Browsing by Subject "Bioenergy"

Now showing 1 - 7 of 7
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    Developing a Decision Support Tool for Visualizing Renewable Natural Gas Production in Minnesota via ArcGIS Technology
    (2022) Chaffee, Wyatte R.L.
    This video presentation is about the first ever interactive map for visualizing Minnesota's renewable natural gas (RNG) potential! RNG is biogas (methane, carbon dioxide and other trace gasses) that has been cleansed to match the methane purity of natural gas. This renewable and sustainable alternative can be used as a replacement for natural gas in Minnesota's current infrastructure. This map displays all active feedlots from 2018 and over 50 wastewater treatment plants. Each of these locations have had calculations completed to determine their theoretical RNG production. More information on these calculations can be found at the bottom of the website's details, when observing a specific location. Use this link to view the map: https://arcg.is/qWjzi0 Credits: Wyatte Chaffee, Dr. Lingkan Ding , and Dr. Bo Hu This research was funded by the University of Minnesota Twin Cities' Undergraduate Research Opportunities Program (UROP).
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    Development of agroforestry systems for bioenergy crop production and soil conservation.
    (2012-10) Gamble, Joshua D.
    Agroforestry systems have been proposed as a means of dedicated bioenergy crop production that can potentially satisfy a broad suite of social, economic, and environmental objectives. Strategic placement of such systems may help to maximize economic returns from marginal crop land and reduce agricultural non-point source pollution. However, little is known about the performance of perennial bioenergy crops in agroforestry systems in the North Central Region. Moreover, the effectiveness of these crops in reducing certain types of agricultural non-point source pollution relative to conventional annual cropping systems is unknown. Therefore, experiments were conducted to 1) evaluate the establishment and productivity of dedicated woody and herbaceous perennial bioenergy crops in riparian alley cropping agroforestry systems, and 2) to evaluate the effects of dedicated perennial bioenergy crops on surface runoff and sediment loss relative to conventional and alternative annual cropping practices. In the first experiment, basal area of poplar clone ‘NM6’ averaged 1,045 and 1,744 mm2 tree-1 at two sites after two seasons, while that of willow clone ‘Fish Creek’ averaged 770 and 1,609 mm2 tree-1. Prairie cordgrass and a native polyculture were among the most productive herbaceous crops at both sites, averaging between 7.1 and 11.9 Mt ha-1 by the second growing season. During the first two years following establishment, competition for resources did not reduce establishment success or productivity of woody and herbaceous crops along the tree-crop interface. These results suggest that hybrid poplar and willow along with certain herbaceous bioenergy crops may be well suited to alley cropping on riparian sites, though more research is needed to evaluate crop persistence and productivity within the alley cropping environment. In the second experiment, a native grass mixture reduced the average sediment concentration in surface runoff by 87% and 90% relative to a corn-soybean rotation and no-till corn, respectively. Sediment concentrations in surface runoff from short-rotation willow did not differ from the corn-soybean rotation, but were reduced in fall surface runoff by 51% relative to no-till corn. These results suggest that soil conservation can be improved in short-rotation willow systems, but confirm previous findings that native grasses can provide excellent sediment retention relative to annual systems.
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    The Economics of Perennial Bioenergy Crop Production Under Risk and Uncertainty: Understanding Economic and Policy Incentives
    (2015-07) Smith, David
    In order to reduce economic and national security risks, U.S. energy policy, in 2005 and 2007, mandated production of renewable biofuels. By 2014, the renewable biofuel industry was consuming approximately one-third of domestic corn and soybean production. To meet this growing demand, conservation and pastureland has been cultivated with corn and soybean, resulting in a reduction in ecosystem services, such as carbon storage, wildlife habitat and water quality. Perennial bioenergy crops (e.g., switchgrass) offer a more sustainable alternative. However, unlike annual crops, farmers and landowners have little experience with perennial bioenergy crop production. Uncertainty in production and prices will impact the supply of these novel crops into an emerging market. Using a stated preference method, I show that agricultural landowners are willing to produce perennial bioenergy crops, given competitive returns, but only on a portion of their land. These results suggest that risk and uncertainty are important considerations in perennial bioenergy crop supply. Next, using a state-contingent approach to choice under uncertainty, I characterize the comparative static effects of government incentives to promote perennial bioenergy crop production. I show that uncertainty can dampen the impact of these incentives and in some cases even decrease perennial bioenergy acreage. Finally, I estimate the magnitude of the relative risks and the fixed cost hurdle using a discrete/continuous structural model. I show that agricultural landowners perceive a relatively high level of risk from perennial bioenergy crop production and are less willing to produce short rotation woody crops than perennial grasses.
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    Productivity, recovery, diversity, and function of aspen-dominated forests vary in response to biomass harvest severity
    (2014-08) Curzon, Miranda Thomas
    Given uncertainty surrounding future climate and disturbance regimes, balancing objectives that include continuing to provide current forest products, meeting future resource demands, and maintaining ecosystem services presents a formidable challenge to forest managers. This research explored the short- and medium-term impacts of removing harvest residues for bioenergy feedstocks on aspen-dominated forests of the Lake States region. On sandy soils the removal of residues reduced standing biomass compared with stem-only harvest (SOH) 15 years after treatment, but no negative effect on aboveground biomass was observed following whole-tree harvest (WTH) on clayey or silty loam soils. Maximum diameter and the density of stems (> 5 cm diameter at breast height) declined on silty loam and sandy soils in response to increased severity in compaction and organic matter removal, respectively, indicating that structural development may be slowed. Although three species diversity measures and four functional diversity measures were used to assess community response to harvest disturbance, only indicator species analysis detected a functionally-relevant shift in community composition and structure that followed the most severe treatment combination on silty loam. This result highlighted the importance of employing multiple measures of diversity and composition to assess harvest impacts. Observations 2 years following bioenergy harvest with retention of aggregated overstory reserve trees indicate that both residue removal and overstory retention influence understory community composition. However, species diversity measures differed only between controls and disturbed areas (aggregates, SOH, WTH). Herbaceous plants considered interior forest obligates, such as Trientalis borealis, occurred in the aggregate understory, suggesting potential for small aggregates (0.1 ha) to serve as refugia for some species, at least in the short-term. Aspen sucker densities 0-5 m from the aggregate in the adjacent harvested areas were indistinguishable from densities 20 m from the aggregate edge, indicating ecological objectives might be achieved through aggregate retention without a trade-off in initial regeneration densities. Overall, results indicate that responses to the level of disturbance associated with harvest residue removal differ among sites, even when dominated by the same overstory species, but there is potential for severe disturbance to reduce standing biomass, shift community composition, and alter function and structure.
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    Resource assessment and analysis of aspen-dominated ecosystems in the Lake States.
    (2010-08) Domke, Grant Michael
    Utilization of renewable resources for energy in the United States has increased substantially over the past decade. These increases have been driven by energy policy aimed at reducing dependence on foreign oil, boosting economic development, and curbing fossil fuel emissions. In recent years, state governments have passed laws mandating further reductions in energy consumption and greenhouse gas emissions, and increases in energy conservation and use of renewables. Such legislation and pending federal action has led to renewed interest in the use of forest-derived biomass for energy production. There are a variety of sources of forest-derived biomass in the Lake States and much debate over the carbon costs or benefits associated with the utilization of this material for energy. The aspen forest type is dominated by the most commercially utilized tree species in the region (Populus tremuloides and to a much lesser extent, P. grandidentata and P. balsamifera) and occupies more than 10 million acres of timberland in Michigan, Minnesota, and Wisconsin. Aspen is a short-lived, fast-growing tree species, which typically regenerates from adventitious suckers following harvest or stand-replacing disturbance, making it ideally suited for biomass production. This dissertation describes: 1) the status and trends of aspen-dominated ecosystems in the Lake States, 2) an analysis of biomass production potential in native and hybrid aspen communities in northern Minnesota, 3) a model framework for the estimation of carbon flows associated with the procurement and utilization of harvest residues for energy, and 4) the development of a spreadsheet-based model for rapid estimation of biomass availability.
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    University of Minnesota Extension Master Gardener CenUSA Biochar Demonstration Gardens 2012-2015
    (2017) Davenport-Hagen, Lynne; Weisenhorn, Julie; Meyer, Mary H.; Sui, Luna Xiaoye
    Soil serves as the foundation of all gardens, and thus incorporating beneficial amendments before planting is of the utmost importance to a healthy, roductive crop. Increased interest and research in biomass and biofuels has promoted the use of biochar, a coproduct of the pyrolysis process, as one amendment to improve soil health. Urban soils, the site of many home and community gardens, can be carbon-poor, so we wondered if biochar would benefit home gardeners and grow more productive plants. Soils at four demonstration sites in Minnesota were amended with hardwood biochar. With the help of Extension Master Gardener volunteers, we grew, harvested and measured common garden crops over four years to see if those grown in biochar-amended soils were more productive. Variables in weather, crops and volunteer interpretation of data did not provide conclusive results. However, the poorer soils amended with biochar showed some increase in soil pH and percent organic matter, and clay loam soils were less compacted. Most crop yields showed improvement over the four years; however, we believe these increased yields were likely affected by a combination of factors (rainfall, air temperatures) and cannot be directly attributed to the addition of biochar.
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    Using Mean-Reverting Prices and Real Options to Analyze District Heating and Combined Heat and Power in a Northern Minnesota City
    (2014-07) Smale, Andrew D.
    This paper examines alternative investment strategies for a biomass-powered District Heating (DH) system for a small city in Northern Minnesota, including Combined Heat & Power (CHP) as a method of producing both heat and electricity. Stochastic, mean-reverting commodity prices and Real Options analysis techniques are also incorporated into a financial examination of the project. The analysis finds that, given certain tax incentives, a DH+CHP project could be attractive for a profit-seeking investor. The analysis also reveals that upfront investment risk could be lowered by using an incremental Real Options approach.