A ccording to EIA data, national, annual electricity transmission and distribution losses average about 7% of the electricity tha t is transmitted in the United States.
EIA has estimates for total annual losses related to electricity transmission and distribution (T&D) and other losses in the State Electricity Profiles

. National level data are in the U.S. Total Profile (see link a bottom left of the Profiles page). The data are in "Table 10: Sup ply and Disposition of Electricity" of each Profile; scroll down each Profile page to find Table 10 and see the row for Estimated Losse s in the Table.

To calculate T&D losses as a percentage, divide Estimated Losses by the result of Total Disposition minus Direct Use. Direct Us e electricity is electricity that is generated at facilities that is not put onto the electricity transmission and distribution g rid, and therefore does not contribute to T&D losses.

Last updated: June 15, 2011



### Other FAQs about Electricity Can I choose the electricity supplier where I live? Can I generate and sell electr icity to an electric utility? Does EIA have city or county-level energy consumption and price data? Does EIA have data on peak and hourly electricity demand? Does EIA have electricity prices by State? Does EIA have information on the service territories of U.S. electric utilities? Does EIA have maps or information on the location of electric power plants and transmission lines? Does EIA publish electric utility rate, tariff, and demand charge data? How is electricity used in U.S. homes? How many and what kind of power plants are there in the United States? How many nuclear power plants are in the U.S. and where are they located? How many smart meters are installe d in the U.S. and who has them? How much coal, natural gas, or petroleum is used to generate a kilowatt-hour of electricity? How much does it cost to build different types of power plants in the United States? How much does it cost to generate electricity with different types of power plants? How much electricity does a typi cal nuclear power plant generate? How much electricity does an American home use? How much electricity is lost in transmissi on and distribution in the United States? How much electricity is used for cooling in the United States? How much electricity is used for lighting in the United States? How much energy is consumed in the world by each sector? How old are U.S. power plants? What is U.S. electricity generation by energy source? What is a capacity factor? What is the difference between electricity gen eration capacity and electricity generation? What is the efficiency of different types of power plants? How much electricity is lost in transmission and distribution in the United ... http://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3

1 of 2 6/27/2012 10:01 A MWhat is the outlook for home hea ting fuel prices this winter? What percentage of world energy consumption and el ectricity generation comes from renewable energy? How much electricity is lost in transmission and distribution in the United ... http://www.eia.gov/tools/faqs/faq.cfm?id=105&t=3

2 of 2 6/27/2012 10:01 A MU.S. Climate Change Technology Program – T echnology Options for the Near and Long Term November 2003 – Page 34 

### 1.3.2 TRANSMISSION AND DISTRIBUTION TECHNOLOGIES Technology Description The electric utility industry is restructuring itself from a regulated environment to operation under competitive wholesale electricity markets. However, the electric transmission and distribution (T&D) systems remain regulated entities that connect deregulated generation to the end-use customer. Construction of U.S. transmission above 230 kV is expected to increase by only 6% (in line-miles) during the next 10 years, while demand is expected to increase more than 20%. The resulting increase in the intensity of use of existing facilities will increase energy losses and transmission congestion, and is likely to cause grid reliability problems and threaten the continued growth of wholesale electricity trade. Energy losses in the U.S. T&D system were 7.2% in 1995, accounting for 2.5 quads of primary energy and 36.5 MtC. Losses are divided such th at about 60% are from lines and 40% are from transformers (most of which are for distribution). Technologies that can im prove efficiency and redu ce carbon emissions are highvoltage DC (HVDC) transmission, high-strength compos ite overhead conductors, and power transformers and underground cables that use high-temperature superconducto rs (see related technology profile). High-efficiency conventional transformers also could have significant im pacts on distribution system losses. In addition, energy storage and real-time system monitoring and control systems could improve system reliability and customer access to competitive generation, including renewable pow er producers. There is no active U.S. program for HVDC development or improved dist ribution transformer technologies. System Concepts

• Composite-core, low-sag transmission conductors can transport two to three times as much power as conventional conductors over the same righ ts-of-way and with no tower modifications.

• Energy storage will facilitate more optimal use of exis ting infrastructure and increase the dispatchability of renewable resources.

• Real-time grid operations using measured data a nd automatic, intelligent controllers can improve T&D reliability – and lead to a smart, switchable future ne twork that can anticipate and respond automatically to system contingencies. System Components

• One advanced composite overhead conductor consists of an aluminum metal matrix composite core (replacing the steel core of a conventional cable) surrounded by temperature-resistant aluminum alloy wires.

• Several large- and medium-scale energy-storage system s, using different electrochemistries, have been developed.

• Real-time control uses wide-area measurement system s, synchronized by global positioning system (GPS) satellite clocks that feed system information to artific ial neural net controllers. The controllers reconfigure the system in real time, preventing outages and a llowing maximum use of available transmission capacity

. 

### Technology Status/Applications

• Aluminum composite-core conductors, terminations, and suspensions have been developed by 3M Company and demonstrated in the field by leading U.S. and European utilities. Additional field trials in the United States and accelerated thermal c y clin g tests are p lanned in 2003-2005. This extensive mechanicalU.S. Climate Change Technology Program – T echnology Options for the Near and Long Term November 2003 – Page 35 

### and electrical testing is required to predict the 40-y ear life responses of this new conductor technology. Niche applications including long-s pan river crossings and short lead-time reconductoring over congested existing rights-of-way are now cost-effective. In a ddition, the conductor’s core has 25% lower electrical resistances than steel, enabling hi gher transmission efficiencies.

• Large-scale energy-storage systems ar e entering field demonstrations.

• Wide-area measurement systems used for monitoring, ev ent analysis, and system model studies have been deployed in the Western United States power grid to help analyze system disturbances. Current Research, Development, and Demonstration RD&D Goals

• Accelerated thermal-cycle testing for 3M’s composite conductor in 2003-2005. Field-testing of this conductor began in 2002 on a 230kV transmission lin e on DOE’s Western Area Power Administration grid. Other advanced conductors are expected to unde rgo similar high-current and field tests in 2003-2006.

• Demonstration of the reliability of energy-storage syst ems, and reduction of the cost of such systems by 30%.

• Operation of a prototype smart, switchable grid on a region on the U.S. transmission grid by 2010. The market for conventional utility-control systems approaches $300 M/year. RD&D Challenges

• Development of large-diameter composite conductors fo r high-voltage transmission lines that are both lowcost and high capacity, so as to yield the highest payoffs in grid reliability and competitive market efficiency.

• Energy-storage systems with reduced costs that can meet several applications while using a single system.

• Neural net networks that can be trained in paralle l to perform control functions in real-time control systems.
• A regulatory framework that will allow investors to ma ke credible projections of the return on investment in new transmission capacity. RD&D Activities

• For composite conductors, 3M Company cost-share d on a DOE effort in FY2002 and FY2003 to perform field tests and accelerated, controlled ther mal tests on several conductor sizes.

• DOE is cost-sharing an energy-storage effort with industry. EPRI has a newly reformed energy storage target. Recent Successes

• DOE’s National Transmi ssion Grid Study , released in May 2002, examined issues surrounding U.S. transmission system upgrades and expansion, and c ontains 51 recommendations for actions to remove constraints on the U.S. transmission grid.

• Real-time monitoring tools have been developed by DOE and installed in California with funding by the California Energy Commission, and at the North Ameri can Electric Reliability Council (NERC) to monitor and display voltage and frequency over wide areas.

• Demand response (DR) projects are a ssisting independent transmission sy stem operators (ISOs) with DR program design, and identifying DR capabilities to respond to markets for energy and contingency
reserves. Commercialization and Deployment Activities

• Commercial deployment of high-current composite conductors awaits U.S. field trial results, and manufacturing cost reductions for all but high-value niche applications.GridWorks: Overview of the Electric Grid http://www.energetics.com/gridworks/grid.html

1 of 2 11/15/2007 12:28 PM Overview of the Electric Grid

Electric power is essential to modern society. Economic prosperity, national security, and public health and safety cannot be achieved without it. Communities that lack electric power, even for short periods, have trouble meeting basic needs for food, shelter, water, law, and order. In 1940, 10% of energy consumption in America was used to produce electricity. In 1970, that fraction was 25%. Today it is 40%, showing electricity's growing importance as a source of energy supply. Electricity has the unique ability to convey both energy and information, thus yielding an increasing array of products, services, and applications in factories, offices, homes, campuses, complexes, and communities. The economic significance of electricity is staggering. It is one of the largest and most capital-intensive sectors of the economy. Total asset value is estimated to exceed $800 billion, with approximately 60% invested in power plants, 30% in distribution facilities, and 10% in transmission facilities. Annual electric revenues - the Nation's "electric bill" - are about $247 billion, paid by America's 131 million electricity customers, which includes nearly every business and household. The average price paid is about 7 cents per kilowatt-hour, although prices vary from state to state depending on local regulations, generation costs, and customer mix.
There are more than 3,100 electric utilities: 213 stockholder-owned utilities provide power to about 73% of the customers 2,000 public utilities run by state and local government agencies provide power to about 15% of the customers 930 electric cooperatives provide power to about 12% of the customers Additionally, there are nearly 2,100 non-utility power producers, including both independent power companies and customer-owned distributed energy facilities. The bulk power system consists of three independent networks: Eastern Interconnection, Western Interconnection, and the Texas Interconnection. These networks incorporate international connections with Canada and Mexico. Overall reliability planning and coordination is provided by the North American Electric Reliability Council, a voluntary organization formed in 1968 in response to the Northeast blackout of 1965.

Electric Generation America operates a fleet of about 10,000 power plants. The average thermal efficiency is around 33%. Efficiency has not changed much since 1960 because of slow turnover of the capital stock and the inherent inefficiency of central power generation that cannot recycle heat. Power plants are generally long-lived investments; the majority of the existing capacity is 30 or more years old. The roughly 5,600 distributed energy facilities typically combine heat and power generation and achieve efficiencies of 65% to 90%. Distributed energy facilities accounted for about 6% of U.S. power capacity in 2001. The profile of the electric power generation industry is changing rapidly, however. A shift in ownership is occurring from regulated utilities to competitive suppliers. The share of installed capacity provided by competitive suppliers has increased from about 10 percent in 1997 to about 35 percent today. Recent data suggest this trend is slowing. Also, cleaner and more fuel-efficient power generation technologies are becoming available. These include combined cycle combustion turbines, wind energy systems, advanced nuclear power plant designs, clean coal power systems, and distributed energy technologies such as photovoltaics and combined heat and power systems. Because of the expected near-term retirement of many aging plants in the existing fleet, growth of the information economy, economic growth, and the forecasted growth in electricity demand, America faces a significant need for new electric power generation. In this transition, local market conditions will dictate fuel and technology choices for investment decisions, capital markets will provide the financing, and Federal and state policies will affect siting and permitting. It is an enormous challenge that will require a large commitment of technological, financial, and human resources in the years ahead.

Electric Transmission Even with adequate electric generation, bottlenecks in the transmission system interfere with the reliable, efficient, and affordable delivery of electric power. America operates about 157,000 miles of high voltage (>230kV) electric transmission lines. While electricity demand increased by about 25% since 1990, construction of transmission facilities decreased about 30%. In fact, annual investment in new transmission facilities has declined over the last 25 years. The result is grid congestion, which can mean higher electricity costs because customers cannot get access to lower-cost electricity supplies, and because of higher line losses. Transmission and distribution losses are related to how heavily the system is loaded. U.S.-wide transmission and distribution losses were about 5% in 1970, and grew to 9.5% in 2001, due to heavier utilization and more frequent congestion. Congested transmission paths, or "bottlenecks," now affect many parts of the grid across the country. In addition, it is estimated that power outages and power quality disturbances cost the economy from $25 to $180 billion annually. These costs could soar if outages or disturbances become more frequent or longer in duration. There are also operational problems in maintaining voltage levels. America's electric transmission problems are also affected by the new structure of the increasingly competitive bulk power market. Based on a sample of the nation's transmission grid, the number of transactions have been increasing substantially recently. For example, annual transactions on the Tennessee Valley Authority's transmission system numbered less than 20,000 in 1996. They exceed 250,000 today, a volume the system was not originally designed to handle. Actions byGridWorks: Overview of the Electric Grid http://www.energetics.com/gridworks/grid.html

2 of 2 11/15/2007 12:28 PM transmission operators to curtail transactions for economic reasons and to maintain reliability (according to procedures developed by the North American Electric Reliability Council) grew from about 300 in 1998 to over 1,000 in 2000. Additionally, significant impediments interfere with solving the country's electric transmission problems. These include: opposition and litigation against the construction of new facilities, uncertainty about cost recovery for investors, confusion over whose responsibility it is to build, and jurisdiction and government agency overlap for siting and permitting. Competing land uses, especially in urban areas, leads to opposition and litigation against new construction facilities.

Electric Distribution The "handoff" from electric transmission to electric distribution usually occurs at the substation. America's fleet of substations takes power from transmission-level voltages and distributes it to hundreds of thousands of miles of lower voltage distribution lines. The distribution system is generally considered to begin at the substation and end at the customer's meter. Beyond the meter lies the customer's electric system, which consists of wires, equipment, and appliances - an increased number of which involve computerized controls and electronics which ultimately operate on direct current. The distribution system supports retail electricity markets. State or local government agencies are heavily involved in the electric distribution business, regulating prices and rates-of-return for shareholder-owned distribution utilities. Also, in 2, 000 localities across the country, state and local government agencies operate their own distribution utilities, as do over 900 rural electric cooperative utilities. Virtually all of the distribution systems operate as franchise monopolies as established by state law. The greatest challenge facing electric distribution is responding to rapidly changing customer needs for electricity. Increased use of information technologies, computers, and consumer electronics has lowered the tolerance for outages, fluctuations in voltages and frequency levels, and other power quality disturbances. In addition, rising interest in distributed generation and electric storage devices is adding new requirements for interconnection and safe operation of electric distribution systems. Finally, a wide array of information technology is entering the market that could revolutionize the electric distribution business. For example, having the ability to monitor and influence each customer's usage, in real time, could enable distribution operators to better match supply with demand, thus boosting asset utilization, improving service quality, and lowering costs. More complete integration of distributed energy and demand-side management resources into the distribution system could enable customers to implement their own tailored solutions, thus boosting profitability and quality of life.
Summary North America's world-class electric system is facing several serious challenges. Major questions exist about its ability to continue providing citizens and businesses with relatively clean, reliable, and affordable energy services. The recent downturn in the economy masks areas of grid congestion in numerous locations across America. These bottlenecks could interfere with regional economic development. The "information economy" requires a reliable, secure, and affordable electric system to grow and prosper. Unless substantial amounts of capital are invested over the next several decades in new generation, transmission, and distribution facilities, service quality will degrade and costs will go up. These investments wil l involve new technologies that improve the existing electric system and possibly advanced technologies that could revolutionize the electric grid. For additional information, please refer to the Electricity Delivery System fact sheet ( PDF 897 KB ). Download Adobe Reader

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