Smart Power Grid

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Smart Grid is a transformed electricity transmission and distribution network or "grid" that uses robust two-way communications, advanced sensors, and distributed computers to improve the efficiency, reliability and safety of power delivery and use. Smart Grid is called several other things, including "Smart Power Grid," "Smart Electric Grid," "Intelligrid," "FutureGrid," etc. Deploying the Smart Grid became the policy of the United States with passage of the Energy Independence and Security Act of 2007 (Title 13), but Smart Grid is being promoted by the European Union and nations all over the world.

The term Smart power grid may best be defined as bringing the power of communications and modern computing to the grid itself to upgrade the current electric power grid so that it can operate more efficiently, reliably and safely. Such an upgrade is equivalent to bringing the power of the Internt to the transmission, distribution and use of electricity - it will save consumers money and reduce CO2.

Today's alternating current power grid was created in 1896, based on Nikola Tesla's design published in 1888. (See War of Currents) Many implementation decisions that are still in use today were made for the first time using the limited emerging technology available 120-years ago. Specific obsolete power grid assumptions and features (like centralized unidirectional[[1]] electric power transmission, electricity distribution, and demand-driven control) are the result of experimental 19th century possibilities.

The development of modern micro-electronics, and especially the entry of the microprocessor, opened new ways to significantly improve power grid control. The evolutionary integration of intelligent, distributed, and highly-adaptive control systems made available with microelectronics is being referred as the smart grid in Title XIII of the U.S. Energy Independence and Security Act of 2007.[1]

This evolving intelligent power distribution network includes the possibility to reduce power consumption at the client side during peak hours (Demand Side Management), facilitating grid connection of distributed generation power (with photovoltaic arrays, small wind turbines, micro hydro, or even combined heat power generators in buildings), grid energy storage for distributed generation load balancing, and improved reliability against many different component failure scenarios (in contrast to today's catastrophic widespread power grid cascading failures).

Contents

[edit] Overview

The electrical grid is an interconnected system of power plants, power lines, wires, etc. moving and delivering electricity from power plants to end users. Also referred to as a transmission and distribution (T&D) network, today’s grid faces challenges to keep pace with the modern digital economy and information age, which require higher load demands, uninterruptible power supplies, and other high-quality, high-value services. Additionally, microprocessor-based technologies can alter the nature of the electrical load and result in electricity demand that is incompatible with a power system that was built to serve an “analog economy.” This can lead to electric service reliability problems, power quality disturbances, blackouts, and brownouts. However rapid advances in communications and information technology now provide electric utilities with opportunities to invest in critical grid infrastructure that can serve the growing demand for high quality, “digital-grade electricity.”[2]

Simply put, Smart Grid is the application of communications and Information Technology(IT) to the electric power transmission and distribution networks themselves. Smart grid is more than smart meters, which entails replacing analog mechanical meters with digital meters. Smart meters are transformed when connected to a real-time, broadband and Internet-enabled Smart Grid that extends from the generation plants to each electrical outlet (smart sockets) or device attached to the grid.


The original power grid technology has its control systems embedded in the generating plants, transmission lines and substations; information flows one way, from the users and the loads they control back to the utilities. The utilities attempt to meet the demand and succeed or fail to varying degrees (brownout, rolling blackout, uncontrolled blackout).  The total amount of power loaded by the users can have a very wide probability distribution which require a lot of spare generating plants in standby mode to respond to the rapidly changing power usage. This one-way flow of information is expensive; the last 10% of generating capacity may be required as little as 1% of the time, and brownouts and outages can be costly to consumers.

Demand Side Management (DSM) is the next step in sophistication.  This can be as simple as timers to switch off electric water heaters during peak-demand periods, but such systems are unable to respond to contingencies.  The full Smart grid allows generators and loads to interact in real time, using modern information and communications technology.  Managing demand to eliminate the peak fraction of demand eliminates the cost of generators, cuts the wear and extends the life of equipment, and allows users to get more value from the system by putting their most important needs first. [3]

[edit] Purpose

The major driving forces to alter the current power grid can be divided in four, general categories.

  • Increasing reliabilty, efficiency and safety of the power grid (prevent outages, lower CO2, lower electricity bills).
  • Enabling decentralized power generation so homes can be both energy client and supplier (provide consumers with interactive tool to manage energy usage).
  • Inclusion of flexibility to power consumption at the clients side and supplier selection (enables distributed generation, solar, wind, biomass).
  • Increase GDP by creating more new, "clean" energy jobs related to renewables, plug-in electric vehicles, etc.

[edit] Safety and uptime increase

[edit] Connection scheme

Although multiple routes are touted as a feature of the smart grid, the old grid also featured multiple routes. Although the initial power lines in the grid were built using a radial amodel, later on connectivity was guaranteed via multiple routes, referred to as a network structure. This, however also created a new problem: if the load is too heavy for one substation, it will fail, and this extra load will be shunted to other routes, which eventually may fail also, causing a domino effect. See power outage. A technique to prevent this is islanding or rolling black out.

[edit] Decentralization of power generation

Another element of fault tolerance is decentralized power generation. Decentralized power generation allows individual consumers to generate power onsite, using whatever generation method they find appropriate. This allows individual loads to tailor their generation directly to their load, making them independent from grid power failures.

[edit] Flexibility on client and supplier side

[edit] Load adjustment

The total load connected to the power grid can vary significantly over time. Although the total load is the sum of many individual choices of the clients, the overall load is not a stable, slow varying, average power consumption. Imagine the increment of the load if a popular television program starts and millions of televisions will draw current instantly. Traditionally, to respond to a rapid increase in power consumption, faster than the start-up time of a large generator, some spare generators are put on a dissipative standby mode. A smart grid may warn all individual television sets, or another larger customer, to reduce the load temporarily (to start up a larger generator) or continuously (in case of limited resources).

With mathematical prediction algorithms it is possible to predict how many standby generators need to be used, to reach a certain failure rate. In the traditional grid, the failure rate can only be reduced at the cost of more standby generators. In a smart grid, the load reduction of even a small part of the clients may enlight the problem.

[edit] Pricing mechanism

In many countries, including the Netherlands and the UK, the electric companies installed double tariff electricity meters in many homes, to encourage people to use their electric power during night time, when the overall demand from the industry was very low. During night time the price was reduced significantly, enabling users to save money for washing etc. This idea will be further explored in a smart grid, where the price could be changing in seconds and electric equipment is given methods to react on that. Also personal preferences of customers e.g. to use only green energy, can be incorporated in such a new power grid.

Electrical energy counter with double index to distinguish power consumption during day and night time
Electrical energy counter with double index to distinguish power consumption during day and night time

[edit] General economics developments

As customers can choose their electricity suppliers, depending on their different tariff methods, the focus of transportation costs will be increased. Reduction of maintenance and replacements costs will stimulate more advanced control.


A smart grid precisely limits electrical power down to the residential level, network small-scale distributed energy generation and storage devices, communicate information on operating status and needs, collect information on prices and grid conditions, and move the grid beyond central control to a collaborative network.[4] Table 1[5] provides a summary comparison of today’s grid with a 21st Century Smart Grid of the Future.

Table 1 - Smart Grid of the Future

20th Century Grid 21st Century Grid
Electromechanical Digital
One-way communications (if any) Two-way communications
Built for centralized generation Accommodates distributed generation
Radial topology Network topology
Few sensors Monitors and sensors throughout
“Blind” Self-monitoring
Manual restoration Semi-automated restoration and, eventually, self-healing
Prone to failures and blackouts Adaptive protection and islanding
Check equipment manually Monitor equipment remotely
Emergency decisions by committee and phone Decision support systems, predictive reliability
Limited control over power flows Pervasive control systems
Limited price information Full price information
Few customer choices Many customer choices

Some defining functions of a smart grid include:

  • “Self-healing” – Using real-time information from embedded sensors and automated controls to anticipate, detect, and respond to system problems, a smart grid can automatically avoid or mitigate power outages, power quality problems, and service disruptions.
  • Empower Consumers – A smart grid incorporates consumer equipment and behavior in grid design, operation, and communication. This enables consumers to better control “smart appliances” and “intelligent equipment” in homes and businesses, interconnecting energy management systems in “smart buildings” and enabling consumers to better manage energy use and reduce energy costs. Advanced communications capabilities equip customers to exploit real-time electricity pricing, incentive-based load reduction signals, or emergency load reduction signals.
  • More Reliable – Technologies better identify and respond to manmade or natural disruptions. Real-time information enables grid operators to isolate affected areas and redirect power flows around damaged facilities.
  • Accommodate Generation Options – As smart grids continue to support traditional power loads they also seamlessly interconnect fuel cells, renewables, microturbines, and other distributed generation technologies at local and regional levels. Integration of small-scale, localized, or on-site power generation allows residential, commercial, and industrial customers to self-generate and sell excess power to the grid with minimal technical or regulatory barriers. This also improves reliability and power quality, reduces electricity costs, and offers more customer choice.
  • Optimize Assets – A smart grid can optimize capital assets while minimizing operations and maintenance costs. Optimized power flows reduce waste and maximize use of lowest-cost generation resources. Harmonizing local distribution with interregional energy flows and transmission traffic improves use of existing grid assets and reduces grid congestion and bottlenecks, which can ultimately produce consumer savings.

[edit] Technology

Newer retrofit US domestic digital electricity meter (Elster REX) with 900MHz mesh network topology
Newer retrofit US domestic digital electricity meter (Elster REX) with 900MHz[6] mesh network topology[7]
Elster A3 ALPHA meter collector connecting mesh networked smart meters to the metering automation server
Elster A3 ALPHA meter collector connecting mesh networked smart meters to the metering automation server[8]

Smart grid development does not require large-scale technological innovation. Many smart grid technologies are already used in other applications such as manufacturing and telecommunications. Smart grid development for the most part can use existing technologies, applying them in new ways to grid operations. In general, smart grid technology can be grouped into five key areas:[9]

  1. 2-way Integrated Communications technologies have the potential to enhance grid communications. Many are already in use but not yet fully integrated. These include: substation automation, advanced meter reading (AMR), demand response, distribution automation, supervisory control and data acquisition (SCADA), energy management systems, RF mesh networks, other wireless technologies, power-line carrier, and fiber-optics. Integrated communications will allow for real-time control, information and data exchange to optimize system reliability, asset utilization, and security.
  2. Sensing and Measurement technologies are essential to evaluating equipment health, grid integrity, energy theft prevention, congestion relief, and control strategies support. Technologies include: advanced microprocessor meters (smart meter) and meter reading equipment, wide-area monitoring systems, dynamic line rating, electromagnetic signature measurement/analysis, time-of-use and real-time pricing tools, advanced switches and cables, backscatter radio technology, and digital relays.
  3. Advanced Components are responsible for the electrical behavior of the grid, applying the latest R&D in superconductivity, fault tolerance, storage, power electronics, and diagnostics. Technologies within these broad R&D categories include: flexible alternating current transmission system devices, high voltage direct current, first and second generation superconducting wire, high temperature superconducting cable, distributed energy generation and storage devices, composite conductors, and “intelligent” appliances.
  4. Advanced Control technologies are devices and algorithms that enable rapid diagnosis of and precise solutions to specific grid disruptions or outages. These technologies rely on and contribute to each of the other four key areas. Three technology categories for advanced control methods are: distributed intelligent agents (control systems), analytical tools (software algorithms and high-speed computers), and operational applications (SCADA, substation automation, demand response, etc.).
  5. Improved Interfaces and Decision Support provide operators and managers with the tools and training required to operate a smart grid. They convert complex data into easily understood information for decision making. Technologies include visualization techniques that reduce large quantities of data into easily understood visual formats, software systems that provide multiple options when systems operator actions are required, and simulators for operational training and “what-if” analyses.

[edit] How Does a Smart Grid Get Built?

The Smart Grid is ready to be built now. Deploying Smart Grid to the entire United States and other countries will, however, take place over several years as the system evolves through the incremental deployment and integration of “Smart Grid” technology. For example, a utility might change out its conventional electro-mechanical house meters with solid state, two-way communicating meters. These advanced meters will provide enhanced service to customers while providing the utility with new capabilities for operating and maintaining the grid. Installing advanced meters is one step in a utility’s evolution towards a smart grid. But before a utility installs an advanced metering system, or any type of smart system, it must make a business case for the investment. Most utilities find it difficult to justify installing a communications infrastructure for a single application (e.g. meter reading). Because of this, a utility typically must identify several applications that will use the same communications infrastructure – for example, reading a meter, monitoring power quality, remote connection and disconnection of customers, enabling demand response, etc. Ideally, the communications infrastructure will not only support near-term applications, but unanticipated applications that will arise in the future. Regulatory or legislative actions can also drive utilities to implement pieces of a smart grid puzzle. Each utility has a unique set of business, regulatory, and legislative drivers that guide its investments. This means that each utility will take a different path in creating its smart grid and that different utilities will create smart grids at different rates.

Austin Energy has been working on building its smart grid since 2003, when it first replaced 1/3 of its manual meters with smart meters. Since then, the company has build and service oriented architechture to connect all major systems, deployed mobile wireless technology for its workers, and replaced a significant amount of legacy systems. Most recently, in January of 2008 it signed an expansion agreement to replace the remaining 2/3 of its manual meters with smart meters by December of 2008. Currently managing about 200,000 devices real-time (smart meters, smart thermostats, and sensors across its service area), Austin Energy is years ahead of most utilities in uderstanding how to build an enterprise architecture, how to manage the data, which systems can use the data, and in creating programs for users of its services. By Q1 of 2009, Austin Energy will be have the first smart grid ever built and be managing over 500,000 devices real-time.

http://www.cellnethunt.com/pdf/NR_AustinEnergyAgreement08.pdf http://www.smartgridnews.com/artman/publish/Industry/Austin_Energy_Delivers_Opportunity.html http://nextgenpe.com/currentissue/article.asp?art=273073&issue=244

In the spring of 2008, Xcel Energy announced its plans to build the first fully integrated "Smart Grid City" in the nation in Boulder, Colorado. Xcel's webpage on the project is available at: http://www.xcelenergy.com/XLWEB/CDA/0%2c3080%2c1-1-1_15531_43141_46932-39884-0_0_0-0%2c00.html.

[edit] R&D Programs

IntelliGrid – Created by the Electric Power Research Institute (EPRI), IntelliGrid is a vision of the future electric delivery system. The IntelliGrid Consortium is a public/private partnership that integrates and optimizes global research efforts, funds technology R&D, works to integrate technologies, and disseminates technical information.[10] IntelliGrid architecture provides methodology, tools, and recommendations for standards and technologies for utility use in planning, specifying, and procuring IT-based systems, such as advanced metering, distribution automation, and demand response. The architecture also provides a living laboratory for assessing devices, systems, and technology. Several utilities have applied IntelliGrid architecture including Southern California Edison, Long Island Power Authority, Salt River Project, and TXU Electric Delivery.

Modern Grid Initiative (MGI) is a collaborative effort between the U.S. Department of Energy (DOE), the National Energy Technology Laboratory(NETL), utilities, consumers, researchers, and other grid stakeholders to develop a common, national vision to modernize the U.S. electrical grid. MGI supports demonstrations of key systems and technologies that serve as the foundation for an integrated, modern power grid. DOE’s Office of Electricity Delivery and Energy Reliability (OE) sponsors the initiative, which builds upon Grid 2030 and the National Electricity Delivery Technologies Roadmap and is aligned with other programs such as GridWise and GridWorks.[11]

Grid 2030 – Grid 2030 is a joint vision statement for the U.S. electrical system developed by the electric utility industry, equipment manufacturers, information technology providers, federal and state government agencies, interest groups, universities, and national laboratories. It covers generation, transmission, distribution, storage, and end-use.[12] The National Electric Delivery Technologies Roadmap is the implementation document for the Grid 2030 vision. The Roadmap outlines the key issues and challenges for modernizing the grid and suggests paths that government and industry can take to build America’s future electric delivery system.[13]

GridWise – A DOE OE program focused on developing information technology to modernize the U.S. electrical grid. Working with the GridWise Alliance,the program invests in communications architecture and standards; simulation and analysis tools; smart technologies; test beds and demonstration projects; and new regulatory, institutional, and market frameworks. The GridWise Alliance is a consortium of public and private electricity sector stakeholders, providing a forum for idea exchanges, cooperative efforts, and meetings with policy makers at federal and state levels.[14]

GridWise Architecture Council (GWAC) was formed by the U.S. Department of Energy to promote and enable interoperability among the many entities that interact with the nation’s electric power system. The GWAC members are a balanced and respected team representing the many constituencies of the electricity supply chain and users. The GWAC provides industry guidance and tools to articulate the goal of interoperability across the electric system, identify the concepts and architectures needed to make interoperability possible, and develop actionable steps to facilitate the interoperation of the systems, devices, and institutions that encompass the nation’s electric system.

GridWorks – A DOE OE program focused on improving the reliability of the electric system through modernizing key grid components such as cables and conductors, substations and protective systems, and power electronics. The program’s focus includes coordinating efforts on high temperature superconducting systems, transmission reliability technologies, electric distribution technologies, energy storage devices, and GridWise systems.[15]

[edit] The Future and the Consumer

Evidence of changing consumer attitudes comes via a survey conducted in the summer of 2007. The survey interviewed almost 100 utility executives and sought the opinions of 1900 households and small businesses from the U.S., Germany, Netherlands, England, Japan and Australia [16]. The results are quite revealing. One finding: Consumers are awakening to the concept of choice, and they welcome it. Consider these examples:

  1. 83% of those who cannot yet choose their utility provider would welcome that option
  2. Roughly two-thirds of the customers that do not yet have renewable power options would like the choice
  3. Almost two-thirds are interested in operating their own generation, provided they can sell power back to the utility

The real-time, two-way communications that would be available with a true Smart Grid will enable consumers to be compensated for their efforts to save energy and to sell energy back to the grid through net-metering. By enabling distributed generation resources like residential solar panels, small wind and plug-in hybrid electric vehicles, smart grid will spark a revolution in the energy industry by allowing small players like individual homes and small businesses to sell power to their neighbors or back to the grid. The same will hold true for larger commercial businesses that have renewable or back-up power systems that can provide power for a price during peak demand events, typically in the summer when air condition units place a strain on the grid. This participation by smaller entities has been called the "democritization of energy" -- it is similar to former Vice President Al Gore's vision for Smart Grid.

[edit] Footnotes

  1. ^ U.S. Energy Independence and Security Act of 2007. Retrieved on 2007-12-23.
  2. ^ Energy Future Coalition, “Challenge and Opportunity: Charting a New Energy Future,” Appendix A: Working Group Reports, Report of the Smart Grid Working Group. http://www.energyfuturecoalition.org/pubs/app_smart_grid.pdf
  3. ^ Energy Future Coalition, “Challenge and Opportunity: Charting a New Energy Future,” Appendix A: Working Group Reports, Report of the Smart Grid Working Group. http://www.energyfuturecoalition.org/pubs/app_smart_grid.pdf
  4. ^ Mazza, Patrick, “The Smart Energy Network: Electricity’s Third Great Revolution,” c. 2003. http://climatesolutions.org/pubs/pdfs/SmartEnergy.pdf
  5. ^ Global Environment Fund, Center for Smart Energy, “The Emerging Smart Grid: Investment and Entrepreneurial Potential in the Electric Power Grid of the Future,” October 2005. http://www.globalenvironmentfund.com/GEF%20white%20paper_Electric%20Power%20Grid.pdf
  6. ^ EnergyAxis LAN 900MHz Frequency-hopping spread spectrum (FHSS) radio
  7. ^ McMaster University Sustainable Developments in Communities Workshop November 26, 2007
  8. ^ A3 ALPHA Meter/Collector Data Sheet
  9. ^ U.S. Department of Energy, National Energy Technology Laboratory, Modern Grid Initiative, http://www.netl.doe.gov/moderngrid/opportunity/vision_technologies.html
  10. ^ Electric Power Research Institute, IntelliGrid Program, http://www.epri.com/IntelliGrid/default.asp.
  11. ^ U.S. Department of Energy, National Energy Technology Laboratory, http://www.netl.doe.gov/moderngrid
  12. ^ U.S. Department of Energy, Office of Electric Transmission and Distribution, “Grid 2030” A National Vision for Electricity’s Second 100 Years, July 2003, http://www.oe.energy.gov/DocumentsandMedia/Elec_Vision_2-9-4.pdf.
  13. ^ U.S. Department of Energy, Office of Electric Transmission and Distribution, “National Electric Delivery Technologies Roadmap,” http://www.oe.energy.gov/DocumentsandMedia/ER_2-9-4.pdf.
  14. ^ U.S. Department of Energy, Office of Electricity Delivery and Energy Reliability, http://www.electricdistribution.ctc.com/index.htm; GridWise Program fact sheet, http://www.electricdistribution.ctc.com/pdfs/GridWise%20Fact%20Sheet%20Jan05.pdf; and GridWise Alliance, http://www.gridwise.org.
  15. ^ U.S. Department of Energy, Office of Electricity Delivery and Energy Reliability, http://www.oe.energy.gov/randd/gridworks.htm
  16. ^ 2007 IBM Energy and Utilities Global Residential/Small Business Consumer Survey http://www-03.ibm.com/industries/utilities/doc/content/landingdtw/3165578119.html?g_type=pspot

[edit] External links