Browsing by Author "Pratson, Lincoln"
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Item Open Access A Biomass Fuel Assessment for Duke University’s Chilled Water Plant #2(2010-04-30T15:51:51Z) Crowley, RichardThis Masters Project identifies the University’s biomass fuelshed and locates potential supply sources and probable fuel quantities. An Excel workbook couples user-defined transportation, processing, collection and handling, and purchase premium expenses within fuel classes to establish probable purchase costs for each supply source. Results are optimized for a lowest cost fuel mix to meet modeled plant demand based on user defined plant parameters. Finally, total biomass fuel costs are compared to fossil options to determine if biomass is a financially justifiable fuel for Duke to pursue. The results of this study indicate that the university fuelshed likely contains supply for more than 4 times the steam plants fuel requirements. The cost per million British thermal units combusted within the fuelshed is highly variable, ranging from approximately $1.01 for construction / demolition material to over $29 for forest thinnings. Several fuel classes are more economic than current prices for natural gas, ranging from less than a quarter to three quarters of the price of natural gas. The preliminary assessments of purchasing biomass fuel for use in the plant resulted in costs significantly lower than natural gas, and even potentially lower than coal. It is anticipated that the annual fuel costs for a biomass plant could be met for around $2.25 million based on plant parameters modeled and the estimated biomass characteristics (collection, base cost, etc.). Fuel costs are demonstrated to be highly sensitive to changes in fuel properties (mainly distance and moisture content) and plant operating parameters. A large portion of the biomass estimates are derived using employee based proxy equations, and the author was unable to confirm the accuracy of these supply estimates. Finally, the cost modeled is for fuel supply only. This paper does not take into consideration storage, operating / maintenance, or capital outlay, all of which are traditionally higher for biomass than fossil fuels. Despite these uncertainties there is a clearly demonstrated opportunity to fuel the plant with biomass at a cost less than natural gas. Additionally, the large and diverse biomass supply will lend resiliency to market fluctuations.Item Open Access A Geospatial Analysis of Pathways for Carbon Sequestration(2008-04-25T15:01:19Z) Frankel, AnnaThe 2007 IPCC report detailed the warming of the earth is unmistakable and is most likely due to anthropogenic greenhouse gas (GHG) emissions. The earth’s natural processes are unable to reabsorb GHGs at the rate at which they are being emitted, subsequently increasing climate temperatures and affecting ecosystems and populations around the world. Carbon capture and sequestration technologies are a possible mitigating solution to preventing emission of GHGs into the atmosphere. This analysis takes a geospatial approach to understanding the interconnecting pathways between carbon sources and sequestration sinks for future CO2 pipeline networks in the United States. Using geographical information systems (GIS), engineering, environmental, and social factors important to the pipeline siting process are evaluated and combined to make a geographical cost surface. A least cost path sensitivity analysis was performed to ensure confidence in the suitability of the cost surface. The final CO2 pipeline cost surface investigates the spatial dynamics of carbon sequestration and the relative cost elements that will influence the pipeline network. Utilities and other organizations can use the cost surface in future projects as an analytical tool showing areas of relative high and low pipeline costs. A scenario analysis was performed using the final CO2 cost surface as a tool to examine future spatial configurations of sequestration sites. The analysis found that a sequestration scenario with multiple points of CO2 injection across the United States would yield the lowest total relative costs for a national pipeline network.Item Open Access A LEVELIZED COST OF ENERGY ANALYSIS FOR A MECHANICAL VARIABLE SPEED WIND TURBINE(2012-04-26) Canavan, TimItem Open Access A Spatial Approach to Determine Solar PV Potential for Durham Homeowners(2011-04-29) Mulherin, AdamAt present time, solar powered technologies such as photovoltaic (PV) and thermal heating systems supply less than one percent of energy needs in the United States. While conventional forms of energy have proven to be more cost competitive, solar systems can offer a promising alternative. This project examined this viability for a residential neighborhood in Durham, North Carolina. In particular, the analysis focused on the distribution of solar irradiance for fifty homes; each home’s distribution was subsequently used to calculate the energy outputs and financial analysis for proposed PV systems as well as determining the best place for each system to be built that will maximize the system’s outputs and benefits. This type of analysis was possible by modeling solar radiation in a three dimensional environment that combine remotely sensed data, LIDAR-derived, with the spatial analytical capabilities of GIS. The results from this project will ideally be used as the foundation for an informative tool that will guide homeowners as they make decisions regarding solar PV systems.Item Open Access An Analysis of the Distribution and Economics of Oil Fields for Enhanced Oil Recovery-Carbon Capture and Storage(2012) Hall, Kristyn AnnThe rising carbon dioxide emissions contributing to climate change has lead to the examination of potential ways to mitigate the environmental impact. One such method is through the geological sequestration of carbon (CCS). Although there are several different forms of geological sequestration (i.e. Saline Aquifers, Oil and Gas Reservoirs, Unminable Coal Seams) the current projects are just initiating the large scale-testing phase. The lead entry point into CCS projects is to combine the sequestration with enhanced oil recovery (EOR) due to the improved economic model as a result of the oil recovery and the pre-existing knowledge of the geological structures. The potential scope of CCS-EOR projects throughout the continental United States in terms of a systematic examination of individual reservoir storage potential has not been examined. Instead the majority of the research completed has centered on either estimating the total United States storage potential or the potential of a single specific reservoir.
The purpose of this paper is to examine the relationship between oil recovery, carbon dioxide storage and cost during CCS-EOR. The characteristics of the oil and gas reservoirs examined in this study from the Nehring Oil and Gas Database were used in the CCS-EOR model developed by Sean McCoy to estimate the lifting and storage costs of the different reservoirs throughout the continental United States. This allows for an examination of both technical and financial viability of CCS-EOR as an intermediate step for future CCS projects in other geological formations.
One option for mitigating climate change is to store industrial CO2 emissions in geologic reservoirs as part of a process known as carbon capture and storage (CCS). There is general consensus that large-scale deployment of CCS would best be initiated by combining geologic sequestration with enhanced oil recovery (EOR), which can use CO2 to improve production from declining oil fields. Revenues from the produced oil could help offset the current high costs of CCS.
The cumulative potential of CCS-EOR in the continental U.S. has been evaluated in terms of both CO2 storage capacity and additional oil production. This thesis examines the same potential, but on a reservoir-by-reservoir basis. Reservoir properties from the Nehring Oil and Gas Database are used as inputs to a CCS-EOR model developed by McCoy (YR) to estimate the storage capacity, oil production and CCS-EOR costs for over 10,000 oil reservoirs located throughout the continental United States.
We find that 86% of the reservoirs could store ≤1 y or CO2 emissions from a single 500 MW coal-fired power plant (i.e., 3 Mtons CO2). Less than 1% of the reservoirs, on the other hand, appear capable of storing ≥30 y of CO2 emissions from a 500 MW plan. But these larger reservoirs are also estimated to contain 48% of the predicted additional oil that could be produced through CCS-EOR. The McCoy model also predicts that the reservoirs will on average produce 4.5 bbl of oil for each ton of sequestered CO2, a ratio known as the utilization factor. This utilization factor is 1.5 times higher that arrived at by the U.S. Department of Energy, and leads to a cumulative production of oil for all the reservoirs examined of ~183 billion barrels along with a cumulative storage capacity of 41 Mtons CO2. This is equivalent to 26.5 y of current oil consumption by the nation, and 8.5 y of current coal plant emissions.
Item Open Access AN ANALYSIS OF THE FEASIBILITY AND ENVIRONMENTAL IMPACT OF INCORPORATING CLEAN ENERGY INTO AN ISLANDED MICROGRID IN SIERRA LEONE(2014-04-24) Yagjian, Christina; Kelly, IanClarity Project is a fine jewelry company and social enterprise that recently began mining diamonds in Sierra Leone as part of its mission to improve the quality of life of artisanal miners in West African communities. This has presented a new challenge to the company: the site of Clarity Project’s new mining compound is distant from the country’s modest electric grid, leaving Clarity Project to procure its own electric power. The purpose of this project is to determine Clarity Project’s electricity needs, analyze its alternatives for meeting those needs, and evaluate the costs and environmental impacts of those alternatives. Using data obtained on site in Sierra Leone and meteorological data from NASA, we developed a model that predicts the load profile of the mining compound, forecasts the expected amount and temporal availability of electricity from photovoltaic arrays on site, and projects the use of diesel generators and battery storage to supplement the solar power. The model then calculates the present value of the capital and operating expenses for the microgrid as well as the carbon dioxide emissions associated with generating electricity for the compound. Our analysis has determined that (1) the least expensive option, based on capital expenses and operating expenses discounted to present value, would be to rely solely on diesel generators; (2) the cost of relying solely on renewable energy during Sierra Leone’s dry season would be approximately double the all-diesel option over a five-year time horizon and about 60 percent greater over a 25-year time horizon (and the availability of renewable energy falls significantly during the rainy season); and (3) incorporating solar power and battery storage, while more expensive, would allow Clarity Project to avoid emitting nearly 20 metric tonnes of carbon dioxide per year.Item Open Access An Economic and Policy Analysis of the Introduction of High-Speed Rail in California: Phase One from the San Francisco Bay Area to Los Angeles and Anaheim(2012-04-26) Tucker, DavidShould Phase One of California’s high-speed rail (HSR) system be built? With a rapidly growing population and congested airports and highways, California plans to build the nation’s first, true HSR system, with 800 miles of track connecting all major cities with 220 mph trains. California High-Speed Rail Authority (CHSRA) now estimates capital construction costs for Phase 1 alone (the 520-mile San Francisco to Los Angeles / Anaheim segment) will be $98.1 - $117.6 billion, up from a previous $40 billion estimate. The Rail Authority also asserts that comparable, expanded, intra-state transportation (airport/highway) capacity would have $171 billion in capital costs. Despite highly attractive (but debatable) HSR system economic/environmental benefit claims, California faces criticism for the project, a lack of funding to complete it, and must now decide how to proceed. To answer the basic research question, this author chose a research objective of analyzing comparative capital construction costs of Option 1 (building the HSR system) and Option 2 (a combination of expanded highways/airports), in Net Present Value terms, on the assumption that California will definitely need to build something to ease existing congestion and accommodate significant population growth across the next several decades (7.6 to 17.2 million more Californians by 2040). Numerous HSR studies were consulted, but none contained NPV analyses, save for a CHSRA study with minimal back-up data and questionable conclusions. This author constructed dozens of spreadsheet-based scenarios to analyze the effects of varying numerous cost-related factors for Options 1 and 2. Sensitivity analysis also varied discount rates and included an estimation of HSR total cost that includes Operations and Maintenance costs and Capital Asset Renewal costs. Key research findings indicated that, based on current capital cost data, the HSR system should be built, even before considering possible strong benefits. HSR could save California $25 billion in NPV terms versus Option 2 (4% real discount rate), and would still save half that much even when conservatively including O&M and CAR estimations for Option 1 only. Varying discount rates and other parameters did not materially alter this conclusion, though the magnitude of savings changes when varying the discount rate.Item Open Access An Environmental Analysis of Proposed Efficiency Improvements for the Edwin L. Jones Cancer Research Building(2010-04-27T00:30:46Z) Benonis, ChristopherIn the fall of 2009 Duke University initiated an energy audit of the Edwin L. Jones Cancer Research Building. The audit recommended a series of potential efficiency improvements, using energy cost reductions as the primary decision criteria. This project investigates the potential impact of proposed improvements on Duke’s climate neutrality goals by quantifying the associated greenhouse gas reductions. The project also evaluates mechanisms for pricing these benefits and prioritizing other campus facilities for future audits. Project results indicate that implementing the proposed Jones Building improvements could reduce total non-transportation campus emissions by approximately 1% and that similar improvements to all campus research facilities could reduce emissions by more than 10%.Item Open Access An Environmental and Financial Analysis of Improved Stove Projects in Guatemala(2010-04-28T18:50:29Z) Hahm, MilleneImproved stove projects in Guatemala yield potential social benefits and represent sound financial investments for potential investors. Using the AMS IIG methodology provided by the UNFCCC, the implementation of improved stoves, specifically the HELPS ONIL stoves, could yield significant reductions of carbon emissions. With over 2.2 million households in Guatemala, an analysis shows that a 1% adoption rate per year of the ONIL stove could reduce carbon dioxide emissions by 900,000 tCO2e per year in 2019. Following the implementation schedule offered up by the ONIL CDM project, by 2019 up to 1.7 million tCO2e could be reduced per year, which represents just over 10% of Guatemala’s carbon emissions. Within the 10-year framework of the proposed project, emissions could be reduced by up to 1.7 billion tCO2e (cumulative). An NPV (net present value) analysis demonstrates that stove projects also represent cost effective and potentially profitable investment opportunities. Depending on the deal structure agreed upon between project developers and investors, CERs could cost as little as $1 per CER for an entity seeking to invest in CERs to use for compliance. Also, as long as CER contract costs remain below $13 per CER, stove projects could result in positive NPV projects for investors, yielding respectable profits. However, the Clean Development Mechanism along with the European Emissions Trading Scheme is critical in creating a market for carbon credits, thus supporting the widespread implementation of improved stoves. Unfortunately, some social impacts are not easy to quantify. Because of a variety of land-use factors, such as agriculture and logging practices, deforestation impacts are difficult to calculate. It is difficult to quantify the health benefits of improved stoves because of confounding factors such as living conditions and nutrition. While the figures presented are merely estimates of the potential impact on emissions levels, they demonstrate benefits to be gained by implementing improved stove projects, not only in carbon dioxide emissions reductions but also in overall quality of life.Item Open Access Analysis of Global Sea Level Rise Impact Risk Assessments(2011-04-28) Ward, MollyGlobal sea levels currently are rising and will continue to rise far into the future. This rise engenders significant risks to life and the environment, as it creates negative physical, economic, and societal impacts across the globe. If the various geographic regions across the globe are to adequately prepare for the rising sea, it is necessary to conduct risk assessments to determine which specific impacts to address. This paper examines a diversity of risk assessments conducted by regions worldwide. It includes a range of studies that assess regions with differing economic capacities, types of terrain, location, and that implement a range of methodologies. It examines and compares the impacts included in the analyses, as well as the variable inputs that were implemented to conduct the assessments. Through a comparison of the components and results of a variety of risk analyses, this study provides valuable insights into the diverse impacts that may be selected for inclusion in future sea level rise studies. The goal of this study is to assist regions in tackling the problem of sea level rise by providing a foundation to streamline the process for future assessments. Based on the assessed reports, the results demonstrate that the most commonly analyzed impacts are those to a region’s economy and population. Additionally, the impacts to a region’s infrastructure, particularly transportation infrastructure, and total land surface appear to be of great importance. The variable inputs that appear to be most commonly applied to assess the impacts are storm surge and a range of sea level rise scenarios, as opposed to one specific future sea level rise quantity. Overall, there is no correlation between a study region and the quantity of impacts analyzed or depth of the impacts assessed. The majority of the studies were conducted with quantitative methods. However, it is recommended that future assessments also include a qualitative perspective. Lastly, omissions of variables from the reports are explored. Future impact studies should include location-specific trends in sea level rise, as opposed to assessing the impacts based on the global average future sea level rise prediction. It is also important to incorporate the speed of the rise in a dynamic analysis, as well as any uncertainties in a report’s input variables.Item Open Access ANALYSIS OF THE MICROGRID MARKET FOR SMALL AND MEDIUM-SIZED MUNICIPALITIES AND ELECTRIC COOPERATIVES(2021-04-30) Hancock, Thomas; Hu, Yuxin; Yang, YueyiA growing number of electricity users ranging from large production facilities to homeowners are installing microgrids to increase the resilience and reliability of their power supply. While this growth has largely been driven by private entities, microgrids also offer municipal utilities, rural cooperatives, and local governments a means to provide improved services to their constituents, provided the costs can be appropriately controlled. In this project, we investigate the market potential for microgrid adoption by small and medium-sized municipalities and electric cooperatives. Insights around this market segment are drawn from semi-structured interviews with representatives from not only municipalities and electric cooperatives, but also major utilities, local government regulatory agencies, and microgrid experts. The findings from these discussions indicate that municipal utilities have potential to be a healthy market for microgrids as they avoid conflicts with monopoly distribution companies and their government affiliation provides an opportunity to improve community resilience. To accelerate microgrid deployment in this sector, a framework is developed for assessing the viability of microgrid adoption for municipalities and cooperatives. This framework is also used to identify a list of representative utilities that demonstrate the key characteristics of this market segment.Item Open Access Analyzing Energy Outlooks: Focusing on North America and the United States of America(2012-04-27) Molinari, TerrenceThere are broad ranges of organizations that produce energy forecasts for different purposes. The U.S. Department of Energy produces an International Energy Outlook through their Energy Information Administration (EIA), whose objective is to provide facts for public policy decisions. The International Energy Agency (IEA) produces a World Energy Outlook to ensure their members maintain energy security and have research to achieve clean, cheap and affordable energy sources. Furthermore, various public companies produce outlooks, such as BP and ExxonMobil, which both do so in an effort to promote discussion around energy issues. Assumptions made about policy, technology, economic development, and demographics strongly affect the different models used in each survey. The objectives of analyzing these outlooks together are to determine how and where they differ, and to explain these differences quantitatively and qualitatively. The most influencing factor, for all the energy types, was the scenario assumption, namely policy and technology assumptions. Projections that differ the most, or were most similar, can be generally explained by understanding the policy and technology assumptions behind each survey. The EIA provides projections for consumption in production for the status quo, in regards to policy and technology innovation. The IEA used policies that were announced and implements them cautiously. They also take into account foreseeable technology advances. BP and ExxonMobil incorporate the most likely or most practical policy and technology advances in their projections. Evaluating the differences and the goals of each forecast will allow for a non-biased, well-rounded understanding and discussion of energy projections from these different organizations. Each organization believes it is important to continue the discussion of energy markets world-wide. Each outlook has differences that impede discussion, thus this study suggests a standardization of energy forecasts in order to not only enable discussion, but also truly expand discussion from not just people in the know, but to the common folk.Item Open Access Assessing the Potential for Community Solar in Durham, North Carolina(2012-04-27) Iler, StuartSeveral barriers work against the deployment of rooftop solar photovoltaic systems in Durham and across the country. These include high initial investments that can outweigh benefits, operation and maintenance responsibilities, potentially lengthy payback periods, and significant transaction costs. The community solar model – which encompasses a set of innovative ownership, financing, and other mechanisms – is one option for overcoming these obstacles. There are many potential benefits of community solar, with two primary objectives being reduced initial costs and increased access to renewable energy. Other potential benefits include better economies of scale, more flexibility in choosing an optimal solar site, greater public awareness and understanding of solar energy, the potential for local job creation, and the opportunity to test new ownership and financing structures. This project assesses the degree to which community solar might provide benefits in Durham as measured by two key metrics: reduced costs and increased access to renewable energy. A Geospatial Information Systems (GIS) analysis of three Durham study areas was conducted to estimate the size of possible rooftop solar systems and the amount of annual energy they would provide. A simple energy cost ratio – obtained by dividing total installed cost by annual energy output – was calculated for each parcel, and then averages were determined for each of three parcel categories: residential, commercial, and community service. Graphs were also created to illustrate the relationships between suitable solar rooftop areas, differences in energy cost ratios, and parcels of different types. The analysis provides evidence that the community solar approach has the ability to both reduce the costs of and increase access to renewable solar energy. Although some residential parcels have rooftops that could host cost-efficient systems, for many homeowners a financial advantage might be realized through investment in a community solar project. The study also found that approximately 10% of residential parcels are not suitable for solar systems, while an additional 18% are suitable only for systems smaller than 1 kW. For these people, as well as for those who live in apartment buildings, the opportunity to invest in community solar would be a tangible increase in access to the benefits of renewable energy. As such, the paper concludes by recommending that legislation extending the net metering concept to community energy be adopted at the North Carolina state level.Item Open Access Aviation Fuel Supply Chain Risk Assessment for the United States Air Force(2023-04-28) Zhang, Qirui; Alabaishi, Yasser; Signorelli, TreyThe increase in frequency and severity of natural disasters and extreme weather events due to climate change is a growing concern for the Operational Energy Office of US Air Force (USAF). Through a series of secondary research, supply chain modelling, and analysis, this study analyzes the current climate risk to the USAF’s Aviation Fuel supply chain along the Gulf and East coasts of the United States. Leveraging these findings, this report models risk reduction through the strategic integration of Sustainable Aviation Fuel into the existing supply chain. The collection of data and modeling techniques employed in this study will enable the USAF to initiate exploration of cost-risk analysis for the integration of SAF in its supply chain operations in the future.Item Open Access Balancing Wind Down Ramps With Demand Response: The opportunity for load participation in ancillary service markets spurred by high wind penetration(2012-04-27) Brumleve, Nick; Ballal, Sangeeta; Nourafshan, AndrewLarge “down-ramps,” inherent in the pronounced variability of wind power generation, are a threat to grid stability as the share of wind resources increases in power markets. Balancing Authorities face the challenge of how best to address the externalities that wind variability places on the grid. Our analysis assesses U.S. power markets that offer the greatest opportunities for demand response to act as a wind balancing resource. More specifically, this study evaluates market opportunities for third-party demand response aggregators to bid the capacity of responsive load into ancillary services markets to address these “down-ramp” events. This evaluation was performed through both the establishment of a qualitative framework and the creation of a quantitative, Microsoft Excel-based, model. In the qualitative framework, we reviewed the existing wind integration literature to identify the critical characteristics of a balancing authority that are predictive of the local grid’s relative capability to accommodate wind ramping behavior. In this framework, we additionally outline key qualities of loads that make them viable candidates for the demand response services required in the balancing of wind ramps. Lastly, we discuss several potential approaches for forecasting future wind penetration in a balancing authority. We have found that demand response for wind balancing can be a favorable emerging business opportunity in a power system at the confluence of these three aforementioned analyses: 1) the balancing authority’s structure and other conditions lead to a limited ability to effectively respond to increasing wind penetration, and demand response is an eligible resource to participate in balancing markets, 2) the balancing authority has a sufficient concentration of load types that are viable and appropriate demand response candidates for the balancing of wind ramps and 3) there are expectations of high future wind penetration in the system. For our quantitative analysis, we have developed a modeling tool designed to project the total size of the down ramps caused by various wind penetration levels in a given balancing authority. These projected down ramps are then related to the generation assets of the balancing authority to evaluate the efficacy with which wind ramps can be balanced with incumbent generation and to assess additional ancillary services required that could be met with demand response, among other sources. Finally, the qualitative and quantitative evaluation frameworks we have developed are applied to a case study of the Southwestern Public Service (SPS) balancing authority in the Southwest Power Pool, where there is high wind penetration and an evolving ancillary services market. Ultimately, while we find SPS to be a very strong candidate for demand response-derived wind balancing on a number of metrics, through our quantitative analysis we nevertheless find that an abundance of installed generation capacity in the balancing authority somewhat mitigates the deleterious impact of large wind down ramps, and substantially higher wind penetrations must be achieved before SPS is truly constrained. However, demand response still may provide the least cost option for wind balancing even at lower wind penetrations. There are current policy and market barriers directly precluding load response in ancillary service markets in the Southwest Power Pool, however given policy changes happening at the national and regional levels, it appears this trend may be reversing in the near term. The tool set we have developed here will allow third-party demand response providers to effectively and relatively quickly assess the relative merits of the business opportunity associated with attempting to sell demand response as a wind-balancing product in a given power system. In addition, the insights provided herein may illuminate several key considerations for a balancing authority seeking to address the efficacy with which wind down ramps can be balanced in future grid operations.Item Open Access BALANCING WIND DOWN RAMPS WITH DEMAND RESPONSE: The opportunity for load participation in ancillary service markets spurred by high wind penetration(2012-04-27) Ballal, Sangeeta; Nourafshan, Andrew; Brumleve, NicholasLarge “down-ramps,” inherent in the pronounced variability of wind power generation, are a threat to grid stability as the share of wind resources increases in power markets. Balancing Authorities face the challenge of how best to address the externalities that wind variability places on the grid. Our analysis assesses U.S. power markets that offer the greatest opportunities for demand response to act as a wind balancing resource. More specifically, this study evaluates market opportunities for third-party demand response aggregators to bid the capacity of responsive load into ancillary services markets to address these “down-ramp” events. This evaluation was performed through both the establishment of a qualitative framework and the creation of a quantitative, Microsoft Excel-based, model. In the qualitative framework, we reviewed the existing wind integration literature to identify the critical characteristics of a balancing authority that are predictive of the local grid’s relative capability to accommodate wind ramping behavior. In this framework, we additionally outline key qualities of loads that make them viable candidates for the demand response services required in the balancing of wind ramps. Lastly, we discuss several potential approaches for forecasting future wind penetration in a balancing authority. We have found that demand response for wind balancing can be a favorable emerging business opportunity in a power system at the confluence of these three aforementioned analyses: 1) the balancing authority’s structure and other conditions lead to a limited ability to effectively respond to increasing wind penetration, and demand response is an eligible resource to participate in balancing markets, 2) the balancing authority has a sufficient concentration of load types that are viable and appropriate demand response candidates for the balancing of wind ramps and 3) there are expectations of high future wind penetration in the system. For our quantitative analysis, we have developed a modeling tool designed to project the total size of the down ramps caused by various wind penetration levels in a given balancing authority. These projected down ramps are then related to the generation assets of the balancing authority to evaluate the efficacy with which wind ramps can be balanced with incumbent generation and to assess additional ancillary services required that could be met with demand response, among other sources. Finally, the qualitative and quantitative evaluation frameworks we have developed are applied to a case study of the Southwestern Public Service (SPS) balancing authority in the Southwest Power Pool, where there is high wind penetration and an evolving ancillary services market. Ultimately, while we find SPS to be a very strong candidate for demand response-derived wind balancing on a number of metrics, through our quantitative analysis we nevertheless find that an abundance of installed generation capacity in the balancing authority somewhat mitigates the deleterious impact of large wind down ramps, and substantially higher wind penetrations must be achieved before SPS is truly constrained. However, demand response still may provide the least cost option for wind balancing even at lower wind penetrations. There are current policy and market barriers directly precluding load response in ancillary service markets in the Southwest Power Pool, however given policy changes happening at the national and regional levels, it appears this trend may be reversing in the near term. The tool set we have developed here will allow third-party demand response providers to effectively and relatively quickly assess the relative merits of the business opportunity associated with attempting to sell demand response as a wind-balancing product in a given power system. In addition, the insights provided herein may illuminate several key considerations for a balancing authority seeking to address the efficacy with which wind down ramps can be balanced in future grid operations.Item Open Access Balancing Wind Down Ramps With Demand Response: The opportunity for load participation in ancillary service markets spurred by high wind penetration(2012-04-27) Nourafshan, Andrew; Ballal, Sangeeta; Brumleve, NickLarge “down-ramps,” inherent in the pronounced variability of wind power generation, are a threat to grid stability as the share of wind resources increases in power markets. Balancing Authorities face the challenge of how best to address the externalities that wind variability places on the grid. Our analysis assesses U.S. power markets that offer the greatest opportunities for demand response to act as a wind balancing resource. More specifically, this study evaluates market opportunities for third-party demand response aggregators to bid the capacity of responsive load into ancillary services markets to address these “down-ramp” events. This evaluation was performed through both the establishment of a qualitative framework and the creation of a quantitative, Microsoft Excel-based, model. In the qualitative framework, we reviewed the existing wind integration literature to identify the critical characteristics of a balancing authority that are predictive of the local grid’s relative capability to accommodate wind ramping behavior. In this framework, we additionally outline key qualities of loads that make them viable candidates for the demand response services required in the balancing of wind ramps. Lastly, we discuss several potential approaches for forecasting future wind penetration in a balancing authority. We have found that demand response for wind balancing can be a favorable emerging business opportunity in a power system at the confluence of these three aforementioned analyses: 1) the balancing authority’s structure and other conditions lead to a limited ability to effectively respond to increasing wind penetration, and demand response is an eligible resource to participate in balancing markets, 2) the balancing authority has a sufficient concentration of load types that are viable and appropriate demand response candidates for the balancing of wind ramps and 3) there are expectations of high future wind penetration in the system. For our quantitative analysis, we have developed a modeling tool designed to project the total size of the down ramps caused by various wind penetration levels in a given balancing authority. These projected down ramps are then related to the generation assets of the balancing authority to evaluate the efficacy with which wind ramps can be balanced with incumbent generation and to assess additional ancillary services required that could be met with demand response, among other sources. Finally, the qualitative and quantitative evaluation frameworks we have developed are applied to a case study of the Southwestern Public Service (SPS) balancing authority in the Southwest Power Pool, where there is high wind penetration and an evolving ancillary services market. Ultimately, while we find SPS to be a very strong candidate for demand response-derived wind balancing on a number of metrics, through our quantitative analysis we nevertheless find that an abundance of installed generation capacity in the balancing authority somewhat mitigates the deleterious impact of large wind down ramps, and substantially higher wind penetrations must be achieved before SPS is truly constrained. However, demand response still may provide the least cost option for wind balancing even at lower wind penetrations. There are current policy and market barriers directly precluding load response in ancillary service markets in the Southwest Power Pool, however given policy changes happening at the national and regional levels, it appears this trend may be reversing in the near term. The tool set we have developed here will allow third-party demand response providers to effectively and relatively quickly assess the relative merits of the business opportunity associated with attempting to sell demand response as a wind-balancing product in a given power system. In addition, the insights provided herein may illuminate several key considerations for a balancing authority seeking to address the efficacy with which wind down ramps can be balanced in future grid operations.Item Open Access Beach and sea-cliff dynamics as a driver of long-term rocky coastline evolution and stability(Geology, 2012) Limber, Patrick WaylandRocky coastlines, with wave-battered headlands interspersed with calm sandy beaches, stir imaginations and aesthetic sensibilities the way few other landscapes do. Despite their prevalence (sea cliffs or bluffs are present along nearly 75% of the world’s oceanic coastlines), we know very little about how rocky coastlines evolve. Quantitative studies of large-scale (>1 km) rocky coastline evolution are just beginning, and this work asks several unresolved and fundamental questions. For example, what determines the planform morphology of a rocky coastline? Can it reach an equilibrium configuration and cross-shore amplitude? What rocky coastline processes and characteristics scale the formation time and size of sea stacks? The overarching theme of the following four chapters is the dynamics between beaches and sea-cliffs. Sea-cliff erosion and retreat is a primary source of beach sediment on rocky coastlines. As cliffs contribute sediment to the beach, it is distributed by alongshore sediment transport, and the beach can control future rates of sea-cliff retreat in two main ways: in small amounts, sediment can accelerate cliff retreat by acting as an abrasive tool, and in larger amounts, the beach acts as a protective cover by dissipating wave energy seaward of the sea-cliff. These feedbacks have been observed on rocky coastlines and in laboratory experiments, but have not been explored in terms of their control on large-scale and long-term (i.e., millennia) rocky coastline evolution. The aim of this dissertation is to explore the range of ways that beach and sea-cliff dynamics can drive rocky coastline evolution with simple analytical and numerical models, and to generate testable predictions.Item Open Access Building an Energy Efficiency Supply Curve: A Case Study of Rubenstein Hall at Duke University(2012-04-17) Devoy, KealyDuke University has a deep commitment to sustainability and a clear track record of constructing highly efficient buildings. The new North Carolina Building Energy Conservation Code requires that new construction be 30 percent more efficient than the ASHRAE 90.1-2007 standard. To determine the impact of meeting this new code, an energy model of Rubenstein Hall was constructed as if the building were being built new today. This model was used to assess the effect of energy efficiency projects on the building’s overall energy use. Projects fell into four categories: heating ventilating and air conditioning, thermal performance, solar gain, and lighting. The results of the analysis found that the entirety of the new NC Building Energy Conservation Code could be met through four projects, each with no upfront costs: reducing the minimum percentage of outside air to 15 percent (from 17-21 percent), altering the time at which thermostats return to set points from 5am to 7am, reducing the lighting power density to 0.9 watts per square foot (from 1.8 watts per square foot), and maximizing the window area at 30 percent of total wall area. These projects will result in a building that uses 43 percent less energy use than the ASHRAE 90.1-2007 standard, more than meeting the goals of the code. The energy efficiency supply curve generated in this report can inform decision making during the design phase of new campus buildings, as well as guide efficiency upgrades in existing buildings. Overall, Duke should have no problem meeting the NC ECC. That being said, there are still operational and physical changes that can lead to reduced energy use, which should be pursued to the fullest extent.Item Open Access BUSINESS MODELS FOR EXTRACTING MORE USEFUL LIFE FROM LITHIUM ION BATTERY SYSTEMS(2017-04-25) Bartlett, Dennis; Herman, Ted; Klinkman, AndrewDemand for new lithium-ion battery (LIB) systems is forecast to double between 2015 and 2020. However, current battery disposal practices mean that by 2020, tens of GWhs of still-useful lithium ion storage capacity could be directed towards landfills. While automotive companies are actively engaged in “second life” concepts for their electric vehicle batteries, it is not apparent that non-automotive batteries have similar applications. Non-automotive batteries have many different chemistries and form factors, and suffer from weak economics in the recycling process. This project explores the entrepreneurial viability of finding a “second-life” for non-automotive LIB systems. Specifically, we explore (1) capturing this low cost “waste” stream from primary users of batteries, (2) diagnosing and refurbishing used LIB systems, and (3) selling these systems to secondary users. Environmental benefits are quantified via (1) mineral conservation and (2) avoided emissions attributable to further unlocked levels of renewable energy supported by increased storage levels on the power grid.