Energy & power systems guide
Electricity Units: W, kW, MW, Wh, kWh and MWh
A plain-language guide to common power and energy units used from households to bulk grids.
Systems note: terminology, market structures, voltage classes and reliability rules vary by jurisdiction. Use current local standards and utility information for real projects.
Where this fits
A plain-language guide to common power and energy units used from households to bulk grids.
Core system ideas
Watts, kilowatts and megawatts measure power; watt-hours, kilowatt-hours and megawatt-hours measure energy.
The prefixes scale by thousands: 1 MW equals 1,000 kW, while 1 MWh equals 1,000 kWh.
Unit discipline matters when comparing generation, storage duration, demand and energy use.
Interfaces and tradeoffs
The most useful way to understand this topic is to place it in the chain from energy conversion to customer service. Definitions, units and system boundaries should be explicit before comparing technologies.
What organizations measure
Consistent units and clearly stated time periods.