ELECTRICAL

VOLT (V)

Measure of electrical “pressure”.

KILOVOLT (kV)

1,000 volts.

WATT (W)

Unit of Electrical Power (746W = 1 horse power).

KILOWATT (kW)

1,000 Watts. A single bar electric fire typically has a demand of 1 kilowatt.

MEGAWATT (MW)

1,000,000 Watts (1,000kW).

UNIT OF ELECTRICITY

Measure of electrical energy - equivalent to the use of 1 kilowatt for 1 hour (1kWh).

FREQUENCY

Number of cycles of alternating current occurring each second. The ESB system operates at 50 cycles per second.

THERMAL EFFICIENCY

Efficiency of conversion of thermal energy to mechanical/electrical energy.

COMBUSTION TURBINE

Turbine operating directly from fuel combustion gases and not requiring a steam/water cycle. The operating principle is similar to that used in aircraft jet engines.

COMBINED CYCLE

A combustion turbine operating in conjunction with a heat recovery boiler and conventional turbine plant to achieve a high thermal efficiency.

PEAK DEMAND

Also Peak Load. Maximum instantaneous demand for electricity.

LOAD CENTRE

Localised area of high energy demand. Dublin is the country’s largest load centre.

SPINNING RESERVE

Additional running capacity (over and above instantaneous demand) necessary to cater for sudden loss of the largest generating unit in operation.

LOAD SHEDDING

Conscious disconnection of load when demand on the system exceeds generating capacity, in order to prevent collapse of the system.

FUELS

BIOMASS

Generally taken to be fast growing trees (approximately 5 years) which can be used as fuel for the generation of electricity.

HEAVY FUEL OIL (H.F.O.) and

Heavy refinery product remaining when all light oils and gases have been separated from basic crude oil.

RESIDUAL FUEL OIL (R.F.O.)

Used mainly for electricity generation.

DISTILLATE FUEL OIL

Refined oil product (similar to diesel) suitable for use in combustion turbines.

LIQUID PETROLEUM GAS (L.P.G.)

Refined oil product (e.g. domestic bottled gas).