A megawatt (MW) is a unit of power equal to one million watts. It is commonly used to measure the capacity of large energy systems, including solar farms, power plants, and grid infrastructure.

Megawatts help describe how much electricity a system can produce at a given moment. According to the U.S. Energy Information Administration, electricity generation and power plant capacity are often measured in megawatts to represent output at scale¹.

How a megawatt compares to other energy units

Electric power is measured in watts, with larger systems using higher units to describe capacity.

Common conversions include:

• 1 kilowatt (kW) = 1,000 watts

• 1 megawatt (MW) = 1,000,000 watts

• 1 gigawatt (GW) = 1 billion watts

Megawatts are typically used for commercial and utility-scale systems, while kilowatts (and kilowatt hours) are more common for residential solar installations.

Why megawatts matter in energy

Megawatts are used to measure how much electricity a system can produce at a specific point in time.

This measurement helps:

• Compare the size and output of different power plants

• Understand grid capacity and energy supply

• Track growth in renewable energy, including solar

The U.S. Department of Energy uses megawatts to describe energy capacity across technologies, including solar deployment².

Megawatt vs. megawatt-hour

Megawatts and megawatt-hours measure different things:

• Megawatt (MW): a unit of power that measures capacity at a specific moment

• Megawatt-hour (MWh): a unit of energy that measures electricity produced or used over time

For example, a solar facility may have a capacity of 1 megawatt but produce multiple megawatt-hours of electricity over the course of a day.

How megawatts relate to solar energy

Megawatts are commonly used to describe larger solar energy systems and total installed capacity.

• Utility-scale solar projects are measured in megawatts or gigawatts

• Community solar and commercial systems are often measured in megawatts

• Residential systems are typically measured in kilowatts

According to the Solar Energy Industries Association, solar capacity in the United States is tracked in megawatts and gigawatts to reflect total installed power across the country³.

For homeowners, understanding megawatts helps provide context for how residential systems compare to larger energy projects. For a deeper breakdown of how these units compare in real-world solar systems, see How Many Watts to Run a House.

Takeaways

• A megawatt is equal to one million watts

• It is used to measure large-scale electricity generation and system capacity

• Megawatts describe power, while megawatt-hours measure energy over time

• Solar energy systems are measured in different units depending on scale

• Residential solar systems are smaller but contribute to overall energy capacity