Tariffs and Metering

Practice vocabulary flashcards covering electricity tariffs, billing structures, maximum demand schemes, and power factor fundamentals based on Phase 6 apprentice electrical notes.

ESB (Electricity Supply Board)

A major Irish semi-state body originally granted statutory monopoly rights to generate and supply electricity, which underwent progressive market deregulation beginning in the year 2000.

Commission for Regulation of Utilities (CRU)

The regulatory body that supervised and approved ESB Customer Supply tariffs from 2001 to 2010 to foster competition and protect consumer pricing.

Electric Ireland

The rebranded commercial identity adopted by ESB Customer Supply and ESB Independent Energy after the deregulation threshold was met in 2011.

Calorific Value

The total amount of heat released from the complete combustion of a specified quantity of fuel; also known as heat value or heating value.

Ardnacrusha

The ESB's first hydroelectric generating station, opened on the River Shannon in 1947, designed to utilize renewable water power for national electrical demand.

Daily Load Curve

A graphical representation showing the continuous fluctuations in national electricity demand over a 24-hour period for an average working day.

Load Dispatch Office

The central operational body responsible for forecasting electrical demand patterns and issuing daily output directives to individual generating stations.

Base Load

The minimum permanent level of electrical energy demanded around the clock, generated by the most cost-effective stations running 24 hours per day.

Pumped Storage

The strategy of using spare, low-cost off-peak night generation capacity to pump water to an elevated reservoir, releasing it during peak hours to drive turbines.

Turlough Hill

The location of Ireland's sole pumped storage generating station, situated in County Wicklow.

Active Power ($\text{kW}$)

The true or wattfull power converted by electrical equipment into useful mechanical work and heat, measured directly by $\text{kWh}$ meters.

Reactive Power ($\text{kVAr}$)

The wattless component of electrical power required by inductive equipment to establish and sustain electromagnetic fields, alternately absorbed and returned to the system twice per cycle.

Apparent Power ($\text{kVA}$)

The total vector combination of active power ($\text{kW}$) and reactive power ($\text{kVAr}$) delivered to a circuit, calculated as $\text{kVA} = \sqrt{\text{kW}^2 + \text{kVAr}^2}$.

Power Factor (PF)

The ratio of active power ($\text{kW}$) to apparent power ($\text{kVA}$), expressed mathematically as $\cos(\theta)$, representing the efficiency of power utilization.

Meter Point Reference Number (MPRN)

A unique reference number shown on utility bills that identifies a consumer's specific physical connection point to the ESB Network.

Meter Reading Codes (A, C, E)

Bill markings indicating the data origin of a meter reading: 'A' denotes an actual read by ESBN, 'C' denotes a customer-submitted read, and 'E' denotes an estimated calculation.

Standing Charge

A fixed charge billed on a daily basis to recover supply and connection overheads, regardless of the quantity of electrical energy consumed.

Public Service Obligation (PSO) Levy

A mandatory government levy charged to all final electricity consumers to recover additional expenses incurred from sustainable, renewable, and indigenous generation schemes.

Demand Costs

The portion of electrical tariff costs reflecting the capital investment required to construct, maintain, and operate generation, transmission, and distribution assets.

Energy Costs

The portion of an electricity tariff reflecting the direct cost of primary fuels consumed during the generation of electrical energy.

Customer Costs

Tariff cost components covering administrative outlays, metering infrastructure, customer billing services, and local low-voltage network operations.

Magnitude of Load

The total sum of all connected electrical equipment ratings in an installation, which rarely represents the operating demand due to duty cycles and mutually exclusive equipment.

Maximum Demand

The highest agreed level of electrical power drawn by a consumer, requiring the utility to size network transformers, lines, and switchgear accordingly.

Demand Charge

A targeted surcharge applied to Low Voltage Maximum Demand customers for usage exceeding $30\,\text{kW}$ between 17:00 and 19:00 on weekdays from 1st November to the end of February.

15-Minute Averaging Period

The standard measurement interval over which the ESB calculates maximum demand for billing purposes, taking the mean power level rather than transient instantaneous peaks.

50% Rule

A commercial billing mechanism stipulating that billed Maximum Demand must equal the highest of either the current period's reading or $50\%$ of the peak demand recorded in the previous five billing periods (subject to a $30\,\text{kW}$ minimum).

Winter Demand Reduction Incentive (WDRI)

An incentive scheme during November/December and January/February that confines maximum demand recording to a 2-hour window (17:00–19:00 weekdays), replacing the standard 13-hour window.

Diversity Factor

The ratio between the actual maximum load and the total connected load ($\text{Diversity Factor} = \frac{\text{Actual maximum load}}{\text{Total connected load}}$), having a value that is always less than one.

Load Factor

The proportional relationship between the magnitude plus duration of the actual electrical load and the magnitude plus duration of the available electrical supply.

Maximum Import Capacity (MIC)

The agreed maximum apparent power (in $\text{kVA}$) contracted by a customer from the grid, establishing the baseline for recurring capacity charges.

Capacity Charge

A recurring standing charge billed to commercial users based on their contracted Maximum Import Capacity ($\text{kVA}$) per billing interval.

Low Voltage Maximum Demand Tariff

A commercial tariff structure applied to installations metered at $400/230\,\text{V}$ possessing a Maximum Import Capacity (MIC) of $50\,\text{kVA}$ or greater.

Wattful Current Component

The component of alternating current that is in phase with the voltage, represented by $W = V \times A \times \cos(\theta)$, which produces useful tangible power.

Wattless Current Component

The quadrature component of alternating current at right angles ($90^\circ$) to the voltage ($\text{VAr} = V \times A \times \sin(\theta)$), causing system conductor heating without delivering mechanical work.

Capacitive kVA

The rating of reactive power capacitance needed to raise system power factor from $\cos(\phi_1)$ to $\cos(\phi_2)$, calculated using $\text{Capacitive kVA} = \text{kW}(\tan(\phi_1) - \tan(\phi_2))$.

Individual Power Factor Correction

The method of improving power factor by wiring static capacitors directly across each individual inductive load, relieving sub-distribution cables of excess reactive currents.

Bulk (Group) Power Factor Correction

An automated system where capacitor banks installed across main intake busbars are dynamically switched in and out to regulate overall facility power factor.

Low Power Factor Surcharge

A financial penalty levied on electricity consumers whose overall installation power factor falls below $0.95$ (lagging or leading) in Ireland.

Smart Meter

An electronic metering device that records electrical consumption in detailed time intervals and communicates bidirectional data to the utility to enable accurate billing and dynamic pricing.