produce liquor and a fibrous material. The fiber, which can be processed into compost, is a bulky material with low levels of nutrients and can be used as a soil conditioner or a low level fertilizer. A high proportion of the nutrients remain in the liquor, which can be used as a liquid fertilizer.

Biofuel Production

A variety of fuels can be produced from waste resources including liquid fuels, such as ethanol, methanol, biodiesel, Fischer-Tropsch diesel, and gaseous fuels, such as hydrogen and methane. The resource base for biofuel production is composed of a wide variety of forestry and agricultural resources, industrial processing residues, and municipal solid and urban wood residues. Globally, biofuels are most commonly used to power vehicles, heat homes, and for cooking.

The largest potential feedstock for ethanol is lignocellulosic biomass wastes, which includes materials such as agricultural residues (corn stover, crop straws and bagasse), herbaceous crops (alfalfa, switchgrass), short rotation woody crops, forestry residues, waste paper and other wastes (municipal and industrial). Bioethanol production from these feedstocks could be an attractive alternative for disposal of these residues. Importantly, lignocellulosic feedstocks do not interfere with food security.

Ethanol from lignocellulosic biomass is produced mainly via biochemical routes. The three major steps involved are pretreatment, enzymatic hydrolysis, and fermentation. Biomass is pretreated to improve the accessibility of enzymes. After pretreatment, biomass undergoes enzymatic hydrolysis for conversion of polysaccharides into monomer sugars, such as glucose and xylose. Subsequently, sugars are fermented to ethanol by the use of different microorganisms.

Unending Benefits of Biomass Energy

Biomass is material originating from plant and animal matter. Biomass energy uses biomass to create energy by burning organic materials. The heat energy released through burning these materials can heat homes or water. Heated water produces steam, which in turn can generate electricity. Using organic materials to create heat and power is an eco-friendlier alternative compared to using fossil fuels.

Indefinitely Renewable

The majority of the world’s energy comes from burning fossil fuels. Fossil fuels are a finite resource. Once fossil fuel resources run out, new fuel sources will be needed to meet global energy demands. Biomass offers a solution to meet this need.

Organic waste material from agriculture and logging operations, animal manure, and sludge from wastewater treatment are all viable fuels for generating biomass energy. As long as the earth is inhabited, these materials will be readily available.

Reduce, Reuse, Recycle

Waste organic material that would typically be disposed of in landfills could be redirected for biomass energy use. This reduces the amount of material in landfills and slows the rate at which landfills are filled. Some of the most common waste products used for biomass energy are wood chips and agricultural waste products. Wood materials can easily be converted from already existing wood structures that will be destroyed, such as wooden furniture and log cabins, preferably both would also come from responsible logging and practices as well.

As more organic material is diverted from landfills, the number of new landfills needed would be reduced. Older landfills are at risk for leaking leachate. Leachate contains many environmental pollutants that can contaminate groundwater sources.

Burning fossil fuel releases carbon into the atmosphere which was previously trapped below ground. Trapped carbon isn’t at risk for contributing to global climate change since it can’t interact with air. Each time fossil fuels are burned, they allow previously trapped carbon to enter the atmosphere and contribute to global climate change. In comparison, biofuel is carbon-neutral.

The materials used to create biomass energy naturally release carbon into the environment as they decompose. Living plants and trees use carbon dioxide to grow and release oxygen into the atmosphere. Carbon dioxide released by burning organic material will be absorbed by existing plants and trees. The biomass cycle is carbon-neutral as no new carbon is introduced to the system.

Smaller Carbon Footprint

The amount of unused farmland is increasing as agriculture becomes more efficient. Maintaining open land is expensive. As a result, farmers are selling off their property for new developments. Unused open agricultural land could be used to grow organic material for biofuels.

Converting open tracts of land to developed areas increases the amount of storm-water runoff. Storm-water runoff from developed areas contains more pollutants than storm-water runoff from undeveloped areas. Using open areas to grow biomass sources instead of creating new developments would reduce water pollution.

Biomass-Resources

A quick glance at popular biomass resources

Forested areas also provide sources of biofuel material. Open land converted to sustainable forestry would create new animal habitats and offset carbon emissions from existing fossil fuel sources as more plants and trees would be available to absorb carbon dioxide.

Societal Benefits

Burning fossil fuels releases sulfur dioxide, mercury and particulate matter into the atmosphere which can cause asthma, cancer and respiratory problems. Biomass energy emits less harmful byproducts compared to fossil fuels, which means cleaner air and healthier people.

Biofuel can improve rural economies by providing more people with unused land the opportunity to grown biomass material for energy use. Workers would be needed to harvest and process the materials needed to generate biofuel.

Since biofuel is a renewable energy source, energy providers can receive tax credits and incentives. Countries with land resources will be less reliant on foreign fossil fuel providers and can improve their local economies.

Increasing biofuel energy usage can reduce forest fires. Selectively reducing brush can still reduce the risk of wildfires spreading. Exposing underbrush and groundcover to rainfall decreases the change of it drying out and creating optimal, fire spreading conditions.

Denmark and Biomass Energy

Denmark is an example of how effective biomass energy can be in developing energy efficiency. Approximately 70 percent of renewable-energy consumption in Denmark comes from biomass.

Woody biomass creates an increasing percentage of heating from combined heat and power (CHP) plants with a goal to for 100 percent of hearing to be derived from woody biomass by 2035. Another form of biomass is agricultural biomass. This form utilizes materials such as straw and corn to create end-products like electricity, heating and biofuels.

The Danish Energy Agency has developed a plan including four scenarios that will help Denmark become fossil fuel free by 2050. The biomass scenario involves CHP for electricity and district heating, indicating that biomass energy is important in Denmark’s energy sector today and will play an increasingly important role in the future.

Biomass offers an eco-friendly and renewable method of reducing pollution and the effects of global climate change. And, like other forms of renewable energy, the products needed to develop biomass energy are readily available.

Renewable Energy and its Applications

renewables-applicationsRenewable energy. Clean energy. Green energy. Sustainable energy. Alternative Energy. Renewal Energy. No matter what you call it, energy such as wind, solar, biomass and hydroelectric is having an impact on your life and could have an even bigger impact in the future. Renewable energy, in the most basic terms, is precisely what it sounds like. It’s power that comes from sources that regenerate, unlike fossil fuels, which only exist in a limited amount.

From 2000 to 2016, the use of renewables in the United States more than doubled and is expected to continue to grow. In 2016, they made up about 10 percent of total energy consumption and 15 percent of electricity generation. Consumption of renewable energy has grown in large part due to government incentives and requirements for renewable energy and the desire to switch to cleaner fuel in order to protect the environment.

There are a number of different sources of renewable energy in use today. Here are some of the most common ones.

Solar Energy

The U.S. solar industry has grown at an average annual rate of 68 percent over the last decade in the form of rooftop solar panels for individual buildings, solar farms built by utility companies and community solar projects, which produce solar for energy users in a certain area through a collection of solar panels.

In Australia the solar industry is also increasing with a record breaking 3.5 million panels installed last year. Queensland was the leader in solar panels that were installed.

Solar photovoltaic panels capture sunlight and convert it directly into electricity, which can power a small device such as a watch or sent into the grid to be distributed to a utility’s customers.

Wind Energy

People have been using windmills to utilize the wind’s energy for a long time, but today wind turbines are used to capture that energy and turn it into electricity. There are approximately 53,000 wind turbines operating in the United States today.

Wind turbines consist of a large tower, which is often around 100 feet tall, and several blades that use the power of the wind to spin. The blades are connected to a shaft that spins a generator in order to create electricity.

Like solar energy, power generated with wind can either be used for a specific application such as pumping water or powering a farm, or transferred into the electrical grid to meet other energy needs.

Biomass Energy

Biomass is another common form of renewable energy. Biomass is any natural substance such as wood, plant matter, gas from landfills and even municipal solid waste that contains stored energy from the sun.

When those substances are burned, they release that energy, which can be used as heat or fuel. Biomass can also be made into a liquid or gas that can be used as fuel.

Bioliquids, such as ethanol and biodiesel, are frequently used to power vehicles. Around 40 percent of the corn grown in the U.S. today is used for biofuels. Researchers are currently exploring new ways biomass can be used and additional substances that could be used for biomass energy.

Hydro Energy

Hydropower, energy generated with water, is one of the oldest and the most common renewable energy resource in the U.S., making up 6.5 percent of utility-scale electricity generation and 44 percent of generated renewable energy.

When water flows, it produces energy. We capture this energy by allowing moving water in rivers, waterfalls or elsewhere to turn generators that produce electricity. Hydroelectric plants can also be man-made, as is the case with dams. Man-made reservoirs hold water through the use of dams. That water is then released to flow through a turbine and create electricity.

Benefits Galore

The main benefit of renewable energy sources is the fact that they release very little greenhouse gases and so are better for the environment. Because electricity makes up the largest share of our greenhouse gas emissions, changing how we get our energy is crucial in the fight against global warming.

Biofuels are increasingly being used to power vehicles

Biofuels are increasingly being used to power vehicles

Another key advantage is the fact that they are renewable, which means we won’t ever run out of them. This stability could make access to energy more stable in the future. It can also keep energy prices more predictable, because the markets are subject to changes in supply.

Renewable energy is also flexible and can power large areas or single homes. Additionally, renewable energy projects create a number of well-paying jobs and tend to have a significant economic impact.

Key Drawbacks

Just like with fossil fuels, there are some disadvantages as well. Renewable energy plants are subject to fluctuations in wind, sunlight and other natural resources, meaning some days or in some particular months, a facility might produce more electricity than others. Today, in areas where renewables are common, fossil fuels are often used to make up any shortcoming in renewable energy production.

Due to their reliance on natural occurrences, renewables may fare better in some areas than others. An area with lots of direct sun all day long will be more suitable for a solar plant than somewhere that’s often dark and cloudy. Renewable energy farms also often require large areas of land, and while renewable energy tends to be cheap, initial construction and development costs can be quite high.

Despite these disadvantages, renewables are proving an important part of the energy mix of today and of the future, especially in the face of environmental concerns and worry about the availability of fossil fuels. Chances are we won’t see the end of the growing renewable energy industry any time soon.

About the Author

Emily Folk is a freelance writer and blogger on topics of renewable energy and conservation. To get her latest posts, check out her blog, Conservation Folks, or follow her on Twitter.

A Glance at Drop-in Biofuels

drop-in-biofuelsBiofuel commercialization has proved to be costly and lingering than expected due to its high production cost and modification to flexibility in engines. Drop-in fuels are alternatives to existing liquid fuels without any significant modification in engines and infrastructures. According to IEA, “Drop-in biofuels are liquid bio-hydrocarbons that are functionally equivalent to petroleum fuels and are fully compatible with existing petroleum infrastructure”.

What are Drop-in Biofuels

Drop-in biofuels are can be produced from oilseeds via trans-esterification, lignocellulosic biomass via thermochemical process, sugars and alcohol via biochemical conversion or by hybrids of the above methods. Drop-in fuels encompass high hydrogen to carbon ratio with no/low sulfur and oxygen content, low water solubility and high carbon bond saturation. In short drop-in fuel is a modified fuel with close functional resemblance to fossil fuel.

Existing biofuels – bioethanol and biodiesel – have wide variation from fossil fuels in their blend wall properties – high oxygen content, hydrophilicity, energy density and mainly compatibility in existing engines and infrastructures. Oxygenated groups in biofuel have a domino effect such as reduction in the energy density, production of impurities which are highly undesirable to transportation components, instability during storage etc.

Major advantages of drop-in fuels over existing fuels are as follows:

  • Reduced sulphur oxide emissions by ultra low sulphur content.
  • Reduced ignition delay by high cetane value
  • Reduced hydrocarbons and nitrogen oxides emissions
  • Low aromatic content
  • Low olefin content, presence of olefin compounds undergo auto-oxidation leading to surface depositions.
  • High saturates, therefore leaving minimum residues
  • Low particulate emissions
  • No oxygenates therefore has high stability.

Potential Biomass Feedstock

Drop-in biofuels can be produced from various biomass sources- lipids (vegetable oils, animal fats, greases, and algae) and lignocellulosic material (such as crop residues, woody biomass, and dedicated energy crops). The prominent technologies for biomass conversion to drop-in fuel are the thermochemical and the biochemical process.

The major factor playing role in selection of biomass for thermochemical methods is the energy content or heating value of the material, which is correlated with ash content. Wood, wood chips accounts for less than 1% ash content, which is favorable thermal processing than biochemical process, whereas straws, husks, and majority of the other biomass have ash content ranging up to 25% of dry mass.

Free sugar generating plants such as sugarcane and sweet sorghum, are desirable feedstock for Acetone-Butanol-Ethanol fermentation and have been widely implemented. Presently there is a focus to exploit lignocellulosic residues, rich in hydrocarbon, for fuel production. However, this biomass requires harsh pretreatment to remove lignin and to transform holocellulose (cellulose & hemicelluloses) into fermentable products.

The lignocellulose transformation technology must be circumspectly chosen by its life cycle assessment, as it resists any changes in their structural integrity owing to its complexity. Lignocellulosic biomass, when deoxygenated, has better flexibility to turn to drop-in fuels. This is because, in its native state of the feedstock, each oxygen atom consumes two hydrogen atoms during combustion which in turn reduces effective H: C ratio. Biomass feedstock is characterized with oxygen up to 40%, and higher the oxygen content higher it has to be deoxygenated.

Thermochemical Route

Thermochemical methods adopted for biomass are pyrolysis and gasification, on thermolysis of biomass produce intermediate gas (syngas) and liquid (bio crude) serving as precursors for drop-in fuel. Biomass when exposed to temperature of 500oC-600oC in absence of oxygen (pyrolysis) produce bio-oil, which constitutes a considerable percentage of oxygen. After down streaming by hydroprocessing (hydrotreating and hydrocracking) the rich hydrocarbon tar (bio-oil) can be converted to an efficient precursor for drop-in fuel.

At a higher temperature, above 700, under controlled oxygen, biomass can be converted to liquid fuel via gas phase by the process, gasification. Syngas produced is converted to liquid fuel by Fischer-Tropsch with the help of ‘water gas shift’ for hydroprocessing. Hydroprocessing after the thermochemical method is however costly and complex process in case of pyrolysis and inefficient biomass to fuel yield with gasification process.

Biochemical Pathway

The advanced biocatalytic processes can divert the conventional sugar-ethanol pathway and convert sugars to fatty acids. Modified microbial strain with engineered cellular machineries, can reroute the pathway to free fatty acid that can be transformed into butanol or drop-in fuel with necessary processing.

Schematic for the preparation of jet fuel from biomass

Schematic for the preparation of jet fuel from biomass

Biological processing requires operation under the stressful conditions on the organisms to reroute the pathways, in additional to lowering NADPH (hydrogen) consumption. Other value added products like carboxylic acid, polyols, and alcohol in the same biological routes with lower operational requirements have higher market demands and commercial success. Therefore little attention is given by chemical manufacturers to the biological pathways for drop-in fuel production.

The mechanisms of utilization of lignocellulosic biomass to fuel by biological pathway rely heavily on the availability of monomeric C5 and C6 sugars during fermentation. Ethanol is perhaps the best-known and commercially successful alcohol from ABE fermentation. However, butanol has various significant advantages over ethanol- in the perception of energy content, feasibility to existing infrastructures, zero blend wall, safety and clean aspects. Although butanol is a closer drop-in replacement, existing biofuel ethanol, is a major commercial competitor. Low yield from fermentation due to the toxicity of butanol and complexity in down streaming are the vital reasons that hamper successful large scale butanol production.

Challenges to Overcome

Zero oxygen and sulphur content mark major challenges for production of drop-in fuels from conventional biomass. This demands high hydrogen input on the conventional biomass, with H: C ratio below 0.5, like sugar, starch, cellulose, lignocellulose to meet the effective hydrogen to carbon ratio of 2 as in drop-in fuel. This characterizes most of the existing biomass feedstock as a low-quality input for drop-in fuels. However oleochemicals like fats, oils, and lipids have closer H: C ratio to diesel, gasoline and drop-in fuels, thus easier to conversion. Oleochemical feedstock has been commercially successful, but to prolong in the platform will be a major challenge. Lipid feedstock is generally availed from crop-based vegetable oil, which is used in food sectors. Therefore availability, food security concerns, and economics are the major constraints to sustaining the raw material. Consequently switching to lignocellulosic biomass feedstock for drop-in holds on.

Conclusions

Despite the hurdles on biomass characteristics and process technology for drop-in fuel, it is a vital requirement to switch to better replacement fuel for fossil fuel, considering environmental and economic benefits. Understanding its concepts and features, drop-in fuel, can solve existing greenhouse emission debate on current biofuels. Through crucial ambiguities existing on future of alternative fuels, drop-in fuel has a substantial potential to repute itself as an efficient sustainable eco-friendly fuel in the naear future.

References

  • Neal K Van Alfen: ENCYCLOPEDIA OF AGRICULTURE AND FOOD SYSTEMS, Elsevier, Academic Press.
  • Pablo Domínguez de María John: INDUSTRIAL BIORENEWABLES:A Practical Viewpoint: Wiley & Sons.
  • Ram Sarup Singh, Ashok Pandey, Edgard Gnansounou: BIOFUELS- PRODUCTION AND FUTURE PERSPECTIVES, CRC Press.
  • Satinder Kaur Brar, Saurabh Jyoti Sarma, Kannan Pakshirajan : PLATFORM CHEMICAL BIOREFINERY-FUTURE GREEN CHEMISTRY, Elsevier.
  • Sergios Karatzos, James D. McMillan, Jack N. Saddle: Summary of IEA BIOENERGY TASK 39 REPORT-THE POTENTIAL AND CHALLENGES OF DROP-IN BIOFUELS, IEA Bioenergy.
  • Vijai Kumar Gupta, Monika Schmoll, Minna Maki, Maria Tuohy, Marcio Antonio Mazutti: APPLICATIONS OF MICROBIAL ENGINEERING, CRC Press.

Bioethanol: Challenges in India

bioethanol-indiaGlobal demand for fuel efficiency, environmental quality and energy security have elicited global attention towards liquid biofuels, such as bioethanol and biodiesel. Around the world, governments have introduced various policy measurements, mandatory fuel blending programmes, incentives for flex-fuel vehicles and agricultural subsidies for the farmers. In India, the government launched Ethanol Blended Petrol (EBP) programme in January 2013 for 5% ethanol blended petrol. The policy had significant focus on India’s opportunity to agricultural and industrial sectors with motive of boosting biofuel (bioethanol and biodiesel) usage and reducing the existing dependency on fossil fuel.

The Government of India initiated significant investments in improving storage and blending infrastructure. The National Policy on Biofuels has set a target of 20% blending of biofuel by 2017. However, India has managed to achieve only 5% by September 2016 due to certain technical, market and regulatory hurdles.

In India, sugarcane molasses is the major resource for bioethanol production and inconsistency of raw material supply holds the major liability for sluggish response to blending targets.  Technically speaking, blend wall and transportation-storage are the major challenges towards the biofuel targets. Blending wall is the maximum percent of ethanol that can be blended to fuel without decreasing the fuel efficiency.

Various vehicles are adaptable to various blending ratio based on the flexibility of engines. The technology for the engine modification for flex fuel is not new but making the engines available in India along with the supply chain and calibrating the engine for Indian conditions is the halting phase. The commonly used motor vehicles in the country are not effectual with flex fuel.

Sugarcane molasses is the most common feedstock for bioethanol production in India

Sugarcane molasses is the most common feedstock for bioethanol production in India

Ethanol being a highly flammable liquid marks obligatory safety and risk assessment measures during all phases of production, storage and transportation. The non-uniform distribution of raw material throughout the country, demands a compulsory transportation and storage, especially inter-state movement, encountering diverse climatic and topographic conditions.

Major ethanol consumers in India are potable liquor sector (45%), alcohol based chemical industry (40%), the rest for blending and other purposes. The yearly profit elevation in major sectors is a dare to an economical ethanol supply for Ethanol Blending Programme. Drastic fluctuation in pricing of sugar cane farming and sugar milling resulted to huge debt to farmers by mill owners. Gradually the farmers shifted from sugarcane cultivation other crops.

Regulatory and policy approaches on excise duty on storage and transportation of ethanol and pricing strategy of ethanol compared to crude oil are to be revised and implemented effectively. Diversifying the feedstocks (especially use of lignocellulosic biomass) and advanced technology for domestic ethanol production in blending sectors are to be fetched out from research laboratories to commercial scale. Above all the knowledge of economic and environmental benefits of biofuel like reduction in pollutants and import bills and more R&D into drop-in biofuels, need to be amplified for the common man.

Is Green Car Fuel A Reality?

drop-in-biofuelsVehicles remain a huge global pollutant, pumping out 28.85Tg of CO2 in Maharashtra alone, according to a study by the Indian Institute for Science in Bangalore. However, vehicles cannot be discarded, as they form the lifeblood of the country’s towns and cities. Between electric vehicles and hybrids, work is being done to help rectify the situation by making use of green car fuel and technological advancements.

Emissions continue to be a huge issue, and there are two main options for helping to rectify that. The first is electric, which is seeing widespread adoption; and the second, biomass fuel, for more traditional vehicles. Between the two, excellent progress is being made, but there’s much more to be done.

How electric is helping

Electric cars are favoured heavily by the national authorities. A recent Times of India report outlined how the government is aiming for an all-electric vehicle fleet by 2030 and is pushing this through with up to US$16m of electric vehicle grants this year. Green vehicles are obviously a great choice, improving in-city noise and air pollution whilst providing better vehicular safety to boot; a study by the USA’s MIT suggested that electric vehicles are all-around safer than combustion.

However, where EVs fall down to some extent is through the energy they use. As they are charged from the electricity grid, this means that the electricity is largely derived from fossil fuels – official statistics show that India is 44% powered by coal. Ultimately, however, this does mean that emissions are reduced. Fuel is only burned at one source, and oil refining isn’t done at all, which is another source of pollutants. However, as time goes on and the government’s energy policy changes, EVs will continue to be a great option.

The role of biofuels

Biofuels are seeing a huge growth in use – BP has reported that globally, ethanol production grew 3% in 2017. Biofuel is commonly a more favoured option by the big energy companies given the infrastructure often available already to them. While biofuel has been slow on the uptake in India, despite the massive potential available for production, there are now signs this is turning around with the construction of two US$790m biofuel facilities.

Biofuels are increasingly being used to power vehicles around the world

The big benefit of biofuel is that it will have a positive impact on combustion and electric vehicles. The Indian government has stated they intend to use biofuel alongside coal production, with as much as 10% of energy being created using biofuel. Therefore, despite not being emission-free, biofuel will provide a genuine green energy option to both types of eco-friendly vehicle.

Green car fuel is not entirely clean. The energy has to come from somewhere, and in India, this is usually from coal, gas, and oil. However, the increase in biofuel means that this energy will inevitably get cleaner, making green car fuel absolutely a reality.

Role of Biomass Energy in Rural Development

biomass-balesBiomass energy systems not only offer significant possibilities for clean energy production and agricultural waste management but also foster sustainable development in rural areas. The increased utilization of biomass wastes will be instrumental in safeguarding the environment, generation of new job opportunities, sustainable development and health improvements in rural areas.

Biomass energy has the potential to modernize the agricultural economy and catalyze rural development. The development of efficient biomass handling technology, improvement of agro-forestry systems and establishment of small, medium and large-scale biomass-based power plants can play a major role in rural development.

Sustainable harvesting practices remove only a small portion of branches and tops leaving sufficient biomass to conserve organic matter and nutrients. Moreover, the ash obtained after combustion of biomass compensates for nutrient losses by fertilizing the soil periodically in natural forests as well as fields.

Planting of energy crops on abandoned agricultural lands will lead to an increase in species diversity. The creation of structurally and species diverse forests helps in reducing the impacts of insects, diseases and weeds. Similarly the artificial creation of diversity is essential when genetically modified or genetically identical species are being planted.

Improvements in agricultural practices promises to increased biomass yields, reductions in cultivation costs, and improved environmental quality. Extensive research in the fields of plant genetics, analytical techniques, remote sensing and geographic information systems (GIS) will immensely help in increasing the energy potential of biomass feedstock.

Rural areas are the preferred hunting ground for the development of biomass sector worldwide. By making use of various biological and thermal processes (anaerobic digestion, combustion, gasification, pyrolysis), agricultural wastes can be converted into biofuels, heat or electricity, and thus catalyzing sustainable development of rural areas economically, socially and environmentally.

Biomass energy can reduce 'fuel poverty' in remote and isolated communities

Biomass energy can reduce ‘fuel poverty’ in remote and isolated communities

A large amount of energy is utilized in the cultivation and processing of crops like sugarcane, wheat and rice which can met by utilizing energy-rich residues for electricity production. The integration of biomass-fueled gasifiers in coal-fired power stations would be advantageous in terms of improved flexibility in response to fluctuations in biomass availability and lower investment costs.

There are many areas in India where people still lack access to electricity and thus face enormous hardship in day-to-day lives. Biomass energy promises to reduce ‘fuel poverty’ commonly prevalent among remote and isolated communities.  Obviously, when a remote area is able to access reliable and cheap energy, it will lead to economic development and youth empowerment.

Resource Base for Second-Generation Biofuels

second-generation-biofuelsSecond-generation biofuels, also known as advanced biofuels, primarily includes cellulosic ethanol. The feedstock resource base for the production of second-generation biofuel are non-edible lignocellulosic biomass resources (such as leaves, stem and husk) which do not compete with food resources. The resource base for second-generation biofuels production is broadly divided into three categories – agricultural residues, forestry wastes and energy crops.

Agricultural Residues

Agricultural (or crop) residues encompasses all agricultural wastes such as straw, stem, stalk, leaves, husk, shell, peel, pulp, stubble, etc. which come from cereals (rice, wheat, maize or corn, sorghum, barley, millet), cotton, groundnut, jute, legumes (tomato, bean, soy) coffee, cacao, tea, fruits (banana, mango, coco, cashew) and palm oil.

Rice produces both straw and rice husks at the processing plant which can be conveniently and easily converted into energy. Significant quantities of biomass remain in the fields in the form of cob when maize is harvested which can be converted into energy.

Sugarcane harvesting leads to harvest residues in the fields while processing produces fibrous bagasse, both of which are good sources of energy. Harvesting and processing of coconuts produces quantities of shell and fibre that can be utilised while peanuts leave shells. All these lignocellulosic materials can be converted into biofuels by a wide range of technologies.

Forestry Biomass

Forest harvesting is a major source of biomass energy. Harvesting in forests may occur as thinning in young stands, or cutting in older stands for timber or pulp that also yields tops and branches usable for production of cellulosic ethanol.

Biomass harvesting operations usually remove only 25 to 50 percent of the volume, leaving the residues available as biomass for energy. Stands damaged by insects, disease or fire are additional sources of biomass. Forest residues normally have low density and fuel values that keep transport costs high, and so it is economical to reduce the biomass density in the forest itself.

Energy Crops

Energy crops are non-food crops which provide an additional potential source of feedstock for the production of second-generation biofuels. Corn and soybeans are considered as the first-generation energy crops as these crops can be also used as the food crops. Second-generation energy crops are grouped into grassy (herbaceous or forage) and woody (tree) energy crops.

Grassy energy crops or perennial forage crops mainly include switchgrass and miscanthus. Switchgrass is the most commonly used feedstock because it requires relatively low water and nutrients, and has positive environmental impact and adaptability to low-quality land. Miscanthus is a grass mainly found in Asia and is a popular feedstock for second-generation biofuel production in Europe.

Woody energy crops mainly consists of fast-growing tree species like poplar, willow, and eucalyptus. The most important attributes of these class species are the low level of input required when compared with annual crops. In short, dedicated energy crops as feedstock are less demanding in terms of input, helpful in reducing soil erosion and useful in improving soil properties.