Showing papers in "IEEE Power & Energy Magazine in 2013"

Time in the Sun: The Challenge of High PV Penetration in the German Electric Grid

Abstract: Energy supply systems are facing significant changes in many countries around the globe. A good example of such a transformation is the German power system, where renewable energy sources (RESs) are now contributing 25% of the power needed to meet electricity demand, compared with 5% only 20 years ago. In particular, photovoltaic (PV) systems have been skyrocketing over the last couple of years. As of September 2012, about 1.2 million PV systems were installed, with a total installed peak capacity of more than 31 GWp. During some hours of 2012, PV already contributed about 40% of the peak power demand. It seems that Germany is well on the way to sourcing a major portion of its energy needs from solar installations. PV must therefore provide a full range of services to system operators so as to replace services provided by conventional bulk power plants.

Harmonizing AC and DC: A Hybrid AC/DC Future Grid Solution

Abstract: It has been over 100 years since Thomas Edison built the first direct current (dc) electricity supply system on 4 September 1882, at Pearl Street in New York City. Many prominent events occurred in the electricity supply industry after that. The first one, ?the war of currents,? started in 1888. Thomas Edison and his dc distribution system were on one side, and George Westinghouse and Nikolai Tesla with the alternating current (ac) system were on other side. The war ?ended? in about 1891 when ac won as the dominant power supply medium. The key behind the ac win was the invention of the transformer that could easily step up medium voltage to high and extra-high voltage for long-distance power transfer from a remote ac generation station to load centers hundreds of kilometers away with lower transmission losses. Transformers can also step down high voltage back to low voltage at load stations to supply the low-voltage equipment. Since the end of the war, ac power systems have been developed and expanded at a tremendous speed from the initial small isolated networks, with each supplying only lighting and motor loads with a few hundreds of customers, to its current scale of super interconnected networks each supplying billions of customers over large geographic areas in one or several countries. The voltage levels and capacities of transmission networks have increased from the first commercialized three-phase ac system with only 2.4 kV, 250 kW in the town of Redlands, California, United States, to the first commercial long-distance, ultra-high-voltage, ac transmission line in China with 1,000 kV, 2,000 MW. Transmission distance has been increased from several miles to over thousands of kilometers (miles). With such major achievements, it is little wonder that the ac power system became the top engineering achievement of the 20th century. Does this mean that dc is gone? The answer is an unambiguous no. What has happened in the past 50 years, such as applications of advanced control technologies in conventional power system loads, the power electronics based high-voltage dc (HVdc) transmission, and the additional renewable power sources in low-voltage distribution system, calls for a rethink about dc and ac in electricity supply systems.

Energy Comes Together in Denmark: The Key to a Future Fossil-Free Danish Power System

Abstract: The transition of the Danish energy system to a system based only on renewable energy in 2050 carries many challenges. For Denmark to become independent of fossil energy sources, wind power and biomass are expected to become the main sources of energy. Onshore and offshore wind farms are expected to provide the majority of electricity, and biomass and electricity are expected to become the major sources of heating. On the way toward the 100% renewable goal in 2050, the Danish government has proposed a 2035 midterm goal to cover the energy consumption for power and heat with renewables.

The Flexibility Workout: Managing Variable Resources and Assessing the Need for Power System Modification

Abstract: Wind and solar generation may consequently be difficult to predict over some time scales. Large penetrations of variable generation (VG) lead to increases in the variability and uncertainty in the system's generation output, driving a need for greater flexibility. This flexibility will need to come either from flexible generation technologies or from alternative sources of flexibility such as flexible demand and storage. This article will discuss the additional flexibility needs introduced by variable generation from wind and solar power and will describe general approaches to analyzing the need for and provision of additional flexibility in the power system in both the operational and planning time frames.

Microgrids for Fun and Profit: The Economics of Installation Investments and Operations

Abstract: A vision shared by many experts is that future communities (residential and commercial developments, university and industrial campuses, military installations, and so on) will be self-sufficient with respect to energy production and will adopt microgrids. With power generation capacities of 10-50 MW, microgrids are usually intended for the local production of power with islanding capabilities and have capacity available for sale back to macrogrids. A typical microgrid portfolio includes photovoltaic (PV) and wind resources, gas-fired generation, demand-response capabilities, electrical and thermal storage, combined heat and power (CHP), and connectivity to the grid. Advanced technologies such as fuel cells may also be included. This article describes the problems encountered in analyzing prospective microgrid economics and environmental and reliability performance and presents some results from the software tools developed for these tasks.

Key Connections: The U.S. Department of Energy?s Microgrid Initiative

Abstract: This article provides an overview of ongoing microgrid activities being undertaken by OE and its Smart Grid R&D Program. In addition, it discusses the process OE has undertaken to engage microgrid stakeholders to jointly identify the remaining areas in which there are R&D gaps and develop a plan to address those gaps.

Bright Future: Solar Power as a Major Contributor to the U.S. Grid

Abstract: The decreased costs of solar technologies have led to the prospect of a move for photovoltaic (PV ) and concentrating solar power (CSP ) from niche applications to major contributors to the U.S. electricity grid. This development has motivated a number of technoeconomic analyses of the potential deployment of both PV and CSP under varying economic conditions. Two studies sponsored by the U.S. Department of Energy (DOE ) and completed in 2012 can help us understand the potential opportunities and challenges for solar deployment on a large scale. These studies evaluated both the potential mix of renewable energy technologies that could serve a large fraction of the U.S. electricity demand and the associated evolution of the U.S. grid to 2050.

Balance of Power: Toward a More Environmentally Friendly, Efficient, and Effective Integration of Energy Systems in China

Abstract: To fulfill the Chinese government's targets for energy conservation and emission reductions, significant efforts to increase efficiency and reduce emissions in the energy system have been made by developing combined heat and power plants, expanding transmission, and incorporating renewables. These elements are not always compatible with each other, however. Renewables in particular face difficulties being integrated into the energy system, and a significant portion of this generation is often curtailed, in particular generation from wind. This article describes the work currently being done in China to move toward better energy system integration, including certain institutional and regulatory changes, continental-scale grid connection, microgrids, and storage. Further opportunities for flexible interaction between electricity and heat along with carbon capture and storage and the potential for increased gas supply from shale resources are also discussed.

A Good Fit: Japan¿s Solar Power Program and Prospects for the New Power System

Abstract: The Japanese earthquake and tsunami of 11 March 2011 spurred numerous discussions and debates regarding the national energy policy of Japan. One of the outcomes of this process was a new feed-in tariff (FIT) program to promote renewable energy, including photovoltaic (PV) systems, that went into effect on 1 July 2012. This new incentive program is expected to completely change the PV market in Japan, which has historically been dominated by residential PV applications. The FIT will drive not only the residential sector but also the nonresidential sector, including the new entrants to the Japanese power generation business: megawatt-scale PV power plants. Accelerating the introduction of renewable energy is important not only for diversifying Japan's sources of energy (for energy security) and combating global warming (for the environment) but also for the development of green industries (for the economy). It is essential that Japan create an environment conducive to the expansion of renewable energy in Japan by identifying the appropriate mix of regulatory measures (e.g., FITs), public support, and private-sector voluntary efforts best suited to each energy source. This article describes the current status of the PV market in Japan; the new FIT program and its impacts on the PV market; and further institutional, technical, and R&D challenges for PV dissemination.

Ivory Tower of Power: Microgrid Implementation at the University of California, San Diego

Abstract: University campuses offer a perfect setting in which to establish a microgrid and maximize its operational benefits. The university setting also offers a unique collection of intellectual resources. In addition to improving operational efficiency, lowering operating costs, and reducing the campus's overall carbon footprint, a university microgrid is an ideal laboratory in which to conduct research to advance modern power system operation and integration of distributed renewable generation for the power delivery industry as a whole. It also provides opportunities for new graduate student research and learning.

Knowledge Is Power: Efficiently Integrating Wind Energy and Wind Forecasts

Abstract: The paper discusses the general wind power forecast error curve and how several power systems have exploited the shape of this curve to successfully incorporate significant amounts of wind energy at very low cost. The paper examined some of these systems in more detail to better understand how wind variability and wind forecast uncertainty are efficiently handled through these approaches. The paper also show that these elegant approaches for integrating wind into dispatch, although quite simple from a weather forecasting point of view, actually clarify the requirements and increase the value of sophisticated wind power forecasts in other time frames and for additional users. Taken together, these approaches can efficiently and reliably incorporate wind energy in power system operations and power markets.

Finding Flexibility: Cycling the Conventional Fleet

Abstract: Adding new generation, load, or transmission to the grid changes the operation of the incumbent power system. Wind and solar generation plants are no different, but their impact on the rest of the grid is exacerbated by the facts that wind and solar energy is nondispatchable and such generators produce variable output. And because wind and solar effectively bid into the market at very low or negative cost, they are preferred resources in the dispatch stack. They are used by system operators whenever possible, unless there are generator operating limits or transmission constraints.

Code Shift: Grid Specifications and Dynamic Wind Turbine Models

Abstract: Grid codes (GCs) and dynamic wind turbine (WT) models are key tools to allow increasing renewable energy penetration without challenging security of supply. In this article, the state of the art and the further development of both tools are discussed, focusing on the European and North American experiences.

PV Measures Up for Fleet Duty : Data from a Tennessee Plant Are Used to Illustrate Metrics That Characterize Plant Performance

Abstract: Conventional power plant performance metrics are designed for dispatchable generation. These can be difficult to apply to variable generators such as wind and solar power. This article describes additional metrics that can be applied to photovoltaic (PV ) power plants and illustrates these metrics using measured data collected from a 1-MW PV plant in Tennessee over a one-year period. The article persuades that new metrics will be needed to measure and effectively employ PV for duty in a traditional generation fleet.

Energy Comes Together: The Integration of All Systems [Guest Editorial]

Abstract: The articles in this special section focus on energy systems integration (ESI) which enables the effective analysis, design,and control of these interactions and interdependencies along technical, economic, regulatory, and social dimensions.

Emergency Response: U.S. System Frequency with High Wind Penetration

Abstract: The reliable operation of a power system depends on maintaining frequency within predetermined limits around the nominal operating frequency (60 Hertz in North America). A fundamental aspect of operating an electric power grid reliably is that the amount of power produced at any given instant must match almost exactly the amount of power being consumed. If extra power is produced, the frequency will tend to increase. If less power is produced, the frequency will tend to decrease. The frequency of the interconnected grid is mostly controlled by adjusting the output of generators in order to maintain a balance between generation and load. This balancing and frequency control occur over a continuum of time, using different resources that fall into the categories of primary, secondary, or tertiary controls.

Islands in the Storm: Integrating Microgrids into the Larger Grid

Abstract: Evening is falling and the skies darken. A storm has been brewing all day, and now it settles in. Rain begins to fall and the winds increase. This is the type of storm that promises to keep utility field crews up all night. As night progresses, the storm starts to cause damage to the electrical system with downed trees, lightning strikes, and flooding problems. Sections of the city begin to experience power outages, and from a nearby hill, one can see areas of darkness as lights flicker out. Crews are being dispatched to locate problems and start the repair process. This is the way the electrical system responds to major storms today. Steps are taken to restore service as quickly as possible, but some outages are inevitable. If we look at this storm and its effects from the vantage point of a time in the future when microgrids have been established throughout the electrical system, however, things will be very different. This article discusses some of the engineering issues associated with the integration of microgrids into the larger electrical grid. It does not attempt to address all of the issues associated with microgrids, nor does it represent Southern California Edison's position on the deployment or merits of microgrids. Much more work in this area is still needed.

Ecocity Upon a Hill: Microgrids and the Future of the European City

Abstract: Smart grids are fundamentally important for transforming today?s electricity grids in order to address growing demand; renewable, intermittent, and distributed generation; and environmental pressures. Microgrids are an integral part of this transformation. But as in all transformations, there are challenges as well as opportunities. The purpose of this article is to present several European microgrids, focusing on their relative roles with respect to each other and to the overall energy ecosystem. We hope this will provide insights into how microgrids may evolve in the years to come.

The Vulnerable Amazon: The Impact of Climate Change on the Untapped Potential of Hydropower Systems

Abstract: Climate change can have an impact on natural and human systems. This is usually the case with renewable-energy-based energy systems, given their close dependence on climate conditions. For instance, long-term changes in temperature, precipitation, and wind shear, among other factors, can affect the operation of existing energy systems and even compromise the viability of new entrepreneurships. Therefore, global climate change can add a significant amount of uncertainty to the already uncertain operation of renewable energy systems. This article gives an overview of the issues related to climate change impacts on hydropower production with a focus on Amazonian regions.

Leading the Charge: Microgrids for Domestic Military Installations

Abstract: In today's interconnected battlefield, our war fighters are increasingly reliant on capabilities at domestic military installations to support critical missions, often in near real time. Many of the domestic installations of the U.S. Department of Defense (DOD) also support everything from sensitive research and development facilities such as microelectronics and biological laboratories to large industrial plants such as shipyards and aviation depots. These facilities depend on the electricity provided by the commercial electric grid. Extended-duration outages on the domestic electric grid will therefore both significantly affect the operational mission of the DOD and bring substantial economic consequences. The changing nature of electricity markets presents new opportunities for the DOD to reduce electricity costs while addressing its energy security needs. Demand response, ancillary service markets, and real-time pricing offer large consumers of electricity such as military installations a significant opportunity to use installation assets during grid-tied operation. Nevertheless, this is an opportunity the DOD can only exploit if it does so in a secure fashion, well protected from cyber threats.

Ideas for Tomorrow: New Tools for Integrated Building and District Modeling

Abstract: The energy systems in our buildings and building districts form a tight network of several energy sources, such as renewables and fossil fuels, and energy flows, such as electricity and heat. Over the years, the integration and interaction of these sources and flows have become more and more interwoven.

Rising Temps, Tides, and Wildfires: Assessing the Risk to California's Energy Infrastructure from Projected Climate Change

Abstract: Climate change affects both energy demand and supply through various parameters These parameters include warmer air and water caused by higher temperatures, changes in the flow of rivers, snowfall and ice accretion, coastal inundation, wildfires, soil conditions, cloudiness, and wind speeds Increases in energy demand and supply loss create a combined problem for ensuring an adequate supply of fuels and electricity Projections of these parameters, combined with those of energy demand and supply over the next century, are needed to improve our understanding of the increased vulnerability of the energy sector

The Power of Collaboration: Engaging All Parties in Renewable Energy Infrastructure Development

Abstract: To make our energy systems more sustainable and address climate change, society must transition its electricity infrastructure toward zero emission sources over the coming century. Many governments have already accepted this fact, passing ambitious policies to bring renewable energy up to 20% or more of the electricity mix within the next decade. Wind, solar, biomass, wave energy, and hydropower are all likely to grow rapidly as fossil fuels are replaced. This shift will require significant investments in infrastructure for electricity generation, transmission, and distribution.

Microgrids: There May Be One in Your Future [Guest Editorial]

Abstract: The articles in this special section focus on the development, applications, and technologies that support microgrids.

Latin America Goes Electric: The Growing Social Challenges of Hydroelectric Development

Abstract: Hydroelectricity was, for many years, one of the main ways to meet the new electricity needs of Latin American countries. This is evidenced by the presence of some of the larger plants worldwide and the high hydroelectric participation in all electricity matrices (Figure 1). Faced with growing prospects for future economic development, an underlying concern is how to respond to the important and growing demands for electricity. In several countries, governments and electric companies have opted to continue with the construction of hydropower plants, especially large-scale ones, as the main means of meeting this challenge. However, major projects formulated in recent years have been put in check by various difficulties, some even stopped. Despite the different political, regulatory, and economic conditions that exist in Latin America, there are common elements in the difficulties faced by these projects. While in the past, large-scale hydroelectricity was the successful response to higher electricity consumption, societies have changed, and this technology faces new cultural, social, and political conditions.

Connecting the Dots: Regional Coordination for Offshore Wind and Grid Development

Abstract: By 2020, it is expected that about 42 GW of offshore wind capacity will be built in European waters and 30 GW off the shore of China. According to the U.S. Department of Energy's National Offshore Wind Strategy, estimates for the United States are for approximately 10 GW of offshore capacity by then. This article gives an overview of current developments in this area from a power system point of view, namely, the offshore grid deployment that needs to accompany the offshore wind generation development. General ideas are given concerning political plans and related studies about technology issues, regulatory and market arrangements, and experience with offshore grid demonstration projects.

Planning for the Long Haul: Investment Strategies for National Energy and Transportation Infrastructures

Abstract: Anthropogenic carbon dioxide (CO2) emissions and the resulting influence on global climate change have motivated nations throughout the world to reconsider how we obtain, move, and utilize energy. Use of the Sankey diagrams produced annually by Lawrence Livermore National Labs (see https://flowcharts.llnl.gov) indicates that in 2011, energy harvested in the United States was converted to electricity (40%), used for transportation (28%), or used for heating and industrial processes (32%). Similarly, in 2010, energy-related CO2 emissions were due to electric conversion (40%), transportation (33%), and heating and industrial processes (27%). (Including non-CO2 greenhouse-gas emissions does not significantly change these percentages.) Because energy-related CO2 emissions come from the combustion of fossil fuels (coal, petroleum, and natural gas), there has been much emphasis on reducing reliance on these fuels or shifting some use of coal or petroleum to the use of cleaner-burning natural gas, along with reducing energy consumption via efficiency improvements and conservation.

It Takes a Village: Rural Electrification in East Africa

Abstract: Access to electric energy is an ?indispensable element of sustainable human development,? according to the International Energy Agency Without access to modern, commercial energy, poor countries can be trapped in a vicious circle of poverty, social instability, and underdevelopment About 16 billion people?more than 20% of the world?s population?have no access to electricity Moreover, about 24 billion people use traditional biomass for cooking and heating Developing regions account for 99% of those who live without electricity, and four out of five live in rural areas of South Asia and sub-Saharan Africa

Pearl Street in Miniature: Models of the Electric Generating Station [History]

Abstract: The inspiration for this history article was supplied by Thomas J. Blalock, a frequent contributor of interesting and informative history articles to these pages. Recently, Tom sent me a photocopy of p. 459 of the 2 March 1929 issue of Electrical World. One of a number of short entries under "Briefer News" on the page was "New York Edison Makes Models of Old Pearl Street Station." The piece discussed three working scale models of Thomas Alva Edison's pioneering Pearl Street, Manhattan, central generating station. The models were built in the mechanical construction shops of the New York Edison Company, a direct predecessor of the present Consolidated Edison Company of New York (Con Edison). In the margin of the photocopy, Tom wrote the following note: "Carl, I wonder if any of these still exist?" Thus began my quest to locate any survivors of the three models built in the late 1920s.

Distribution System Modeling and Analysis [Book Reviews]

Abstract: This new edition is very timely given the international attention on smart grids, including increased demand for better modeling and analysis methods to support planning and operations of smart distribution systems. The book is an authoritative textbook on the subject of distribution system modeling and analysis. It develops models for each component in a distribution feeder using generalized matrices and develops the modified ladder technique to perform load flow analysis and a method in the phase domain to perform short circuit analysis.