Renewable Energy Definitions

Published by: Nick Meissner

Feeling overwhelmed with all this new terminology relating to power systems? Watts... kW, Volts, Amps... it's enough to make your head spin! Well, if that describes you - don't worry! Here is a quick, laymen - terms definitions.


Used to measure the amount of work able to be done with a given amount of electricity. Amps x Volts = Watts.

kW (kilowatt)

Watts divided by 1,000 (1kW = 1,000 watts; 4kW = 4,000 watts, 0.5 kW = 500 watts).


Are used to measure the “force” of electricity flowing. One common example is to compare electrical volts with water pressure, or pounds per square inch (PSI). Volts do not measure how much electricity is flowing, but rather the force or pressure at which it is flowing.  Watts / Amps = Volts.


Used to measure the quantity of electricity passing a certain point in a given period of time.    This is independent of force or pressure (volts) and when compared to water, is comparable to gallons per minute (GPM). Watts / Volts = Amps.


Used to measure how many watts have been consumed or produced over a given period of time. 1 watt-hour = 1 watt for 1 hour; 10 watt-hours = 10 watts for 1 hour (also 5 watts for 2 hours or 20 watts for 0.5 hours).

kWh (kilowatt hour)

Watt-hours divided by 1,000 (1kWh = 1,000 Watt-hours; 3kWh = 3,000 Watt-hours). This is the typical measurement used by utility companies on your power bill.

AH (amp-hour)

The number of amps flowing over a period of time (1 amp flowing for 1 hour = 1 AH; 4 amps flowing for 1 hour = 4 AH; 4 amps flowing for 2 hours = 8 AH; 4 amps flowing for 0.5 hours = 2 AH). Often used for batteries.


Multiple batteries wired together in such a way that voltage increases, but the amp-hour capacity does not.


Multiple batteries wired together in such a way that voltage stays the same, but the amp-hour capacity increases.

AC Electricity

Alternating current (AC) is the type of electricity produced by power companies and delivered to homes via power lines.  Because of that, almost all appliances are made to operate on AC power.  While high voltage AC power is able to be transmitted over long distances, it cannot be stored.

DC Electricity

Direct current (DC) is the type of electricity that is used in batteries of all kinds, since it may be stored (unlike AC).  However, most appliances are set up to operate on AC power, and DC appliances are hard to come by (but there are a small number of specialty DC appliances available that are often more energy efficient than their AC counterparts but may cost significantly more).


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