⚡How is Electricity Measured? The Ultimate Guide (2021)

⚡How is Electricity Measured? The Ultimate Guide (2021)

How is Electricity Measured?

The Ultimate Guide

written by Stanley Udegbunam || Dec 30, 2020

how is electricity measured


Electricity is measured in different units of power which include the watt, kilowatt and megawatt.


This is the smallest unit measurement of electric power.

Household electrical appliances like electric iron and water heater have electrical rating plates on them.

The plate outlines the power rating of the appliance in Watts.

    power nameplate

    electricity rating plate or power nameplate

    Kilowatt (KW)

    Due to high power demand from electrical appliances, the power rating is expressed in kilowatt (KW) rather than Watt(W).

    1KW= 1000W

    Hence for the electric kettle above, 3,000W = 3KW

    Some home electric showers consume up to 10.5 KW

    Megawatt (MW)

    It is a much larger amount of energy used to measure the power output of cities, power plants and large factories.

    1MW= 1000KW  = ( 1 million watt)

    Palo Verde nuclear power plant in Arizona is the largest nuclear power plant in the United States.

    The power plant is endowed with three reactors and total net summer electricity generating capacity of about 3,937 MW.

    Tokyo Electric Power Co.’s (TEPCO) Kashiwazaki-Kariwa plant in Japan is currently the world’s largest nuclear power plant.

    It has a net capacity of 7,965MW.

    Gigawatt (GW)

    Gigawatt is suitable for measuring the capacity of large power plants or power grid. 

    1GW= 1000MW 

    100 MW = 1 million Kilowatt = 1 billion watt

    therefore, 1 GW = 1 billion watt

    1GW= 1000MW

    100 MW = 1 million Kilowatt = 1 billion watt

    therefore, 1 GW = 1 billion watt

    In 2019, U.S nuclear generation capacity exceeded more than 98 gigawatts.

    power line

    AFRILCATE article – how is electricity measured?


    Electricity production and consumption are most commonly measured in kilowatt-hours (kWh).

    A kilowatt-hour means one kilowatt (1,000 watts) of electricity produced or consumed for one hour.

    It indicates the amount of energy that would be expended if a 1,000-watt appliance runs for an hour:

    1KWH= 1000W in 1 HR

    So if you switched on a 50 watt light bulb, it would take 20 hours to expend 1 kWh of energy.

    A  2,500-watt electric kettle would use 1 kWh in just 25 minutes.

    Whereas a 4000-watt cooker utilized for 1 hour will consume 4 kWh of electricity.

    Electricity bill usually indicates the number of kilowatt-hours (kWh) consumed by households during the period stated on the bill.

    In 2018, the average annual electricity consumption for a U.S. residential utility customer was 10,972 kilowatt-hours (kWh).

    This amounts to an average of about 914 kWh per month.

    What Is Thermal Energy: The Ultimate Learning Guide (updated)

    What Is Thermal Energy: The Ultimate Learning Guide (updated)

    What is Thermal Energy?:

    The Ultimate Learning Guide

    written by Stanley Udegbunam || Dec 29, 2020

    thermal energy: ultimate learning guide



    Thermal Energy is energy obtained from the vibration of atoms and molecules of a substance due to its rise in temperature. Thermal Energy is also known as heat energy


      Matters are made up of particles or molecules that vibrates constantly along their mean free path.

      When this matter is heated up, the molecules of the substance closer to the heat source first absorbs the heat.

      The vibration of the excited molecule increases and it collides faster with surrounding molecules.

      The heat is transferred upon collision to these surrounding molecules, they get excited, their vibration increases and they transfer this heat energy further out to other molecules.

      Through continuous collision, the thermal (heat) energy is gradually transmitted along the mean free path of the object until the entire object is completely heated up.

      A point of thermal equilibrium is said to be reached when all the molecules of the object possess the same heat energy.

      At thermal equilibrium, all the molecules of the object vibrate and collide at the same speed.

      It’s impossible to talk about thermal energy without mentioning temperature.

      Temperature is the degree of hotness or coldness of a substance and its measured with a thermometer.

      The temperature readings of a thermometer are either calibrated in Celsius, Kelvin or Fahrenheit scale.

      Increasing the temperature of the heat source will lead to higher molecular excitation of the object and a faster collision.

      By so doing, the heat will be transferred at a faster rate and the thermal energy of the object will increase.

      Increased temperature —> Increased vibration/collision —> Higher thermal Energy

      Thermal energy is a type of kinetic energy since it transmitted through the movement and collision of molecules. 

      Recall: Kinetic energy is associated with motion.


      1. Heat from the sun
      2. Heat from a burner
      3. Chilling a warm drink
      4. A burning object
      5. Baking in an oven
      6. The Energy from the earth’s core

      1. Heat from the sun

      The energy from the sun is a form of thermal energy.

      The heat from the sun gets to us through radiation.

      Radiation is the transport of thermally generated electromagnetic waves.

      We recently published a reader-friendly article about radiation.

      See it here: Ultimate Guide on Radiation


      2. Heat from a burner

      The is one of the common examples of thermal energy in households.

       The burner gets heated up and when an object is placed on it, the thermal energy is transferred through conduction to the pot or kettle.


      Chilling a warm drink

      If ice cubes are placed in a glass of lemonade,

      the heat energy from the lemonade will be transferred to the ice through convection and the ice will melt.

      Eventually, the lemonade and water from the ice will be at the same temperature, a state of thermal equilibrium.

      The lemonade initially possessed higher thermal energy by virtue of the temperature difference.

      thermal ice heat transfer

      A burning object

      Once an object is set ablaze it possesses thermal energy.

      If you lit a match stick and you bring your hands a bit close, you will feel a burning sensation as a result of heat energy produced.

      (disclaimer: please don’t bring your hands close unless you have superpowers)

      burning match stick

      Baking in an oven

      Ovens are sources of thermal energy.

      Most ovens have a temperature adjusting knob, which increases the amount of heat transferred for faster cooking. 

      The heat is transmitted to the food by convection from the walls of the oven.

      thermal energy oven

      The energy from the earth’s core

      Energy gotten from the sub-surface of the earth is called geothermal energy.

      Geothermal energy is also an example of thermal energy. 

      It’s obvious from the name: GEO (meaning earth) + “thermal” energy. 

      it’s used for heating homes and buildings and also a useful resource for power generation.

      sub-surface geothermal energy


      As a form of energy, thermal energy is measured in Joules (J).

      However, in many applied fields in engineering, the British thermal unit (BTU) and the calorie are often used.

      The standard unit for the rate of heat transferred is the Watt (W), defined as one joule per second.


      Heat is the amount of energy in a body, temperature is a measure of the intensity of the heat.

      There’s this confusion that normally exits between temperature and heat, you can check out our comparison article for better clarification.

      Heat vs Temperature

      An increase in temperature will lead to a corresponding increase in thermal energy.

      Thermal energy is considered a type of kinetic energy since it involves the movement of molecules.

      Heat energy is just another name for thermal energy.

      Heat is transferred from hotter regions to cooler regions through either conduction, convection or radiation.

      thermal energy of burning wood

      burning wood

      Lightning 101 🌩️: The Ultimate Information Guide (updated)

      Lightning 101 🌩️: The Ultimate Information Guide (updated)

      Lightning 101 🌩️:

      The Ultimate Information Guide

      written by Stanley Udegbunam || Dec 28, 2020

      lightning 101



      Lightning is the visible electrical discharge in the atmosphere that occurs when cloud regions acquire excess electrical charge strong enough to break through the air resistance.

      Lightning is the result of rapid charge movements in storm clouds.


        Lightning is caused by imbalanced electric charges of cloud particles.

        Different sized frozen water droplets, ice, and hails in cloud regions often collide with each other.

        These collisions create electrical charges with some particles been positively charged and others, negatively charged.

        Collision continues until the cloud becomes electrically saturated. At this point, the cloud is said to be charged up.

        The lighter particles are positively charged and they rise to the top of the cloud.

        The heavier particles, been negatively charged falls to the bottom of the cloud.

        When individual charges grow large enough, an electric field is set up and lightning is released between oppositely charged regions.


        An electrically saturated cloud region contains positively charged particles in the upper region and negatively charged particles in the lower cloud region.

        Those charges in the clouds can cause changes on the ground.

        The negatively charged cloud particles closer to the earth’s surface makes objects in the air beneath and on the ground level become positively charged.

        This creates an electric field between the cloud and the ground surfaces.

        The thunderhead pull from the cloud’s negative charged particles forces the ground positively charged particles to cluster at high points.

        Air resistance acts as insulators between the cloud and ground surface.

        When the charge becomes strong enough, it breaks through the resistance.

        At this point, a stream of negative charges from the cloud called stepped leader rushes downwards towards high points on the ground which already contains clustered positive charges.

        Due to the electrical attraction, the positive charge from the ground also rushes upward to link up with the negative charge, and a bright flash which we call lightning is formed.

        What is seen to be only a single flash is actually a series of return strokes of electrical energy reaching back up into the cloud.

        In other words, lightning strikes the ground due to imbalanced electrical charges formed between the ground surfaces and cloud regions.

        The energy of the lightning strike contains hundreds of millions of volts and lasts only a fraction of seconds.

        The sound heard after a lightning strike is called thunder.

        lightning striking the ground


        Thunder is caused by the rapid expansion of the air surrounding the path traveled by a lightning bolt.

        A bolt of lightning heats the air along its path causing it to expand rapidly.

        The expansion creates a shock wave that turns into a booming sound wave, known as thunder.

        We see lightning strike first before we hear the accompanying thunder because light travels faster than sound.

        During a thunderstorm, lightning can occur within a cloud, between adjacent clouds, between the cloud and the air, or between the cloud and the ground.

        This gives rise to various types of lighting.


        1. Intra-Cloud Lightning
        2. Inter-Cloud Lightning
        3. Cloud-to-Ground Lightning
        4. Sheet Lightning
        5. Forked Lightning
        6. Heat Lightning
        7. High – Altitude Lightning
        8. Anvil Lightning
        9. Ball Lightning
        different lightning types

        1. Intracloud Lightning: This is the most common type of lightning. This occurs when there are both positive and negative charges within the same cloud. About three-quarters of all lightning on Earth never leaves the cloud where it formed.
        2. Intercloud Lightning: This is when a lightning strike occurs between charged particles of different clouds and the strike travels in the air between them.
        3. Cloud-to-Ground Lightning: This is lightning that strikes from the negatively charged bottom of the cloud traveling to the positively charged ground below. It’s the most dangerous type of lightning and each bolt can contain up to one billion volts of electricity.
        4. Sheet Lightning: This lightning appears as flashes of light that seem to light up or illuminate entire clouds. The name is often interchanged with intracloud lighting.
        5. Forked Lightning: This appears as jagged lines of light. They can have several branches. Forked lightning can be seen shooting from the clouds to the ground, from one cloud to another cloud, or from a cloud out into the air. This lightning can strike up to 10 miles away from a thunderstorm.
        6. Heat Lightning: This is a term used to describe lightning flashes that are too far away from you to hear the thunder. The reason that it is called heat lightning is that it appears most often on a hot summer day when the sky is clear overhead.
        7. High – Altitude Lightning: This lightning type has been given other names such as “red sprites,” “green elves,” and “blue jets.” This form of lightning appears as brightly colored flashes, high above thunderstorms. You can’t see these types of lightning from the ground.
        8. Anvil Lightning: Popularly called “the bolt from the blue”, they are much more powerful than normal lightning strikes, and therefore cause more bodily and property damage. They are rare supercharged positive that can travel long distances, up to 25 miles before crashing into a section of negatively charged earth. Due to the long-distance traveled, these strikes can sneak up on people who don’t even know a thunderstorm is miles away hence its popular name – “the bolt from the blue”.
        1. Ball Lightning: This is a very rare form of lightning. Ball lightning is usually spherical in shape and about one foot in diameter. Hissing noises originate from such balls and they sometimes make a loud noise when they explode. Ball lightning has proven difficult to verify in nature but floating orbs of electricity have been reported during thunderstorms around the world.


        Lightning is more deadly than hurricanes and tornadoes and about 2,000 people are killed worldwide by lightning each year.

        Here are some tips to keep you safe during thunderstorms.

        • Stay away from structures with exposed openings like convertible cars/tractors and also open surfaces like fields, sheds, carports, picnic shelters and open-air stadiums.
        • Swimming pools are notoriously dangerous during thunderstorms because water conducts electricity so easily. 
        • Lightning can send jolts through electric lines or water lines into a house, injuring the people inside. Hence, it’s a bad idea to bathe, wash dishes, or use appliances during a storm. 
        • Always avoid being the highest object anywhere—or taking shelter near or under the highest object, including tall trees. Do not stand near lightning rods or underground pipes. 
        • if you can hear thunder, you may be at risk of being struck. Take this advice, “When thunder roars, go indoors.”
        lightning ignites burning tree

        lightening can be hazardous ⚡: observe safety measures.

        🌩️ 27 Mind-Blowing Facts about Lightning (updated)

        🌩️ 27 Mind-Blowing Facts about Lightning (updated)

        🌩️ 27 Mind-Blowing Facts about Lightning (updated)

        written by Stanley Udegbunam || Dec 28, 2020

        lightning facts for kids

        Lightning is the visible electrical discharge in the atmosphere that occurs when region of clouds acquires excess electrical charge strong enough to break through the air resistance.

        In today’s article, we will be looking at mind-blowing facts about lightning that are really worth knowing.

        Without further ado, let’s get started.


           27 Lightning Facts

          1. The greatest concentration of lightning strikes is in central Africa and south Americans.
          2. The irrational fear of lightning is known as keraunophobia.
          3. The study of lightning is called fulminology.
          4. Lightning once took down a $78 million Atlas-Centaur 67 rocket in March 1987.
          5. Worldwide estimates that lightning occurs 50-100 times a second.
          6. A single bolt of lightning is around 50,000F, approximately 5 times hotter than the surface of the sun.
          7. The odds of being struck in your lifetime is 1 in every 3,000.
          8. Lightning kills about 2,000 people a year.
          9. In the US, lightening occurs most often in Florida. Its hot, moist climate is perfect for creating thunder cloud, which produces lightening.
          10. In Venezuela, there’s something called “Catatumbo” lightning, where there’s almost constant lightning strikes, averaging over 100 strikes per hour.
          11. Lightning can carry over 100 million volts of electricity.
          12. Lightning is not confined to thunderstorms. It’s been seen in volcanic eruptions, extremely intense forest fires, surface nuclear detonations, heavy snowstorms, and in large hurricanes.
          13. You can deduce the distance of the storm by counting the time difference between the lightning and the thunder (5 seconds = 1 mile away).
          14. Park ranger Roy Sullivan holds the Guinness Record for surviving seven lightning strike
          15. The rapid expansion of heated air causes the thunder.
          16. During electrical storms, people are advised to seek shelter inside the building and if caught in the open avoid high ground and isolated trees.
          17. Positive lightning is particularly dangerous, because they travel long distance up to 25 miles and sneak on people who don’t even know about the thunderstorm miles away.
          18. If you can hear thunder, you are within 10 miles (16 kilometers) of a storm and can be struck by lightning. Seek shelter and avoid situations in which you may be vulnerable.
          19. A house or other substantial building offers the best protection from lightning. For a shelter to provide protection from lightning, it must contain a mechanism for conducting the electrical current from the point of contact to the ground.
          20. An umbrella can increase your chances of being struck by lightning if it makes you the tallest object in the area.
          lightning strike facts

          facts about lightning

          21. An umbrella can increase your chances of being struck by lightning if it makes you the tallest object in the area.

          22. Lightning comes out of the ground as well as down from the sky. A bolt of lightning leaps up from the ground to meet the incoming bolt from the sky. The bolt from the ground travels very fast that’s why we can’t see it.

          23. Benjamin Franklin came up with early lightning protection – the idea of securing lightning rods to the tops of buildings in order to protect structures from the impact of lightning strikes.

          24. “Lightning never strikes twice” is just a myth, lightning can strike the same location many times especially if it’s a tall, pointy, isolated object. The Empire State Building gets hit an average of 23 times a year.

          25. The human body doesn’t store electricity. It is perfectly safe to touch a lightning victim to give them first aid.

          26. Lying flat on the ground makes you more vulnerable to electrocution, not less. Lightning generates potentially deadly electrical currents along the ground in all directions—by lying down, you’re providing more potential points on your body to hit.

          27. Men are nearly four times more likely to be killed by lightning than women.

          It’s because men spend more time outdoors, especially fishing, doing more vulnerable activities than women.

          Also, men are more reluctant to go inside if they hear thunder.

          Think about it: You’re out on the water fishing with nowhere to take shelter, and you happen to be the tallest thing around.

          If you were lightning, you’d hit a fisherman, too.

          What is Light Energy? 💡 The Best Illumination Guide (2021)

          What is Light Energy? 💡 The Best Illumination Guide (2021)


          The Best Illumination Guide

          written by Stanley Udegbunam || Dec 28, 2020

          light energy - best illumination guide



          Light energy is energy within the range of the electromagnetic spectrum that is visible to the human eyes.

          Light energy is a type of kinetic energy and it travels in waves.


          Light energy is produced through the release of tiny packets of energy called photons.

          A photon is the smallest discrete amount of electromagnetic radiation.

          Energized electrons release photons as extra energy in order to maintain it’s stability.

          According to quantum physics, a light beam is made of zillions of tiny packets of photons, streaming through the air.

          photons produces light energy


          Light travels as a wave. It moves in a straight line until something alters its path.

          Its path is altered if it’s reflected, refracted, or absorbed.

          Unlike sound and water waves, it does not need a material medium for its propagation.

          Light can travel through a vacuum.


          In vacuum, the speed of light is 186,282 miles per second (299,792 km/s).

          This is approximately 3 × 108 m/s.

          In theory, nothing can travel faster than light.


          The major source of light energy on earth is the sun.

          Fireflies and glow worms also emit their own light. This ability is called bioluminescence.

            Other sources of light energy include:

            • Thermal sources – burning firewood, gas, lited match stick etc.
            • Electrical sources – led, bulbs etc.
            • Chemical sources – explosions.
            bulbs - electric source of light

            lightbulbs – electrical sources


            Common examples of light energy in everyday life include:

            1. Sunlight.
            2. Fire (heat source)
            3. Bulbs
            4. Laser lights
            5. Comic bodies


            fire - heat source

            heat source

            laser light

            laser light


            1. Light is required for human vision. The eyes will be useless without light.
            2. Light energy is also used by plants to produce food, a process called photosynthesis.
            3. Light energy from the sun serves as feed to solar panels which helps solve power outages.
            4. Light energy is responsible for object coloration. The color of an object is the wavelength of light it reflects.
            5. Light energy is required for city illumination. Street lights, stop signs and traffic lights all emit light energy.
            city illumination

            city illumination

            What is Kinetic Energy? The Ultimate Learning Guide (2021)

            What is Kinetic Energy? The Ultimate Learning Guide (2021)


            The Ultimate Learning Guide

            written by Stanley Udegbunam || Dec 27, 2020

            kinetic energy: The Ultimate learning guide



            Kinetic energy is the energy possessed in a body by virtue of its motion.

            Kinetic energy is a scalar quantity which means it has magnitude but no direction.


            The formula for kinetic energy is:

            K.E =  1/mv2


            K.E is the kinetic energy of the object

            m is the mass of an object

            v is the velocity of an object

            Hence, Kinetic energy depends on mass and velocity.


            1. A river flowing at a certain speed possesses kinetic energy.
            2. A truck moving down the road at a certain speed has more kinetic energy than a car traveling at that same speed because the truck has more mass than the car.
            3. A flying plane has a very high kinetic energy not only because of its large mass but also because of its high velocity.
            4. Bullets from guns have high kinetic energy due to the large amount of velocity possessed by the bullet.
            5. When we work, run or jog, we possess some amount of kinetic energy.
            kinetic energy examples

            a bicycle in motion possesses kinetic energy


            • Radiant Energy: A type of kinetic energy that travels in waves through medium or space.

            Examples include the Sun, the light bulb, the glowing coil on an electric cooker.

            • Sound Energy: This is energy produced by the vibration of an object. Sound energy needs a medium for its propagation and travels out in all directions. They can’t travel in a vacuum. Examples include voices and musical instruments. 
            • Thermal Energy: This is also a type of kinetic energy that exists due to motion and collision of atoms and molecules. Example: a heated cooking spoon.
            • Electrical Energy: This is energy resulting from the flow of electric charges. Examples include electric Iron, lightning.
            • Mechanical Energy: This is the energy stored in objects. It is the sum of kinetic energy and potential energy. Example: A moving tricycle.


            The standard metric unit of measurement for kinetic energy is the Joule.

            1 Joule = 1 kg • m2/s2


            An object of mass 5kg is moving at a constant velocity of 15ms-1. Calculate its K.E


            K.E = 1/2mv2

            K.E = 1/2 × 5 × 152 = 562.5 J


            1. Determine the kinetic energy of a 825-kg convertible car that is moving with a speed of 22.4 m/s. 

            (Tap on the option tab to reveal answer)

            a. 3.540 Joules

            X wrong!!

            b. 2.07 × 10^5 Joules

            ✔ Correct

            2. If the convertible car in the above problem is moving with three times its speed, what would be its new kinetic energy?

            a. 1.47 × 10^3 Joules

            X wrong!!

            b. 1.86 × 10 ^ 6 Joules

            ✔ Correct

            3. Mohammed Ali, the former Africa boxing champion, had a kinetic energy of 15,000J just prior to rendering a knock-out punch to his opponent.

            If Ali’s mass is 180 kg, then what is the speed of the blow?

            a. 16.67 m/s

            ✔ Correct

            b. 23.18 m/s

            X wrong!!

            4. A 900-kg propulsion jet moving at 30 m/s has 405,000 Joules of kinetic energy. Estimate its new kinetic energy if it is moving at 15m/s.

            a. 101,250 J

            ✔ Correct

            b. 205,700 J

            X wrong!!

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