Understanding best practice regarding interruptible connections for wind generation: lessons from national and international experience

The aim of this study is to explore different practices for accelerating the integration of generating facilities to the electricity network using smart solutions. Case studies from Great Britain, Ireland and Northern Ireland and the Unites States were selected. The paper assesses and compares the different Principles of Access (POA) that have been implemented in these countries, such as Last-in First-out (LIFO), Pro Rata and Market-based. The social optimality of these approaches is also discussed. The paper also evaluates how the risk (regarding curtailment and investment) is allocated between parties (distributor network operators, generators and customers). Even though the cases are diverse, important findings and lessons have been identified which may assist UK distribution network operators to address the issue of increasing the connection of distributed generation while managing efficiently and economically energy exports from generators

Spillovers of U.S. Unconventional Monetary Policy to Emerging Markets: The Role of Capital Flows

A growing literature stresses the importance of the “global financial cycle”, a common global movement in asset prices and credit conditions, for emerging market economies (EMEs). It is argued that one of the key drivers of this global cycle is monetary policy in the U.S., which is transmitted through international capital flows. In this paper, we add to this discussion and investigate empirically whether U.S. unconventional monetary policy (UMP) between 2008 and 2014 is related to financial conditions in EMEs, and, whether it is transmitted through portfolio flows. We find that a U.S. UMP shock significantly increases portfolio flows from the U.S. to EMEs for almost two quarters. The rise in inflows is accompanied by a persistent increase in several real and financial variables in EMEs. Moreover, we find that, on average, EMEs reacted with an easing of their own monetary policy stance in response to an expansionary U.S. shock

Gain scheduled and robust H∞ control above rated wind speed for wind turbines

This paper investigates two different approaches for individual pitch control for wind turbines. The first one is a gain scheduled decentralised control design and the second one is a robust H∞ loop shaping control design. Both controllers work well in the region above rated wind speed, exhibiting a response that is mostly independent of wind speed. The investigation is conducted based on the NREL 5MW benchmark wind turbine. Turbine modeling and control is conducted in FAST and Simulink

A social cost benefit analysis of grid-scale electrical energy storage projects: a case study

This study explores and quantifies the social costs and benefits of grid-scale electrical energy storage (EES) projects in Great Britain. The case study for this paper is the Smarter Network Storage project, a 6 MW/10MWh lithium battery placed at the Leighton Buzzard Primary substation to meet growing local peak demand requirements. This study analyses both the locational and system-wide benefits to grid-scale EES, determines the realistic combination of those social benefits, and juxtaposes them against the social costs across the useful lifecycle of the battery to determine the techno-economic performance. Risk and uncertainty from the benefit streams, cost elements, battery lifespan, and discount rate are incorporated into a Monte Carlo simulation. Using this framework, society can be guided to cost-effectively invest in EES as a grid modernization asset to facilitate the transition to a reliable, affordable, and clean power system

Using smart power management control to maximize energy utilization and reliability within a microgrid of interconnected solar home systems

Over the past 20 years, off-grid solar home systems (SHS), comprised of solar panels, batteries, a charge controller and loads, have proved the most popular and immediate solution increasing energy access, mainly through rural electrification, across the Global South. Although deployed in significant numbers, issues remain with SHS cost, reliability, utilization and sustainability. Interconnection of SHS to form a microgrid of connected prosumers and consumers may offer a solution that, by employing smart management of the power distribution amongst connected households, has the potential to ‘unlock’ latent generation and storage capacity and so improve reliability and security of supply, reduce the system cost per head, and ultimately the levelized cost of energy supplied. These factors combine to improve the overall sustainability, efficiency and flexibility of SHS technology. This paper presents the functionality of a Smart Power Management (SPM) that seeks to distribute power across prosumers/consumers connected to a microgrid of interconnected SHS, to maximise the utilisation of available generation and storage across the system and so improve the reliability and affordability of the energy supplied. The SPM is applied and appraised using a simulation involving representative generation and demand profiles for a village with a high penetration of SHS technology. The power management methodology utilizes algorithms applied to manage power flows between customers. The simulated results demonstrate significant improvements in reliability of supply within the microgrid during low generation season

Interactions between Dpr11 and DIP-γ control selection of amacrine neurons in Drosophila color vision circuits

Drosophila R7 UV photoreceptors (PRs) are divided into yellow (y) and pale (p) subtypes. yR7 PRs express the Dpr11 cell surface protein and are presynaptic to Dm8 amacrine neurons (yDm8) that express Dpr11’s binding partner DIP-γ, while pR7 PRs synapse onto DIP-γ-negative pDm8. Dpr11 and DIP-γ expression patterns define ‘yellow’ and ‘pale’ color vision circuits. We examined Dm8 neurons in these circuits by electron microscopic reconstruction and expansion microscopy. DIP-γ and dpr11 mutations affect the morphologies of yDm8 distal (‘home column’) dendrites. yDm8 neurons are generated in excess during development and compete for presynaptic yR7 PRs, and interactions between Dpr11 and DIP-γ are required for yDm8 survival. These interactions also allow yDm8 neurons to select yR7 PRs as their appropriate home column partners. yDm8 and pDm8 neurons do not normally compete for survival signals or R7 partners, but can be forced to do so by manipulation of R7 subtype fate

Sequence-Dependent Dynamics of Synthetic and Endogenous RSSs in V(D)J Recombination

Developing lymphocytes of jawed vertebrates cleave and combine distinct gene segments to assemble antigen–receptor genes. This process called V(D)J recombination that involves the RAG recombinase binding and cutting recombination signal sequences (RSSs) composed of conserved heptamer and nonamer sequences flanking less well-conserved 12- or 23-bp spacers. Little quantitative information is known about the contributions of individual RSS positions over the course of the RAG–RSS interaction. We employ a single-molecule method known as tethered particle motion to track the formation, lifetime and cleavage of individual RAG–12RSS–23RSS paired complexes (PCs) for numerous synthetic and endogenous 12RSSs. We reveal that single-bp changes, including in the 12RSS spacer, can significantly and selectively alter PC formation or the probability of RAG-mediated cleavage in the PC. We find that some rarely used endogenous gene segments can be mapped directly to poor RAG binding on their adjacent 12RSSs. Finally, we find that while abrogating RSS nicking with Ca²⁺ leads to substantially shorter PC lifetimes, analysis of the complete lifetime distributions of any 12RSS even on this reduced system reveals that the process of exiting the PC involves unidentified molecular details whose involvement in RAG–RSS dynamics are crucial to quantitatively capture kinetics in V(D)J recombination

Optical analysis of CH3NH3SnxPb1–xI3 absorbers: a roadmap for perovskite-on-perovskite tandem solar cells

Organic–inorganic perovskite structures in which lead is substituted by tin are exceptional candidates for broadband light absorption. Herein we present a thorough analysis of the optical properties of CH3NH3SnxPb1–xI3 films, providing the field with definitive insights about the possibilities of these materials for perovskite solar cells of superior efficiency. We report a user's guide based on the first set of optical constants obtained for a series of tin/lead perovskite films, which was only possible to measure due to the preparation of optical quality thin layers. According to the Shockley–Queisser theory, CH3NH3SnxPb1–xI3 compounds promise a substantial enhancement of both short circuit photocurrent and power conversion efficiency in single junction solar cells. Moreover, we propose a novel tandem architecture design in which both top and bottom cells are made of perovskite absorbers. Our calculations indicate that such perovskite-on-perovskite tandem devices could reach efficiencies over 35%. Our analysis serves to establish the first roadmap for this type of cells based on actual optical characterization data. We foresee that this study will encourage the research on novel near-infrared perovskite materials for photovoltaic applications, which may have implications in the rapidly emerging field of tandem devices.Unión Europea Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 307081 (POLIGHT)España, Ministerio de Economía y Competitividad AT2014-54852- R