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Greening Grass

With the availability of agricultural biomass, North American companies are promoting the benefits of converting grass into energy in an effort to spur the industry.
By Matt Soberg | November 01, 2011

With a multitude of economical and environmental reasons to utilize grass-to-energy technology, why hasn’t the industry become more prominent in North America? 


The U.S. DOE has identified millions of acres of land available for energy crops and predicts tons of biomass, including energy crops, would be available annually by 2030 in its 2011 Billion-Ton Update. Similarly, the Union of Concerned Scientists concluded that significant potential exists for the Midwest region of the U.S. to capture its local agricultural base to reduce fossil fuel imports in its report “A Bright Future for the Heartland: Powering the Midwest Economy with Clean Energy.”   

   
Innovative feedstock and boiler companies have taken advantage of agricultural resources. Feedstock companies are harvesting various grasses, including Giant King Grass and switchgrass, to manufacture products such as pellets, briquettes and logs.  Other companies are developing technology to cleanly and efficiently process the agricultural products for power and thermal energy.  


With most wood waste already committed for pressed wood products and pellets, agricultural pellets are starting to emerge, according to Carl Kukkonen, CEO of Viaspace Inc., who projects the pellet market will grow to 46 million metric tons annually by 2020.  


Jim Trussler, co-founder and CEO of LST Energy, hopes agricultural biomass, specifically hay, will show up on the renewable resource radar in North America.  Trussler notes that hay is a clean, cheap and local renewable resource that can cut consumers’ heating prices in half at current fuel prices.  
“We have the ability to build the industry from the ground up and do it right,” says Paul Cerosaletti, senior educator for Cornell Cooperative Extension, when referring to the ag biomass industry. “We need to get more examples of heating with biomass out into the public and show its benefits.” 


Government agencies and research organizations are realizing the potential of agricultural biomass while private companies are implementing business strategies in an attempt to kick-start the market. The industry sees the benefits of grass as an alternative fuel, but what will it take for the industry to get to the next level?


Grass Feedstock


Innovative companies from across the continent are developing creative ways to grow grasses with bioenergy in mind. Grasses range from naturally grown to dedicated energy crops. Science has shown that grasses can be combusted effectively and efficiently to create energy and minimize greenhouse gas (GHG) emissions.


Renewable Energy Resources Inc. produces briquettes from switchgrass for thermal or combined-heat-and-power systems. The company is merging established briquette technology with switchgrass ecology to create a market-ready energy solution for small- to large-scale applications. The company is based in Vermont with a market emphasis on other states such as New York and Pennsylvania.
RER manufactures briquettes from grass that can be burned in boilers and furnaces by itself or in combination with other fuels and used on farms and by institutional, industrial and utility customers.
The company transfers grass from “field to flue,” says John Bootle, RER founder, with field inspection, harvest, transfer, compaction and delivery to the boiler as parts of their grass-to-fuel process. He says crop-derived biomass will be important as a future thermal heat source because studies project that the availability of ag feedstocks will be significantly higher than wood.


The benefits of grass biomass, according to Bootle, include faster carbon emission reduction than wood, low-cost sustainability, local production and local economic development. Switchgrass will deliver about 14.4 million Btu per ton, and users can expect to save more than 50 percent on their fuel bills compared to oil, according to RER. 


Switchgrass may be chopped, burned or compacted into briquettes. RER promotes its briquettes as having the advantages of more efficient combustion, lower particulate emissions and considerably reduced storage and transportation costs than simply chopped biofuel.


Switchgrass grows well in poorer soils, and may be grown in most states east of the Rocky Mountains into Southern Canada. RER is seeking farmers and landowners who would like to plant biomass crops on under-utilized or unproductive land. 


Likewise, recognizing agricultural potential from the central region of the U.S., Missouri-based Show Me Energy Co-op is committed to establishing an innovative, profitable model for the production of biomass-based fuels. “This model may be replicated across the country by small producer-owned cooperatives that will provide a positive economic impact on the regions in which they are located,” according to Steve Flick, the co-op’s chairman of the board.


The co-op started approximately five years ago, consists of farmer stockholders and its objective is to create jobs and economic development through agricultural innovation. The co-op purchases large round bales and turns the grass into a pellet product for combustion purposes. Without impacting the food supply for animals and humans, the group has benefited Missouri by increasing the value of farmland, creating green collar jobs and advancing rural economic development.


On the West Coast, but with a similar perspective, California-based Viaspace Green Energy Inc. transforms Giant King Grass, which can grow 15 feet high, into pellets and logs. The company globally markets its harvest as a high-yield dedicated energy crop that is a low-carbon replacement for coal to generate power and heat.


While dependence on coal and imported oil has led to a major increase in environmental issues, biomass is carbon neutral, according to Viaspace. The company explains that plant material burned in a power plant releases carbon dioxide back into the atmosphere but it is reabsorbed when the next crop grows making it carbon neutral.  


Giant King Grass can be burned either directly or in pellet form as a replacement for coal or oil in power plants or used to produce biomethane in anaerobic digesters. Giant King Grass is a nonfood crop and can be grown on marginal lands not suitable for growing food crops. Viaspace says the grass is low cost because it yields more than 44 dry tons per acre annually. Combusting grass results in one-fourth the cost of solar or wind energy. Ag-to-energy is predictable and constant, as agricultural biomass can power a plant 24/7.


“As pellet demand increases, agricultural pellets, especially pellets from dedicated sustainably grown energy crops will be in great demand,” Kukkonen says.


Combustion Technologies


In addition to an existing supply chain, it is necessary to have the energy generation technologies to capitalize on biomass benefits. Various companies are actively developing boilers and furnaces compatible with agricultural feedstocks that minimize the challenges of slagging or clinkering. 
Skanden Energy is a start-up company, based in the Northeast U.S., which markets commercial- and residential-scale multifueled biomass boilers using gasification to process feedstocks such as agricultural biomass in in loose, chip, pellet, briquette or bale form.


In addition to the multifueled boiler systems that can process biomass with up to 50 percent moisture, the company markets residential pellet boilers. The boilers range from 30,000 to 10 million Btus. To ensure the feedstock gets to the boiler efficiently, Skanden also provides storage and fuel feeding equipment, including silos, bins, moving wedge floors, bale cutters, conveyors and automatic bale feeders. 


“We take automation to a new level,” according to Skanden. “We offer multiple cleaning devices that remove ash automatically from the combustion chamber, boiler tubes and exhaust gases.” The company provides control panels that can be connected to the Internet to notify the consumer and the fuel supplier about fuel and maintenance issues.  


Skanden’s multifueled boilers are manufactured with stainless metals that eliminate corrosive tendencies and encourage multifuel use. Laura Colban, Skanden’s CEO, says independent tests have shown the boilers are more than 90 percent efficient. 


Colban adds that although the interest in agricultural fuels is increasing, some financial obstacles exist in the short-term with companies receiving renewable energy-releated grants that are restricted to woody biomass technology. “There is a need for agricultural biomass to be on par with other renewable energy sources,” Colban says. 


Canada, known for its well-established wood pellet industry, is also seeking to enhance agricultural biomass as a viable renewable fuel source. Nova Scotia-based start-up LST Energy has developed a pellet burning furnace with a specially designed burner pot that eliminates clinkers found in previously marketed biomass burners, according to Trussler. LST intends to manufacture and market a wide variety of clean burning furnaces across North America.


Trussler believes the system is an enabling technology, facilitating biomass production by promoting problem-free burning. The use of hay as a heat source was inhibited by the formation of clinkers, which must be regularly removed to ensure efficient burning, thereby frustrating those utilizing biomass fuel, he adds.  


LST hopes its furnace technology creates a bridge between the vast benefits of biomass heat and usable industrial and residential applications. Trussler says the initial market will be the agricultural community, where the benefits of crop resources as a feedstock source can be utilized.


The production of hay as a biomass resource would have a significant effect on rural economic development. According to Trussler, 70 to 80 percent of the money spent on hay fuel would be re-injected into the local economy versus only 10 percent for oil. 


Interest in LST’s boiler technology has come from Nova Scotia and the Northeast U.S. The Nova Scotia Department of Agriculture independently tested the boiler and found that the grass pellets can be burned successfully and reliably in its furnace, according the ag department’s report. 


Also in the report, grass pellets were compared to wood pellets in regards to combustion performance and emissions, and showed similar performance to that of wood pellets. “No ash sintering was observed and ash discharge was in the form of powder instead of lumped particles, which are usually observed for high-ash biomass fuel,” the report says. 


Future of Ag-to-Energy


For the ag-to-energy industry to overcome challenges, Cerosaletti says that “just as people say eat local, we need to heat local,” meaning utilizing local resources, such as grass, when planning the future of thermal energy options. He also says the premise “build it and they will come” may hold true for the agricultural biomass industry. There is a need for a large anchor company or municipality to commit to agricultural biomass as a future energy source, and the result just might be development of more widespread technology and markets.


Cornell University in Ithaca, N.Y., has initiated a grass energy research project, the Catskill Grass Bio-Energy Project, through the Cornell Cooperative Extension of Delaware County. The pilot project was developed to analyze the production to consumption of grass biomass burning technologies and involves installing pellet furnaces and boilers on a small business scale.


As part of a report on combustion technology and the future of biomass thermal energy, Cerosaletti says that the energy content of agricultural biomass is 95 percent that of wood. In analyzing boiler technology, he says problems have arisen through clinkering and corrosion, and that manufacturers need to maintain service after the sale when mechanical problems arise.


With a large population of people that want to be energy independent, the local agricultural market can support the local economy’s energy needs. Cerosaletti says there is an opportunity for the biomass appliance industry to develop heating units that work with a large range of feedstocks including agricultural resources.

Author: Matt Soberg
Associate Editor, Biomass Power & Thermal
(701) 746-8385
msoberg@bbiinternational.com

 

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