Farm-scale energy production from agricultural residues

1. Farm-scale energy production from agricultural residues Gary Banowetz USDA/ARS Corvallis, OR Cooperative research performed with Farm Power, Inc., Spokane County, WA.

2. Biomass has provided the basis for renewable energy, jobs, and rural development in other parts of the U.S. • There is federal mandate to produce 36 billion gallons of biofuels in the U.S. by 2022. (U.S. currently produces under 10 billion gallons) • There are state mandates in OR, WA, ID, etc. to develop specific % of renewable power by 2015 – 2020. • State and federal incentives exist to make all this happen. • In short, there is considerable “push and pull” in the marketplace for renewable energy, new jobs, and rural development. Iowa, Minnesota, and others have large participation in this market. Why not the Pacific Northwest?

3. Western agriculture is diverse > 200 commodities

4. For comparison, 83% of Iowa cropland is used for production of two crops: corn and soybean. Corn provides basis for ethanol industry; Soybean provides basis for biodiesel production. Due to success of the bioenergy industry in the Midwest, their facilities are commonly used as a model for implementing bioenergy production in the rest of the country. That model currently favors construction and utilization of plants that produce > 50 million gallons of biofuel per year. (Capital costs around $80 million) Economies of Scale are significant!

5. In addition to significant financing, you need commitment from suppliers to provide sufficient feedstock (corn) to supply the plant. • 200 square miles of cropland (approximately 15 miles square) can support one 50 million gallon/yr ethanol plant. • In Iowa, • You don’t need to haul corn very far to provide sufficient feedstock to enable large scale production and take advantage of Economies of Scale. • Crop is dedicated for energy production from planting. • .

6. Initial interest (1970s-1980s) to convert straw into bioenergy in the Northwest attempted to utilize the Midwest model: How far do you need to transport feedstock in Pacific Northwest to supply 50 million gallon/yr plant?

7. It depends. In general, a long ways.

8. Straw is an abundant feedstock in the PNW. • >16 million tons per year • > 6 million tons available over and above NRCS recommendations for conservation purposes Banowetz et al., 2007. Assessment of straw biomass feedstock resources in the Pacific Northwest. Biomass and Bioenergy 32:629-634.

9. Table 1. Amounts of total cereal grain straw production and straw available for biofuel use in the Pacific Northwest states of Idaho, Oregon and Washington. State total straw production available straw (tons) (tons) Idaho 6,477,158 2,584,140 Oregon 2,572,630 758,907 Washington 7,570,898 2,969,317 Totals for region16,620,686 6,312,364

10. Total regional energy consumption: Transportation fuels: 7.9 billion gallons per year Electricity: 152 billion kWh Straw has potential to provide feedstock to produce 7-8 % of the power or fuel.

11. In short, considerable amounts of biomass are already being produced in the region, and some of this biomass could be utilized for bioenergy production. The amount of straw is generally correlated with the amount of water the crop receives. Straw densities are greatest in wet western parts of the region or where irrigation is used to produce the crop. Scale that is appropriate for economical bioenergy productionis dependent on feedstock density because this has a large impact on the cost ($$) and energy input involved in supplying a conversion facility.

12. Across the region, the average density of available straw is 1 ton per acre. Appropriate scale of production depends on local straw densities, quantities, and alternative markets. We mapped sites for plants with 1, 100, and 100 million kg of straw per year

13. We concluded that the economics of large scale processing of agricultural residues that are available in the Pacific Northwest will continue to be a challenge in much of the region, given the continued increases in the costs of collection and transportation of the biomass. Accordingly, we focused our research efforts to: • Identify a scale of production that reflected local feedstock availability, targeting a scale appropriate for on-farm or “near- farm” to minimize amount of $$ and energy inputs; • Develop a process that generated minimal waste streams; • Develop technology that would be affordable (<$350,000) to individual farmers; • Implement a system that would be profitable and make “energy sense”.

14. First question: what technology could meet these criteria? • Biological process, like that used for corn-to-ethanol, or cellulosic ethanol requires large volumes of water and generates solid and liquid waste. We focused our efforts on thermochemical approach. Thermochemical processes (i.e., gasification, pyrolysis, combustion) use thermal processes to convert feedstock into syngas and char. Thermochemical processes utilize all the carbon in a feedstock, unlike fermentation which just utilizes sugars.

15. What can you do with syngas? • Syngas contains combustible gases that can be burned or otherwise used to provide energy for other processes: • Syngas can be ported into the intake manifold of a diesel generator to replace some of the diesel fuel needed to power the engine; • Catalytic technology is being developed that converts syngas components into hydrocarbon fuels (i.e., “grassolene”, synthetic diesel fuel); • Heat produced during the production of syngas can be captured and used to power Sterling engine, or to provide heat for other commercial applications.

16. Our hypothesis: small scale technologies that permit economic conversion near the production site could be developed to provide the basis for a distributed network of bioenergy production. • Formed partnership with Farm Power, Inc. (a nonprofit), that eventually included Inland Power and Light, Schneider Electric, USDA Rural Development and concerned citizens to develop a viable alternative to grass straw burning in eastern Washington. BPA contributed a generator and collaborated with Inland to permit purchase of power from project.

17. We first worked with Western Research Institute (Laramie) to test possibility of gasifying straw with small gasifier. Using a novel design, we could produce syngas from Kentucky bluegrass straw. (Boateng et al. 2007. Gasification of Kentucky bluegrass straw in a farm-scale reactor. Biomass Bioenergy 31:153-161.)

18. Local-scale Straw-to-Energy Conversion Producing syngas from straw was straightforward in a lab environment. A more fundamental question however is, is this process feasible in the real-life environment of a farm? Permitting requirements? Labor requirements? Compatible with annual operation cycle of farm? We worked our way through the permitting processes and ultimately constructed a gasifier in a on-farm new facility built by Farm Power utilizing an appropriation from Senator Patty Murray.

19. On-farm research site in Spokane County

20. Unit is approximately 24’ tall, weighs approximately 2000 pounds. Gasifier in steel support structure

21. Second tier of support structure

22. View from top tier of support structure

24. Multiplex data acquisition device enabled for remote access

25. How the process works • 1) Ignite a propane/air mixture to heat the system to 700° C (15 minutes). • Introduce feedstock (straw/mill screenings) at a controlled rate to the gasifier from a point approximately six feet above the propane flame. • Turn off the propane, continue supplying appropriate quantity of air to support partial combustion. System is now self-supporting. • Generate syngas through system, measure the percentages of CO, CH4, CO2 and O2. • Collect char at bottom of cyclone – char represents about 10% of the weight of the biomass that is fed to the gasifier. • 6) Direct syngas to flare, or to diesel generator.

26. What have we accomplished? • Developed a system for straw collection that does not involve the energy inputs of baling followed by bale de-construction. • 2) We gasify straw and mill screenings at 700 ° C and produce a medium heat value syngas that consists largely of CO and CH4. • 3) We secured a grant from USDA Rural Development to automate the process in order to reduce the amount of labor involved in operating the system. • 4) Syngas is routed to a 100 kW diesel generator where it replaces 75-80% of the diesel fuel required to run the engine. • 5) We feel that the system, in its current configuration, could be marketed profitably for approximately $350,000.

27. What’s left to be done? • “Clean” the syngas of particulate matters and tars. • Automate the process to reduce labor requirements and ensure syngas quality (in-line gas analysis). • Conduct an economic and life cycle analysis to determine the efficiency, profitability, and payback period of the system. • Conduct optimization studies to determine best use of the straw. • Test other feedstocks: juniper, logging residues.

28. Sustainability: • ARS conducted multi-year studies at three different sites in the Willamette Valley to quantify the impact of tillage and residue management on soil quality (including carbon) and soil erosion. (Steiner et al., 2006, Agronomy Journal) • In high rainfall areas of Willamette Valley, removal of straw from the production system had little impact on soil carbon. Other fertility metrics are currently being measured.

29. How suitable are straw residues as feedstock for thermochemical processes and how many plant nutrients are removed from the production system by straw harvest? • Mineral content a concern for thermochemical conversion (Si, Cl, K, etc.) • Genotypic differences exist in characteristics for both conversion routes, plant breeding opportunities to improve feedstock suitability.

30. Mineral analyses of multiple accessions of Kentucky bluegrass, tall fescue and perennial ryegrass. Estimates of the amount of K, P, and other minerals removed with straw harvest.* *Banowetz et al. 2009 Mineral content of grasses grown for seed in low rainfall areas of the Pacific Northwest and analysis of ash from gasification of Kentucky bluegrass straw. Energy and Fuels (in press).

31. We have similar data for : • Tall fescue, perennial ryegrass, orchardgrass, and Kentucky bluegrass grown in the Willamette Valley (Banowetz et al., 2009. Energy and Fuels). • Switchgrass – six cultivars, each grown at five locations in midwest (El Nashaar et al., 2008. Bioresource Technology) • Native grasses – nine species collected from four locations in the western U.S. (El-Nashaar et al., 2009. Bioresource Technology) • Wheat – 20 cultivars grown at three location in Oregon (El-Nashaar et al., Energy and Fuels, 2010) • Triticale – 8 cultivars grown in western Oregon.

32. Is there a productive use for the char? • Fundamental question is, what is composition of char? • Varying quantities of N, P and K, C and Ca • Extremely low concentrations of heavy metals • Extremely low concentrations of dioxins, etc. • Greenhouse studies have been conducted to study the effects of char on; • Soil pH (yes) • Nutrient contribution (some) • Biomass production (some at high levels of char)

33. Research team: ARSFarm Power Steve Griffith Gady Farms (David and Larry) George Mueller-Warrant Jack Zimmer Jerry Whittaker Jed Morris Gary Banowetz Board of Directors Inland Power and Light BPA Schneider Electric USDA Rural Development US-DOE