What Is a Megawatt? MW vs MWh Explained Simply
Updated October 5, 2026
A megawatt (MW) is a unit of power equal to 1,000 kilowatts, or one million watts. It measures how fast electricity is produced or used at a given moment. A megawatt-hour (MWh) measures energy: one megawatt delivered for one hour. Mixing these two up is the most common mistake in energy news.
The units, from small to large
| Unit | Equals | Rough example |
|---|---|---|
| Watt (W) | — | An LED bulb uses ~10 W |
| Kilowatt (kW) | 1,000 W | A microwave or space heater ~1–1.5 kW |
| Megawatt (MW) | 1,000 kW | A modern onshore wind turbine ~3–6 MW |
| Gigawatt (GW) | 1,000 MW | A large nuclear reactor ~1 GW |
| Terawatt (TW) | 1,000 GW | Total global generating capacity is several TW |
MW vs. MWh: power vs. energy
Think of water. Megawatts are the flow rate, how fast water comes out of the tap. Megawatt-hours are the volume, how much water ends up in the bucket.
- A 100 MW solar farm produces up to 100 MW at peak sun. Over a year it might generate roughly 200,000 to 250,000 MWh, depending on location.
- A battery described as "100 MW / 400 MWh" can discharge at 100 MW for about 4 hours. The first number is power and the second is energy, so their ratio is the duration.
How many homes does a megawatt power?
An average U.S. home uses about 10,500 kWh of electricity per year (EIA), which works out to an average draw of roughly 1.2 kW. In theory, 1 MW running continuously could supply about 800 average homes. In practice the answer depends on the source:
- A plant that runs most hours, such as nuclear, supports close to that figure per MW.
- Solar and wind run only part of the time, so press releases typically quote fewer homes per MW, often 150 to 300 for solar.
"Homes powered" is a loose communication tool, not an engineering measure. Look for MWh per year when you can.
Capacity factor: the missing piece
Capacity factor is actual output over a year divided by the maximum possible if the plant ran at full power every hour. U.S. averages are roughly 90%+ for nuclear, about 35% for onshore wind and about 25% for utility solar, per EIA data. Capacity factor is why 1 MW of solar and 1 MW of nuclear produce very different amounts of energy.
MWe, MWt and MWac/MWdc
- MWe vs. MWt: thermal plants report thermal power (MWt) and electric output (MWe). A reactor rated at 3,000 MWt may produce about 1,000 MWe.
- MWac vs. MWdc: solar panels are rated in DC. The grid connection is AC. A solar project's DC rating is usually 20% to 35% higher than its AC rating.
Bottom line
MW tells you how big something is at any instant. MWh tells you how much it actually delivers. Whenever you read about a power plant, battery or data center, check which one is being quoted. For anything that doesn't run around the clock, ask about capacity factor too.
Frequently asked questions
How many kilowatts are in a megawatt?
1,000 kilowatts equal one megawatt.
What is the difference between MW and MWh?
MW measures power, the rate of energy at a moment. MWh measures energy: one megawatt sustained for one hour.
How many homes can 1 MW power?
Running continuously, about 800 average U.S. homes. For solar and wind, which don't run all the time, figures of roughly 150–300 homes per MW are commonly quoted.