Pumping biofuel out of Johnson grass

Master distiller Brian Neary found that Johnson grass is packed with energy and developed a process to turn it into bioethanol – without threatening food security. Annelie Coleman reports.
Issue date : 10 – 17 April 2009

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Master distiller Brian Neary found that Johnson grass is packed with energy and developed a process to turn it into bioethanol – without threatening food security. Annelie Coleman reports.

Brian Neary, a master distiller from Bothaville in the Free State, has successfully developed a process of producing bioethanol from perennial and invasive Johnson grass (Sorghum halepense) by converting its cellulose. The project is still in the pilot phase, but the long-term goal is to produce biofuel sustainably from this renewable source, which also doesn’t threaten food security.

“I believe ecologically friendly, renewable, sustainable biomass is the answer to biofuel production in the near future,” enthuses Brian. “I’m opposed to using food feedstock because of the cost and threat to food security.” Brian found Johnson grass’s sucrose levels exceed 16 brix just before it goes into seed. Around 70% of the plant dry matter consists of complex carbohydrates like cellulose. The more cellulose available, the more valuable the plant becomes as a source of ethanol.
“Preliminary results at the plant prove Johnson grass is an excellent source of biomass,” says Brian.

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Cheaper than cane ethanol
Brian says he and his team produce high-quality bioethanol at a fraction of the cost of sugar-cane ethanol. “Our calculations so far show a fine, fuel-grade bioethanol can be produced for about R3,96/â„“ at 96,5% proof. It’s possible to produce 4 500â„“ to 5 000â„“ of ethanol from 50t of Johnson grass”. Initial tests show Johnson grass yields 18t/ha to 24t/ha of feedstock at a moisture content of 23%. Three cuttings per year amount to an average annual production of 50t/ha. “At R120/t delivered at the distillery, our suppliers will earn no less than R6 000/ha/year,” says Brian.

“Our plant is unique, but not so sophisticated that it needs to be run by scientists. It’s fairly simple and production facilities could be established rather cheaply in all provinces. As the conversion is a cold process, minimal power is needed to generate steam or boil water.” It will cost about R6 million to R8 million to build a plant able to produce 3,78 million litres of bioethanol a year. The annual yield from 835ha planted to Johnson grass will be enough, Brian says.

More energy for less
Beginning with the planting of the grass and ending with transportation and distribution, Brian calculated that for every unit of energy put into cellulosic ethanol production six to 10 are produced. This is much higher than ethanol derived from maize (at a ratio of 1:1,4). Petrol, in contrast, requires more energy to produce than the energy units it yields. “My calculations show producing ethanol from Johnson grass uses up to 70% less fossil fuel in the production process than petrol, so fewer green house gasses are released into the atmosphere,” says Brian.

Ideal for emerging farmers
“I think the government should take note of the bigger picture,” says Brian. “This is an ideal crop for farmers on marginal land, who could produce it relatively cheaply with very few input and production costs. “Emerging farmers wouldn’t need a large financial outlay to cultivate it and an average gross income of R6 000/ha would be higher than the current nett yield out of maize.” He is now looking for investors to get the industry off the ground. “Bioethanol can play an immensely important role in lessening South Africa’s dependence on fossil fuels,” he says. “I blend 15% ethanol from Johnson grass with the petrol in one of my cars and it’s going beautifully.”
Contact Brian Neary on (071) 678 7033, e-mail [email protected] or visit www.grasoline.co.za.     |fw