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Electricity Monthly Update

With Data for March 2015  |  Release Date: May 28, 2015  |  Next Release Date: June 24, 2015

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Highlights: March 2015

  • Total net generation decreased 2.4% compared to March 2014, as temperatures across the country were well above average during the month, resulting in a decreased demand for heating.
  • The natural gas price for New York City (Transco Zone 6 NY) saw a significant decrease in price from the previous month, going from $15.40/MMBtu in February 2015 to $3.73/MMBtu in March 2014.
  • Hawaii's average revenue per kilowatthour was down 22% from last March as lower world oil prices benefit the state's electricity sector.

Key Indicators

  March 2015 % Change from March 2014
Total Net Generation
(Thousand MWh)
324,248 -2.4%
Residential Retail Price
(cents/kWh)
12.35 0.9%
Retail Sales
(Thousand MWh)
302,108 1.0%
Heating Degree-Days 588 -13.8%
Natural Gas Price, Henry Hub
($/MMBtu)
2.87 -41.5%
Natural Gas Consumption
(Mcf)
740,011 25.6%
Coal Consumption
(Thousand Tons)
58,445 -19.1%
Coal Stocks
(Thousand Tons)
155,564 31.5%
Nuclear Generation
(Thousand MWh)
64,547 3.4%



Electric utilities invest in enhanced distribution system efficiency

Electric utilities are investing in a technology known as Volt/VAR Optimization (VVO). This technology makes power delivery over their distribution systems more efficient by using less energy to satisfy electricity demand and by enhancing reliability. As of 2013, more than 630 of the almost 2,000 U.S. utilities that serve end-use customers at distribution voltages have installed VVO. Of the 276,000 distribution circuits that deliver electricity to customers, 22% of them have this technology.

High penetration rates of this VVO technology are apparent for utilities serving large metropolitan areas. The table shows utilities with high VVO penetration rates of the top 20 utilities in customers served. For example, Consolidated Edison Co-NY, which serves New York City, has installed VVO technology in all of its 4,388 distribution circuits.

The amount of work (energy) that electricity can provide is the product of voltage and current. Voltage is a measure of the potential energy per electric charge, and current is a measure of the average velocity at which the electrons are moving. Voltage (measured in volts) is analogous to pressure in a water or gas system, while current (measured in amperes) is analogous to the velocity of the flow, as in water or gas.

Utility State VVO/Total Distribution Circuits VVO Penetration Rate Largest City(ies)
Consolidated Edison Co-NY Inc. NY 4,388/4,388 100% New York City
Duke Energy Progress - (NC) NC 989/989 100% Raleigh-Durham
Oncor Electric Delivery Company LLC TX 2,921/3,177 92% Dallas/Ft. Worth
Georgia Power Co. GA 2,250/2,497 90% Atlanta
Florida Power & Light Co. FL 2,717/3,171 86% Miami
Duke Energy Florida, Inc. FL 919/1,243 74% Tampa, St. Petersburg
Niagara Mohawk Power Corp. NY 3,074/4,186 73% Buffalo
Los Angeles Department of Water & Power CA 1,662/2,273 73% Los Angeles
San Diego Gas & Electric Co. CA 1,174/2,030 58% San Diego
Source: U.S. Energy Information Administration, Annual Electric Power Industry Report (Form EIA-861), 2013.
** A distribution circuit is any circuit with a voltage of 35 kilovolts (kV) or less that serves end-use customers.

Most electricity flows from generators to consumers in the form of alternating current (A/C) power. In an A/C electrical system, voltage and current vary like sine waves at the system frequency. In North America, the system frequency is 60 hertz, or 60 times per second.

The waves of voltage and current that make up A/C power are not always in phase, i.e., may not overlap. As voltage and current become more out of phase, their product (called real power) is reduced. The amount of the reduction in real power is called reactive power. All electric end-use equipment or devices use real power. However, some equipment that use magnets, such as electric motors, also consume some reactive power. The optimal mix of real and reactive power depends on the type of equipment consuming electricity on the distribution circuit.

Most electric generating units are able to produce a certain amount of reactive power. As power travels over transmission lines the share of reactive power increases. The goal is to try to match the mix of real and reactive power supplied to a distribution circuit with reactive power needs of consumption equipment. To enhance this matching, electric distribution companies have developed systems and methods in their distribution circuits for controlling real/reactive power. This type of system is known as Volt/VAR Optimization.

VVO uses real-time information and controls that activate capacitor banks, voltage regulators, transformer load-tap changers, and, in some cases, distributed generation. VVO can reduce energy losses and improve reliability, and is an important component of smart grid.

Last year, EIA began collecting distribution circuit data.


Principal Contributor:

Stephen Scott
(Stephen.Scott@eia.gov)

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