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This is the second in a series of articles describing biomass R&D activities, beginning with feedstock production through the conversion cycle to production of biobased energy products. This article focuses on conversion processes.

In order to reduce America's dependence on petroleum imports, the United States Department of Energy (DOE) and the United States Department of Agriculture (USDA) conduct research and development through the Biomass Initiative and their own departmental program efforts to foster a new domestic biomass industry. The biomass industry already serves many markets, including industrial process heat and steam, electrical power generation, transportation fuels such as ethanol and biodiesel, and valuable chemicals and products that would otherwise be derived from petroleum.

The government sponsors research and development on biomass processing and conversion technologies aimed at reducing the financial and technological risk of deploying the technologies in order to develop the U.S. Biomass Industries. From such technologies, industrial "biorefineries" will be systematically developed that produce a variety of fuels, power, chemicals, and other products that were previously derived from petroleum - similar to today's petroleum refineries. Biorefinieries exist today in the form of wet and dry corn mills producing ethanol, and pulp and paper mills producing process heat and steam, electricity, and chemicals from black liquor. However, these industries could integrate new technologies - such as replacing Tomlinson recovery boilers with black liquor gasification technologies in pulp mills - in order to improve efficiencies for converting biomass to fuels, power, or products. Biorefinery technologies can also be systematically integrated into the petroleum and petrochemical industries in order to reduce their dependence on fossil fuels.

Since there are many ways to convert biomass into value-added products, biorefineries could be based on a number of conversion processes, such as mechanical, thermal, chemical, or biochemical processes. Many of these technologies are being researched to optimize efficiencies and product outputs. Currently, the DOE's Office of the Biomass Program (OBP) conducts most of the government's research on processing and conversion of biomass, and has chosen to focus on two "platforms" as the most promising for an integrated biorefinery - the Sugar Platform and the Thermochemical Platform . Additionally, the USDA's Agricultural Research Service (ARS) and Cooperative State Research, Education, and Extension Service (CSREES) also conduct a large amount of research on processing and conversion technologies, including understanding scientific fundamentals of plant biology and developing environmentally acceptable processing technologies.

The OBP is at the forefront of a national effort to develop sugar platform technology that breaks down biomass (the bulk of which is cellulose, hemicellulose, and lignin) into its raw component sugars so that those sugars can be fermented or otherwise converted to valuable fuels and chemicals. The process design for the sugar platform starts with thermochemical pretreatment, followed by enzymatic saccharification. The dilute-acid thermochemical pretreatment hydrolyzes the hemicellulose, breaking it down into a mixed sugar solution with lignin rich solid residues. Because cellulose is naturally wrapped in a sheath of hemicellulose and lignin, both of these actions make the cellulose more accessible to further processing. The cellulose is then enzymatically hydrolyzed to release its sugars (glucose). The biomass sugars produced are either fermented to make fuel ethanol or subjected to biological/catalytic processing to make other products. The residual lignin can either be catalytically converted to make other products, or gasified or combusted to provide heat and power for the plant's operation or export.

The OBP researches scientific fundamentals underlying sugar platform technology, as well as new concepts that hold promise to greatly improve overall processing economics. To be competitive with fossil fuels, the Program's technical goal is to reduce the cost of sugar feedstock streams suitable for fermentation. The cost decrease, combined with private industry's work on improving fermentation strains, is aimed at producing ethanol that is cost competitive in the current fuel ethanol markets.

Today, the industrial sugar platform exists in the corn processing industry (wet and dry corn mill operations) and in the nearly three-billion gallon per year fuel ethanol industry. These industries are a foundation for next generation technology that will produce products from lower cost sugar sources (e.g. corn stover). The OBP is working with industry and university partners on R&D that addresses the barriers to achieving technical goals. The sugar platform integration efforts seek to resolve practical challenges involved in industrial scale application of sugar platform technology. This includes work on pretreatment, enzymes, process integration, and fundamental knowledge of recalcitrance. The OBP also works extensively to develop "bridges" between future biomass-to-ethanol technology and the current ethanol industry, and to exploit the many opportunities that exist for adopting or advancing cellulosic ethanol production or other sugar platform technologies.

Other processing and conversion R&D by OBP focuses on the thermochemical platform, which transforms solid biomass to gas or liquid by heating it with limited oxygen. Biomass combustion, such as burning wood, has been one of the primary ways of deriving energy from biomass, but it is not very efficient. Converting solid biomass to a gaseous or liquid fuel by heating it with limited oxygen prior to combustion can greatly increase the overall efficiency, and also make it possible to further process the biomass gas or liquid into valuable chemicals or materials. Thermochemical processing even has much higher efficiencies than biological conversion because it readily converts all the major components of biomass - most importantly lignin, which has high heat content.

This research is helping lead a national effort on developing thermochemical technologies to more efficiently tap the enormous energy potential of lignocellulosic biomass. In addition to gasification, pyrolysis, and other thermal processing, program research focuses on cleaning up and conditioning the converted fuel, a key step for effective commercial use of thermochemical platform chemicals.

The main technical barrier to achieving the objective of the thermochemical platform is reducing the cost and improving the quality of intermediates in order to make final products cost competitive with existing commercial commodities. For example, one of OBP's goals is to reduce the cost of producing syngas to be competitive with fossil fuels. R&D projects in gasification, pyrolysis, and hydrothermal processing have been identified to address the thermochemical platform's technical barriers.

The federal government looks towards industry to apply a wide range of technologies to develop products from sugars, lignin, synthesis gas, pyrolysis oils, and other intermediate chemicals developed with these platform technologies. As mentioned, existing U.S. industries such as the forest products industry are key stakeholders for developing future biorefineries. The forest products industry already has an established infrastructure for collection and processing biomass resources. Currently, biomass in the form of pulping liquors and wood wastes (a.k.a. "hog fuel") are burned in boilers for electricity and process heat and steam. However, it may be more desirable - or even a higher national priority - to use biorefinery technologies on pulping liquors and other wood wastes for generating syngas, pyrolysis oils, or other intermediates that could then be used directly or converted into liquid transportation fuels, chemicals, or even hydrogen. Thus, this industry has the existing foundation for establishing biorefineries using processing and conversion technologies already being developed to produce a variety of fuels, electricity, and chemicals in conjunction with pulp and paper products.

While the OBP is currently focusing on the sugar and thermochemical platform as the two most promising technology areas, there are also a variety of other platforms with potential for supporting large-scale biomass technology development.

• "Biogas" - Decomposing biomass with natural consortia of microorganisms in closed tanks known as anaerobic digesters produces methane (natural gas) and carbon dioxide. This methane-rich biogas can be used as fuel or as a base chemical for biobased products.
• "Carbon-Rich Chains" - Natural plant oils such as soybean, corn, palm, and canola oils are in wide use today for food and chemical applications. Transesterification of vegetable oil or animal fat produces fatty acid methyl ester, commonly known as biodiesel. Biodiesel already provides an important commercial air-emission reducing additive or substitute for petroleum diesel, but it, its glycerin byproduct, and the fatty acids from which it is made could all be platform chemicals for biorefineries.
• "Plant Products" - Selective breeding and genetic engineering can develop plant strains that produce greater amounts of desirable feedstocks, chemicals, or even compounds that the plant does not naturally produce, getting the biorefining done in the biological plant rather than the industrial plant.

You can find more information on the DOE's Biomass Program and USDA's ARS and CSREES R&D efforts on biomass processing and conversion technologies at their Web sites. The Biomass R&D Technical Advisory Committee has also developed a Roadmap for Biomass Technologies in the United States.

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Approximately 962 trillion Btus of energy were consumed in the state of New Mexico in 2000. The majority of that energy was provided by coal and petroleum, representing 38 percent and 32 percent of the total energy consumed, respectively. Energy supplied by natural gas accounted for 29 percent of the total, while hydroelectric power provided less than 1 percent. Biomass supplied 4.6 trillion Btus of energy, or less than 1 percent of the total.¹

While forest products are the most widespread and traditionally used biomass feedstock in New Mexico, projects involving municipal wastewater sludge, municipal solid waste, and cattle manure are currently underway. The U.S. Forest Service and the New Mexico State Forestry Division are working together on two wood chip fueled power systems to operate at local schools and a conference center. The cities of Albuquerque and Las Cruces are using the anaerobic digestion of municipal wastewater sludge to generate methane gas, which is then used to produce electricity and heat - to - power wastewater facilities. New Mexico State University and the City of Albuquerque have recently teamed to conduct a long-term study on a municipal solid waste bioreactor.² New Mexico State University has also designed a pilot plant two-phase anaerobic digestion system that converts cattle manure into biogas (72 percent methane) and compost. The compost created in this bioreactor contains higher nitrogen content than aerobically produced manure, and the entire process uses less water and less processing time than traditional methods.³

There are multiple financial incentives supporting the use of biomass energy in the state of New Mexico. The Clean Energy Grants Program supports the use of "clean energy" technologies, including biomass, at the local and state government level and in public schools, colleges and universities, and tribal entities. The grants are funded by House Bill 251 of 2004, totaling $500,000 annually, and are to be awarded through a solicitation conducted by the Energy Conservation and Management Division of the New Mexico Energy, Minerals, and Natural Resources Department. The Mainstay Energy Rewards Program - Green Tag Purchase Program offers Mainstay Energy customers who have installed renewable energy systems the opportunity to sell the renewable energy credits associated with the installation. Biomass and biofuel electricity systems are compensated at a rate of 0.1 cent to 1 dollar per kWH, depending on the energy production of the system and the length of the contract. The Renewable Energy Production Tax Credit program, though limited, allows for a one cent per kWH tax credit to go against the corporate income tax for companies using zero-emission technology (including biomass) to generate electricity.⁴

New Mexico also has several policy incentives to encourage the use of biomass energy. Interconnection standards regulate how smaller, renewable technology-based electricity producers can connect to larger power grids. Line extension regulations require electric utilities to provide customers with information on alternative energy systems in their area. The Mandatory Utility Green Power Option requires investor-owned utilities and cooperatives to offer a voluntary renewable energy tariff for customers who want the option to purchase additional renewable energy. Net metering regulations require all utilities regulated by the New Mexico Public Regulation Commission (NMPRC) to offer net metering for cogeneration facilities and small power producers with systems of 10 kW or less. Municipal utilities are exempt because they are not regulated by the PRC. Investor-owned utilities are required to produce 5 percent of all energy they generate for New Mexico customers from solar, wind, hydropower, biomass, or geothermal sources by 2006 under the Renewables Portfolio Standard (RPS). Generation from renewable sources must increase by at least 1 percent per year until the portfolio standard of 10 percent is attained in the year 2011⁵

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