Electricity is generated at various kinds of power plants, wind and solar farms by utilities and independent power producers. The vital link between power production and power usage, transmission lines carry electricity at high voltages over long distances from power plants to communities. This is what ATC does. Electricity from transmission lines is reduced to lower voltages at substation. Distribution companies then bring the power to your workplace and home.
Because electricity cannot be stored, it must be generated, transmitted and distributed at the moment it is needed. The high-voltage transmission grid is the vital link between power plants that generate electricity and the people who need it.
Communication systems must be able to handle a wide range of speed and data flow requirements, and the switching network and distributed database will have to be designed. Although similar systems exist today e. Such a communications system should be ready for deployment by , possibly continuing into the — time period. For a sense of scale, each of the approximately control centers in the Eastern Interconnection oversees about high-voltage substations on average.
Each substation shown on the right takes measurements that are collected by its own data-gathering system. These measurements are communicated internally by a local area network LAN. A substation server communicates these data to the rest of the system through a high-speed network of switching routers shown as circles that can move the data efficiently as needed to specific monitoring and control applications.
Measurement and communication technologies create a picture of the state of the systems, which control technology can use for greater reliability and security including self-healing following a disruption and more efficient operation and optimization of assets.
This will enable the evolution of better controls to make the grid increasingly reliable and efficient. In contrast, FACTS devices already in use as fast local controllers can control voltages and power flows with response times measured in milliseconds. Moreover, fast wide-area controls, combining rapid communications with remotely controlled FACTS devices, are becoming feasible. Time-stamped measurements will make multiple inputs available to the controller, which can then send out multiple output signals to several FACTS controllers simultaneously.
With these technologies, many types of grid monitoring and control will become possible. Cascading failures can be predicted, and defensive actions such as islanding can prevent the spread of the disturbance. Advanced distribution controls can accommodate two-way power flow from distributed generation by balancing the load on all the distribution feeders.
In addition, demandside responses can be efficiently coordinated if appropriate sensors and communications are in place. Such control technologies could begin to be deployed by Measurement, communications, and control technologies are already being deployed to a modest degree and could be fully deployed by About 15, transmission substations will require new sensors, measurement systems, and LANs.
To add high-bandwidth communications hardware mainly fiber-optic cables across the transmission system of approximately , miles of network and 20, switches, investment in both hardware and software will be needed. The costs of developing the needed software to operate the hardware for control will be significant. Technologies for distribution systems are different in character from transmission. Sensing, monitoring, and communications technologies will need to be.
These controls will be particularly important as smart metering is introduced into distribution networks. Additional investment will also be needed for coordination between transmission level-controls and distribution-level controls. These tools need to be further improved because of the massive amounts of data that are available in real time and the need to use these data in system control. This section examines improved decision-support technology IDST , including those tools necessary for split-second decision making by system operators during emergencies as well as for long-term decision making on investments needed in the grid itself.
A recurring theme in blackout investigations has been the need for better visualization capabilities and decision-support tools over a wide geographic area. In many circumstances, a human operator will require at least some seconds to make a decision, but automatic controls operate on the order of milliseconds.
IDST enables grid operators and managers to make faster decisions by converting the complex power-system data into information that can be understood at a glance.
Improved visualization interfaces and decision-support technologies will increase reliability, decrease outages due to natural causes and human error, and enhance asset management. Grid visualization. Real-time analysis of system stability will require online analytical tools that process the vast amount of data and automatically determine what actions should be taken to prevent an incipient disturbance from spreading.
This objective requires completing the analysis within a fraction of a second and presenting it visually in a control room for fast responses to deteriorating conditions. The algorithms have not yet been developed to perform these functions, but they could be deployed by and would be continually improved in the — timeframe and beyond.
Decision support. Decision-support technologies can identify existing, emerging, and predicted problems and provide analysis to support solutions. By analyzing the consequences of each contingency and its probability of occurrence, decision-support systems can quantify relative risk and severity. These relative risks can be integrated into a composite risk factor and presented to the operator to assist in decision making.
Further work on decision-support algorithms will be needed to make them available for deployment before , with continuing improvements in the — timeframe and beyond. Systems operator training. Advanced simulators currently under development will give operators a real-time, faster-than-real-time, or historic view of the power system and its parameters.
These dynamic simulators, together with industry-wide certification programs, will significantly improve the skill sets and performance of system operators. Such simulators could be ready for deployment by , as soon as the visualization and decision-support algorithms are in place. IDST, together with system-operator training, will then need to be continuously evaluated and improved. Improved software and artificial intelligence for IDST could begin to be deployed by , and deployment is likely to continue into the — timeframe.
Decision tools are also needed for decisions that occur over longer timescales than do real-time operating decisions. Decisions include forecasting the load, scheduling dispatchable generation and long-term contracts to meet the load, conducting auction markets, using power contracts to check on possible congestion on the transmission system, and modifying the power contracts if congestion is indicated.
The decision tools needed for these tasks are mostly new or have been significantly modified in recent years. Longer-term planning for new generation and transmission capacity must deal with considerable uncertainty, especially where the industry has been restructured and no one organization holds the ultimate responsibility for building adequate generation.
Transmission is still regulated, but transmission planning is dependent on knowing where the new generating plants are going to be located. Computerized planning decision tools must be improved to handle increased uncertainty for the to year time horizon.
It is anticipated that renewables will present unique challenges, and the addition of probabilistic methods not in use today may help system operators respond to the changing generation mix. The two tool sets should be seamlessly coordinated with one another and connected to the operations and operations-planning databases so that customer trouble calls can be coordinated with maintenance crews, spare part inventories, and system operations.
Several major conditions must be met before IDST can be effectively implemented. First, modern measurement, communications, and control technologies must be implemented along with the power electronics technologies needed to enable automated controls. In addition, development is needed in applications that integrate advanced visualization technologies with geospatial tools to improve the speed of comprehension and decision making.
Some of these technologies could begin to be implemented well before The key technologies discussed above are in various stages of development, with many already having been deployed in a limited way. However, the primary challenge will be the integrated deployment of these technologies to achieve the desired characteristics and performance of a modern grid.
For example, the capabilities of power electronics would be maximized by coupling them with real-time measurement, communications, control, and decision-support tools. All these technologies can be improved upon and would benefit from cost reduction.
A few, such as large-scale storage, are simply impractical now. In addition, the nation is facing a critical shortage of power engineers, the very people who will be needed to implement modernization. Projecting the costs of modernizing the U. First, EPRI projected that superconducting cables would be added to the system over the next 20 years, but the committee concluded that high costs and slow technological development would preclude commercial deployment before In addition, recent real escalation in materials and construction costs were accounted for by using the national average transmission and distribution indexes 33 percent for transmission, 40 percent for distribution.
These changes are described in Annex 9. The investment in superconducting cables has been removed from the total investment needed for the transmission system. It has also been removed from the synergies calculation. These changes are described in detail in Annex 9. For example, existing lines could carry greater loads if improved control systems prevented overloading, so some new lines would not be needed. Estimated costs in the two studies are very similar.
Neither report explicitly accounted for the construction of new transmission lines to bring power from remote wind or other renewable energy sources to load centers. These lines could be longer than those from conventional power sources and carry power at a lower capacity factor, thus increasing costs.
According to a DOE report on achieving 20 percent of U. Actual expenditures will be highly dependent on the routes chosen and the capacities of the lines, but additional costs on the order of tens of billions of dollars seem plausible. Large-scale power generation from photovoltaics or solar thermal technology is a longer-term possibility if cost reductions are achieved.
Much of this power. A comparison between these two studies is made in more detail in Annex 9. Construction of such lines will depend on the regulatory environment and government policy; the transmission technology is available, although further improvements would be beneficial. Representatives of EPRI and the Edison Electric Institute EEI , which funded the Brattle study, have suggested that the split would be approximately one-third during the first 10 years and the remaining two-thirds over the second 10 years.
If modernization were not included, however, utilities would have to continue using existing technologies for control, sensing, and monitoring equipment, and the nation would be deprived of the many benefits discussed here. Costs to consumers could be reduced through more efficient electricity markets; national security could be.
On a more local scale, a recent study by the University of San Diego considered the value of a modern distribution system to the San Diego area. The following sections, however, provide some specific examples of potential benefits from modernizing the system. EPRI estimates the annual cost of power disturbances to the U. Thus improving grid reliability and efficiency could result in substantial economic benefits. These energy price signals will allow customers to more effectively participate in the electricity market, based on current supply-and-demand influences.
Overall, markets will be more efficient when consumer decisions are based on realistic prices. There will also be a reduction in grid congestion and forced power outages. A modernized grid will enable a wide array of new options for load management, distributed generation, energy storage, and. In addition, the ability to handle a high level of electricity generated from domestic renewable energy sources has national security benefits as well as the environmental benefits discussed in the next section.
Moreover, sophisticated analytical capabilities can detect and prevent or mitigate the consequences of an attack or disaster, and probabilistic analytical tools can identify inherent weaknesses in the grid so that they can be integrated into an overall national security plan. Guidelines for cyber-security are already in place , but these may not be adequate for a fully deployed communications and control system. Cyber-security has to be an integral part of modernizing the grid.
A modern grid could improve the diversity of energy supplies by allowing larger proportions of renewable energy into the U. Natural gas is also a concern because projected rates of consumption may lead to importing increased amounts of liquefied natural gas, some from politically unstable areas of the world.
Little oil is used for electric generation, but the modern grid will reduce oil imports by helping to make electric vehicles commercially viable. Modernizing the power delivery system is an essential step in reducing emissions of carbon dioxide and other pollutants such as SO x , NO x , and mercury:.
Self-generation refers to electricity generation that the end user owns and controls. See Chapter 6 for further discussion.
Modern demand-response technologies such as grid-friendly appliances that can be controlled by the utility to shift load to off-peak times can be better accommodated, thereby reducing demand that must be met by inefficient generating equipment.
Battery electric vehicles BEVs can be better accommodated, particularly after The electricity provided by wind power varies significantly over the course of a day and over the year because of natural variations in wind speed.
As a general rule, a power-delivery system can handle the loss of 10—20 percent of the local generating capacity as long as adequate reserve capacity is available. Because intermittent sources cannot be depended on, the spinning reserve has to include a significant fraction of the renewable capacity in addition to the largest unit of conventional power.
Self-generation is a special case of distributed generation. End users generate some portion of their own energy needs, utilizing, for example, rooftop solar panels. Under some conditions, any excess power may be sold to the utility. Grid modernization is not needed for integrating intermittent renewable-electricity sources in relatively small percentages of the overall electricity supply.
This is discussed in greater detail in Chapter 6. Wind and solar power are the main intermittent renewable-energy sources. Other renewables, such as hydropower, geothermal, and biofuels, are not intermittent. The changes needed to accommodate renewables are discussed in more detail in the technology section of this chapter; they involve large-scale storage as well as high-voltage long-distance transmission.
Many high-quality renewable resources, such as wind in the Dakotas and solar resources in the deserts of the Southwest, are located far from population centers. More transmission capacity will be required to bring electricity from these locations to areas of high demand, potentially using technologies such as HVDC transmission. Other low-emission and renewable resources are likely to be used as distributed generation e.
The modern grid will enable better integration of these resources by incorporating two-way power flow and smart metering on the distribution system. Many modern demand-response technologies can be regulated in response to grid conditions. With the implementation of time-of-day pricing, such technologies could allow for more cost-effective and efficient electric power generation i. With the addition of such technologies, the impact on the grid could also be small even by A modern grid can operate more efficiently, reducing the need for construction of new generators and transmission lines.
Approximately 10 percent of the total power produced in the United States is lost in the process of delivering it to the end user. For example, reactive power flow over a transmission line not only increases losses in the transmission line but also significantly reduces the power-carrying capacity of the line; the use of power electronics, however, can reduce such flow of reactive power. In addition, power electronics can reduce losses by shifting power flow to the most advantageous transmission paths and by the use.
Plug-in hybrid vehicles are discussed in further detail in Chapter 4. The American Public Power Association reports that about fatalities and flash burns occur annually in the electric utility business Trotter, Improved monitoring and decision-support systems would quickly identify problems and hazards. For example, the ability to identify equipment that is on the verge of failure is certain to save lives and reduce severe injuries.
In addition, by reducing the risk of long-term outages following terrorist attacks or natural disasters, modernization could help prevent public health and safety catastrophes. The benefits would be substantial and quite likely to far outweigh the costs.
Nevertheless, modernization is unlikely to happen unless it is also in the interests of those who must implement it. Several barriers have the potential to impede this implementation.
First, the technologies that utilities would employ to modernize the grid entail additional costs and uncertainties—particularly regarding how well they will work relative to older technologies. Second, some utilities may be reluctant to invest the additional funds required for modernization even when it would appear to make sense to do so. Third, there is a lack of regulatory and political support that could provide incentives for modernization.
Finally, there is difficulty in communicating the need for modernization to the public and to regulatory and political decision makers. In January , a DOE standard will take effect requiring higher efficiency in all new distribution transformers. The DOE estimates that between and the energy saved by this measure will be equivalent to the energy used by 27 million households in the United States in a single year.
Given the expected life of distribution transformers, 5 percent are expected to be replaced each year under this new standard DOE, Yet the rate of technology research, development, and deployment in the power industry is low compared to that of other industries. Also, modernization technologies must be deployed in unison to achieve their full benefits, posing challenges in integrating technologies. For example, universal communications standards as well as a common architecture that promotes interoperability are needed.
However, the security issues that are involved in an open system must be met with industry-approved and -adapted standards and protocols. Modernization will cost more than simply building more transmission lines and replacing aging equipment. Even though the additional investment would eventually pay off, financial markets and regulatory constraints drive utilities to minimize investments.
The companies, however, must bear the full cost of modernizing the parts of the grid that serve their customers. This barrier is more significant for the transmission system, which is inherently interconnected: many entities own and regulate different parts of it. Cooperation will be needed among utilities and regulatory agencies. As noted above, utilities are cautious about adopting new technologies that may involve some risk. This is especially true when familiar technologies have lower first costs and utilities are given no incentive to invest more than the minimum required to maintain operations.
If modernization is to occur and produce all the advantages it offers, legal and regulatory changes are likely to be necessary. Legislators and regulators have not taken a strong leadership role regarding grid modernization, nor have they adopted a clear and consistent vision for.
There has been significant focus in recent years on individual technologies and on energy-related issues such as environmental impact, but less attention has been paid to developing a vision that integrates technologies, solves the various grid-related issues, and provides the desired benefits to stakeholders and society.
For example, a wholesale pricing structure that recognizes the value of reliability and signals when transmission system upgrades are necessary would help provide investment predictability. In addition, policies regarding the grid are often inconsistent because they are set by multiple groups—individual states state energy policies and public utility commissions [PUCs] ; the Federal Energy Regulatory Commission FERC ; and environmental agencies.
Inconsistent policies among states and between state and federal regulators, for example, prevent effective collaboration across transmission regions.
Also, time-of-day rates for consumers that reflect actual wholesale market conditions are not yet widely implemented, thereby preventing the level of demand-side involvement needed in the modern grid. Net metering policies that provide customers with retail credit for energy generated by them are also not widely deployed, which reduces the incentive for end users to install rooftop photovoltaics or other generating technologies. Finally, regulatory policies often do not reward customers for investments that provide substantial societal benefits, such as credits for local storage that has been made dispatchable.
Dispatchable energy storage is a set of technologies for storing electricity to be deployed quickly dispatched into the grid when other power sources become unavailable. Some electric utility executives assert that their customers value lower rates more than the benefits of a modernized grid, which would increase costs in the short term NETL, b.
In order to overcome this barrier, significant efforts need to be made to communicate the benefits of a modern grid to all stakeholders. Improved communication with the public is also necessary regarding the costs and benefits associated with the current transmission system in particular, which is experiencing ever increasing congestion and needs expansion. It is difficult to site new transmission lines.
Many proposals for new lines generate considerable opposition, usually based on aesthetic, property value, or health and safety concerns. For example, American Electric Power, a large Midwest utility, recently experienced a year approval process for a new mile kV transmission line.
Many of the technologies needed to modernize the grid can be deployed before , but most of the technical challenges will involve seamlessly integrating these technologies. Not only must multiple technologies work in concert across a huge and sprawling system, but the system is owned and operated by numerous often regional stakeholders with diverse perspectives, incentives, and constraints.
Given these factors, a broad vision and an accompanying road map are required to achieve consensus on common goals and to guide the integrated deployment of modern technologies that meet the performance requirements of the modern grid, as described previously in this chapter. The complexity of the transmission system suggests that the development of clear metrics to measure societal benefits will be essential to measuring progress. The types of metrics that may be considered include reductions in electricity demand forecasting error from 6 percent to, say, less than 0.
These reasons included a redesignation by Congress of 19 miles of the New River in Virginia as wild and scenic, problematic interfaces between the states and federal agencies, and public opposition.
For example, PUCs could look for methods to establish accountability for transmission availability, to measure and internalize the value of lost load and power quality, and to measure and appropriately reward utilities for contributions to efficiency improvement and market transformation.
With such a vision in place, modern technologies could be seamlessly deployed across regions. For example, they would be incorporated whenever new facilities were built, while control centers could be gradually modernized.
Communications and control software, as well as tools for improved decision support, could then begin to be implemented. In contrast, the modernization of distribution systems can occur on a regional level, and programs are emerging in the United States as well as around the world. Pilot projects involving smart meters have begun in many areas.
AEP expects to have all 5 million of its customers on this system by Bjelovuk, Other countries that have already implemented partial distribution-system modernization programs report very positive results.
The key components of the modern grid FACTS devices, custom power, HVDC and HVAC technologies, and storage have largely been developed, as noted earlier, and measurement, communications, and control technologies to manage these components will be deployable on a large scale, along with the associated decision-support tools, before.
Development of a nationwide strategy to modernize the U. Recently, many factors, including changes in the regulatory structure of the power industry, have lowered the reliability of this critical national infrastructure.
However, many technologies capable of meeting these challenges are currently available or will be available before Ad vanced equipment. Many power electronics devices and transmis sion line technologies are currently commercially available and can be deployed before These technologies are not widely deployed at present. Me asurements, communications, and control. Most measurement, com munications, and control technologies are currently available and can begin to be deployed before ; however, software development is still needed.
Further work is needed to establish a standard communications protocol. Such a protocol could be deployable before Improved decision-support tools. Improved decision-support technolo gies could begin to be deployed before ; however, they will require the co-deployment of modern measurements, communications, and controls, as well as power electronics, to be effective.
Further work is needed to develop and implement algorithms for rapid decision making and advanced search and optimization. This software is likely to be deployable before In particular:. Tr ansmission. The modernization of the transmission system will ben efit greatly from a comprehensive national vision based on consensus among the many stakeholders. The transmission system is national in scale, and the major benefits of a modern system come from the operation of many technologies in concert across the entire system rather than from technologies deployed in isolation.
State, regional, and national planning is needed on how the nation will deliver 20 percent of its energy and beyond from renewables, especially wind and solar. If such a vision is established and it addresses the many barriers to modernization, the transmission system could be modernized by Smart meters and related technologies can improve the efficiency and economics of distribution.
Modernization of the distribution system can occur regionally, allowing for rapid parallel deployment while encouraging experimentation to develop best practices. This modernization is already occurring in limited areas; however, it would benefit from a nationwide consensus on best practices such as standardization of communication methods to better enable smart meters and. The distribution systems could be modernized by if such a consensus is reached nationwide. This situation is further compounded by the risk-averse nature of the electric utility industry.
The exclusion of societal benefits such as avoiding costs to the public from widespread blackouts in the return on investment for the transmission system is a barrier to industry investment in modern transmission technologies. Regulatory and legislative. The lack of a comprehensive national vision for the transmission system could form a barrier to transmission mod ernization.
There is limited multiregional planning and coordination of improve ments to the transmission system. Overarching consensus-based standards for grid modernization are necessary but do not currently exist. An open-protocol communications architecture and mechanisms for. Cultural and communications. Active public opposition stemming from environmental or cost concerns could form a barrier to construction of new transmission lines.
To integrate renewable sources such as wind and solar on a large scale, the transmission system will need to accommodate their variability. This objective can be met with backup generation such as gas-fired power plants or by large-scale storage technologies, such as compressed air energy storage CAES. Backup generation or CAES could be deployed before Many renewables are likely to be deployed as distributed generation such as rooftop PV panels , which will require two-way power flow capability.
Transmitting power from high-quality renewable resources to popula tion centers creates economic challenges. These challenges include securing the rights of way for the needed corridors and making a business case for the transmission lines. The level of technology research, development, and deployment in the U.
Washington, D. Centolella, P. Ohio PUC. DOE U. Department of Energy. Federal Register 72 , October Available at www1. Accessed July Electricity Supply. Accessed May 8, Annual Energy Outlook Department of Energy, Energy Information Administration. Palo Alto, Calif. Available at www. Princeton, N. Accessed May 11, A Vision for the Modern Grid.
Nevius, D. Owens, D. San Diego. Trotter, J. Safety programs that work. This annex provides selected additional information to support the material in the main text of Chapter 9.
The first section provides information on reliability measures. CAIDI tracks the average duration typically expressed in minutes of customer interruptions over a given time period. SAIFI tracks the average number of customer interruptions in power service in a given period of time. SAIDI tracks the average number of customer interruptions in power service in a given time period. Results of applying these indexes are shown in Figures 9.
The modern grid must meet the ever expanding needs of society and at the same time be reliable, secure, economic, efficient, environmentally friendly, and safe. Emergency response. A modern grid provides advanced analysis for predicting problems before they occur and assessing problems as they develop. This capability allows actions that respond more effectively and minimize disruptions.
Expressed in minutes, the average SAIDI in the state of Ohio has been holding approximately steady over the last 7 years. As better information, control, and communication tools become available to assist the operators and field personnel of a modern grid, it can be restored much faster and at lower cost. Routine operations. With the help of advanced visualization and control tools, fast simulations, and decision-support systems, the operators of a modern grid can better understand its real-time state and trajectory, provide recommendations for secure operations, and allow appropriate controls to be initiated.
These capabilities could help achieve significant reduction of the system peak-to-average ratio, thereby saving resources. The modern grid provides advanced tools for comprehending conditions, evaluating options, and exerting a wide range of control actions to optimize grid performance, whether from reliability, environmental, efficiency, or economic perspectives. System planning. Grid planners must analyze projected growth in supply and demand to guide their decisions about where to build, what to.
The data-mining and data-modeling capabilities of a modern grid will provide much more accurate information for answering those questions while potentially realizing significant savings. To acquire these characteristics each of which is discussed in turn below , it will not be enough simply to add isolated technologies to the existing system. Technologies will need to be integrated with one another and also have a common basis for communication across regions.
Thus creating a transmission system that displays these characteristics will require a multiregional effort based on consensus among all of the key stakeholders and reflecting a common approach to deployment across the various transmission regions.
Given the regional nature of the distribution system, such a common vision for distribution is less essential. The following is an in-depth discussion of the seven characteristics. The transmission system must be designed to accommodate large baseload generation, such as nuclear and coal, as well as sources that do not typically operate in baseload mode, such as renewables.
In addition, the distribution system must accommodate smaller distributed-energy sources. Large-scale baseload generation resources may require backup generation and, possibly, also power electronics to ensure that power flows are accommodated. Smart devices on transmission and distribution lines and at substations allow a utility to more efficiently manage voltage levels and more easily find out where an outage or other problem is on the system.
Smart grids can sometimes remotely correct problems in the electrical distribution system by digitally sending instructions to equipment that can adjust the conditions of the system.
Construction of electricity infrastructure in the United States began in the early s and investment was driven by new transmission technologies, central station generating plants, and growing electricity demand, especially after World War II.
Now, some of the older, existing transmission and distribution lines have reached the end of their useful lives and must be replaced or upgraded. New power lines are also needed to maintain the electrical system's overall reliability and to provide links to new renewable energy generation resources, such as wind and solar power, which are often located far from where electricity demand is concentrated.
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