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United States Department of Agriculture

Agricultural Research Service

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Location: Renewable Energy and Manure Management Research

2010 Annual Report

1a.Objectives (from AD-416)
The long-term objective of this project is to develop the technology and demonstrate the equipment needed to provide heat and power for stationary on-farm energy uses. Modern agricultural activities require large amounts of heat and power to achieve the production efficiencies required to meet the demands for food, feed, fiber, and energy. Cities, industries, and service organizations require more and more of the energy produced by large central generating plants; therefore, farmers and ranchers have to seek ways to produce their own energy. Traditionally, farmers and ranchers have produced their own energy by burning wood and crop residues. They also used water, wind, and animal energy to provide the needed power. During the last 80 years, farmers have used alternative fuels derived from petroleum and coal. Now that petroleum-based energy is in limited supply and expensive, producers must return to the basic, natural, renewable energy sources. The project will focus on the following three objectives: Objective 1: Develop (1) hybrid biodiesel/wind/solar- and (2) hybrid wind/solar-based technologies that enable commercial on-farm production of heat and power. Subobjective 1A: Use hybrid wind/solar energy systems to pump water for irrigation in the Southern High Plains; Subobjective 1B: Develop industrial control algorithms that allow for the safe and efficient integration of biodiesel/wind/solar hybrid systems into agricultural operations for the production of heat and power; Subobjective 1C: Use heat from sun to either heat or preheat water for dairies in the Southern High Plains. Objective 2: Develop hybrid wind/solar-based technologies that enable commercial on-farm production of hydrogen. Objective 3: In collaboration with USDA-ARS NCAUR, develop microbial fuel cell-based technologies that enable commercial on-farm production of power from manures. Subobjective 3A: Identify microorganisms that are electricigens or microbial consortia that can act as electricigens that are derived from either beef or dairy concentrated animal feeding operations (CAFO); Subobjective 3B: Determine the potential power output of identified electricigens-microbial consortia in low- (H-cell type) and high-power (ministack-type) fuel cell configurations using various types and forms of 'manure fuels;' Subobjective 3C: Evaluate microbial consortia-bioreactor designs for the efficient generation of H from manure wastes.

3.Progress Report
This project replaced project 6209-13610-006-00D and was not approved until Dec. 2009. From Oct. through Dec. 2009 we continued to finish experiments started in the previous 5-year project plan. 1. We continued to collect data on solar water pumping systems to improve a chart to help consumers and pump installers decide what type pump is best to use in particular applications (daily water volume and pumping depth). To develop this chart, thousands of hours of data were collected on several different pumps, pumping depths, and photovoltaic (PV) array power settings. In general, the testing has shown that for the Southern Great Plains, solar systems are a better match than wind systems for remote water pumping. 2. Wind farm royalty is possibly an important revenue source for farmers, so we are analyzing improving the match between wind farm electrical generation and the utility electrical load. Previously we found that combining wind farms with concentrating solar power (CSP) plants will result in a better match to utility electrical loads in Texas and California. This means a large percentage of total electricity used in these states could be obtained from wind and solar energy. An analysis of all states in the southwestern U.S. (Ariz., Calif., Colo., Nev., N. Mex., and Utah) found that solar (both CSP and PV) will be needed to meet as much as 40% of the electrical load. 3. The feasibility of using wind and solar energy for crop irrigation in the northern High Plains of Texas was analyzed. We found that combining a winter crop with a summer crop and using the excess renewable electricity for on-farm uses, rather than selling at low prices to the utility, should result in payback periods of approximately 7 to 8 years with no government incentives. With 55% incentives, the payback period is predicted to be 4 to 5 years. Solar energy potential was a better match to irrigating a winter and summer crop, but wind energy was still significantly less expensive to use in the Great Plains than solar energy. 4. An off-grid hybrid wind/solar system containing a 900-W wind turbine and a 640-W PV array were connected to a helical pump water pumping system. In addition to the manufacturer controller, a controller with a heater dump load was added to absorb excess renewable energy generated by the hybrid wind/solar system and also to keep the wind turbine from running offline. The purpose of the testing is to develop wind/solar hybrid water pumping systems and to determine the optimum amount of solar to add to a wind turbine for irrigation water pumping. 5. Retention lagoon pond sediment was used as the source material for microbial exoelectrogens and/or microbial consortia (E/MC) capable of generating electricity. Sediment microbial fuel cells (SMFC) using carbon electrodes were constructed and used to select for the E/MC capable of producing power. Very low levels of intermittent power production were observed during initial experiments. Additional sampling locations and methods to produce source materials of E/MC will be implemented. Preparations of community DNA samples for evaluation of microbial composition are underway.

1. Improving the cost effectiveness of wind and/or solar powered crop irrigation systems. To develop efficient wind and/or solar powered irrigation systems the power requirements for irrigation should match with the potential power from solar and/or wind energy. An ARS agricultural engineer at the Conservation and Production Research Laboratory in Bushland, Texas, determined (1) that combining a winter crop with a summer crop would significantly improve the match of irrigation energy requirement to wind turbine electrical generation in the Texas northern High Plains, (2) that solar photovoltaic (PV) electrical generation is a better match than wind, to the irrigation requirement of winter and summer crops, and (3) that using a wind turbine with a solar PV array was a better match than using a wind turbine alone. However, it was more cost effective to use wind turbine(s) only, rather than using a solar PV array alone, or a hybrid wind turbine-PV array. It was also found that to improve efficiency and cost effectiveness, the farmer needs to use the excess renewable electricity on the farm rather than selling it at a low price back to the electrical utility. This analysis will help farmers understand how to transition from fossil-fuel powered irrigation systems (natural gas, diesel, coal via utility) to renewable energy powered irrigation systems, such as wind, solar, and bio-diesel.

2. Acoustical testing of Bergey 10-kW grid-tie wind turbine. The manufacturer of a new wind turbine had concerns about the potential noise produced by the turbine. Therefore, acoustical noise data was collected on a redesigned Bergey 10-kilowatt (kW) wind turbine by ARS engineers at the ARS Conservation and Production Research Laboratory at Bushland, Texas. The noise level for the redesigned wind turbine was significantly less at lower wind speeds than an earlier version of the turbine. Decreasing the noise level of the turbine will improve the likelihood of these wind turbines being used on farms.

3. Acoustical testing of 115-kW wind turbine with acoustical array of microphones. There was concern that the flat back airfoils common on many wind turbines might generate significant noise. Therefore, wind turbine blades with flat back airfoils at the blade root were tested at the ARS Conservation and Production Research Laboratory at Bushland, Texas. An array of microphones that pinpointed where the noise emanated from on the wind turbine blades was placed in front of the wind turbine. At low wind speeds the noise was highest for the blade root, whereas at higher wind speeds most of the blade noise was coming from the blade tips. Placing splitter plates on the trailing edge of the flat back airfoils significantly decreased noise at low wind speeds. These results may lead to improved wind turbine blade designs that decrease noise levels without reducing production efficiency.

Last Modified: 4/20/2014
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