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Sustainable Biofuels: Hows ’bout a shot of tequila with that ethanol, sir?

| Tuesday August 26th, 2008 | 1 Comment

biofuels_farm.gif With energy and now food prices rising fast, first generation biofuels have again come under attack from scientists, skeptics and policy makers. But are all biofuel feedstocks created equal? And should they all be lumped together and farmers and industry chastised for and discouraged from investing in them?
Certainly there are those who think not. Greenbiz reported this week on initial progress towards developing an environmentally, socially and economically sound standard for biofuel production. The Roundtable on Sustainable Biofuels, a coalition of farmers, businesses, governments and non-profit groups, last week released a first draft of “Version Zero,” a set of principles for cultivating biofuel crops that it hopes will serve as a guide for producers worldwide.


A wealth of alternatives being overlooked
If it can gain traction, the Roundtable’s sustainable biofuels standard is a positive step in the right direction. With some 250 million registered vehicles on the road in the US alone, ethanol and biofuels can play an important, though limited and perhaps transitional, role in addressing energy needs and reducing greenhouse gas emissions.
Corn, palm oil and sugar cane are the predominant ethanol feedstocks. All of them are food and feed crops with relatively large, politically influential agro-industry interests behind them.
As investment capital has poured into the “Big 3″ ethanol sources and the debate over renewable fuel standards and first-generation biofuels rages on, there’s a wealth of other plant and tree species out there that could be used not only to produce ethanol, but can yield varied and numerous other products and benefits, from producing pulp, paper, fiber, biodegradable plastics to medical and health care products, while in the process improving soil conditions, reducing erosion, conserving water and providing wildlife habitat.
Tequila Powered Vehicles in Mexico?
PI%C3%91AS%20GIGANTESa.jpg One such candidate is well-known, notorious and beloved all at the same time: the agave. Currently grown primarily to make tequila, agaves have played an important role in the Mexican economy and society since pre-Columbian times.
Today, a small group of Mexicans from the academic and private sectors is keen to leverage decades of field and lab research to attract support and funding for a demonstration Agave-to-Biofuels project.
“High quality agaves are very good feedstock material for biofuel, in addition to other attributes for the following characteristics: high total sugar density and content; high weight of the fruit and stems; cultivation and harvest cycles of six years; high density of plants per hectare; genetic diversity and high adaptability, low water requirements; CO2 capture, methane metabolism, soil retention, plant nutrition, products from inulin and low maintenance during cultivation,” asserted Remigio Madrigal, a PhD and professor of agricultural biotechnology at the Autonomous University of Chapingo, whose investigations and efforts to conserve agave germ plasm and work with local farmers to support sustainable markets and production gave rise to the project.
From all indications, the agaves cultivated by Prof. Madrigal and his team appear to be vastly superior to corn, palm oil and sugar cane, as well as popular second-generation biomass alternatives such as willow and jatropha.
“We are using an enhanced cultivar of Agave tequilana weber that was developed by Prof. Madrigal after 29 years of biotechnology research,” explained Arturo Velez, the project’s originator.
“This cultivar has been tested during two full life cycles of the plant with amazing results…On an annualized basis, agave produces 100 tonnes of biomass per acre. From these, agave heads–where sugars are– weigh 44 tonnes with 27 to 38 degrees Brix. It takes six kilos of common agave, with around 20 degrees Brix, to produce one liter of tequila. We use seven to eight kilos of our cultivar to produce one liter of distilled ethanol, so each acre of agave produces around 1,500 gallons of distilled ethanol.”
In addition, the group’s selected varieties of agave also yield 100 wet metric tons of biomass per acre annually, or 20 dry metric tons. “Since each tonne of dry biomass can yield up to 180 gallons of cellulosic ethanol, you get 3,600 gallons of cellulosic ethanol per acre,” according to Velez. Adding this to the 1,500 gallons from converting the plants’ sugar yields an extraordinary 5,000 gallons of ethanol per acre.
Myriad products and potential benefits
Moreover, agaves are hardy, widespread across Mexico, can yield a wide range of other ingredients and products, enhance soil nutrition, control erosion and conserve water, and provide sustenance and shelter for wildlife.
“Agave tequilero cultivation in the area Denomination of Origin Tequila (DOT) and registered with the CRT is estimated to be a little more than 100,000 hectares. Casa Cuervo probably has around 23,000 hectares alone. Outside of the DOT land under agave cultivation isn’t registered with the CRT (Consejo Regulador de Tequila), but is probable more than is registered en the DOT,” Prof. Madrigal noted. “There are agave producers in around 20 states of the republic that have problems selling their harvest.”
Agave is a known source of at least 35 other commercially viable substances that are used in food and medicinal products- inulin and fructose sugar syrup- pulp, paper and fiberboard production, textiles and rope, plastics and other commercial and industrial products, Velez continued.
“I claim that there’s no other plant or tree in the world that can produce as much sugar and cellulose…Cellulose is the organic oil substitute – green oil – and sugar can be converted into many things– agave sugars can be even eaten by diabetics without any risk, and have a high probiotic value.”


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  • Daniel

    What is the amount of greenhouse gas emissions roughly when producing agave ethanol? We have to weigh all opportunity costs to get the real picture of how much better this type of ethanol is.