Browsing by Subject "Wind power"
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Item Analysis of the correlation between wind power generation and system response characteristics following unit trips on the ERCOT grid(2010-05) Lovelace, William Edward; Grady, W. M.; Santoso, SuryaElectric power generation using wind turbines is on the rise in not only the United States but the entire globe. While the benefits from such methods of generation include clean and renewable energy, wind turbines may pose a potential risk to the stability of grid operation. Wind turbine generators are similar to conventional generators; however, the manner with which the wind turbine is coupled to the grid may reduce system inertia and increase the magnitude of transient stability problems. This study empirically examines the effect of wind generation on ERCOT system response characteristics following unit trips such as frequency drop, and phasor oscillation frequency and damping. It is shown with a high degree of certainty that an increase in wind generation is leading to a greater phasor oscillation frequency and lesser system inertia. Wind generation may also be leading to less system damping and smaller power frequency drops.Item An approach for evaluating changes in land-use from energy sprawl and other anthropogenic activities with implications for biotic resource management(Environmental Earth Sciences, 2018) Wolaver, Brad; Pierre, Jon Paul; Benjamin, Labay; Travis, LaDuc; Charles, Duran; Wade, Ryberg; Toby, HibbittsThis study presents an improved approach for evaluating land-use changes caused by energy development and other anthropogenic activities. We illustrate this approach by assessing the landscape footprint of energy development in the Eagle Ford Shale Play and Permian Basin. These two hydrocarbon provinces in Texas saw rapid expansion in drilling during 2008–2012. We compare changes in land-use from oil and gas infrastructure construction during this time period with that of wind energy development in West Texas, urbanization in Central Texas, and extensive agricultural areas. This land-change mapping approach is novel because it evaluates a suite of anthropogenic activities in one study, whereas most prior research assessed land-use effects of energy activities separately without comparing them to agricultural and urbanization processes. We found that changes in land-use caused by anthropogenic factors affected 1.06% (3,456 km2) of the ~324,000 km2 study area. Oil and gas development (well pads and pipelines) was ~48% of total changes in land use, changes in agriculture caused ~26%, and urbanization was ~24%. Construction of wind turbine pads and high voltage power transmission lines was less important (~1%). This study is part of an ongoing, multi-year research program generating science to inform the federal Endangered Species Act listing decision for the Spot-tailed Earless Lizard (Holbrookia lacerata). We illustrate this approach for a single species (i.e., H. lacerata) in Texas. Additionally, this technique can facilitate effective management of a variety of biotic resources in other rapidly developing environments globally by identifying what anthropogenic activities are most important and where land-change is most intense so that on-the-ground conservation strategies can be implemented where they are needed most.Item Competitive renewable energy zones in Texas : suggestions for the case of Turkey(2012-05) Ogunlu, Bilal; Baldick, Ross; Rai, VarunAs an energy-importing developing country, Turkey depends heavily on imported petroleum and natural gas. The increase in the global petroleum price has affected the Turkish economy adversely in the last decade. Renewable energy is an important alternative in reducing Turkey’s energy dependency. Turkey’s strategies are improving domestic production and diversifying energy sources for the security of supply. New investments, especially in renewables, have been chosen to achieve these objectives. As a model for Turkey, Texas is the leader in non-hydroelectric renewable energy production in the U.S. and has one of the world’s most competitive electricity markets. However, wind generation creates unique challenges for the Electric Reliability Council of Texas (ERCOT), the transmission system operator of Texas. The market environment has forced the Public Utility Commission of Texas (PUCT) to develop unique deregulated energy markets. In 2005, the Texas Legislature passed Senate Bill 20, in part to break the deadlock between transmission and wind generation development. This legislation instructed the PUCT to establish Competitive Renewable Energy Zones (CREZs) throughout the State, and to designate new transmission projects to serve these zones. In this context, first of all, the electricity market development in Turkey is introduced in terms of renewable energy, especially wind power. Next, considering wind power, the progress in the Texas electricity market is investigated. Subsequently, we examine the development of CREZs in Texas from a regulatory perspective and discuss Texas’ policy initiatives, including the designation of CREZs. Finally, we review the impact of wind power on the primary electricity market of Texas and evaluate market conditions and barriers to renewable energy use in Turkey in order to extract suggestions. This experience may be particularly instructive to Turkey, which has a similar market structure on the supply and transmission sides. This study suggests ways that Turkey might handle renewable applications in combination with existing transmission constraints.Item Economic analysis of wind power integration in the Eastern Sumba grid, Indonesia(2018-06-19) Loa, Olivia Hanjani; Beach, Fred Charles, 1959-The island of Sumba serves as an example of a physically isolated electricity market that continues to burn diesel fuel to generate electricity despite possessing abundant sources of wind power. In an effort to encourage wind power use in Eastern Sumba, NREL has recently conducted a study evaluating the technical feasibility of integrating wind power into the Eastern Sumba grid. A cost-benefit analysis with three economic indicators has been performed for measuring the economic feasibility of integrating an 850-kW wind power system in the Eastern Sumba grid. The results demonstrated that the wind power system carries a much lower generation cost and subsidy rate than the diesel generator with a payback period of 2.9 years. Three cost-reduction scenarios were proposed to bring the generation cost to a breakeven point with the current electricity price. While a breakeven point could not be reached, the combination of CRF and CAPEX reduction scenario has successfully reduced the wind power system generation cost by 35% and cut the current energy subsidy by 94%. This study is hoped to encourage more rigorous renewable energy deployment in Eastern Sumba and to catalyze the process of reaching 100% electrification rate in the Sumba island with renewable energy power generation.Item The energy water nexus : increasing water supply by desalination integrated with renewable power and reducing water demand by corporate water footprinting(2013-08) Clayton, Mary Elizabeth; Webber, Michael E., 1971-Growing populations and periodic drought conditions have exacerbated water stress in many areas worldwide. Consequently, it would be valuable to manage both supply and demand of water to fully address water sustainability. Additionally, the inextricable link of water and energy -- energy is required to pump, treat, and distribute water and water is often used in the production of energy -- creates the need to study the use of these resources together. In response to water stress, some municipalities have considered desalination of saline water as a freshwater supply. Unfortunately, desalination requires a sizeable energy investment and causes significant carbon emissions with conventional approaches. However, renewable energy technologies can be paired with desalination to mitigate concern over the environmental impacts of increased energy use. At the same time, desalination can be operated in an intermittent way to match the variable availability of renewable resources. Both wind and brackish groundwater resources are plentiful in the Panhandle region of West Texas, making an integrated wind-powered desalination facility an option for meeting increasing water demands. Integrating wind power and brackish groundwater desalination generates a high-value product (drinking water) from two low-value resources (saline water and wind power without storage). This thesis presents a thermoeconomic, geographic, and operational analysis of an integrated wind-powered reverse osmosis facility treating brackish groundwater in West Texas. The results demonstrate the favorability of the integrated facility under certain economic, geographic, and operating conditions. Also in response to water stress, corporations are becoming increasingly interested in identifying water vulnerabilities in their operational portfolios to minimize physical, reputational, regulatory, and financial risks associated with potential water shortages. The water footprint is one tool available to assess water use, identify vulnerabilities, and guide mitigation strategies. This thesis provides an accounting methodology for water reporting that includes direct water uses and indirect (embedded in energy, services, and products) water uses in the operations. Further, a case study is considered to illustrate the methodology by assessing the water impact of a mixed-use facility in Palo Alto, California. The results demonstrate the importance of considering the indirect water uses, which requires a more exhaustive analysis.Item Forecasting congestion in transmission line and voltage stability with wind integration(2011-08) Kang, Han; Baldick, Ross; Grady, William M.Due to growth of wind power, system operators are being challenged by the integration of large wind farms into their electrical power systems. Large scale wind farm integration has adverse effects on the power system due to its variable characteristic. These effects include two main aspects: voltage stability and active line flow. In this thesis, a novel techniques to forecast active line flow and select pilot bus are introduced with wind power integration. First, this thesis introduces a methodology to forecast congestion in the transmission line with high wind penetration. Since most wind resources tend to be located far away form the load center, the active line flow is one of the most significant aspects when wind farm is connected to electrical grid. By providing the information about the line flow which can contribute to transmission line congestion, the system operators would be able to respond such as by requesting wind power or load reduction. The second objective of this thesis is to select the weakest bus, called pilot bus, among all load buses. System reliability, especially voltage stability, can be adversely affected by wind variability. In order to ensure reliable operation of power systems with wind power integration, the index to select the pilot bus is developed, and further prediction of voltage profile at the pilot bus is fulfilled. The objective function to select the pilot bus takes account of the N-1 contingency analysis, loading margin, and reactive power sensitivity. Through on the objective function, the pilot bus is representative of all load buses as well as controllable by reactive power regulation. Predicting the voltage profile at the pilot bus is also useful for system operators to determine wind power output.Item Hybrid powertrain performance analysis for naval and commercial ocean-going vessels(2012-08) Gully, Benjamin Houston; Seepersad, Carolyn; Webber, Michael E., 1971-; Hebner, Robert E.; Kiehne, Thomas M.; Chen, DongmeiThe need for a reduced dependence on fossil fuels is motivated by a wide range of factors: from increasing fuel costs, to national security implications of supply, to rising concern for environmental impact. Although much focus is given to terrestrial systems, over 90% of the world's freight is transported by ship. Likewise, naval warfighting systems are critical in supporting U.S. national interests abroad. Yet the vast majority of these vessels rely on fossil fuels for operation. The results of this thesis illustrate a common theme that hybrid mechanical-electrical marine propulsion systems produce substantially better fuel efficiency than other technologies that are typically emphasized to reduce fuel consumption. Naval and commercial powertrains in the 60-70 MW range are shown to benefit substantially from the utilization of mechanical drive for high speed propulsion; complemented by an efficient electric drive system for low speed operations. This hybrid architecture proves to be able to best meet the wide range of performance requirements for each of these systems, while also being the most easily integrated technology option. Naval analyses evaluate powertrain options for the DDG-51 Flight III. Simulation results using actual operational profile data show a CODLAG system produces a net fuel savings of up to 12% more than a comparable all-electric system, corresponding to a savings of 37% relative the existing DDG-51 powertrain. These results prove that a mechanical linkage for the main propulsion engine greatly reduces fuel consumption and that for power generation systems requiring redundancy, diesel generators represent a vastly superior option to gas turbines. For the commercial application it is shown that an augmented PTO/PTI hybrid system can better reduce cruise fuel consumption than modern sail systems, while also producing significant benefit with regard to CO2 emissions. In addition, using such a shaft mounted hybrid system for low speed electric drive in ports reduces NOx emissions by 29-43%, while CO is reduced 57-66% and PM may be reduced up to 25%, depending on the specific operating mode. As an added benefit, fuel consumption rates under these conditions are reduced 20-29%.Item Market strategies for wind power producers considering joint volume-price risks(2018-01-23) Shin, Hunyoung; Baldick, Ross; Arapostathis, Aristotle; Santoso, Surya; Hasenbein, John; Nikolova, EvdokiaThis dissertation studies the strategies of wind power producers (WPPs) who participate in a two-settlement market composed of a day-ahead (DA) market and a real-time (RT) market. When the WPPs sell energy to the DA markets, they become exposed to RT market risks from uncertain generation output and highly volatile RT market prices. This joint volume-price risk causes a risk-averse firm to choose to sell less energy than the expected generation, which discourages the WPP from fully enjoying the benefits of participating in forward electricity markets. Moreover, since the joint volume-price risk usually has a negative correlation, failing to consider the correlation will reduce the wind power producer's profit. We first present a comprehensive discussion of the effect of the wind-price correlation on offer strategies of wind power producers. The process of building an advanced offer curve that considers the joint information of wind power and RT prices are suggested. We also explore the sensitivity of the expected profit, value at risk (VaR), and conditional value at risk (CVaR) for the advanced offer curves to the variation in the probabilistic parameters of wind power and RT price. We find that the offer curve that considers wind-price correlation results in a small improvement in expected profit, but a meaningful reduction in risks. The benefits of the advanced offer curves increase as the correlation becomes more negative or the variance of wind power and prices increase. Second, we explore a risk-hedging strategy for WPPs that is applicable to general U.S electricity markets. This dissertation proposes a financial instrument referred to as a risk exchange that enables the wind power producers to trade random net payments from uncertain prices and generation outputs, after the DA market is cleared. A negotiation for the risk exchange is modeled by a bargaining game based on a conflict of interest in determining the amounts of the risk exchange. Both Nash and Rubinstein's bargaining game models are addressed to analyze the risk exchange bargaining game. Numerical examples demonstrate that the risk exchange is able to reduce RT market risks successfully and encourages the wind power producers to sell more energy to the DA market. Lastly, we focus on how the different time resolutions of RT and DA markets affects the profits and offer decisions of WPPs. Considering the difference in the time resolutions allows the WPPs to assess their expected profit more accurately. It also enables the WPPs to build an offer curve that is more profitable. To this end, however, a WPP must forecast wind power and RT price at the time resolution of the RT market which is finer than the one hour used in the DA market, possibly entailing an increase in forecasting error variance and overfitting issue. Inappropriate forecasting may lead to a wrong profit assessment and offer decisions.Item The technical potential of renewable natural gas (RNG) in the United States, and the economic potential of methanation-derived RNG in Texas(2014-12) Ólafsson, Brynjólfur Víðir; Webber, Michael E., 1971-Renewable Natural Gas (RNG) is a low-carbon fuel source that is derived from the anaerobic digestion (AD) or thermal gasification (TG) of biomass, or produced using renewable electricity through the methanation of carbon dioxide. This thesis uses a thermodynamic balance to determine the total technical potential of RNG in the United States, as well as the future technical potential of methanation-derived RNG based on growth curves for renewable electricity. Furthermore, this work establishes an analytic decision-making framework for determining on a rolling basis, from an economic standpoint, whether to sell electricity directly to the grid, or produce and sell methanation-derived RNG. This framework is used to establish the economic potential of RNG, based on Texas wind resources. This work details the formulation of a model that determines which production option generates more marginal profit, based on fluctuating electricity and gas prices. The model also aggregates the total amount of electricity and RNG sold, assuming that the main objective is to maximize the marginal profit of integrated wind- and methanation facilities. This work concludes that the annual technical potential of methanation-derived RNG nationally was 1.03 Quads in 2011. The technical potential of biomass-derived RNG was 9.5 Quads. Thus, the total 2011 technical potential of RNG in the United States was 10.5 Quads, or equal to roughly 43% of the total US consumption of natural gas that year. Assuming a constant, 80% electrolyser efficiency, the technical potential of methanation-derived RNG is expected to rise at an average rate of 1.4% per year, following growth curves for renewable power, until the year 2040, when it will be 1.54 Quads. The 2011 economic potential of methanation-derived RNG in Texas was between 2.06×10⁷ MMBTU and 3.19×10⁷ MMBTU, or between 19.4% and 30.1% of the corresponding annual technical potential. Furthermore, the total marginal profit increase from introducing the option of producing and selling methanation-derived RNG was around $366 million, given a ‘best case scenario’ for the state of Texas.