http://webx.ubi.pt/~catalao/EGY-D-14-00600R2_Paper.pdf

Energy storage systems supporting increased penetration of renewables in islanded systems

With the development of smart grid technologies, some of the electric demands which are traditionally considered fixed and inflexible will become promising distributed energy resources in future power systems. However, the participation of small scale or household energy sources into balancing power might challenge the operation of electric distribution systems and cause congestions. This paper presents a distribution congestion price (DCP) based market mechanism to alleviate possible distribution system congestions. By employing the locational marginal pricing model, the proposed DCPs are able to reflect the real congestion cost and further direct the schedule of the responses of electric demands. Based on the NordPool Spot market structure, the interactions between aggregators and the distribution system operator are discussed, and the procedure for calculating DCPs is proposed. Finally, a practical Danish 60kV/10.5kV distribution system is employed as the test case to verify the proposed method for mitigating congestion.

/pdf/day-ahead-congestion-management-in-distribution-systems-h4tqk8tbfd.pdf

Day-Ahead Congestion Management in Distribution Systems Through Household Demand Response and Distribution Congestion Prices

The intermittency introduced by the increasing integration of distributed renewable energy sources is challenging the efficient operation of residential distribution systems. A promising solution to tackle this challenge is the implementation of residential demand response through responsive household appliances such as heat pumps, refrigeration devices, and energy storage units. In this article, a peer-to-peer energy trading platform among residential houses is proposed to coordinate demand response schemes and level off potential generation/consumption disturbances in the hour-ahead intraday context. First, the day-ahead and intraday energy management models for residential houses are established considering the characteristics of responsive household appliances and energy storages. The discomfort and possible economic losses for performing demand responses are quantified with respect to the risk preferences of residential customers. The peer-to-peer energy trading platform is developed and a double-auction mechanism employed to promote the collaborative demand response schemes in the face of disturbances. An optimal bidding strategy of residential houses is also proposed. The feasibility of the proposed models and bidding strategy are verified through case studies. It is also illustrated that the residential demand response schemes and intraday peer-to-peer energy trading are effective in managing the uncertainties of load demand and renewable generation.

Intraday Residential Demand Response Scheme Based on Peer-to-Peer Energy Trading

We studied the trapping of positive and negative charges in the chemical structures of polymers under a high electric field using a space charge measurement system. Positive charges accumulated in low-density polyethylene (LDPE), whereas positive and negative charges accumulated in polyimide (Kapton) and also in ethylene tetrafluoroethylene (ETFE) subjected to electron beam irradiation. To determine the charge-trapping sites in the chemical structures, a quantum chemical calculation was carried out using Density Function Theory (DFT) with Gaussian 09. The relationship between the energy band and the isosurface of orbital electrons at various energy levels was obtained. A threedimensional (3D) electrostatic potential distribution map was obtained for positively and negatively charged polymers to determine the relationship between a trapping site and the charge accumulation center in the 3D potential distribution map. Positive and negative charges in Kapton and ETFE films are trapped in trapping sites in chemical structures and the positive charges in an LDPE film are trapped in physical defects.

Determination of charge-trapping sites in saturated and aromatic polymers by quantum chemical calculation

Transitioning to low-carbon energy systems depends on fundamental changes in technologies, policies, and institutions. In Western democracies, public perceptions and engagement with energy have encouraged innovation while also slowing deployment of low-carbon energy technologies (LCETs). Transitioning to low-carbon energy systems requires re-engineering technologies and changing the ways people interact with energy. This shift involves both technological and social changes including modifications in policies and institutional configurations. In Western democracies, public perceptions and engagement with energy have encouraged innovation while also slowing deployment of low-carbon energy technologies (LCETs). To aid understanding of how energy systems are evolving toward lower-carbon technologies in Western democracies, this study reviews the literature on public perception of and engagement with emerging LCETs. Focusing primarily on electricity generating technologies, we explore how multiple factors related to place and process shape public perceptions of and engagement with LCETs, thereby influencing their development and deployment. This study first reviews literature related to how place and process influence emerging LCETs and then provides a comparative example of differential development of wind energy in Texas and Massachusetts (USA) to demonstrate how place and process may interact to influence the patterns of LCET deployment.

/pdf/public-perception-of-and-engagement-with-emerging-low-carbon-3ckl3pnle4.pdf

Public perception of and engagement with emerging low-carbon energy technologies: A literature review

What a little Danish island is showing the world about the future of energy. On Christmas night, Maja Bendtsen and her husband were curled up on the couch watching TV in their cozy house on the Danish island of Bornholm. Suddenly the house lost power. "The lights flickered briefly and then everything went black," Bendtsen recalls. Peeking out the window, they saw that the whole neighborhood was dark. A few quick phone calls confirmed that all of Bornholm was without power. Bendtsen, an engineer with the island's utility, Ostkraft Net, mentally ruled out the obvious culprits: It wasn't a particularly busy night, as Christmas festivities had wrapped up with the midday meal, nor was the weather particularly cold or stormy. She thought of one thing, though, and it made her heart sink. She phoned the Ostkraft control room, where the chief engineer confirmed her suspicion: A ship dragging its anchor in the narrow Baltic Sea channel between Bornholm and Sweden had severed the 60-kilovolt, 70-megawatt undersea power cable that is the island's only external source of electricity. It would take a repair crew more than six weeks to pinpoint the damage, haul the cable to the water's surface, and fix it.

J. Kumagai

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