INCREASED GRAIN costs are making biomass crops like energy cane shown here more attractive for conversion to ethanol

INCREASED GRAIN costs are making biomass crops, like energy cane shown here, more attractive for conversion to ethanol.

Energy cane for biomass promising in South Carolina testing

• Steve Kresovich is part of a team of USC researchers looking for crops that can be adapted to less productive and often under-utilized South Carolina soils. • The end goal, Kresovich says, is to develop biomass crops that can be used to produce energy and that can be grown profitably by South Carolina farmers.

University of South Carolina Biologist Steve Kresovich may have felt like an alien speaking to farmers at a recent Clemson University field day at the Pee Dee Agricultural Research and Extension Center in Florence, S.C., but what he had to say resonated well in terms of dollars and cents to the large crowd attending the event.

Kresovich is part of a team of USC researchers looking for crops that can be adapted to less productive and often under-utilized South Carolina soils.

Finding something that will grow and that has some value to farmers in a rural enterprise is a bit challenging, he admits.

Clemson Agronomist Jim Frederick has tested switchgrass for several years at the PeeDee research center.

The University of South Carolina research team is working in cooperation with Frederick and other Clemson researchers to find fast growing, high volume biomass crops that can be adapted for production in South Carolina.

The end goal, Kresovich says, is to develop biomass crops that can be used to produce energy and that can be grown profitably by South Carolina farmers.

Solving the logistics and marketing problems will be much easier than finding crops that grow well in the state, he adds.

He showed the farm group what looked like a large planting of sugar cane. “This is not sugarcane, this is energy cane,” he said. Energy cane is a highly productive crop that meets the criteria of growing well on less than optimum soil, does well in drought, heat, and cold tolerance — and overall is productive over a wide range of soil and climate conditions in South Carolina.

Kresovich says that energy cane is a cross between commercially grown sugarcane produced in Florida and Louisiana wild relatives of sugarcane.

While commercially grown sugarcane probably wouldn't do well as far north as South Carolina, there are many relatives of sugarcane grown all over the world and in climates similar to those found in the Southeast, Kresovich says.

The biology part of finding productive grain and grass crops to grow on marginal land will be the easy part, he says. “I worked with sugarcane in Texas, and we had one sugar mill that serviced more than 40,000 acres of production. Those are the kind of issues we will face in developing alternative crops for the Southeast,” he says.

The energy cane being grown at the PeeDee Research Station was propagated from vegetative stock and grown as a perennial crop.

Louisiana tests

In similar tests in Louisiana, researchers got 3-4 re-growth periods, and that’s where producers make their money on crops like energy cane, because the bulk of the investment is on the front end of the production process, Kresovich says.

“Typically, if a grower can keep this crop free of disease and insects, and you don’t tear it up when you pull it out of the ground, they do really well on odd years,” he says.

A key to productivity with energy cane and other high volume foliage crops is to keep them productive throughout the year, he adds.

If grown commercially in South Carolina, energy cane would likely be harvested one time. When it’s harvested is not so critical. It could be harvested after a freeze, because you wouldn’t be harvesting it for sugar, as would be the case for sugarcane.

Energy cane production in the Southeast would be much like switchgrass or high producing grass crops. The goal is to produce high volumes of carbon per unit area and per unit cost, Kresovich says.

The U.S. Department of Energy contends delivered cost of biomass to conversion facilities should be in the range of $30 to $40 per dry ton, to be economically feasible for use as biofuels.

However, the production costs for dedicated energy crops range from $50 to $100-plus per dry ton. The key to reducing delivered cost will be high-tonnage crops and highly efficient production systems, but delivering large amounts of biomass (hundreds of millions of tons per year) at rates lower than $50 per dry ton will be difficult, the USC researcher predicts.

The recent rise in corn prices and projections that reduced inventories globally will keep demand up and prices high has generated a lot of interest in growing energy cane and other biomass crops for use in making cellulosic ethanol.

Despite the increase in corn prices, at the current level of technology, it is still more efficient as stock for ethanol than is any similar feedstock used for producing cellulosic ethanol.

Back when corn was selling for $3.50 a bushel, energy cane grown at 35 tons per acre was about $1.25 more costly to convert into cellulosic ethanol.

For cellulosic ethanol to be competitive with corn ethanol given these parameters, the cost of cellulosic ethanol needs to decrease 90 cents per gallon and energy cane yield needs to increase to about 50 tons per acre.

As the price of corn rose to $5 a bushel in recent years, and on up to more than $7 per bushel, corn-based ethanol’s advantage decreased. Still, even with corn at $5 per bushel, corn-based ethanol has a competitive advantage of about 60 cents per gallon over ethanol from energy cane.

With corn prices at $7 per bushel, the cost of corn-based ethanol and energy cane-based ethanol are competitive. And, that’s considering energy cane is being produced at 35 tons per acre.

Kresovich says the potential for production of energy cane in the Southeast is higher than 35 tons per acre, but to reach higher yields, researchers will have to develop better varieties and better production systems.

At the end of the day, farmers are going to have to know that growing energy cane will be as profitable as other crops, or there is going to have to some documented advantages for using this or other biomass crops in rotation with conventionally grown crops, the South Carolina researcher says.

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