Monthly Archives :

January 2014

Arundo Is Better than Switchgrass for Biomass Power Generation

484 309 Miguel Ángel Martínez

Arundo donax, the ancient species of Giant Reed that may have hidden Moses along the Nile River more than 3500 years ago, could also go a long way in solving the U.S.’ 21st century biomass to energy needs. That is, if it can overcome regulatory hurdles and environmentalists bent on characterizing this tall grass as an “out of control” invasive species.

In the U.S., Arundo’s biggest challenge remains whether the Environmental Protection Agency (EPA) will ultimately grant the Giant Reed a Renewable Identification Number (RIN).  A RIN would enable biofuel refiners and fossil fuel blenders to receive credits for complying with the 2005 federally-mandated Renewable Fuels Standard (RFS).

“The EPA hasn’t announced a timetable for RIN approval,” said Wil Glenn, communications director for the Biofuels Center of North Carolina.  “But the agency has already recognized the Giant Reed (Arundo donax) as a crop that can reduce Greenhouse Gas (GHG) emissions by up to 80 percent.”

However, environmentalists note that Arundo has already transformed a significant amount of native southern California riparian habitat into pure stands of this weed-like grass.  In fact, it’s estimated that tens of thousands of acres of Arundo now line southern California drainage systems, after being intentionally introduced nearly two hundred years ago as a hedge against soil erosion.

Originally, native to the grasslands and wetlands of East Asia, its hollow, bamboo-like stems can reach heights of more than 25 feet producing 20 dry tons of biomass per acre.  That’s compared to Switchgrass, which only averages up to 8 tons an acre annually.

But although fast growing and drought-tolerant, Arundo’s seeds are sterile.  Thus, its stems and underground bulb-like rhizomes only propagate via cultivation or movement by forces of nature like hurricanes and flooding.

Despite such cultivation challenges, Arundo’s potential as a biofuel feedstock is already recognized in Europe.

Since late last year, Beta Renewables, whose partners are Chemtex, Novozymes and TPG, has been operating a 20-million gallon a year ethanol production facility in Crescintino, Italy using Arundo donax and wheat straw as feedstock.

“In Italy, we use enzymatic hydrolysis fermentation,” said Delane Richardson, a chemical engineer at Chemtex in Medina, Ohio.  “You extract the sugar from the biomass and the enzymes take the long chain sugars and cut them into digestible C5 and C6 sugars that are then exposed to a patented ethanologen microorganism to produce ethanol.  We want a facility just like it in North Carolina.”

Although the EPA has yet to get onboard, the North Carolina Dept. of Agriculture recently decided against putting Arundo on the noxious weed list, leaving the door open to cultivation.

Richardson says Chemtex would like to build a biomass to ethanol plant in Clinton, North Carolina that would operate on a combination of Arundo, Switchgrass, Fiber Sorghum, Miscanthus, and Rye at a delivered aggregate biomass feedstock cost of $50 or less per dry ton.  However, the largest single component would be 100,000 tons of Arundo, which would account for 7 million gallons (or at least a third) of the Clinton facility’s annual ethanol production.

If the plant’s local biomass supply chains were firmed up, Richardson says the North Carolina facility could be operational by mid-2015.

Richardson says that while the conversion process uses the Arundo’s sugars, as much as 60 percent of the harvested reed is leftover.  It’s this leftover lignin that is generally converted to electricity.  Richardson notes that Beta Renewables’ Italian facility has enough converted electrical power to supply its own needs as well as sell a portion to local utilities.  Chemtex hopes to do something similar with its planned North Carolina facility.

On the other side of the country, however, Portland General Electric (PGE) is running a study to determine whether Oregon’s Boardman coal-fired electric plant can be converted to a total biomass facility after the year 2020.  That’s the deadline for the plant to meet a regulatory ultimatum dictating that the facility cease burning coal.

If it successfully makes the transition to biomass, the 585 MW Boardman plant, which already provides PGE with 15 percent of its electricity, or some 65 percent (374 MW) of the plant’s output, would become the U.S.’ largest biomass-fueled electric generator.

But to do so, PGE would have to have some 8,000 tons of biomass for every day the biofuel generator was operational.  An Arundo test crop, being grown on 90 acres of Morrow County, Oregon farmland, will be harvested, pulverized and then torrefied in a charring process before the Boardman plant actually tests the crop in its facility next year.

“The goal in the test burn is to determine whether it’s feasible to convert this coal-fired power plant to [biomass],” said PGE spokesman Steve Corson.  “Arundo would only be only one of several feedstocks for such a biomass plant.”

Still, it’s estimated that Arundo would produce about 10,000 Btu/lb compared to 8500 Btu/lb for Boardman’s coal operations.

As for the risk of invasiveness in Oregon?

Tim Butler, a weed scientist at the Oregon Dept. of Agriculture, says mitigation control against Arundo invasivity would include strict monitoring of fields; restrictions on how close it could be planted to water; and attention in cleaning farm equipment leaving its fields.

The Giant Reed has been sold in Oregon as an ornamental for decades, says Butler, and thus far, the state appear to be free of wild Arundo stands.

However, Lauren Quinn, an invasive plant ecologist at the University of Illinois at Urbana-Champaign, says that every Weed Risk Assessment (WRA) published for Arundo has indicated high risk.  “We worry about extreme climatic events such as hurricanes moving rhizomes out of cultivation [areas] and about abandonment of plantations after leases expire or if the industry fails,” said Quinn.  She notes there is also a risk of escape via transportation of rhizomes to production fields or bio-refineries.

As weed scientist Joe DiTomaso at the University of California at Davis notes, Arundo is the “weediest” of all the plants being considered for biofuel and, as such, has taken over a lot of stream banks.  Its root fragments can also can spread down river corridors via flooding events, where they eventually create new Arundo colonies.

But when planted on farmland, DiTomaso says Arundo is easy to manage because it doesn’t produce any viable seeds.  Because its only means of spreading are via stem nodes and rhizomes, he says when planted in confined areas away from water, it remains at low risk of invasivity.

“The good news is that Arundo is one of the few crops that meets the yield threshold that we believe is going to make it attractive for farmers to plant,” said Richardson.  “The bad news is that a hundred years ago it was mishandled and became invasive in some environments.”

But at this point, without the RIN, Richardson says the economics for Chemtex’ North Carolina project don’t look promising.  Even so, Richardson says Chemtex is looking at other potential Arundo biofuel plant locations in the Southeast including Virginia, Kentucky and Georgia.  The idea is to target former strip-mining areas, as well as low-production agricultural lands, such as former tobacco-growing areas for Arundo acreage.

“Arundo can be grown on very contaminated soils without herbicides or pesticides and a minimal amount of fertilizer,” said Richardson.  “Plant it once and it lasts 15 years.  That’s versus a corn crop where you’re pushing a tractor through a field five times a year.

Arundo is a win, win, win.”


Energy Crops for Biofuels

1024 554 Miguel Ángel Martínez

A number of energy crops can potentially be grown on marginal land (i.e. land that is not suitable for food production) to provide feedstocks for bioenergy, non-food products and biofuels. Examples of energy crops are shown below.

Using ‘contaminated’ land and ‘poor’ soils for biofuel feedstock production

Cultivation of energy crops can be used for phytoremediation of contaminated or poor soils, while offering the potential of future feedstock production. For example, see Multi-tasking plants for phytoremediation and bioenergy [Source: CABI 2013]. Globally, there is vast potential to grow energy crops on ‘contaminated’ land and poor soils, which are unsuitable for food crops. Current research is focused on trials of energy crop strains that could offer reasonable production potential. Typically, low nutrient levels, and inconsistent soils in marginal land tend to result in low yields, especially in initial years.

In August 2013, the U.S. EPA announced an update of its RE-Powering Mapping and Screening Tool, which has now identified 66,000 locations where contaminated land, landfill and mine sites could be used for cultivation of energy feedstocks.


Miscanthus - an energy crop© Copyright CPL Press
Miscanthus (above) has been trialled extensively in Europe and the US as an energy crop for biofuel production. Trials indicate that that it provides relatively high yields (double that of corn), requires limited fertiliser, few other inputs and adds significant amounts of organic matter to the soil. Othe giant grasses such as Switchgrass are also the subject of trials.

A ten year trial of Miscanthus (2003-2013) by University of Illinois showed an average annual yeild of 10.5 tons per acre (double that of a corresponding area planted with Switchgrass). The trial confirmed that Miscanthus grows well with little or no fertiliser input. After five years, the roots and rhizomes contribute 12 tons of biomass per acre to the soil (dry mass). The extensive root system of Miscanthus makes it suitable for stabilizing slopes or soils.

In March 2012 it was announced Mendel Biotechnology (Mendel Bioenergy Seeds) will carry out a 4-year field trial of PowerCane™ Miscanthus with BP Biofuels, as a potential feedstock for the cellulosic ethanol demonstration plant in Jennings.

Panicum virgatum (Switchgrass)

Extensive research is being carried out into cultivation of Switchgrass as a biofuels feedstock in the US. The plant is a tall-growing, perennial grass that is native to North America.

Samuel Roberts Noble Foundation has developed novel strains of switchgrass that contain lower amounts of lignin and hence boost biofuel yields by over a third [Source: Proceedings of the National Academy of Sciences].

Following a $5m grant from the DOE in 2009, University of Tennessee and Genera Energy have developed a new feedstock logistics systems using chopped switchgrass, which aims to bridge the gap between growers and biofuel producers.

Arundo donax (Giant reedgrass)

Miscanthus - an energy cropArundo donax (Giant reedgrass or Spanish cane) is considered to be one of the most promising species for biomass production in Europe. It is being cultivated as a feedstock for the Beta Renewables commercial scale cellulosic ethanol plant in Crescentino.

Sweet Sorghum

Sweet Sorghum - an energy crop© Copyright SWEETFUEL

Sweet sorghum, as a source of either fermentable free sugars or lignocellulosics, has many potential advantages, including: high water, nitrogen and radiation use efficiency; broad agro-ecological adaptation; rich genetic diversity for useful traits; and the potential to produce fuel feedstock, food and feed in various combinations. Further research on Sweet Sorghum is being carried out bySWEETFUEL – Sweet sorghum: an alternative energy crop (FP7 – 227422)

Sweet Sorghum is also being developed as a biofuel feedstock in the US (e.g.Regional Strategy for Biobased Products in the Mississippi Delta). In April 2013, construction started on a 20 MMgy sweet sorghum-to-ethanol plant in Florida [Ref:Southeast Renewable Fuels LLC ]. Also in the US, NexSteppe has developed low-input, high-yield Sweet Sorghum and ‘High Biomass Sorghum’ strains for use as bioenergy feedstocks. Ceres has also developed varieties of Swet Sorghum that are being commercially planted in Brazil. In March 2013, Chromatin signed an agreement to supply POET with Sorghum for its bioethanol plant in South Dakota. In November 2013, Arcadia Biosciences and DuPont Pioneer are collaborating on a project to use biotech and breeding techniques to improve the productivity of Sorghum.

Short Rotation Coppice (Willow and Poplar)

Short rotation coppice - harvesting© Copyright Choren
Willow and poplar may be grown and harvested in 2-5 year cycles as an energy crop (Short Rotation Coppice). SRC has potential for use as a feedstock for second generation biodiesel, for example as being demonstrated at the Choren BtL plant.

Sugar Cane

sugar cane harvestingSugar cane harvesting. Although sugar cane is a first generation crop, it is generally considered to be sustainable as it offers a high energy balance and high GHG reduction. It has not been shown to have significant impact on food supply or prices in Brazil, where there are 9 million vehicles that use ethanol or ethanol blends from sugar cane.

Phalaris arundinacea (Reed canary grass)

Phalaris arundinacea (Reed canary grass), provides good yields on poor soils and contaminated land and is thus an interesting candidate for bioremediation of brownfield sites as well as a source of biomass for bioenergy (typically as briquettes) or pulp. Is also considered a suitable feedstock for cellulosic ethanol production [Source: VTI Finland].


Flowers of the Jatropha treeCamelina sativa is an oil plant that grows well on marginal land, is cold-tolerant and has an oil-yield of 35-38%. It is being investigated as a sustainable oil crop for biodiesel production. Picture credit: Wikipedia.

Sustainable Oils (a partnership between Targeted Growth, Inc. and Green Earth Fuels, LLC) currently has 30 Camelina breeding trials in the US and Canada. The company provided Camelina-based biodiesel for a Japan Airlines test flight in January 2009.

The Eureka BIOFUEL-CAMELINA Project, coordinated by ISCO, Poland,
is studying the cultivation of Camelina sativa and cameline oil production, biofuel production and evaluation. Biojet fuel derived from Camelina has been successfully used on demonstration flights.


Flowers of the Jatropha tree
Flowers of the Jatropha treeImages of Jatropha curcas © copyright JatroSolutions GmbH, which offers expertise in tropical plant production, including cultivation of Jatropha for biofuel production. The top picture shows pollination of Jatropha by bees. The picture immediately above shows male flower (right) and female flower (left).

Jatropha curcas is a tropical plant that grows well on marginal land, is drought tolerant and has seeds with high oil content (~40%)*. Although the plant contains toxins, and has to be handled and processed with care, Jatropha is considered a good candidate as a biofuels feedstock and is the subject of various trials. For example, Archer Daniels Midland (ADM), Bayer CropScience AG and Daimler AGannounced in early 2009 that they would collaborate on use of Jatropha. NesteOilis also researching the use of Jatropha for biodiesel production. Galp Energia,Portugal is leading a research project on Jatropha for biofuels production in Mozambique.

*In Singapore, Temasek Life Sciences Laboratory and JOil Pte Ltd. have developed Jatropha strains with 75% oleic acid content, compared to the typical 45% percent (May 2012).

Salicornia bigelovii (dwarf saltwort / dwarf glasswort)

A salt mash halophyte that is found on both the east and west coast of the US and Mexico. The plant is of interest as a biofuel feedstock as it grows in desert environments, can be irrigated with seawater, and the seed contains around 30% oil content. It is being grown extensivley across the globe, for example in India.

Cynara cardunculus (Cardoon)

Cynara cardunculus (Cardoon) has been investigated as an energy crop for co-firing with lignite at the PPC Kardia Power Plant, Greece, as part of the FP6 DEBCOproject. The oil, extracted from the seeds of the cardoon (artichoke oil) has also been investigated as a feedstock for biodiesel production.

Brassica carianata (Ethiopian mustard)

Brassica carianata oilseed has been developed as a biofuel feedstock ( Resonance™) by Agrisoma Biosciences (Canada). It is suited to semi-arid areas and produces seed with 44% oil content. In April 2012 Agrisoma announced that Resonance™ will be evaluated as a feedstock for Honeywell Green Jet Fuel™.

Castor bean

Castor oil is also being developed as a potential industrial-scale biofuel feedstock. “Castor bean is a non-edible, high oil-yielding crop (40%-50% seed oil content) with high tolerance for growth under harsh environmental conditions, such as low rainfall and heat” [Source: Evogene].

FP7 Projects on energy crops

ENERGYPOPLAR aims to develop energy poplar trees with both desirable cell-wall traits and high biomass yield under sustainable low-input conditions to be used as a source of cellulosic feedstock for bioethanol production.

SWEETFUEL Sweet sorghum: an alternative energy crop (FP7 – 227422)


Virtual Modelling of Energy Crops

The Eureka E-PLANTS project led by Intesys has produced a 3D model of the virtual plant growth, enabling biofuel feedstock growers to visualise the complex and dynamic interactions between different plant components and experiment quickly with the simultaneous influences of temperature, nutrient levels, moisture and other conditions on rooting and growth.


Carbo-BioCrop project in the UK

Carbo-BioCrop will provide information on the carbon mitigation potential of bioenergy crops. The project is funded as part of the Living With Environmental Change (LWEC) project in the UK. The aim of Carbo-BioCrop is to gain a better understanding of the processes that cause changes in soil organic carbon (SOC) and emmissions of GHGs (CO2, N2O and CH4) under Short Rotation Coppice (willow, poplar) and Miscanthus. In particular, such changes will be quantified when land is converted from arbale or grassland to energy crops.

Support for Energy crops in the United States

In October 2010, USDA published a final rule to implement the Biomass Crop Assistance Program (BCAP). Under the BCAP final rule, USDA will resume making payments to eligible producers. The program had operated as a pilot, pending publication of the final rule. Authorized in the Food, Conservation, and Energy Act of 2008, BCAP is designed to ensure that a sufficiently large base of new, non-food, non-feed biomass crops is established in anticipation of future demand for renewable energy consumption.

Domestic production of renewable energy, including biofuels, is seen as a national imperative the USDA aims to help develop a thriving biofuels industry in every part of the US. A recent USDA report indicated that the initiative will will create jobs, combat global warming, replace our dependence on oil imports and boost the economy [Source: USDA].



Improving the sustainablility of first generation feedstocks

Although expansion of first generation biofuels has decreased since 2008, biodiesel and bioethanol are still produced from crops in existing plants (manufacturing facilities). In the medium term, a number of initiatives have been instigated to make feedstocks more sustainable, until second generation biofuels are available on a commercial scale.

Sustainable winter oilseed rape – 24 page brochure (2007) joint publication of Unilever N.V., and UFOP( UNION ZUR FÖRDERUNG VON OEL- UND PROTEINPFLANZEN E. V.). Also available for download in German (2.3 Mb PDF).

Certified palm oil 


150 150 Miguel Ángel Martínez

Lignocellulosic fuels – those made from plant fiber, instead of food feedstocks like corn or soybeans – are one of the great hopes for greening the transportation sector. They’ve been slow to come to market, but government researchers think they might have found a bacterium that could allow for a cheaper, more efficient “enzyme cocktail,” the collection of chemicals used to turn the gnarly biomass into sugars.

Uso de cookies

Este sitio web utiliza cookies para que usted tenga la mejor experiencia de usuario. Si continúa navegando está dando su consentimiento para la aceptación de las mencionadas cookies y la aceptación de nuestra política de cookies, pinche el enlace para mayor información.plugin cookies

Aviso de cookies