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Base load:
The amount of electrical power that needs to be delivered at all times and during all seasons.
Capacitor:
A dielectric device that momentarily absorbs and stores electric energy.
Capacity:
The maximum power capability of a power-generating system. Common units used are kilowatts or megawatts.
Capacity factor:
The ratio of the energy that a power-generating system produces to the energy that would be produced if it were operated at full capacity throughout a given period, usually one year.
Compact fluorescent light (CFL):
A modern light bulb with integral ballast using a fraction of the electricity used by a regular incandescent light bulb.
Current:
The rate of flow of electricity, measured in amperes, or amps. Analogous to the rate of flow of water measured in litres per second.
Direct current (DC):
Electricity that flows continuously in one direction, such as from a battery.
Efficiency:
The ratio of the output to the input of energy or power, expressed as a percentage.
Energy:
The ability to do work; the quantity of electricity delivered over a period of time. The electrical energy term commonly used is kilowatt hours (kWh), which represents the power (kW) operating over some period of time (hours); 1 kWh = 3600 kilojoules.
Flow:
The quantity of water being used to produce power. This is usually measured in units of cubic metres per second, cubic feet per minute, litres per second or gallons per minute.
Frequency:
The number of cycles through which an alternating current passes in a second, measured in Hertz (Hz).
Generator:
A rotating machine that converts mechanical energy into electrical energy.
Grid:
A utility term for the network of wires that distributes electricity from a variety of sources across a large area.
Head:
The difference in elevation between two water surfaces, measured in metres or feet. Gross head:
The vertical drop between the intake of a pipeline (penstock) and the outlet (location of turbine).
Net head:
The usable head after subtracting losses in the penstock pipe.
Hertz (Hz):
Unit of frequency measurement for AC. Equivalent to "cycles per second," common household utility power is normally 60 Hz in North America.
Inverter:
An electronic device used to convert DC electricity into AC, usually with an increase in voltage.
Joule (J):
The international unit of energy. The energy produced by a power of one watt flowing for one second.
Kilowatt (kW):
The commercial unit of electrical power; 1000 watts.
Kilowatt hour (kWh):
A measurement of energy. One kilowatt hour is equal to one kilowatt being used for one hour.
Load:
The collective appliances and other devices connected to a power source.
Megawatt (MW):
A measurement of power equal to 1 million watts.
Net-metering:
A form of buy-back agreement in which the grid-supplied house electricity meter turns or measures in the utility's favour when grid electric power is consumed by the house, and in the house owner's favour when the house's own generation exceeds its needs and electricity flows into the grid. At the end of the payment period, when the meter is read, the system owner pays the utility the difference between what the house consumed and what was supplied to the grid.
Off-grid:
Not connected to power lines; electrical self-sufficiency.
Output:
The amount of power delivered by a system.
Over speed:
The speed of the turbine runner when, under design conditions, all external loads are removed.
Peak load:
The electric load at the time of maximum demand.
Penstock:
A pipe that conveys water under pressure from the forebay to the turbine.
Phantom loads:
Appliances that draw power 24 hours a day, even when turned off. Televisions, VCRs, microwave ovens with clocks and computers all contain phantom loads.
Power:
The rate of doing work, or more generally, the rate of converting energy from one form to another. Measured in joules/second or watts (1 W = 1 J/s). Electrical power is measured in kilowatts.
Power factor:
The ratio of an appliance's actual power in watts to the apparent power measured in volt-amps (VA). As an example, a 400-W appliance with a power factor of 0.8 would require a power source of 500 VA to drive it properly. This is why loads with poor power factors need larger-than-expected generators to power them.
Run-of-river:
Hydropower systems where water is used at a rate no greater than that which runs down the river.
Transformer:
A device consisting of two or more insulated coils of wire wound around a magnetic material such as iron, used to convert one AC voltage to another or to electrically isolate the individual circuits.
Turbine:
A device that converts kinetic energy of flowing water to mechanical energy. Often used to drive generators or pumps.
Voltage (V):
Measure of electrical potential; the electrical "pressure" that forces an electrical current to flow through a closed circuit.
Watt (W):
The scientific unit of electrical power; a rate of doing work at the rate of one joule per second. Commonly used to define the rate of electricity consumption of an electric appliance.
Source:
Natural Resources Canada
Abbreviations
Ah = ampere hour
AC = alternating current
CFL = compact fluorescent lamp
cfm = cubic feet per minute
DC = direct current
DILC = distributed intelligent load controller
e = efficiency
EC = Environment Canada
ELC = electronic load controller
FDC = flow duration curve
ft. = foot; feet
gpm = gallons per minute
H = gross head
h = net head
Hz = hertz
IGC = induction generator controller
in. = inch
kW = kilowatt
kWh = kilowatt hour
lps = litres per second
m = metre
MAD = mean annual discharge
P = power
PSI = pounds per square inch
Q = flow rate
rpm = revolutions per minute
V = voltage
W = watt
Source: Natural Resources Canada
