Kilowatt-Hour vs. Megawatt: What’s the Difference?

Kilowatt hour kilowatt per hour

Kilowatt-Hour vs. Megawatt: What’s the Difference?

If you have suddenly observed a surge in your electricity bill, you might be wondering how to calculate your monthly energy consumption. You must understand the basic unit for measuring electricity: kilowatt-hour (kWh). However, you may also encounter another unit: megawatt (MW). So, the simplest way to know about both power measurement units is to compare kilowatt-hours to megawatts! 

Kilowatt measures 1,000 watts consumed over a certain period. On the other hand, a megawatt equals 1,000,000 watts and measures more extensive power output, such as power plants. Many people also confuse kilowatt-hours with kilowatt. 

While kW and kWh are connected, they don’t measure the same thing. That is why you should know what kilowatt-hour and megawatt are, their applications, calculation methods, and conversions.

Don’t start sweating; this kilowatt-hour and megawatt comparison has got you covered. So, let’s dive in!

Kilowatt-Hour vs. Megawatt: Side-by-Side Comparison

InventorOliver ShallenbergerJames Watt
Used forMeasuring electric power used over a certain timeMeasure the electric output of a city’s power plant
UnitStandard unit to measure electricity metersStandard unit to measure the power output of cities
Conversion into Watts1,000 watt hours1,000,000 watts

What’s the Difference Between Kilowatt-Hour and Megawatt?

Both kilowatt-hour (kWh) and megawatt (MW) measure electric power, but at different levels.

kWh is used for estimating the electricity of typical households, while MW calculates the output of a massive plant that supplies power to an entire city. That’s the most notable difference between both units. 

Megawatt is the form of the watt, the SI unit for power. Meanwhile, the kilowatt-hour is linked to watt-hours. Let’s get into more details in this kilowatt-hour versus megawatt one-to-one to understand these units better.

Kilowatt-Hour Explained

Watt-hours and kilowatt-hours specify the energy consumed or work performed in an hour. Both these terms are derived from watt and kilowatt, the SI unit for measuring power. One kilowatt is equivalent to 1,000 words. On the other hand, watt defines the amount of power an electrical appliance can produce in a specific period.  

You can better understand the connection between a device’s capacity and time by observing your refrigerator. A 400-watt or 0.4 kW fridge will cool down your meals faster than a 100-watt appliance. 

Considering this relationship, it is crucial to consider the time when calculating the total energy use. That’s when watt-hours (Wh) and kilowatt-hours (kWh) become valuable. 

Simply speaking, speed defines the distance observed over a particular time. Meanwhile, energy expresses power consumed over a specific period. Using the same 400-watt fridge for an hour will consume 4 kWh of energy. 

So, who invented the kilowatt-hour? The unit’s history dates back to the early 1880s when electrical experts tried to find a way to charge household consumers for their electric consumption. This was important to strengthen the power system and create a solid economic system.

In 1888, Oliver Shallenberger of Westinghouse invented the first-ever watt-hour meter. This modern device was inspired by Weston and Thomson’s instruments consisting of a moving coil galvanometer. 

The Difference Between Kilowatt-Hours and Kilowatts Explained

Both kilowatts and kilowatt-hours measure different units. While the former calculates energy or work, the latter estimates power or the rate at which energy is delivered. The SI unit for energy is joules or watt-seconds. Comparatively, watt or joules per second measures power. 

For example, a battery possesses a certain amount of energy. Putting the battery in an appliance delivers the energy at a specific rate or power (kW). You can then measure the amount of kW the battery transfers in an hour (kWh) to estimate its total capacity. 

Kilowatt-Hour Applications 

Kilowatt-hours measure the total electric energy a household uses, including all its small and large appliances. The electricity bills include kilowatt-hours to describe the amount of electricity you have consumed in a month. 

Since one kilowatt consists of 1,000 watts, one kilowatt-hour refers to the rate of using electricity at 1,000 watts in an hour. 

On average, modern refrigerators consume 300 to 400 kilowatt hours a year. Meanwhile, a standard microwave oven uses 215 kWh of energy a year. Overall, a U.S. home consumes 10,632 kWh of electricity annually.

Kilowatt-Hour Calculation and Conversions

You can calculate your daily kWh used to check your energy consumption. Divide the total kWh by the total days included in your electricity bill. An example of a monthly electricity bill is:

Daily electricity consumption (kWh) = Total kWh used / 30

Suppose you consumed 25 kWh of electricity monthly. Then, your average daily energy usage would be:

Daily electricity consumption (kWh) = 25 / 30 

Daily electricity consumption (kWh) = 0.83 kWh

Of course, it’s impossible for someone to use the same amount of energy regularly. For instance, you can be away from home longer today than yesterday, hence different energy consumption. Some other factors that impact daily kWh used are the time of the year, the climate, and your usage. 

To ensure accuracy, you can calculate the total kWh each appliance consumes depending on its daily usage. Let’s say you use a 4 kWh electric heater every day for 5 hours. It will probably take 15 kWh of electricity during that entire period.

Calculating kWh From Watts or Kilowatts

You can easily calculate the kWh an electric device uses if you know its wattage. First, you’ll have to convert the total watts into kilowatts. Simply divide the watts by 1,000 like this:

100 W = 100 / 1,000 = 0.1 kW

50 W = 50 / 1,000 = 0.5 kW

1,500 W = 50 / 1,000 = 1.5 kW

Now, convert your kWh into kW by multiplying it by the total hours you used the appliance for. Suppose you use your 1000-watt microwave for an hour a day. Then, its kWh will be:

kW = 700 / 1,000 = 0.7 kW

0.7 x 1 = 0.7 kWh

So, a 1000 W microwave running for an hour will probably use 0.75 kWh. 

You can easily convert kilowatt hours into other units as well, such as:

  • 1 kWh = 1,000 W
  • 1 kWh = 3.6e+6 J
  • 1 kWh = 3,600 KJ

Megawatts Explained

To understand the difference between a kilowatt-hour and megawatt, we will have to start with the basics — watts and kilowatts. Both units calculate energy. The megawatt (MW) is one unit bigger than the kilowatt. 

One megawatt (MW) translates to 1,000 kilowatts, which equals 1 million watts. The same formula applies to kilowatt-hours (kWh) and megawatt-hours (MWh).

If you leave a 400 (0.4 kW) fridge running for 16.6 days, it will consume about MWh of electricity (400 / 24 = 16.6 days). This way, you can apply any conversion between kilowatt-hours and kilowatts to megawatt-hours and megawatts. Just keep it 1,000 times larger. 

Kilowatt Hour vs Watt
One megawatt is equal to 1,000 kilowatts, which equals one million watts.

©Krisana Antharith/Shutterstock.com

Megawatt Applications

A megawatt is primarily used to measure significant power plants’ output. It also specifies how much electricity an entire town or city needs or consumes. This means the use case of megawatt is at a higher level, and the kilowatt-hour is used on a smaller scale. That’s the most noticeable difference between kilowatt-hour and megawatt.

Megawatts help electricity experts to evaluate the size of a power plant. For instance, they can easily determine that a coal plant can produce 600 MW of electricity. Similarly, 1 MW of energy can fulfill the needs of a block consisting of 750 homes in California.

Gigawatt is an even bigger unit for measuring the power-manufacturing capacity of bigger power plants. 

Megawatt Calculation and Conversions

Since a megawatt is a bigger form of watt, it’s easier to calculate it if you already have the wattage in hand. Simply divide the number of watts by 1,000,000, and you’ll have the power in megawatts. Here is the general formula for its calculation and conversion:

Megawatts = Watts / 1,000,000

Let’s say you want to convert 6,000,000 watts into megawatts. Here is how you can calculate it using the above formula:

Megawatts = 6,000,000 / 1,000,000 = 6 MW

Here are some units into which you can convert megawatts:

  • 1 MW = 1,000,000 W
  • 1 MW = 1,000 kW
  • 1 MW = 0.001 GW

Kilowatt-Hour vs. Megawatt Summarized

Whether you’re concerned about your electricity bill or not, you must understand the difference between kilowatt-hour and megawatt. It will help you stay updated about your electricity consumption and your city’s energy demand. That’s important for every responsible citizen. 

Both units measure power output. However, kWh applies at a residential level, such as the energy consumption in typical households. You will see kWh mentioned on your electricity bill instead of MWh. One MWh equals 1,000 kWh.

According to the Energy Information Administration, an average house in America consumes about 11,000 kWh of electricity annually. So, we can input this figure into the above formulas and calculate our home’s monthly energy use and daily consumption. 

Comparatively, MW measures electricity output at a larger scale, including the energy a power plant produces to keep an entire city lit up. You’ll hear megawatts or gigawatts in any situation where high-scale energy consumption is discussed.

Kilowatt-Hour vs. Megawatt: What’s the Difference? FAQs (Frequently Asked Questions) 

Why is it kilowatt hour?

A kilowatt-hour estimates the power an electrical device consumes an hour in kilowatts or 1,000 watts. For example, heating your meals in a 1,000-watt microwave for an hour takes about 1 kWh of electricity daily.

How many kWh is 1 MWh?

One megawatt-hour (MWh) equals 1,000-kilowatt hours (kWh). To convert 5 mWh into kWh, you must multiply 5 by 1,000 to yield 5,000 kWh. Similarly, you can convert kWh into MWh by dividing the kWh by 1,000.

Which is higher, kWh or MW?

MW is bigger than KWh as it measures the power output of a massive power plant that provides electricity to an entire city. One MW translates to 1,000 kW and 1,000,000 watts. This means 6 MW will equal 6,000 kW and 6,000,000 watts. On the other hand, kWh calculates the energy consumption at a smaller (residential) level.

How many watts in a kilowatt hour?

The kilowatt hour is quite different from a kilowatt. The latter is the unit that describes the amount of energy you use, while the former is the number of kilowatts you use in an hour. Although kilowatt doesn’t refer to the number of watts you consume in an hour, both kWh and kW consist of 1,000 watts. The only difference is the total energy you’ll use for running a one-watt device for an hour.

How do you convert watts into kilowatts?

You can convert watts into kilowatts by dividing the total watts by 1,000. For example, 150W translates to 0.15 kW (150 / 1,000 = 0.15 kW). You can also convert kilowatts into watts by multiplying the total kilowatts by 1,000. For instance, 1.4 kW equals 1,400 watts (1.4 x 1,000 = 1400 watts).

How many watts does an American house use?

The Energy Information Administration (EIA) estimates that an average US household consumes 11,000 kWh of electricity annually. That translates to 29,130 watts (W) a day. You can further divide it by 24 hours to get 1,214 watts on average to fulfill the daily power requirements of one house.

What consumes more energy in a home?

You can reduce your electricity consumption by watching appliances that use more energy in your home. Here is a quick breakdown of some regular chores you perform at home:
  1. Energy-efficient fluorescent lights can help you save up to 75% on your electricity bills. These bulbs consume only 0.025 kWh an hour.
  2. If you do laundry twice weekly, you consume more than 200 kWh annually. After all, an average clothes dryer uses 2.7 KWh on one load.
  3. An average US home consumes about 5,000 kWh annually to operate an electric water heater.
  4. Baking consumes 3.2 kWh, and frying takes 2.4 kWh for an hour.
  5. In summer, a conventional air conditioner uses approximately 30 kWh daily.
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