AGRIFUELS I WHY SWEET SORGHUM

Renewable Energy

Why Sweet Sorghum?

We’re all aware of the potentially devastating effects of climate change for the Earth’s ecology which includes global warming from CO2 release due to burning of fossil fuels and forests, rising sea levels as a result of warming atmospheric temperatures, and even the potential mass extinction of species which could possibly even include humankind.

No one knows for sure what the best way to combat global warming is, but all evidence is pointing toward minimisation of the burning of more fossil fuels as a critical first step.

One of the most difficult challenges of our age will be how we will deal with humanity’s insatiable thirst for energy from fossil fuels – especially, how to produce a transportable, renewable fuel that is efficient enough and inexpensive enough to replace the fossil fuels that are contributing to global warming that we have become so addicted to.

AgriFuels believes that while there is no single answer to this dilemma, a solution can be found through a combination of near-term transition technologies and longer-term higher technology solutions in parallel with a commitment by business and individuals to take action to reduce wasteful energy use.

After more than three years of extensive research and crop testing, AgriFuels identified and selected sweet sorghum as the most efficient commercial crop suited to the 3F concept for renewable energy crop sustainability.

An ideal biofuel crop must cater effectively for all three “Fs” to be sustainable:

FARMERS – The crop must be profitable for farmers or farmers will be unwilling to grow it.
FOOD – If the crop creates no food production then it’s creating a net reduction in existing or potential food crops.
FUEL – The crop should generate high fuel yields per hectare and high energy efficiency with a controllable input price to ensure long term economic and environmental sustainability.

3FS COMPARISON OF SEVERAL POPULAR FUEL FEEDSTOCKS

Crop	Farmer	Food	Fuel	By-product
Grain	Grain Sales	Grain	-	-
Grain	Grain Sales	-	Grain	DDGS (food)
Sugar Cane Sugar Beet	Cane Sales Beet Sales	Sugar Sugar	Molasses Molasses	Electricity/food
Cellulosic Grasses	Fibre Sales	-	Fibre	Electricity/food
Sweet Sorgum	Grain Sales Cane Sales	Grain -	- Sugar Juice	- Electricity/food

Grains (wheat, barley, corn, sorghum grain)
- – Primary food crop is grain for human and animal feed consumption
- – Grain must be used as fuel production feedstock and cannot therefore be used for food
- – Ethanol by-product is DDGS (Dried Distiller's Grain and Solids) - animal feed
- – Fluctuating market price of grain provides uncertain profit for farmers and uncertain input costs for fuel producer
Sugar crops (sugar cane)
- – Sugar is not a primary food crop , rather a processed food additive
- – Sugar by-product molasses can be converted to ethanol
- – Ethanol by-product is bagasse for electricity generation, animal feed, paper pulp, fibre for other products
- – Fluctuating sugar market price creates uncertain profit for farmers and unpredictable input costs for fuel producer.
Cellulosic - grasses, biomass, forest waste
- – Not a food crop
- – Ethanol by-product is biomass residue for electricity generation, animal feed, paper pulp, fibre for other products
- – Fluctuating market price for feedstock creates inability to control input cost for fuel producer
- – Requires expensive acid hydrolysis or new unproven enzymes for C5 and C6 sugar separation prior to fermentation
- – Costly capital equipment investment and relatively unproven commercial technology
- – In 2008, still not economically viable to compete against fossil fuels
Sweet sorghum
- – Primary food crop is sorghum grain. Nutritious grain can be sold for human and animal feed consumption
- – Sugar juice from sweet sorghum cane is converted to ethanol
- – Ethanol by-product is bagasse -- used for electricity generation, animal feed, natural sweeteners, paper pulp and fibre
- – Grain sale provides stable profit for farmers; cane sale provides fixed unit price income for growers
- – Fixed price for sweet sorghum cane sale provides control of input costs for fuel producer

Most noticeably, when compared to grains, sweet sorghum is also future compatible; conforming to a fourth "F": the FUTURE principle. Sweet sorghum and sugar cane, like grasses, produce a waste fibre (referred to as bagasse) that is created as a by-product from the pressing of cane for sugar juice extraction. Bagasse is ideally suited to cellulosic or ligno-cellulosic conversion to ethanol. Utilising sweet sorghum as a primary feedstock not only enables low risk production of ethanol from sugar juices using current technology, but provides for the additional opportunity to utilise emerging technologies in the fibre or cellulosic and ligno-cellulosic conversion to ethanol once those processes become commercially economic.

ETHANOL CONVERSION EFFICIENCY

Sweet sorghum, like sugar cane, is estimated to have a net energy output balance of 8-9 times input, when compared to maize of 1.37. While sugar cane and grain sorghum are relatively efficient for the production of ethanol, sweet sorghum is considerably more efficient still.

The key differentiating factors between the use of sugar cane, grain sorghum and sweet sorghum for renewable energy production are twofold:

Sweet sorghum allows for parallel production of a food and a fuel crop.

Sweet sorghum provides superior ethanol production per hectare per annum.

COMPARISON OF FIVE CROPS COMMONLY USED TO PRODUCE ETHANOL

Sources: Canegrowers QLD; PacificSeeds; Agrifuels; EUBIA; ABARE; Berkely University, USA. * -- Note the 15 tonnes per year of grain/ha/yr for food is in ADDITION to the cane used to produce 12,000 litres/ha/year of ethanol. With sweet sorghum, the grain is taken away to be used for food or animal fodder -- with other sorghum, the grain is used to produce ethanol and therefore not available to produce food or fodder.
Parameter	Sugarcane	Forage Sorghum	Sweet Sorghum	Grain Sorghum	Maize
Crop duration (irrigated crops)	12 months	2 x 4 months	3 x 4 months	2 x 4 months	4 months
Total water requirement/ha/yr	36,000 m³	8,000 m³	12,000 m³	11,000m³	8,100 m³
Grain yield for food (tonnes/ ha/yr)	0	0	15*	0	0
Grain yield for ethanol (tonnes/ha/yr)	-	-	-	12	8.7
Green stalk yield for ethanol (tonnes/ha/yr)	80	160	240	-	-
Total ethanol output (litres/ha/yr)	6,000	8,880	12,000	5,950	3,211

NEAR-TERM VS LONG-TERM SOLUTIONS

Doubtless, one day we'll develop technology that will render biofuels unnecessary (e.g., hydrogen power, super-capacitor, quantum or magnetic powered electric vehicles, etc.) and when that day arrives, biofuels, along with fossil fuels, will no longer be required for mobile power. However, given the state of today’s technological developments, that day is likely at least 40 years away, and until then we’ll need to use so called 'transitional" or “bridging technologies”—technologies and fuels that can stop us from having to consume more fossil fuels until the long-term high technology solutions have been developed, proven and put into widespread use.

Efficiently-produced biofuels fall into this category of “bridging technologies”.

ALL BIOFUELS ARE NOT THE SAME

A COMPLEX EQUATION: In the quest for brevity and “sound-bites” which can be easily and quickly understood by largely uneducated and impatient audiences, the mainstream media tend to over-simplify the situation with biofuels, leading to mischaracterisation and often to dissemination of outright incorrect information.

Biofuels, originally touted as a panacea for replacing liquid fossil fuels, have recently fallen out of favour--primarily as a result of media coverage quoting data questioning the efficiency and economic viability of converting plants and animal fats into useable biofuels. Some of the stories quote scientists who claim that when fully accounted for, that biofuels produce more CO2 to produce than they save.

Unfortunately, this view tells only a part of the complete story.

To fully understand the biofuel equation it’s necessary to look deeper and to investigate the structure, the growing process and the conversion process of each individual biofuel input feedstock.

Beneath each crop lies a complex story, and often, a fundamentally different outcome.

SOME CROPS ARE NATURALLY BETTER FOR BIOFUELS THAN OTHERS...

Corn (or "maize", as it is sometimes called), ( currently one of the most frequently talked about and frequently used plants for biofuel production), has proven far less efficient than originally hoped.

The disappointing news is that growing corn for biofuel generates only 1.37 units of energy for every unit of energy required to produce it. That is, for every 1.37 litres of ethanol produced from corn, it’s necessary to consume the equivalent of 1 litre of fossil fuel, resulting in only 30% more energy than the production process consumed.

Other potential biofuel crops such as wheat, jatropha, sugar beets, potatoes and forest wastes have similar issues that have presented one or more difficulties that make them less than optimal sources for producing biofuels. Potatoes, for example, though very high in ethanol output per hectare, consume a great deal of energy in production and processing and are therefore an ineffective ethanol feedstock.

Additionally, the biological effects of biofuel production from these crops such as high water usage and runoff of toxic fertiliser and pesticide chemicals into river systems are demonstrating that corn and other low-efficiency biofuel inputs feedstocks will not solve fossil fuel replacement issues.*

For an informative look at other biofuel crops, see the recent National Geographic Special Report: "GREEN DREAMS"

FEEDSTOCK COSTS = 55-75% OF VARIABLE COSTS IN A BIOFUEL PLANT

Another serious, in fact, critical issue not anticipated by many biofuel producers is the increasing input costs associated with food-based feedstocks related to fossil fuel price inflation. In a typical ethanol biofuel project as much as 75% of the variable costs in the business model is attributable to the price of the input feedstock. That is, as the price of petrol and petrodiesel have increased, many of the commodities which are used to produce renewable fuels such as corn, wheat, distillers grains and tallow (discarded animal fat from abattoirs) have subsequently increased in price in parallel to the price of the fossil fuels they were expected to replace. As the variable input cost exceeds a certain threshold in the business model the operation of the plant using that feedstock makes its use as a biofuel input uneconomic.

As a result of this strategic failure to anticipate and plan for the input feedstock price increases that have occurred in the past 18 months, many biofuel companies have now failed or suspended operations as it simply costs more to produce the fuel than they are able to sell it for to the open market. As a result of the negative publicity these companies have received, the biofuel industry has lost much of its original lustre and to a degree much of the original enthusiasm for biofuels overall has faded along with the share prices of those companies.

Despite this dilemma with many other crops, sweet sorghum as a biofuel input feedstock continues to show considerable promise as a fossil fuel replacement.

The sugar cane ethanol industry in Brazil for example has proven clearly that biofuels can compete well against fossil fuels, both from an economic perspective, as well as from an environmental perspective.

Sugarcane, like sweet sorghum, contains high levels of sugar per unit volume, which makes it an ideal biofuel input. For example, sugar cane, like sweet sorghum, can generate up to 8 units of energy output for every unit of input compared to the 1.37 units for corn -- Brazil has been producing ethanol from sugar cane which competes favourably with fossil fuel petrol for more than 25 years and much data exists demonstrating its viability.

Unfortunately, sugar cane also has its downsides – primarily that it can’t be grown in most parts of the world, due to:

Long growing season requirement, limiting it to being cultivated only in hot tropical and sub-tropical regions;
High water availability requirement;
High fertiliser usage requirement;
12-14 month growth cycles between harvests, making cashflow a hardship for growers;
Pests and diseases susceptibility (e.g., sugarcane smut) ; and,
Can only be grown on limited, highly fertile land.

AGRIFUELS SWEET SORGHUM -- A POWERFUL RENEWABLE ENERGY CROP FOR THE 21ST CENTURY

Properties: Sweet sorghum is grown worldwide on about 44 million hectares in almost one hundred different countries. It is therefore the fifth most important cereal crop in the world. The major producers are the United States, India, Nigeria, China, Mexico, Sudan and Argentina.

Sweet sorghum is a highly competitive crop and can dominate over many weeds and other plants. Sweet sorghum is a drought resistant plant that needs only about 175 cubic meters of water per crop to thrive. This is not even one quarter of the average water requirement of sugarcane crop. Tillers and heads are produced over a longer time period and therefore short periods of drought do not seriously harm pollination and fertilisation. In a longer drought, sweet sorghum produces fewer and smaller heads. The waxy coating of sorgum foliage makes them resist drying and they lose a smaller percentage of their water content than, for instance, corn leaves.

The planting season of sweet sorghum, at 100-115 days, is relatively short. The average yield for this period of time is varying between 95-125 tons. Sweet sorghum has a very high sugar content, varying from 15 to over 20 percent. Maximum yields are achived at average temperatures of at least 80°F. Photosynthesis is best at day-time temperatures higher than 90°F. During planting time the sorghum seed needs soil temperatures of 60-65°F.

Ethanol is produced from the sweet juice available in the stalk of the crop plant. The grains can still be used for food and feed purposes. Sweet sorghum has a higher vitamin and protein content than honey and can be used for the production of syrup, flour, and a popcorn-like product called pop sorghum kernels. Sweet sorghum is cheaper to produce than other comparable grains. In India for example, its cost of cultivation is about one-third that of sugarcane. (From: http://www.bioenergywiki.net/index.php/Sweet_sorghum)

Even though its sugar is more nutritious and easier to grow than that produced from sugar cane, its primary drawback as a sweetener is the difficulty of converting sweet sorghum sugar into sugar crystals. It is for this reason that sweet sorghum has never thrived as a primary food sugar crop. This issue presents no problem for biofuel production--in fact, due to the biologically simplier structure of the sugars in sweet sorghum its sugar is easier to convert to ethanol than most other sugar crops.

In recent years with tests in India, Europe, Asia, the USA, and now in Australia, Sweet Sorghum has been discovered to be a nearly ideal biofuel crop, with all of the advantages of sugar cane (and more of its own) and almost none of its disadvantages.

Food: Sweet sorghum, similar to grain sorghum grows a high value grain cob that can be sold for human consumption and animal feed.

Fuel: Juice from the cane stem can easily be converted to ethanol by sugar fermentation in a similar process to sugar cane juice.

Future: Sweet sorghum bagasse (cane fibre remained after sugar juice pressing) can be used in many green technology applications and is especially suited to emerging technologies such as cellulosic ethanol conversion.

Hundreds of varieties of sweet sorghum have been bred over the years and varieties can be selected by growers to tailor the output characteristics for any number of requirements such as climate, soil and water availability, height, fibre content, amongst many others.

In essence, sweet sorghum is an almost ideal biofuel crop and this assertion is supported by volumes of academic research the world over. Perhaps its only disadvantage is that it can produce only 1-2 crops per year in colder climates as compared to 3-4 crops per year in sub-tropical and tropical regions.

For detailed academic information supporting sweet sorghum’s claims to its suitability as an idea biofuel, please contact AgriFuels.

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Some of the economic and energy contributions of the by-products mentioned earlier are negated by the environmental pollution costs associated with ethanol production using corn as input feedstock. These are estimated to be more than 6c / per l of ethanol produced (Pimentel, 2003). U.S. corn production causes more total soil erosion that any other U.S. crop (Pimentel and others, 1995; NAS, 2003). In addition, corn production uses more herbicides and insecticides than any other crop produced in the U.S. thereby causing more water pollution.

Further, corn production uses more nitrogen fertilizer than any crop produced and therefore is a major contributor to groundwater and river water pollution (NAS, 2003). In some Western U.S. irrigated corn acreage, for instance, in some regions of Arizona, groundwater is being pumped 10 times faster than the natural recharge of the aquifers (Pimentel and others, 2004b). All these factors suggest that the environmental system in which U.S. corn is being produced is being rapidly degraded. Further, it substantiates the conclusion that the U.S. corn production system is not environmentally sustainable now or for the future, unless major changes are made in the cultivation of this major food/feed crop. Corn is raw material for ethanol production, but cannot be considered to provide a renewable energy source. Major air and water pollution problems also are associated with the production of ethanol in the chemical plant. The EPA (2002) has issued warnings to corn ethanol plants to reduce their air pollution emissions or be shut down. Another pollution problem is the large amounts of wastewater that each corn ethanol plant produces. As mentioned, for each liter of ethanol produced using corn, about 13 l of wastewater are produced. This wastewater has a biological oxygen demand (BOD) of 18,000–37,000 mg/l depending on the type of plant (Kuby,Markoja, and Nackford, 1984). The cost of processing this sewage in terms of energy (4 kcal/kg of BOD) was included in the cost of producing ethanol.