Energy Future - Glossary of Terms

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Glossary of Terms and Definitions

The following words, phrases and subjects are all frequently used in the Energy Future project.

A / B / C / D / E / F / G / H / I / J / K / L / M / N / O / P / Q / R / S / T / U / V / W / X / Y / Z

A

Account classification - The way in which suppliers of electricity, natural gas or fuel oil classify and bill their customers. Commonly used classifications are "Residential," "Commercial," "Industrial," and "Other."
Active power - The component of electric power that performs work, typically measured in kilowatts (kW) or megawatts (MW). Also known as "real power."
Acquisition costs - The cost of equipment or property after adjustments for incentives, discounts, or closing costs, but before any sales tax.
Active solar - As an energy source, energy from the sun collected and stored using mechanical pumps or fans to circulate heat-laden fluids or air between solar collectors and a building.
Actual peak reduction - The actual reduction in annual peak load (measured in kilowatts) achieved by customers that participate in a utility demand-side management (DSM) program.
Aggregator - Any entity that combines the loads of multiple customers to negotiate the purchase of electricity, the transmission of electricity, and other related services for these customers
Allocation - Under an emisions trading scheme, permits to emit can initially either be given away for free, usually under a 'grandfathering' approach based on past emissions in a base year or an 'updating' approach based on the more recent emissions. The alternative is to auction permits in initial market offering.
American Public Power Association (APPA) - The service non-profit organization for the nation's community-owned electric utilities created to advance public policy interests and provide services to ensure adequate reliable electricity at a reasonable price with the proper protection of the environment. Collectively, these utilities serve more than 47 million Americans.
Ancillary services - Services that ensure reliability and support the transmission of electricity from generation sites to customers.
Asset acquisition: A buyout strategy in which key assets of the target company are purchases, rather than its shares.
Average revenue per kilowatt hour - Total monthly revenue divided by the corresponding total monthly sales for the applicable sector and geographic area.

B

Balancing authority (Electric) - The responsible entity that integrates resource plans ahead of time, maintains load-interchange-generation balance within a Balancing Authority Area, and supports interconnection frequency in real time.
Base load - The minimum amount of electric power delivered or required over a given period of time. This can vary depending on seasons, time of day, temperatures, etc.
Base period - The period of time for which data used as the bse of an index number, or other ratio, have been collected. This period is frequently one year, but it may be as short as one day.
Base rate - a fixed kilowatt per hour charge for electricity consumed that is independent of other charges and/or adjustments
Base year - Targets for reducing GHG emissions are often definied in relations to a base year. In the Kyoto Protocol, 1990 is the base year for most countries for the major GHGs; 1995 can be used as the base year for some of the minor GHGs
Baselines - The baseline estimates of population, GDP, energy use and hence resultant GHG emissions without climate policies, determine how big a reduction is required, and also what the impacts of climate change without policy will be.
Billing period - The time between utility meter readings.
Biodiesel - A fuel typically made from soybean, canola, or other vegetable oils; animal fats; and, recycled grease. It can substitute for petroleum-derived diesel or distillate fuel.
Biomass - Organic non-fossil material of biological origin constituting a renewable energy source.
Black swan - This describes the disproportionate role of high-profile, hard-to-predict, and rare events that are beyond the realm of normal expectations in history, science, finance, and technology. These events are considered extreme outliers
Block-rate structure - An electric rates schedule with a provision for charging a different unit cost for various increasing blocks of demand for energy.
Bottom ash - This is a byproduct of coal combustion containing traces of combustibles embedded in forming clinker and sticking to hot side walls of coal-burning furnaces.
Boulder customers - Users of PSCo (Xcel) derived energy services, including residential, commercial, and industrial sectors, within the pyhsical city limit of Boulder.
Boulder SmartGrid City - Pilot program launched in 2008 by Xcel Energy to test new smart grid technologies in Boulder.
British thermal unit (Btu) - The quantitiy of heat required to raise the temperature of 1 pound of liquid water by 1 degree Fahrenheit at the temperature at which water has its greatest density (approximately 39 degrees Fahrenheit
Building shell (envelope) Demand Side Management (DSM) program - A DSM program that promotes reduction of energy consumption through improvements to the building envelope. Includes installations of insulation, weather stripping, caulking, window film, and window replacement).
Bulk power transactions - The wholesale sale, purchase, and interchange of electricity among electric utilities. Bulk power transactions are used by electric utilities for many different aspects of electricity utility operations, from maintaining load to reducing costs.
Bundled utility service (electric) - A means of operation whereby energy, transmission, and distribution services as well as ancillary and retail services, are provided by one entity.

C

Capital cost -The cost of field development and plant construction and the equipment required for industry operations.
Capital stock - Property, plant and equipment used in the production, processing and distribution of energy resources.
CAP tax - Climate Action Plan tax program implemented by the City of Boulder. Tax revenue finances programs designed to reduce community-wide greenhouse gas emissions.
Carbon Dioxide (CO2) - An colorless, odorless, non-poisonous gas taht is a normal part of the ambient air. Of the six greenhouse gases normally targeted, CO2 contributes the most to human-induced global warming.
Carbon intensity - The amount of carbon by weight emitted per unit of energy consumed.
Carbon sink - A reservoir that absorbs or takes up released carbon from another part of the carbon cycle. The four sinks, which are regions of the Earth within which carbon behaves in a systematic manner, are the atmosphere, terrestrial biosphere (usually including freshwater systems, oceans, and sediments (including fossil fuels).
Carbon stocks - The quantity of carbon stored in biological and physical systems including: trees, products of harvested trees, agricultural crops, plants, wood and paper products and other terrestrial biosphere sinks, soils, oceans, and sedimentary and geological sinks.
Carbon Taxes - A surcharge on the carbon content of oil, coal, and gas that discourages the use of fossil fuels and aims to reduce carbon dioxide emissions.
CEM - Continuous Emmissions Monitoring System
Chlorofluorocarbon (CFC) - Any of various compounds consisting of carbon, hydrogen, chlorine, and flourine used as refrigerants. CFCs are now thought to be harmful to the earth's atmophere.
Clean Air Act - This act was designed to control air pollution on a national level. It requires the EPA to develop and enforce regulations to protect the public from airborne contaminants known to be hazardous to human health. This was enacted in 1963.
Climate - The long-term average of a region including typical weather patterns, the frequency and intensity of storms, cold spells, and heat waves. Climate is not the same as weather.
Climate Change - Changes in long-term trends in average climate, such as changes in average temperatures. Any change in climate over time, whether due to natural variability or as a result of human activity.
Cogeneration - The process of capturing and utilizing by-product heat derived from energy generation
Colorado Clean Air Clean Jobs Act - Colorado House Bill 10-1365 with emphasis of repowering or replacing existing coal-fueled power plants with natural gas.
Colorado Renewable Energy Standard (RES) - Colorado policy passed in 2004 calling for a renewable energy requirement of 3% beginning in 2007 and increasing to 10% in 2015 and beyond. In 2007, this requirement increased to 20% renewable by 2020 for investor-owned utilities and increased # of qualifying utilities by including all rural electric cooperatives. The RES also requires qualifying utilities to offer customers a minimum rebate of $2 per watt for solar electric generation, providing incentives for utilities to invest in renewable energy resources that provide net economic benefits to customers.
Combined cycle -Technology that uses otherwise lost waste heat exiting from one or more gas (combustion) turbines to generate electricity. The exiting heat is routed to a conventional boiler or to a heat recovery steam generator for use by a steam turbine. This process increases the efficiency of the electric generating unit.
Combined heat and power (CHP) plant - A plant designed to produce both heat and electricity from a single heat source. This term is being used in place of the term "cogenerator" that has been used in the past technical materials. CHP better describes the facilities because some of the plants included do not produce heat and power in a sequential fashion, and as a result, do not meet the legal definition of cogeneration specified in the Public Utility Regulatory Policies Act (PURPA).
Combined pumped-storage plant - A pumped-storage hydroelectric power plant that uses both pumped water and natural stream flow to produce electricity.
Commingling - The mixing of one utility's generated supply of electric energy with another utility's generated supply within a transmission system.
Community choice aggregation (CCA) - A method that allows communities to come together to purchase power as a larger group, benefiting from more choice and bulk rates. This practice is not currently allowed in Colorado.
Compliance costs - The expenditure of time or money in conforming to government requirements such as legislation or regulation.
Confidence interval - Interval estimate of a population parameter used to indicate the reliability of an estimate.
Conservation - A reduction in energy consumption that corresponds with a reduction in service demand. Service demand can include building-sector end uses such as lighting, refrigeration, and heating; industrial processes; or, vehicle transportation. Unlike energy efficiency, which is typically a technologicl measure, conservatin is better associated with behavior. Examples of conservation include adjusting the thermostat to reduce the output of a heating unit, using occupancy sensors that turn off lights or appliances, and car-pooling.
Conventional fuels - Traditional energy sources or fossil fuels including petroleum, oil, coal, propane, and natural gas.
Cooling degree-days - A measure of how warm a location is over a period of time relative to a base temperature, most commonly specified as 65 degrees Fahrenheit. Computed for each day by subtracting the base temperature (65 degrees) from the average of the day's high and low temperatures, with negative values set equal to zero. Each day's cooling degree-days are summed to create a cooling degree-day measure for a specified reference period. Cooling degree days are used in energy analysis as an indicator of air conditioning energy requirements or use.
Cost-of-service regulation - A traditional electric utility regulation that allows a utility to set rates based on the cost of providing service to customers and the right to earn a limited profit.
Current (electric) - A flow of electrons in an electrical conductor. The strength or rate of movement of the electricity is measured in amperes.
Customer choice - The right of customers to purchase energy from a supplier other than their traditional supplier or from more than one seller in the retail market.
Customer class - Category of consumers or customers classified according to buying patterns, payment behavior, and type of consumption. In this case commercial, industrial, and residential utility customers.
Cycling (natural gas) - The practice of producing natural gas for the extraction of natural gas liquids, returning the dry residue to the producing reservoir to maintain reservoir pressure and increase the ultimate recovery of natural gas liquids. The reinjected gas is produced for disposition after cycling operations are completed.

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D

Debt service coverage ratio (DSCR) - The amount of cash flow available to meet annual interest and principal payments on debt, including sinking fund payments. It is the ratio of cash available for debt servicing to interest, principal and lease payments (Net operating income/ total debt service).
Demand-side management (DSM) - The planning, implementation, and monitoring of utility activities that are designed to encourage consumers to modify patterns of electricity usage, including the timing and level of electricity demand.
Demand response (DR) - Is similar to dynamic demand mechanisms used to manage customer consumption of electricity in response to supply conditions or stress on the grid. For example, having electricity customers reduce their consumption at critical times or in response to market prices. Demand response mechanisms respond to explicity requests to shut off, whereas dynamic devices passively shut off when stress in the grid is sensed.
Deregulation - The elimination of some or all regulations from a previously regulated industry or sector of an industry.
Diminishing returns - A concept in economics that if one factor of production is increased while the other factors are held constant, the output per unit of the variable factor will eventually diminish.
Distributed generation (DG) - the use of small-scale power generation technologies located close to the load being served.
Distribution provider (electric) - Provides and and operates the wire between the transmission system and the end-use customer.
Distribution system - The portion of the transmission and facilities of an electric system that is dedicated to delivering electric energy to an end-user.
District heat - Steam or hot water from an outside source used as an energy source in a building.
Diversity - The electric utility system's load is made up of many individual loads that make demands upon the system usually at different times of the day. The individual loads within the customer classes follow similar usage patterns, but these classes of service place different demands upon the facilities and the system grid. The service requirements of one electrical system can differ from another by time-of-day usage, and/or demands placed upon the system grid.

E

Economy of scale - Reduction in cost per unit resulting from increased production realized through operational efficiencies. This can be accomplished because as production increases, the cost of producing each additional unit falls.
Ecosystem - A community of organisms and its physical environment
EIA - US Energy Information Administration, provides a wide range of information and data products covering energy, stocks, demand, imports, exports and prices; and, prepares analyses and special reports on topics of current interest.
Electric industry restructuring - The process of replacing an electric utility supplier that has a monopoly with competing sellers while still allowing retail customers to receive their power over lines owned by the utility.
Electric plant (pyhsical) - A facility containing prime movers, electric generators, and auxiliary equipment that converts mechanical, chemical, and/or fission energy into electric energy.
Electric power grid - A system of synchronized power providers and consumers connected by transmission and distribution lines and operated by one or more control centers. In the continental US, the electric power grid consists of three systems: the Eastern Interconnect, the Western Interconnect, and the Texas Interconnect.
Electric Power Research Institute (EPRI) - An independent nonprofit funded by the electric utility industry to conduct research, development and demonstrations relating to the generation, delivery and use of electricity in the USA for the benefit of the public. It brings together scientists and engineers as well as experts from academia and the industry to help address challenges in electricity.
Electric rate schedule - A statement of the electric rate and the terms and conditions governing its application. Investor-owned utilities in Colorado are required to obtain the approval of the Public Utilities Commission for any changes to their rate schedules.
Electric Resource Plan (ERP) - This plan is provided by a utility company to show a road map for providing reliable and cost-effective electric services to their customers while addressing the risks and uncertainties inherent in their business. These plans are developed with involvement from PUC and other state agencies, customer and industry advocacy groups, and other stakeholders.
Electricity broker - An entity that arranges the sale and purchase of electric energy, the transmission of electricity, and/or other related services between buyers and sellers but does not take title to any of the power sold.
Electricity demand - The rate at which energy is delivered by generation, transmission, and distribution facilities.
Electricity exchange - A type of energy exchange in which one electric utility agrees to supply electricity to another. Electricity received is returned in kind at a later time or is accumulated as an energy balance until the end of a specified period, after which settlement may be made by monetary payment. Note: This term is also referred to as exchange energy.
Electricity generation - The process of producing electric energy or the amount of electric energy produced by transforming other forms of energy, commonly expressed in kilowatt hours(kWh) or megawatt hours (MWh).
Electricity only plant - A plant designed to produce electricity only.
Electricity sales - The amount of kilowatt hours sold in a given period of time; usually grouped by classes of service, such as residential, commercial, industrial, and other. "Other" sales include sales for public street and highway lighting and other sales to public authorities, sales to railroads and railways, and interdepartmental sales.
Emissions Cap - A mandated restraint in a scheduled timeframe that puts a "ceiling" on the total amount of anthropogenic greenhouse gas emissions that can be released into the atmosphere. This can be measured as gross emissions or as net emissions.
Emissions Trading - A market mechanism that allows emitters (countries, companies or facilities) to buy emissions from or sell emissions to other emitters. Emissions trading is expected to bring down the costs of meeting emission targets by allowing those who can achieve reductions less expensively to sell excess reductions (e.g. reductions in excess of those required under some regulation) to those for whom achieving reductions is more costly.
Energy - The capacity for doing work as measured by the capability of dowing work (potential energy) or the conversion of this capability to motion (kinetic energy). Energy has several forms, some of which are easily convertible and can be changed to another form useful for work. Most of the world's convertible energy comes from fossil fuels that are burned to produce heat that is then used as a transfer medium to mechanical or other means in order to accomplish tasks. Electrical energy is usually measured in kilowatt hours, while heat energy is usually measured in British Thermal Units (Btu).
Energy audit - A program carried out in which an auditor inspects a home or business and suggests ways energy can be saved.
Energy charge - That portion of the charge for electric service based upon the electric energy (kWh) consumed or billed.
Energy cost adjustment (ECA) - The amount per Kwh by which the applicable rates shall be adjusted from billing in each month. It reflects change in the cost of buying energy from independent power producers and in the price of fuel from the levels used to set the Base Fuel Energy Charge.
Energy efficiency - Refers to programs that are aimed at reducing the energy used by specific devices and systems, typically without affecting the services provided. These programs reduce overall electricity consumption (reported in megawatt hours), often without explicit consideration for the timing of program-induced savings. Such savings are generally achieved by substituting technologically more advanced equipment to produce the same level of customer service with less electricity. Examples include high-efficiency appliances, efficient lighting programs, high-efficiency heating, ventilating and air conditioning (HVAC) systems or control modifications, efficient building design, advanced electric motor drives, and heat recovery systems.
Energy source - Any substance or natural phenomenon that can be consumed or transformed to supply heat or power. Examples include petroleum, coal, natural gas, nuclear, biomass, etc.
Environmental Impact Statement - A report that documents the information required to evaluate the environmental impact of a project. It informs decision makers and the public of the reasonable alternatives that would avoid or minimize adverse impacts or enhance the quality of the environment.

F

Federal Energy Regulatory Commission (FERC) - The Federal agency with jurisdiction over interstate electricity sales, wholesale elecric rates, hydroelectric licensing, natural gas pricing, oil pipeline rates, and gas pipeline certification. FERC is an independent regulatory agency within the Department of Energy and is the successor to the Federal Power Commission.
Federal Power Act (FPA) - A federal law enacted in 1935 by Congress to regulate non-federal hydropower projects in order to support comprehensive development of rivers for energy generation and other beneficial uses, such as water supply, flood control, recreation, and wildlife management. The FPA regulations are administered by the Federal Energy Regulatory Commission (see FERC).
Firm power - Power or power-producing capacity intended to be available at all times during the period covered by a guaranteed commitment to deliver, even under adverse conditions.
Fixed Assets - Tangible property used in the operations of an entity, but not expected to be consumed into cash in the ordinary course of events. With a life in excess of one year, not intended for resale to customers, and subjet to deprciation (with the exception of land), they are usually referred to as property, plant, and equipment.
Flue gas desulphurization (FDG)- The current technology used for removing sulfur dioxide from the exhaust flue gasses in power plants that burn coal or oil to produce steam for the steam turbines that drive their electricity generators.
Fly ash - One of the residues generated in combustion of coal and comprises the fine particles that rise with the flue gases. While fly ash can vary considerably, all types contain substantial amounts of Silicon Dioxide and calcium oxide. Fly ash must be captured prior to release and is either stored in coal power plants, placed in landfills, or recycled in production such as concrete.
Forced outage - The shutdown of a generating unit, transmission line, or other facility for emergency reasons or because of a condition in which the generating equipment is unavailable for load due to an unanticipated breakdown.
Fossil Fuel - An energy source formed in the Earth's crust from decayed orgainic material. The common fossil fuels are petroleum, coal and natural gas.

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G

Generating unit - Any combination of physically connected generators, reactors, boilers, combustion turbines, and other prime movers operated together to produce electric power.
Generation - The process of producing electric energy by transforming other forms of energy; also, the amount of electric energy produced, expressed in kilowatt hours.
Generator capacity - The maximum output, commonly expressed in megawatts (MW), that generating equipment can supply to system load.
Geothermal plant - A plant in which the prime mover is a steam turbine. The turbine is driven either by steam produced from hot water or by natural steam that derives its energy from heat found in rock.
Gigawatt (GW) - One billion watts or one thousand megawatts.
Gigawatt hour (GWh) - One billion watt hours.
Global Warming - The progressive gradual rise of the Earth's average surface temperature thought to be caused in part by increased concentrations of greenhouse gases in the atmosphere.
Gross generation - The total amount of electric energy produced by generating units and measured at the generating terminal in kilowatt hours (kWh) or megawatt hours (MWh).
Greenhouse Effect - The insulating effect of atmospheric gases (e.g., water vapor, carbon dioxide, methane, etc.) that keeps the Earth's temperature about 60 degrees Farenheit warmer than it would otherwise be.
Green Pricing - In the case of renewable electricity, green pricing represents a market solution to the various problems associated with regulatory valuation of the nonmarket benefits of renewables. Green pricing programs allow electricity customers to experss their willingness to pay for renewable energy development through payments on their monthly bills.
Grid - The layout of an elecrrical system

H

Heat content - The amount of heat energy available to be released by the transformation or use of a specified physical unit of an energy form (e.g., a ton of coal, a barrel of oil, a kilowatt hour of electricity, a cubic foot of natural gas, or a pound of steam). The amount of heat energy is commonly expressed in British thermal units (Btu).

I

Incentive-Based Regulation - A regulation that uses the economic behavior of firms or households to attain desired environmental goals. Incentive-based programs involve taxes on emissions or tradable emission permits. The primary strength of incentive-based regulation is the flexibility it provides the polluter to find the least costly way to reduce emissions.
Incentive Demand-Side Managment (DSM) program assistance - This DSM program assistance offers monetary or non-monetary awards to encourage consumers to buy energy-efficient equipment and to participate in programs designed to reduce energy usage. Examples of incentives are zero or low-interest loans, rebates, and direct installation of low cost measures, such as water heater wraps or duct work for distributing the cool aire.
Incremental effects - The annual changes in energy use and (measured in megawatt hours) and peak load (measured in kilowatts) caused by new participants in existing DSM programs and all participants in new DSM programs during a given year.
Incremental Energy Costs - The additional costs of producing and/or transmitting electric energy above soem previously determined base cost.
Independent power producer - A corporation, person, agency, authority, or other legal entity that owns or operates facilities for the generation of electricity for use primarily by the public, and that is not an electric utility.
Internal combustion plant - A plant in which the prime mover is an internal combustion engine. An internal combustion engine has one or more cylinders in which the process of combustion takes place, converting energy released from the rapid burning of a fuel-air mixture into mechanical energy. Diesel or gas-fired engines are the principal types used in electric plants. The plant is usually operated during periods of high demand for electricity.
Interruptible load - This Demand-Side Management category represents the consumer load that, in accordance with contractual arrangements, can be interrupted at the time of annual peak load by the action of the consumer at the direct request of the system operator. This type of control usually involves large-volume commercial and industrial consumers.
Investor-owned utility (IOU) - A privately-owned electric utility whose stock is publicly traded. It is rate regulated and authorized to achieve an allowed rate of return.
Islanding - The condition in which a distributed generator continues to power a location even though electrical grid power from the electric utility is no longer present. Islanding can be dangerous to utility works who may not realize that a circuit is still powered.

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J

Jurisdictional utilities - Utilities regulated by public laws.

K

Kilowatt (kW) - One thousand watts.
Kilowatt hour (kWh) - A measure of electricity defined as a unit of work or energy, measured as 1 kilowatt (1,000watts) of power expended for 1 hour. One kWh is equivalent to 3,412 British Thermal Units (Btu).
Kyoto Protocol - An international agreement adopted in December 1997 in Kyoto, Japan. The Protocol sets binding emission targets for developed countries that would reduce their emissions on average 5.2% below 1990 levels. Gases covered under the Protocol include carbon dioxide, methane, nitrous oxide, hydrofluorocarbons (HFCs), per fluorocarbons (PFCs) and sulfur hexafluoride.

L

Load (electric) - An end-use device or customer that receives power from the electric system.
Load leveling - Any load control technique that dampens the cyclical daily load flows and increases baseload generation. Peak load pricing and time-of-day charges are two techniques that electric utilities use to reduce peak load and to maximize efficient generation of electricity.
Load management - The process of balancing the supply of electricity on the network with the electrical load by adjusting or controlling the load rather than the power station output. This can be achieved by direct intervention of the utility in real time.
Load shape - A method of describing peak load demand and the relationship of power supplied to the time of occurance.
"Long tail" risks - The possibility that an investment included in a portfolio will shift more than three standard deviations from its current price.

M

Market-based pricing - Prices of electric power or other forms of energy determined in an open market system of supply and demand under which prices are set solely by agreement as to what buyers will pay and sellers will accept.
Maximum demand - The greatest of all demands of the load that has occurred within a specified period of time.
Megawatt (MW) - One million watts of electricity.
Megawatt hour (MWh) - One thousand kilowatt-hours or 1 million watt-hours.
Municipality - A villagge, town, city, county, or other political subdivision of a State.

N

NERC - A nonprofit corporation formed in 2006 as the successor to the North American Electric Reliability Council. NERC was established to develop and maintain mandatory reliability standards for the bulk electric system, with the fundamental goal of maintaining and improving the reliability of that system. NERC consists of regional reliability entities covering the interconnected power regions of the contiguous United States , Canada , and Mexico .
Net generation - The amount of gross generation minus the electrical energy consumed at the generating station(s) for station service or auxiliaries.
Net present value - The difference between the present value of the expected cash flows from an investment and the amount of investment. The net present value is computed by discounting the cash flow at the required rate of return.
Nominal interest rate - Market interest rate unadjusted to reflect the erosion of the purchasing power due to inflation.
Non-firm power -Power or power-producing capacity supplied or available under a commitment having limited or no assured availability.
North American Electric Reliability Corporation (NERC) - A nonprofit corporation formed in 2006 as the successor to the North American Electric Reliability Council. NERC was established to develop and maintain mandatory reliability standards for the bulk electric system, with the fundamental goal of maintaining and improving the reliability of that system. NERC consists of regional reliability entities covering the interconnected power regions of the contiguous United States, Canada, and Mexico.

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O

Off peak - Period of relatively low system demand. These periods often occur in daily, weekly and seasonal patters and differ for each individual electric utility.
Off peak gas - Gas that is to be delivered and taken on demand when demand is not at its peak.
Ohm - A measure of the electrical resistance of a material equal to the resistance of a circuit in which the potential difference of 1 volt produces a current of 1 ampere.
Open access - A regulatory mandate to allow others to use a utility's transmission and distribution facilities to move bulk power from one point to another on a non-discriminatory basis for a cost-based fee.
Open access (electric) - Federal Energy Regulatory Commission Order No. 888 requires public utilities to provide non-discriminatory transmission service over their transmission facilities to third parties to move bulk power from one point to another on a nondiscriminatory basis for a cost-based fee.
Open access transmission tariff (electric) - Electronic transmission tariff accepted by the U.S. Federal Energy Regulatory Commission requiring those with transmission abilities and resources to allow others to transmit their power through this equipment at the same level of service they enjoy.
Other generation - Electricity originating from these sources: biomass, fuel cells, geothermal heat, solar power, waste, wind, and wood.
Outage - The period during which a generating unit, transmission line, or other facility is out of service.

P

Passive solar heating - a solar heating system that uses no external mechanical power, such as pumps or blowers, to move the collected solar heat.
Peak demand - The maximum load during a specified period of time.
Peak load plant - A plant that usually houses old, low-efficiency steam units, gas turbines, diesels, or pumped-storage hydroelectric equipment that can be used during peak-load periods.
Peaking capacity - Capacity of generating equipment normally reserved for operation during the hours of highest daily, weekly, or seasonal loads.
Photovoltaic and solar thermal energy - Energy radiated by the sun as elecromagnetic waves (radiation) that is converted at electric utilities into electricity by means of solar (photovoltaic) cells or concentrating (focusing) collectors.
Power - The rate of producing, transferring, or using energy, most commonly associated with electricity. Power is measured in watts and often expressed in kilowatts (kW) or megawatts (mW). Also known as "real" or "active" power.
Power marketers - Business entities engaged in buying and selling electricity. Power marketers do not usually own generating or transmission facilities. Power marketers, as opposed to brokers, take ownership of the electricity and are involved in interstate trade. These entities file with the Federal Energy Regulatory Commission (FERC) for status as a power marketer.
Power pool - An association of two or more interconnected electric systems that have an agreement to coordinate operations and planning for improved reliability and efficiencies.
Power production plant - All the land and land rights, structures and improvements, boiler or reactor vessel equipment, engines and engine-driven generator, turbogenerator units, accessory electric equipment, and miscellaneous power plant equipment are grouped together for each individual facility.
Power Purchase Agreement (PPA) - A legal contract between an electricity generator and a power purchaser. The PPA defines all of the commercial terms for the sale of electricity between the two parties.
Price volatility risks - The risk of a change of price for a portfolio as a result of changes in the volatility of a risk factor. Usually applies to portfolios of derivatives instruments, where the volatility of its underlying in a major influencer of prices.
Privately owned electric utility - A class of ownership found in the electric power industry where the utility is regulated and authorized to achieve an allowed rate of return.
Probalistic model - Statistical analysis tool that estimates, on the basis of past historical data, the probability of an event occurring again.
Public Utility Commission (PUC) - The governor-appointed regulatory body that oversees investor-owned utilities, such as Xcel Energy.
Public Utility Regulatory Policies Act of 1978 (PURPA) - The Public Utility Regulatory Policies Act of1978, passed by the U.S. Congress. This statute requires states to implement utility conservation programs and create special markets for co-generators and small producers who meet certain standards. Includes the requirement that states set the prices and quantities of power the utilities must buy from such facilities.
Pumped-storage hydroelectric plant - A plant that usually generates electric energy during peak load periods by using water previously pumped into an elevated storage reservoir during off-peak periods when excess generating capacity is available to do so. When additional generating capacity is needed, the water can be released from the reservoir through a conduit to turbine generators located in a power plant at a lower elevation.
Pure pumped-storage hydroelectric plant - A plant that produces power only from water that has previously been pumped to an upper reservoir.
Privately owned electric utility - A class of ownership found in the electric power industry where the utility is regulated and authorized to achieve an allowed rate of return.

Q

Qualifying facility (QF) - A cogeneration or small power production facility that meets certain ownership, operating, and efficiency criteria established by the Federal Energy Regulatory Commission (FERC) pursuant to the Public Utility Regulatory Policies Act (PURPA).

R

Rate base - The value of property upon which a utility is permitted to earn a specified rate of return as established by a regulatory authority. The rate base generally represents the value of property used by the utility in providing service and may be calculated by any one or a combination of the following accounting methods: fair value, prudent investment, reproduction cost, or original cost. Depending on which method is used, the rate base includes cash, working capital, materials and supplies, deductions for accumulated provisions for depreciation, contributions in aid of construction, customer advances for construction, accumulated deferred income taxes, and accumulated deferred investment tax credits.
Rate base (electric) - The value of property, upon which, a utility is permitted to earn a specified rate of return as established by a regulatory authority.
Rate equity - Measure of returns on an investment's equity portion. The ratio of earnings in relation to the amount of equity invested.
Ratemaking authority - A utility commission's legal authority to fix, modify, approve, or disapprove rates as determined by the powers given the commission by a state or federal legislature.
Rates - The authorized charges per unit or level of consumption for a specified time period for any of the classes of utility services provided to a customer.
Regional Transmission Group - A utility industry concept that the Federal Energy Regulatory Commission (FERC) embraced for the certification of voluntary groups that would be responsible for transmission planning and use on a regional basis.
Regulation - The governmental function of controlling or directing economic entities through the process of rulemaking and adjudication.
Reliability - A measure of the ability of the system to continue operation while some lines or generators are out of service. Reliability deals with the performance of the system under stress.
Renewable Energy - Energy obtained from sources such as geothermal, wind, photovoltaic, solar, and biomass that are constantly created in the environment.
Renewable Energy Certificates (RECs) - Also known as Green tags, renewable energy credits, or Tradeable Renewable Certificates (TRCs) - Tradable, non-tangible energy commodities in the US that represent proof that a given amount of electricity has been generated from an eligible renewble energy resource. These certificates can be sold and traded or bartered, and the owner of the REC can claim to have purchased renewable energy.
Reserve margin (operating) - The amount of unused available capability of an electric power system (at peak load for a utility system). Usually expressed as a percentage of total capability.
Retail sales (electric) - Sales made directly to the customer that consumes the energy product.
Retail wheeling - The process of moving electric power from a point of generation across third-party-owned transmission and distribution systems to a retail customer.
Revenue - The total amount of money received by an entity from sales of its products and/or services; gains from the sales or exchanges of assets, interest, and dividends earned on investments; and other increases in the owner's equity, except those arising from capital adjustments.
Right-of-way (electric) - A corridor of land on which electric lines may be located. The transmission owner may own the land, own an easement, or have certain franchise or license rights to construct and maintain lines on the property.
Risk-mitigation - A systematic reduction in the extent of exposure to a risk and/or the likelihood of its occurrence. Also called risk reduction.
Running and quick-start capability - The net capability of generating units that carry load or have quick-start capability. In general, quick-start capability refers to generating units that can be available for load within a 30-minute period.

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S

Sales for resale (electric) - A type of wholesale sales that covers energy supplied to other electric utilities, cooperatives, municipalities, and federal and state electric agencies for resale to ultimate consumers.
Scheduled outage - The shutdown of a generating unit, transmission line, or other facility for inspection or maintenance, in accordance with an advance schedule.
Small power producer (SPP) - Under the Public Utility Regulatory Policies Act (PURPA), a small power production facility (or small power producer) generates electricity using waste and renewable (biomass, conventional hydroelectric, wind, solar, and geothermal) energy as a primary energy source. Fossil fuels can be used, but renewable resource must provide at least 75 percent of the total energy input. (See Code of Federal Regulations, Title 18, Part 292.)
Smart Grid - A system for electric transmission or distribution that incorporates information technology to enable a variety of actions including: allowing customers to partipate interactively in managing their electric consumption using information, control, and options for energy efficiency not previously available; integrating electrical systems using universal interoperability standards; monitoring, diagnosing, and responding to power-quality deficiencies; optimizing the use of system assets and enhancing overall efficiency through improved load factors and better management of outages.
Solar Investment Tax Credit (ITC) - This credit encourages the use of renewable energy by offering a 30% tax credit to owners or long-term lessees for qualified property that meets established performance and quality standards including solar systems on residential and commercial properties. Under current law, the ITC will remain in effect until the end of 2016.
Spot fuel purchases - A single shipment of fuel or volumes of fuel purchased for delivery within one year. Spot purchases are often made by a user to fulfill a certain portion of energy requirements, to meet unanticipated energy needs, or to take advantage of low-fuel prices.
Stability (electric) - The ability of an electric system to maintain a state of equilibrium during normal and abnormal conditions or disturbances.
Standby facility - A facility that supports a utility system and is generally running under no-load. It is available to replace or supplement a facility normally in service.
Standby service - Support service that is available as needed to supplement a customer, a utility system, or another utility if a schedule or an agreement authorizes the transaction. The service is not regularly used.
Steam electric power plant (conventional) - A plant in which the prime mover is a steam turbine. The steam used to drive the turbine is produced in a boiler where fossil fuels are burned.
Stranded benefits - Benefits associated with regulated retail electric service which may be at risk under open market retail competition. Examples include conservation programs, fuel diversity, reliability of supply, and tax revenues based on utility revenues.
Stranded costs - Costs that a regulated utility may be allowed to collect from a newly formed local utility to make up for lost revenues or investments the regulated utility made based on an assumption that they would be serving the newly formed utility’s customers. These costs are calculated based on a set of specific federal guidelines.
Substation - Facility equipment that switches, changes, or regulates electric voltage.
Switching station - Facility equipment used to tie together two or more electric circuits through switches. The switches are selectively arranged to permit a circuit to be disconnected or to change the electric connection between the circuits.
System (electric) - Physically connected generation, transmission, and distribution facilities operated as an integrated unit under one central management or operating supervision.
System operator (electric) - An individual at a control center whose responsibility it is to monitor and control that electric system in real time.
System Average Interruption Duration Index (SAIDI) - Commonly used as a reliability indicator by electric power utilities. It measures the average outage duration for each customer served; calculated as Sum of all customer interruption durations / Total number of customers served.
System Average Interruption Frequency Index (SAIFI) - Commonly used as a reliability indicator by electric power utilities. It measures the average number of interruptions that a customer would experience; calculated as Total number of customer interruptions / Total number of customers served.

T

Tariff riders - Rates that are applied to more than one of a utility's tariffs. One of the most common is a fuel cost adjustments rider that applies a standard cost of fuel to all tariffs. Riders are often updated more frequently than the tariff as a whole.
Terawatt hour - One trillion watt hours.
Thermal rating (electric) - The maximum amount of electrical current that a transmission line or electrical facility can conduct over a specified time period before it sustains permanent damage by overheating or before it sags to the point that it violates public safety requirements.
Transformer - An electrical device for changing the voltage of alternating current.
Transmission (electric) - An interconnected group of lines and associated equipment for the movement or transfer of electric energy between points of supply and points of delivery to customers.
Transmission (electric) (verb) - The movement or transfer of electric energy over an interconnected group of lines and associated equipment between points of supply and points at which it is transformed for delivery to consumers or is delivered to other electric systems. Transmission reaches its end when the energy is transformed for distribution to customers
Transmission line (electric) - A system of structures, wires, insulators and associated hardware that carry electric energy from one point to another in an electric power system. Lines are operated at relatively high voltages varying from 69 kV up to 765 kV, and are capable of transmitting large quantities of electricity over long distances.
Transmission operator (electric) - The entity responsible for the reliability of its localized transmission system, and that operates or directs the operations of the transmission facilities.
Transmission owner (electric) - The entity that owns and maintains transmission facilities.
Transmission service provider (electric) - The entity that administers the transmission tariff and provides transmission services.
Transmitting utility - A regulated entity that owns wires used to transmit wholesale power. It may or may not handle the power dispatch and coordination functions. It is regulated to provide non-discriminatory connections, comparable service and cost recovery.
Turbine - A machine for generating rotary mechanical power from the energy of a stream of fluid (such as water, steam, or hot gas). Turbines convert the kinetic energy of fluids to mechanical energy through the principles of impulse and reaction, or a mixture of the two.

U

US Energy Information Administration (EIA) - provides a wide range of information and data of products covering energy, stocks, demand, imports, exports and prices while also preparing analyses and special reports on topics of current interest.
Ultimate customer - A customer that purchases electricity for its own use and not for resale. These can be commercial or residential.
Utility distribution companies - The entities that will continue to provide regulated services for the distribution of electricity to customers and serve customers who do not choose direct access. Regardless of where a consumer chooses to purchase power, the customer's current utility, also known as the utility distribution company, will deliver the power to the consumer.
Utility occupational tax - The tax on Xcel Energy to offset revenue that would have been collected as part of a "franchise fee" had the city signed to the proposed 20-year franchise agreement with Xcel Energy.

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V

Voltage reduction - Any intentional reduction of system voltage by 3 percent or greater for reasons of maintaining the continuity of service of the bulk electric power supply system.

W

Watt (W) - The unit of electrical power equal to one ampere under a pressure of one volt. A watt is equal to 1/746 horse power.
Watt hour (Wh) - The electrical energy unit of measure equal to one watt of power supplied to, or taken from, an electric circuit steadily for one hour.
Weather - Describes the short-term (i.e., hourly and daily) state of the atmosphere. Not the same as "climate."
Western Electricity Coordinating Council (WECC) - One of nine regional electric reliability councils under NERC. It is the regional entity responsible for coordinating and promoting Bulk Electric System reliability in the Western Interconnection.
Wheeling service - The movement of electricity from one system to another over transmission facilities of interconnecting systems. Wheeling service contracts can be established between two or more systems.
Wholesale competition - A system that gives a distributor of power the option to buy power from a variety of power producers. The power producers are able to compete to sell their power to a variety of distribution companies.
Wholesale power market - The purchase and sale of electricity from generators to resellers (who sell to retail customers), along with the ancillary services needed to maintain reliability and power quality at the transmission level.
Wholesale sales - Energy supplied to other electric utilities, cooperatives, municipals, and Federal and state electric agencies for resale to ultimate consumers.
Wholesale transmission services - The transmission of electric energy sold, or to be sold, in the wholesale electric power market.
Wires charge - A broad term referring to fees levied on power suppliers or their customers for the use of the transmission or distribution wires.

X

Y

Z

1. Acquisition costs: The cost of equipment or property after adjustments for incentives, discounts, or closing costs, but before any sales tax.

Last Updated on Friday, 15 March 2013 09:05