Message Passing for Integrating and Assessing Renewable Generation in a Redundant Power Grid

A simplified model of a redundant power grid is used to study integration of fluctuating renewable generation. The grid consists of large number of generator and consumer nodes. The net power consumption is determined by the difference between the gross consumption and the level of renewable generation. The gross consumption is drawn from a narrow distribution representing the predictability of aggregated loads, and we consider two different distributions representing wind and solar resources. Each generator is connected to D consumers, and redundancy is built in by connecting R of these consumers to other generators. The lines are switchable so that at any instance each consumer is connected to a single generator. We explore the capacity of the renewable generation by determining the level of "firm" generation capacity that can be displaced for different levels of redundancy R. We also develop message-passing control algorithm for finding switch settings where no generator is overloaded.Comment: 10 pages, accepted for HICSS-4

The European Union-Russia- China energy triangle. Bruegel Policy Contribution Issue #16 December 2019

Concern is growing in the European Union that a rapprochement between Russia and China could have negative implications for the EU. We argue that energy relations between the EU and Russia and between China and Russia influence each other. We analyse their interactions in terms of four areas: oil and gas trading, electricity exchanges, energy technology exports and energy investments. We discuss five key hypotheses that describe the likely developments in these four areas in the next decade and their potential impact on Europe: 1. There is no direct competition between the EU and China for Russian oil and gas; 2. China and the EU both have an interest in curbing excessive Russian energy rents; 3. The EU, Russia and China compete on the global energy technology market, but specialise in different technologies; 4. Intercontinental electricity exchange is unlikely; 5. Russia seems more worried about Chinese energy investments with strategic/political goals, than about EU investments. We find no evidence of a negative spillover for the EU from the developing Russia-China energy relationship.But, eventually, if these risks – and in particular the risk of structural financial disintermediation – do materialise, central banks would have various instruments to counter them

Anatomy of a Log House in Adams County, Pennsylvania and Its Unspoken Language

Sixteen years after the end of the Revolution, and on the eve of the formation of Adams county, the United States became embroiled in a quasi-war with France (1797-1801) which strained the federal treasury. As a result of the diplomatic disagreement, Congress approved several bills to fund America\u27s military build-up. One of these, the U.S. Evaluation Tax of July 9, 1798, was signed into law to raise two million dollars in revenues. The direct or window tax was levied based on landholdings, buildings and the number of glass lights, and slaves-in essence, a federal property tax. Although the window tax was considered a burden by most contemporaries, it was a blessing for modern cultural scientists. Fulfilling their duty by compiling at least five schedules for each township, the assessors described each major structure on nearly every farmstead and in every village and town in York county, noting building dimensions, number of stories, number of windows and lights, and construction materials. Although some schedules have not survived, the remainder graphically illustrate that most of the dwelling houses in Adams county by the summer of 1798 were made of wood. [excerpt

Modeling and Control of High-Voltage Direct-Current Transmission Systems: From Theory to Practice and Back

The problem of modeling and control of multi-terminal high-voltage direct-current transmission systems is addressed in this paper, which contains five main contributions. First, to propose a unified, physically motivated, modeling framework - based on port-Hamiltonian representations - of the various network topologies used in this application. Second, to prove that the system can be globally asymptotically stabilized with a decentralized PI control, that exploits its passivity properties. Close connections between the proposed PI and the popular Akagi's PQ instantaneous power method are also established. Third, to reveal the transient performance limitations of the proposed controller that, interestingly, is shown to be intrinsic to PI passivity-based control. Fourth, motivated by the latter, an outer-loop that overcomes the aforementioned limitations is proposed. The performance limitation of the PI, and its drastic improvement using outer-loop controls, are verified via simulations on a three-terminals benchmark example. A final contribution is a novel formulation of the power flow equations for the centralized references calculation

Estimating offsets for avian displacement effects of anthropogenic impacts

Biodiversity offsetting, or compensatory mitigation, is increasingly being used in temperate grassland ecosystems to compensate for unavoidable environmental damage from anthropogenic developments such as transportation infrastructure, urbanization, and energy development. Pursuit of energy independence in the United States will expand domestic energy production. Concurrent with this increased growth is increased disruption to wildlife habitats, including avian displacement from suitable breeding habitat. Recent studies at energy-extraction and energy-generation facilities have provided evidence for behavioral avoidance and thus reduced use of habitat by breeding waterfowl and grassland birds in the vicinity of energy infrastructure. To quantify and compensate for this loss in value of avian breeding habitat, it is necessary to determine a biologically based currency so that the sufficiency of offsets in terms of biological equivalent value can be obtained. We describe a method for quantifying the amount of habitat needed to provide equivalent biological value for avifauna displaced by energy and transportation infrastructure, based on the ability to define five metrics: impact distance, impact area, pre-impact density, percent displacement, and offset density. We calculate percent displacement values for breeding waterfowl and grassland birds and demonstrate the applicability of our avian-impact offset method using examples for wind and oil infrastructure. We also apply our method to an example in which the biological value of the offset habitat is similar to the impacted habitat, based on similarity in habitat type (e.g., native prairie), geographical location, land use, and landscape composition, as well as to an example in which the biological value of the offset habitat is dissimilar to the impacted habitat. We provide a worksheet that informs potential users how to apply our method to their specific developments and a framework for developing decision-support tools aimed at achieving landscape-level conservation goals

A Town Meeting on Energy : Prepared for Interior Alaskans

On March 26, 1977, an all-day Town Meeting on Energy was held at the Hutchison Career Development Center on Geist Road in Fairbanks, Alaska. This event was sponsored by the Alaska Humanities Forum in cooperation with the Fairbanks North Star Borough School District; the Institute of Water Resources at the University of Alaska, Fairbanks; and the Fairbanks Town and Village Association. This publication reports the activities during and the information resulting from this town meeting.Published through a grant from the Alaska Humanities Forum under the auspicies of the National Endowment for the Humanities

Fuel supply chain analysis of Turkey

In spite of its natural sources, Turkey depends on other countries in terms of energy production, and a transfer from conventional fossil sources to sustainable energy sources is strongly necessary. Among the sustainable energy sources, biomass is the subject of this study. The characteristics, logistic aspects, environmental aspects, economical, legal and technical aspects are investigated in order to show that the possible biomass co-firing is very important for the construction of economic, sustainable and environmentally friendly energy systems

Risk Assessment of a Wind Turbine: A New FMECA-Based Tool With RPN Threshold Estimation

A wind turbine is a complex system used to convert the kinetic energy of the wind into electrical energy. During the turbine design phase, a risk assessment is mandatory to reduce the machine downtime and the Operation & Maintenance cost and to ensure service continuity. This paper proposes a procedure based on Failure Modes, Effects, and Criticality Analysis to take into account every possible criticality that could lead to a turbine shutdown. Currently, a standard procedure to be applied for evaluation of the risk priority number threshold is still not available. Trying to fill this need, this paper proposes a new approach for the Risk Priority Number (RPN) prioritization based on a statistical analysis and compares the proposed method with the only three quantitative prioritization techniques found in literature. The proposed procedure was applied to the electrical and electronic components included in a Spanish 2 MW on-shore wind turbine