Glossary by "C"
1. A charge rate that, under ideal conditions, is equal to the energy storage capacity of an electricity storage device divided by 1 hour. For example, a storage device that can store 5 kiloWatt-hours of electric energy has a C rate of five kiloWatts, also known as a C rate of 1. And, a C rate of 5 means energy storage divided by 12 minutes. 2. 1 C is the charge rate necessary to charge a battery in one hour. 10 C charges in 6 minutes and 0.1 C charges in 10 hours. 3. C rate is the charge rate a) for a specific storage device/system or type, b) under ideal conditions, c) that is equal to the energy storage capacity of the device divided by 1 hour. For example, a storage device that can store 5 kiloWatt-hours of electric energy has a C rate of five kiloWatts, also known as a C rate of 1. A C rate of 5 for the same system means energy storage capacity of five kilowatt-hours divided by 12 minutes whereas a C Rate of 1/5 would indicate discharge of a 5 kiloWatt-hour storage device divided by five hours.Source: ESA Technical Working Group
California Public Utilities CommissionAcronym(s): CPUC
CPUC regulates investor-owned utility companies (IOUs) and sets the rates customers pay for electricity.
The rate at which equipment can either generate, convert or transfer energy.Source: ESA Technical Working Group
A capacity emergency exists when a Balancing Authority Area
A value indicating the average percentage of full capacity used over a given period of time. For example, a generating facility which operates at an average of 70% of its normal full capacity over a measured period has a capacity factor of 0.7 for that period.Source: ESA Technical Working Group
Use of storage to provide energy to fill-in when variable generation (i.e. solar and wind) output is below the generator’s rated power output; done to provide constant power output.Source: ESA Technical Working Group
Capital expendituresAcronym(s): CAPEX
All costs associated with design, purchase, installation/construction and financing of investments in/purchase of capital equipment.Source: ESA Technical Working Group
The uncontrolled successive loss of system elements triggered by an incident at any location. Cascading results in widespread electric service interruption that cannot be restrained from sequentially spreading beyond an area predetermined by studies.
The uncontrolled successive loss of bulk electric system facilities triggered by an incident (or condition) at any location resulting in the interruption of electric service that cannot be restrained from spreading beyond a pre- determined area.
The inherent voltage at which the storage system operates. For electrochemical batteries; the inherent voltage of individual cells, which is driven by the underlying chemical reaction(s) within the cell.Source: ESA Technical Working Group
The process of injecting energy to be stored into the storage system.Source: ESA Technical Working Group
The rate at which storage can be charged.Source: ESA Technical Working Group
Circuit recloserSee: RecloserSource: ESA Technical Working Group
Coalition to Advance Renewable Energy through Bulk StorageAcronym(s): CAREBS
CAREBS promotes energy storage and provides a policy voice for the energy storage community.
Generation of useful electric and heat energy using the same conversion system (e.g. internal combustion engine, combustion turbine or fuel cell).Source: ESA Technical Working Group
Combined cooling, heating and powerSee: CogenerationAcronym(s): CCHPSource: ESA Technical Working Group
Combined cycle gas turbineAcronym(s): CCGT
Combined cycle gas turbine plants utilize more than one cycle to generate electricity with waste heat used to make steam, generating additional electricity through a steam turbine.
Combined heat and powerSee: CogenerationAcronym(s): CHPSource: ESA Technical Working Group
Competitive power supplier
An entity that owns and/or operates one or more independent power facilities that are not regulated under the traditional terms. These suppliers are regulated and monitored by the Federal Energy Regulatory Commission (FERC).
Conservation voltageSee: Conservation voltage reduction
Conservation voltage reductionAcronym(s): CVR
Operation of T&D equipment at the minimum allowable voltage to improve energy efficiency and/or to reduce peak demand. Most CVR schemes contain two fundamental components: reactive power compensation and voltage optimization. Reactive power compensation is achieved through the operation of shunt capacitors in order to maintain the power factor at the substation transformer within a prescribed band. Voltage optimization is achieved through the operation of substation voltage regulators in order to regulate the voltage at specific end of line points within a prescribed range.
1. For batteries; a charging process during which the electric current into the battery is constant. 2. For batteries; a charging process during which the electric current into the battery is constant. Charging is stopped when the battery is fully charged and constant-voltage charging is used.Source: ESA Technical Working Group
For batteries; a charging process during which the voltage applied to a battery’s terminals is constant.Source: ESA Technical Working Group
A transmission facility (line, transformer, breaker, etc.) that is approaching, is at, or is beyond its System Operating Limit or Interconnection Reliability Operating Limit.
The unexpected failure or outage of a system component, such as a generator, transmission line, circuit breaker, switch or other electrical element.
1. The provision of capacity deployed by the balancing authority to meet the disturbance control standard (DCS) and other North American Electric Reliability Corporation (NERC) and regional reliability organizations’ contingency requirements. 2. Reserves set aside to support the transmission system in the case of the worst foreseeable contingency event (often referred to as N-1)
An agreed upon electrical path for the continuous flow of electrical power between the parties of an Interchange Transaction.
Control performance standardAcronym(s): CPS
The reliability standard that sets the limits of a Balancing Authority
The total cost incurred by the utility to generate, transmit and deliver electricity and to provide customer service.Source: ESA Technical Working Group
Facilities, systems, and equipment which, if destroyed, degraded, or otherwise rendered unavailable, would affect the reliability or operability of the Bulk Electric System.
Critical peak pricingAcronym(s): CPP
A program involving “high” or “very high” prices (relative to normal prices) that are assessed during “critical peak” periods (when demand is at or near supply).Source: ESA Technical Working Group
CurrentSee: Electric currentSource: ESA Technical Working Group
The amount of current per unit area such as the amount of current flowing through a wired per unit of cross sectional area of the wire that is perpendicular to flow of current. Current density is a vector quantity whose direction is the same as the direction of current flow.Source: ESA Technical Working Group
1. A reduction in the scheduled capacity or energy delivery of an Interchange Transaction. 2. A temporary reduction in customer load that occurs or that is imposed because demand exceeds the capacity.
Customer facility charge
An charge that is part of an end-use customer’s electricity bill that may be used to cover—among other utility costs— cost to maintain utility facilities and infrastructure needed to provide electric service to the respective customer. Charges may include, for example, T&D equipment, accounting, meter reading and site-specific services. Facility charges may also be a way to combine several small fixed-cost charges associated with maintaining a customer’s energy account.Source: ESA Technical Working Group
Cutoff voltageSee: End-point voltage
Voltage at the end of useful discharge.Source: BatterySpace
CycleSee: Cycle life
One sequence of storage charging and discharging. Also known as charge-discharge cycle.Source: ESA Technical Working Group
The number of charge-discharge cycles after which storage becomes inoperable or unusable for a given application. In practice, storage may be inoperable or unusable when it can still deliver a portion of its initial rated energy and/or power rating.Source: ESA Technical Working Group