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Turning Grass Into Fuel

By Brian Westenhaus | Fri, 05 November 2010 17:05 | 0

Researchers at the University of Illinois have completed the first extensive geographic yield and economic analysis of potential bioenergy grass crops in the Midwestern United States. It’s the best work yet and suggests some impressive potential.

Federal regulations mandate that 79 billion liters of biofuels must be produced annually from non-corn biomass by 2022. The large grasses, switchgrass and miscanthus, could provide the needed biomass with the added benefits of better nitrogen fixation and carbon capture, higher ethanol volumes per acre and lower water requirements than corn.

UI’s Madhu Khanna, professor of agricultural and consumer economics said, “These two particular crops are among the more promising nonfood crops currently available for large-scale production.” Switchgrass is large prairie grass native to the Midwest; miscanthus, a sterile hybrid, is widely cultivated in Europe as a biofuel crop. Others such as sweet sorghum could be competitive and the waterborne organisms such as algae also could get competitive.  But right now the grasses have the mass potential.

The UI team wanted to determine whether biofuel grasses could be viable cash crops in the U.S. and to explore how this viability varies by location.

Professor Atul Jain said, “This is the first study to look at both the agricultural potential and socioeconomic costs of grass crop production. We came to the conclusion that in order to study the potential to grow these grasses in this region, we have to have an integrated assessment study of socioeconomics and biophysical aspects.”

The paper exploring the results, as of this writing, is available in full from October issue of the journal Global Change Biology Bioenergy.

This very sharp team recognizes that growing conditions throughout the Midwest can vary widely; the team performed a county-by-county analysis to gain a high-resolution picture of crop potential rather than generalizing the study across the entire region.

A transition to energy crops is going to face some intense scrutiny from farmers.  Khanna explains, “This research suggests that in order to induce land owners to use their land for bioenergy crops, yield is a critical factor that will influence that decision. We wanted to look not only at the implication for a representative landowner, but also how it differs across location.”

Jain points out, “We have to consider the biophysical aspects – where the crops can grow in terms of soil, water and nutrient availability, and climate conditions.”  The team began by predicting local yields for the two grass crops. They used an integrated sciences system model, a biophysical model used not only for yields but also estimated carbon uptake and possible atmospheric effects from changes in land use.

The researchers found that, in general, the yield is very high for miscanthus – up to three times higher than switchgrass in the Midwest. Even through switchgrass is native to the region; it doesn’t grow well in higher latitudes like Minnesota or Wisconsin because it has poor tolerance for cold temperatures.  For both grasses, yield varies considerably throughout the Midwest, generally lower in the north and much higher in the south.

Heads up – most notably, for the southernmost counties – much of southern Illinois and nearly all of Missouri – the model predicts greater production of grasses than of current corn and soy crops. This could be a key factor in farmers’ decisions to cultivate biofuel crops.  Should the model hold with some real world applications the energy zone using the large grasses is getting the early boundaries.

Then the researchers estimated the minimum price at which a landowner would need to sell the two grasses to break even on costs. They conducted a detailed analysis of production over the life of the plants and the costs involved at each step, and then compared the cost to the return from corn and soybeans.  Here is where the scientific application will meet reality.  No two farms are going to be alike.  The costs can vary widely.

The team realizes this at least in part – “There’s a number of factors that would impact the profitability of growing these crops as opposed to growing corn and soybeans, which include the cost of establishing these grasses as well as maintaining, storing and transporting them,” Khanna said.  “Another issue is the cost of the land itself. A farmer who converts land from corn and soybeans to miscanthus or switchgrass is giving up his profits from corn and soy.”

Unlike annual crops that provide a farmer with a crop and an income every year, miscanthus and switchgrass require a lag of at least two years before harvesting. In addition, the cost of harvesting current crops is nearly one-third of the cost of producing biomass, according to Khanna. In the U.S., such large-scale grass harvesting hasn’t been attempted, making cost estimates difficult. The most comparable crops currently grown are hay and alfalfa, which have yields only one-sixth to one-tenth of the possible volume from miscanthus.  These are two very serious issues.  The obvious one is a very patient banker would be needed – a two year income loss probably wouldn’t work nor would any bank regulator tolerate such a plan.  Then the equipment costs are going to be astronomical – new untried designs built in small volumes could destroy the economics of the entire effort.

The risks don’t stop there. The costs vary between switchgrass and miscanthus. Miscanthus has a much higher yield, but also a much higher initial cost. Miscanthus is planted from small sprouts called rhizomes, which are much more expensive and difficult to plant than switchgrass seed. However, miscanthus has a longer lifespan, so planting would be less frequent. These are tradeoffs farmers would have to consider when deciding to cultivate biofuel grasses.

But the research offers intense and very high potential hope.  Khanna said, “We find it’s more profitable to grow miscanthus and switchgrass in areas where the yield of miscanthus and switchgrass is high, but the yield of corn and soybeans is low. In areas like southern Illinois or Missouri where corn is not as productive as in central and northern Illinois or Iowa, these grasses are likely to be more competitive.”

That might be the key lesson from the research.

Even more interesting is the team will explore the cost of growing these grasses on non-cropland, or marginal land that’s ill-suited for food productions. The grasses require less water and less fertilizer than corn or soybeans, and could thrive on land that’s currently unused for reasons of soil composition or difficult maintenance. It would cost a lot less for farmers to convert that land than acreage that’s currently producing high amounts of other crops, cutting back one of the major tradeoffs of biomass production.

For those interested in farming’s future the paper is an important read. The suggestion is to get it soon as journal publishers often put these behind a payment barrier without any forward notice.

Today the processes to get fuels from the large grasses aren’t mature or market ready.  More over those farmers in locations where the economics are profitable will most likely take years to make the transition, as a full farm shift with a large investment followed by two years of no income simply wouldn’t work and the replant years would need spaced apart as well.  That fact affects the process facility plans; it might take a decade for an area to get to full production.

For biomass to get to market there will need to be coordination from the landowner to the fuel consumer.  As the research team illustrates the risks along the way are substantial, and the opportunity good.  For farmers to change though, putting their livelihoods and futures at risk, the certainty is going to have to be much better than a study result.

From Kansas City MO to Pittsburgh PA there is change coming.

By. Brian Westenhaus

Source: Will Grass Biomass be a Viable Fuel Source

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