Kilowatt: everything you need to know


When we contract the electrical power of our home, we have to take into account the kilowatt. This is the unit of power in common use that equals 1000 watts. In turn, the watt is a unit of boosting the international system equivalent to one joule per second. This is a very interesting term to know to know more about the electrical power that we contract.

Therefore, we are going to dedicate this article to tell you everything you need to know about the kilowatt and its characteristics.

What is the kilowatt

kilowatt hour

Kilowatt (kw) is a commonly used unit of power, equivalent to 1000 watts (w). The watt (w) is the international system unit of power, equivalent to one joule per second. If we use the unit used in electricity to express watts, we can say that watts are electrical energy produced by a potential difference of 1 volt and a current of 1 amp (1 volt amp).

The watt hour (Wh) is also commonly known as the unit of energy. The watt hour is a practical unit of energy, equivalent to the energy produced by one watt of power in one hour.

Common kilowatt-related mistakes

electric power

Kilowatts are sometimes confused with other related units of measure.

Watt and Watt-hour

Strength and energy are easy to confuse. Power can be said to be the rate at which energy is consumed (or produced). One watt is equal to one joule per second. For example, if a 100 W light bulb stays on for an hour, the energy consumed is 100 watt-hours (W • h) or 0,1 kilowatt-hours (kW • h) or (60 × 60 × 100) 360.000 joules (J).

This is the same energy required to make a 40W bulb glow for 2,5 hours. The capacity of a power plant is measured in watts, but the energy produced annually is measured in watt hours.

The last unit is rarely used. It is usually directly converted to kilowatt hours or megawatt hours. The kilowatt-hour (kWh) is not a unit of power. The kilowatt hour is a unit of energy. Due to the tendency to use kilowatts instead of kilowatt hours to shorten the energy term, they are often confused.

Watt-hour and Watt per hour

Using incorrect terminology when referring to power in kilowatt hours can cause further confusion. If you read it as kilowatt-hours or kWh, it can get confusing. This type of device is related to power generation and can express the characteristics of power plants in interesting ways.

The above unit types, such as watts per hour (W / h), reflect the ability to change power per hour. The number of watts per hour (W / h) can be used to characterize the rate of power increase of a power plant. For example, a power plant that reaches 1 MW from zero to 15 minutes has a rate of increase in power or speed of 4 MW / hour.

The power of hydroelectric plants is growing very fast, which makes them very suitable for handling peak loads and emergencies. Most of the energy production or consumption in a period is expressed in terawatt-hours consumed or produced. The period used is usually a calendar year or a fiscal year. One terawatt • hour equates to approximately 114 megawatts of energy consumed (or produced) continuously in one year.

Sometimes, the energy consumed during the year will be balanced, representing the installed power, making it easier for the recipient of the report to see the conversion. For example, a continuous consumption of 1 kW per year will result in an energy demand of approximately 8.760 kW • h / year. Watt years are sometimes discussed at conferences on global warming and energy use.

Difference between power and energy consumption

In many physics books, the symbol W is included to indicate work (from the English word work). This symbol must be distinguished from units in watts (work / time). Usually, in books, works are written with the letter W in italics or similar to freehand drawing.

Power is expressed in kilowatts. For instance, home appliances. Power represents the energy required to operate the equipment. Depending on the performance provided by this device, it may require more or less power.

Another aspect is energy consumption. Energy consumption is measured in kilowatt hours (kWh). This value depends on how much power the device consumes at a specific time and how long it consumes power.

Origin and history

james watt

The watt was named after the Scottish scientist James Watt in recognition of his contribution to the development of steam engines. The unit of measurement was approved by the Second Congress of the British Association for the Advancement of Science in 1882. This recognition coincided with the beginning of commercial water and steam production.

The Eleventh Congress of Weights and Measures in 1960 adopted this unit of measurement as the unit of measurement for power in the International System of Units (SI).

electrical power

Power is the amount of energy that is produced or consumed for each unit of time. This time can be measured in seconds, minutes, hours, days ... and power is measured in joules or watts.

The energy that is generated through electrical mechanisms measures the ability to generate work, that is, any type of “effort”. To understand it better, let's put simple examples of work: heating water, moving the blades of a fan, producing air, moving, etc. All this requires work that manages to overcome the opposing forces, forces such as gravity, the force of friction with the ground or air, the temperatures already present in the environment ... and that work is in the form of energy (energy electrical, thermal, mechanical ...).

The relationship established between energy and power is the rate at which energy is consumed. That is, how energy is measured in the joules consumed per unit of time. Each July consumed per second is one watt (watt), so this is the unit of measure for power. Since a watt is a very small unit, kilowatts (kW) are typically used. When you see the bill for electricity, appliances and so on, they will come in kW.

I hope that with this information you can learn more about the kilowatt and its characteristics.

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