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News Article | May 22, 2017
Site: phys.org

He'd probably say, "What the hell is this?" according to Kevin Self, senior vice president of strategy, business development, and government relations for Schneider Electric North America, and a member of ISEN's executive council. Conversely, Self notes, if Thomas Edison, the father of the modern-day grid, were to look outside in 2017 and see all the wires and poles, he'd say, "Yep, nothing has changed in 100 years." Nonetheless, after decades of stagnation, power grids are modernizing. Utilities are using consumer data to optimize usage. "Prosumers"—consumers who also produce electricity—are emerging, with a greater interest in managing their own usage. Energy storage is a priority. Still, many wonder if these changes will bring the sweeping effects that many envision. Fuel, Renewables, and the Decline of Coal Electricity demand has stabilized in the United States and production is plentiful, with natural gas sustaining much of the country's requirements. "From an industry standpoint, people have been [thinking] that gas in the United States will remain cheap and plentiful for many years to come," says Tom O'Flynn, executive vice president and chief financial officer of AES, a multinational energy distributor based in Arlington, Virginia, and a member of ISEN's executive council. Meanwhile, non-hydroelectric sources of renewable energy—most notably wind power and solar—have begun to gain market share. In just seven short years from 2009 to 2016, wind power tripled as improvements to turbine technology saw gains in efficiency and a reduction in costs. Solar generation quadrupled between 2013 and 2016, topping off at 33.3 billion kilowatt-hours in that final year as more people and businesses installed rooftop solar panels. Another reason for the increase in renewables has been the rise of battery storage. As part of a grid storage system, batteries can retain electricity from these intermittent resources when production outpaces consumption, and use it later when needed. "We're using batteries to store power for when the wind isn't blowing or the sun isn't shining," O'Flynn says. As the use of renewables has grown, the use of coal has begun to shrink. Both wind and solar are cheaper than coal on average, with wind costing $0.05 per kilowatt-hour and solar coming in at$0.06 per kilowatt-hour. Coal on average costs between $0.09 and$0.27 per kilowatt-hour, once you factor in health and environmental costs. "A coal plant's life expectancy is being jeopardized by the rising cost of operations, maintenance, and capital improvements," O'Flynn says. "These are being replaced with cost-effective gas and an increasing amount of solar and wind as costs per hour continue to decline." Trends aside, coal will still have its place for some time, O'Flynn says, especially in fast-growing economies with an immediate need for electricity generation, and where local gas is not available. "The energy puzzle going forward is about balancing capacity resources," he says, "because what you need are resources that are available 24/7." Changing how we produce electricity also means changing how that power is delivered. In other words, says Adilson Motter, Charles E. and Emma H. Morrison Professor of Physics and Astronomy at Northwestern, "the power grid needs a reboot." Over time, consumption has grown, and the grid hasn't expanded fast enough to catch up. The result is a strained system that suffers from outages and other interruptions that cost Americans $150 billion annually, according to a US Department of Energy (DOE) report. "Which is why we need to rethink the system to prevent this type of loss," Motter says. Currently, the grid system is being overhauled, from replacing physical components to installing modern outage and distribution management systems. An ISEN team led by Motter and Takashi Nishikawa, research associate professor of physics and astronomy at Northwestern, secured a$3.2 million DOE grant to examine ways to avoid outages and help increase stability. "We need some way to compensate for the loss of stability due to the intermittent nature and other salient properties of renewables," says Nishikawa, who, with his colleagues, is working on a new control architecture for the grid that can address the problem. Their project builds on the prospect that the power grid will soon evolve to include two-way communication between utility companies and consumers, including realtime pricing—a defining characteristic of smart grids. "This opens the possibility of creating incentives to control consumption to match intermittent production through the use of smart appliances," Motter says. He notes that a smart washing machine, for example, would turn on at a time when price is low, which is precisely when there is excess energy production. So, how does a smart grid actually work? Smart grids use information and communications technology to track electricity usage within the system. That data is collected by energy companies and analyzed to help optimize usage. Interest is high. Many companies—startups and multinationals alike—see this as an opportunity to enter an emerging technology field adjacent to an industry known for its strong, asset-based growth. "No one wants to be left behind," says Self of Schneider Electric. "There are thousands of experiments going on right now in cities. It's definitely a state of learning." But of greater interest (and concern) to energy companies is the emergence of the microgrid, a self-contained system that can connect and disconnect from the larger electrical grid. Microgrids are common within medical facilities; in case of a power outage, onsite generators keep respirators and other life-sustaining devices operational. The concept gained greater attention after Hurricane Sandy hit in 2012. While major portions of New York and New Jersey were without power, Princeton University kept the lights on, thanks to its on-campus microgrid. This trend toward modularity could help solve a challenge facing another emerging trend in electricity: the electric vehicle (EV). Thanks to companies like Tesla and the growing prominence of electric-gas motor hybrids, EVs are at a tipping point, poised to become commonplace. But power usage, the EV's internal battery length, and mileage range are still pain points for consumers. Charging stations for EVs are nowhere near as prolific as gas stations. "Right now, you can only get 200 to 250 miles per charge, and then you have to wait a few hours to charge," says Ermin Wei, assistant professor of electrical engineering and computer science at Northwestern. That's where modularity comes in, Wei says. Similar to using batteries to solve the intermittence problem with renewable energy generation, building storage capacity into EVs in the form of "swappable batteries" would help lengthen mileage range, making the automobiles more practical. The extra capacity would also help keep EVs off the grid during peak demand hours, allowing owners to charge at night when pricing is lower. Wei suggests that these "swappables" could be sold to EV owners or discharged into the grid during the day. So why aren't we doing this already? "Right now, it's still very expensive and batteries are big and heavy," Wei says. "We're looking for a breakthrough." Not Too Small for Big Data Amid all this change in production and transportation of electricity on the grid, more questions arise. What about residential customers? How will things change for them? "We have a lot more data coming in now, and if you know how to use that data, you can turn it around into something that's valuable to the customer," says Ty Benefiel, a 2014 graduate of the Kellogg School of Management and CEO of MeterGenius. Based in Indianapolis, MeterGenius works with utilities to provide analytics services to its customers. Benefiel's company employs the same information and communications technology used in smart devices to retrieve electricity usage data, then merges that with additional customer information to recommend ways to cut down on costs. "It's not enough to tell a customer what they spent. We also tell them why they spent and how they can make changes to reduce that in the future," Benefiel says. "We give the customers the answers rather than the homework." Many utilities offer similar services. And smart devices have been around for a while (think Nest thermostats and Bluetooth-enabled light bulbs). But it's the connectivity that Benefiel says will have lasting effects in the future. "As these devices gain the ability to receive signals from the utilities and make smart choices, that's going to be our first real crack at what the future's going to look like," he says. "It could be within the next few years if utilities and energy companies are smart about this."

News Article | May 22, 2017
Site: phys.org

Network visualization map of the US electric grid. Credit: Northwestern University To ensure that the US electric grid remains stable and resilient, power generators in three main regions (Eastern, Western, and Texas) must be synchronized, all operating at the frequency of 60 hertz. Because generators interact with each other through a network of transmission lines, if one generator gets out of sync, it can disrupt the stability of the entire system and lead to outages for power consumers. Integrating renewable energy sources, which generate electricity intermittently, can also lead to disturbances. Through a grant from the US Department of Energy's Advanced Research Projects Agency (ARPA-E), Takashi Nishikawa, research associate professor in Northwestern's Department of Physics and Astronomy, and his colleagues are working to develop a new frequency-based load control architecture for power grids that integrates increased portions of electricity generation from renewables. Here, Nishikawa describes how network visualization maps like the one above help us to understand the locations, strength, and nature of interactions on the grid. ISEN: What does this network map help us visualize? TAKASHI NISHIKAWA: The image visualizes the network of interactions between generators in power plants across the United States. A line is drawn between the locations of two generators that mutually influence their frequencies. The blue network in the background shows the connections between generators through transmission lines and substations. ISEN: What do the colors and clusters represent? TN: Each line is color-coded by how strong the influence is, from dark green (weakest) to white (strongest). A cluster of white links represents a group of generators that are strongly coupled; in such a group, frequency disturbances in one are very likely to disturb others. ISEN: What can we learn from mapping power grid networks? TN: This mapping tells us that the network is very heterogeneous: the mutual influence between some pairs of generators is much stronger than others, with the strength varying across multiple orders of magnitude. This creates a real challenge for modeling and predicting the power grid's dynamics. ISEN: What does your expert eye see when you look at one of these maps? TN: We see a huge difference between the pattern of physical connections among generators through transmission lines and the pattern of influence connecting them through electrical interactions. The latter matters for the behavior of the grid under small disturbances, and studying the mathematical properties of that pattern gives us insights into how to measure, analyze, and control the grid. ISEN: What/who do you hope this mapping will inform? TN: Network visualization informs grid operators, as well as the energy industry and decision makers, of the scale, complexity, and interdependencies associated with the problem of power grid dynamics. Analysis of the influence pattern could be used to identify parts of the grid that are more likely to benefit from upgrades, such as the installation of additional transmission lines. Explore further: Better power grid synchronization may enable smart grids to self-recover from failures

News Article | February 27, 2017
Site: www.marketwired.com

Rolland S.A.,University of Swansea | Mosbah P.,ISEN | Gethin D.T.,University of Swansea | Lewis R.W.,University of Swansea
Powder Technology | Year: 2012

The powder forming industry looks to produce parts of increasing geometrical complexity as it is seen as a very efficient production process. This offers new challenges as three-dimensional states of stress are induced. In particular, granular and porous materials respond very differently to tensile and compressive stresses. Since experiments conducted in the 1990s, little exploration of the Lode dependency of powders was carried out. The present work investigates the effect of Lode dependency through numerical simulation, aiming to establish whether it affects the outcome of a compaction cycle and whether further experimental study of the phenomenon may be justified. To this effect, a Lode dependent model was developed and implemented in a finite element code, then two case studies were carried out. The results show that there is little impact on the density contours within the components and the stress levels during the compaction. As the parts are ejected from the die, surface stress levels are affected and this is of great interest when studying the onset of defects in powder compacts. © 2011 Elsevier B.V.

Launay H.,Lille University of Science and Technology | Parent B.,ISEN | Page A.,University of Strasbourg | Hanoulle X.,Lille University of Science and Technology | Lippens G.,Lille University of Science and Technology
Angewandte Chemie - International Edition | Year: 2013

Kinetics determined by NMR: Whereas most measurements of kinetic parameters of a ligand-protein complex use displacement of the ligand, protein displacement can give accurate off-rates in solution (see picture). Analytical and simulation results are given for the apparent off-rate obtained by protein displacement. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

News Article | December 3, 2016
Site: www.PR.com

Kaddouri S.,Florida Atlantic University | Beaujean P.-P.J.,Florida Atlantic University | Bouvet P.-J.,ISEN | Real G.,Florida Atlantic University | And 2 more authors.
IEEE Journal of Oceanic Engineering | Year: 2014

Hermes is an asymmetrical point-to-point underwater acoustic modem designed for short-range operations at very high bit rates in ports and shallow waters using broadband acoustic signaling (262-375 kHz). In exploring the possible conversion of Hermes into a multiple-input-multiple-output (MIMO) device, single-carrier phase-modulated spread-spectrum sequences were used for channel estimation and deconvolution purposes. It clearly appeared that the channel estimation and deconvolution routines were quite sensitive to rapid time changes in the acoustic channel impulse response (CIR), which usually reflects the presence of Doppler spread produced for the most part by moving boundaries and oscillating sensors. In this paper, the authors study the least square (LS) channel estimation routine ability to track the time-varying nature of the impulse response using broadband, single-carrier pseudonoise (PN) sequences transmitted by a single source and collected by a single receiver. In addition, the authors evaluate a trend estimation technique, based on the empirical modal decomposition (EMD) method applied to the LS estimate of the CIR. Simulated data produced with a Rayleigh channel model and experimental data collected in a marina are used. This paper shows that the channel estimation method can estimate the time-varying impulse response of the acoustic channel with a high resolution of both time and delay (down to 7 $\mu$s) at the expense of high computational requirements. In analyzing the time variation of the main and secondary echoes for a signal-to-noise ratio (SNR) of 32 dB, simulated results indicate that the root mean square error (RMSE) between theoretical and LS estimated response is 7.8% for the main path with an equivalent Doppler spread of 10 Hz and 15.7% for the second path with an equivalent Doppler spread of 15 Hz. Applying the trend estimation technique to the LS CIR greatly reduces this error, down to 2.9% for the main path and to 4.7% for the second path. The experimental data clearly show that the routine can closely track the time variations of the main echo and provide a meaningful estimate of the Doppler spread. © 2013 IEEE.

Defoort M.,École Centrale Lille | Floquet T.,École Centrale Lille | Kokosy A.,ISEN | Perruquetti W.,École Centrale Lille
2007 European Control Conference, ECC 2007 | Year: 2015

This paper presents a decentralized architecture for the navigation of a formation of autonomous mobile robots evolving in an uncertain environment with obstacles. The motion planning scheme consists in decentralized receding horizon controllers that reside on each vehicle to achieve coordination among formation agents. The advantage of the proposed algorithm is that each vehicle only requires local knowledge of its neighboring vehicles. The main requirement for designing a conflict free trajectory that satisfy the coupling constraints, in a decentralized way, is that each robot do not deviate too far from its assumed trajectory designed without taking into account the coupling constraints. Having established an open loop control strategy for motion planning, an effective saturated closed-loop controller based on integral sliding mode for trajectory tracking is presented. Finally, some simulation results demonstrate the effectiveness, real-time and high robustness properties of the proposed architecture. © 2007 EUCA.

Sakamoto N.,University of Tokyo | Frappe A.,ISEN | Stefanelli B.,ISEN | Kaiser A.,ISEN | Mita Y.,University of Tokyo
2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems, TRANSDUCERS 2015 | Year: 2015

This paper reports successful wireless drive of a 100 μm × 500 μm × 5 μm MEMS thermal actuator via micro-scale coupled magnetic resonances. Receiver inductor is 500 μm × 500 μm, which is the same scale as the actuator. There is no need for rectifier circuit to drive the actuator, enabling power transmission with zero conversion loss. The transmission efficiency of the system was also evaluated and the efficacy of magnetic resonant coupling for micro-scale power transmission was verified. The system using downsized transmitter inductor was also evaluated and we verified that it has capability of driving the actuator wirelessly. © 2015 IEEE.

Werquin A.,ISEN | Frappe A.,ISEN | Muller J.,ISEN | Kaiser A.,ISEN
2011 IEEE 9th International New Circuits and Systems Conference, NEWCAS 2011 | Year: 2011

Polar architectures offering good efficiency tend to be generalized to broadband standards with high Peak to Average Power Ratio and rigorous emission mask. Some well-known sources of spectral distortions as delay between phase and envelope paths and PA nonlinearities reduce the relevance of such technique. This paper analyses another drawback which is the spectral regrowth produced by filtering the phase signal and not the envelope signal that is done in an architecture based on a digital PA. Three kind of spectral distortions are observable. The first one is Adjacent Channel Leakage Ratio degradation due to spectral regrowth in adjacent channels depending on the oversampling ratio. The two other effects attenuate and enlarge the out-of-band images what could be used to alleviate the filtering requirements for wideband systems. © 2011 IEEE.