MW vs. MWh: Do You Know Your Electric Units?

by Enerdynamics staff

Most discussions in the electric industry require fluency in electric units. Whether it is a conversation about power plants, customer demand, new technologies, regulatory issues, or market prices, industry insiders will assume you understand units. But many in the electric industry aren’t as comfortable with units as they need or want to be. Following is a quick primer for those who want a basic understanding of key electric units.

Electric units include units of demand or capacity and units of energy or usage. To see what these units are and how they relate, keep reading below or watch the following video:

Units of demand and capacity

Demand reflects the instantaneous amount of work required to perform the function desired (such as creating light or physical force, powering a microchip, etc.). Similarly, capacity reflects the instantaneous ability to provide energy required to do work (such as generator capability to provide electricity, transmission capability to transmit electricity, etc.). Demand and capacity are commonly measured in the following units:

W = watt
kW = kilowatt
MW = megawatt
GW = gigawatt

To convert between these, you can use the following:

1 kW = 1,000 W
1 MW = 1,000 kW
1 GW = 1,000 MW

Units of energy/usage

Energy or usage reflects demand or capacity multiplied by the amount of time that demand or capacity is in use.  For instance, a 15-watt light bulb used for 2 hours creates 15 watts X 2 hours = 30 watt-hours of usage. Energy and usage are commonly measured in the following units:

Wh = watt-hour
kWh = kilowatt-hour
MWh = megawatt-hour
GWh = gigawatt-hour

The conversions between the units are:

1 kWh = 1,000 Wh
1 MWh = 1,000 kWh
1 GWh = 1,000 MWh

To give you a sense of the size of units, here are some typical values for demand, capacity, and usage in the electric industry:

So, there you have it. You are now familiar with the most common units used in the electric industry!


This article has been adapted from an entry in Enerdynamics’ Energy Knowledgebase, which is an online resource of important terms and concepts explained simply and clearly.  It is available through Enerdynamics’ eLearning Portal. For more information email us a or call us at 866.765.5432 x700.

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