Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


AgriLife Research study estimates costs of mesquite biomass delivery for bioenergy use

Operating on the thought that, if it is not feasible, it's not going to be done, a group of Texas AgriLife Research scientists is studying the costs of getting potential bioenergy sources such as mesquite to the processed stage.

AgriLife Research scientists from the Texas AgriLife Research and Extension Service center at Vernon, Dr. Seong Park, economist; Dr. Jim Ansley, range ecologist; Dr. Mustafa Mirik, associate research scientist; and Marc Maindrault, a visiting forestry student intern from France, have completed a study on costs of delivered biomass.

The costs of feedstock delivered to a fictional wood-fired bioelectricity plant were considered under two general biomass densities – moderate and high – and across two harvest scenarios in which the minimum biomass density acceptable for harvest within each area differed, Park said.

They found that higher harvest and transport costs are offset by essentially no production costs and therefore it may have potential as a bioenergy feedstock under certain densities and total land areas, Park said.

The study conducted a sensitivity analysis to determine how changes in a variety of factors would affect cost of delivered biomass to the power plant, he said. Values for the "best case" and "worst case" scenarios were $347 per acre and $561 per acre, respectively.

"The full economic story cannot be told until we have a clear end product," Park said. "That is why this study focused only on the costs of delivery of the biomass."

The variation of cost of biomass was found to be similar on both sites, although one site had a larger range of costs and higher risk than the other, Park said.

Because rangeland trees like mesquite and juniper occur naturally and have scattered distribution, he said key factors in determining economics is: total amount of land area involved and amount of land within the total area that has patches of brush of sufficient biomass density for harvest. These were called "suitable harvest areas."

"Our analysis found that biomass density and harvesting costs are the two major factors affecting cost of delivered biomass," Park said. "While biomass use – or capacity – of the bioelectricity plant and the percentage of suitable harvest areas strongly affect land-related factors, including feedstock transport costs, these have relatively minor effects on cost of delivered biomass compared to harvesting costs."

Most emphasis for the biofuel industry has been placed on feedstocks such as energy cane, perennial grasses and sweet sorghum because they can be grown in high density situations with lower harvest costs, he said. However, woody feedstocks are being evaluated for their potential benefits because they are not grown on cropland and require lower cultivation costs.

Woody species such as willows that grow in wetter climates have been considered. More recently, researchers like Ansley have been considering the potential of shrubs and trees on rangelands such as mesquite and juniper for bioenergy uses.

"These trees likely will not be considered for ethanol conversion – they won't result in liquid fuel for the automobile tank – but may have other uses as a bioenergy feedstock such as electricity generation," Ansley said.

Park said there are several advantages to mesquite and similar woody plants that may offset the lower growth rates and potentially higher harvest and transportation costs. Particularly, these plants are abundant in existence, are drought-tolerant and grow without additional costs of planting, cultivation, irrigation and fertilization. And they resprout after harvest.

Also, they don't grow on land typically needed to grow food crops, they have higher energy content than switchgrass and they can be harvested year-round, he said.

"Also, we found that water content of mesquite and juniper wood at harvest is lower than most cellulosic feedstocks; thus, drying costs could be reduced," Park said.

One major problem with mesquite as a feedstock is its variable growth form, which vary from tree to tree and stand to stand. Any harvesting operation would have to contend with this variation, he said. And the regrowth is much slower – about 10 years before it could be re-harvested. But the greater amount of available land area where this material grows offsets this to some degree.

"Harvesting the regrowth is a key factor in the long-term planning of this species as a bioenergy feedstock," Park said.

The study was based on several key assumptions, including that the bioenergy industry could use rangeland biomass through a system where harvesting and transportation would be vertically integrated, and that landowners would be willing to participate in a long-term contract with bioelectricity plants for a sustainable flow of product to the plant.

Location of the bioelectricity plant was centered relative to the location of the feedstock source in the scenarios studied, Park said.

If the industry grows large enough, custom harvesters dedicated to harvesting and transporting the mesquite would likely operate more efficiently than if the bioenergy company tried to maintain its own harvesting equipment.

The tougher growth form of mesquite and the remote locations where it will be harvested create a higher probability for downtime from mechanical failure that may be better absorbed by businesses that are solely dedicated to this task, he said.

Another difference in utilizing mesquite biomass compared to other dedicated energy crops is that the business arrangement would have to be made with multiple landowners to obtain enough stock to sustain the plant, Park said.

"The landowners would have to agree to have the mesquite trees harvested according to a long-term strategic plan that would include allowing the trees to resprout and grow to be harvested again in the future," he said.

Ansley said landowners would benefit from additional grass growth and increased livestock production for many years after a harvest, but would then have to allow the regrowth to get large enough to re-harvest. He estimated that in a 10-year re-harvest schedule, the landowner would have seven to eight years of increased grass production before it would begin to level off.

Dr. Jim Ansley | EurekAlert!
Further information:

More articles from Power and Electrical Engineering:

nachricht Solid progress in carbon capture
27.10.2016 | King Abdullah University of Science & Technology (KAUST)

nachricht Greater Range and Longer Lifetime
26.10.2016 | Technologie Lizenz-Büro (TLB) der Baden-Württembergischen Hochschulen GmbH

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

How nanoscience will improve our health and lives in the coming years

27.10.2016 | Materials Sciences

OU-led team discovers rare, newborn tri-star system using ALMA

27.10.2016 | Physics and Astronomy

'Neighbor maps' reveal the genome's 3-D shape

27.10.2016 | Life Sciences

More VideoLinks >>>