Power measurement units

   Since power generation is a process of energy conversion, we should refer here to energy measurement units. Energy is generally (mechanical, electrical, or thermal) measured by the Joule unit.

In the case of mechanical energy 
Mechanical energy can be expressed in three different images (all images of the same energy but with different transformations):

1. Potential Energy, PE = mass x gravity acceleration x height
2. Kinetic Energy, KE= 0.5 mass x velocity ²
3. Work,: the final achievement of this mechanical energy, which is moving something for a certain distance, Work = Force x distance

All of them are measured by the unity of the joule. 

   The joule expresses the amount of work done by a force of one Newton when you push a object to a distance of one meter: Joules = Work = Mechanical Energy (J) = Force (N) x Distance (mt)

And in the case of electric power

The same unit (joule) represents the electricity consumed in the second within any electrical device with a power of one Watt:

   Electrical Energy = Power (watt) × time (sec) = Volt × Amp × Sec = Joules

Since this unit represents a small amount of energy, we can use larger units such as kWatt-Hour

1 (KWH) = 1000 x 60 x 60 = 36 x 10⁵ Joule

^{1 W.H = 3600 Joule}

^{Note: joule is also equivalent Electrically:}

• The energy obtained by an electric charge of 1 colum when moving between voltages of 1 volt.
• Energy required to conduct an electric current of 1 amp between the difference voltage of 1 volt during 1 second.

   The origin of electrical energy can be chemical as in batteries, or mechanically as in generating plants, or as in solar cells. What is important here is to emphasize that electric energy comes only from other energy.

In the case of thermal energy

Energy is often measured in a unit called calorie in the English system measured in another unit, (the British Thermal Unit, BTU),one Joule represents the energy consumed Q to raise the temperature of one gram of water to one degree Celsius.

𝐴𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝐻𝑒𝑎𝑡=𝑄=𝑚(𝑘𝑔) × 𝑐(𝑆𝑝𝑒𝑐𝑖𝑓𝑖𝑐 𝐻𝑒𝑎𝑡 𝑐𝑜𝑛𝑠𝑡)× Δ𝑇(℃)

The relationship between Joule and Calorie is:

1 Calorie = 4.18 Joule

The temperature degrees can be expressed in three different ways:

1. Using degrees Celsius. 
2. Using Kelvin scale K₀ (Temperature Absolute), And we get added 273 to degrees Celsius.
3. Fahrenheit measurement (the most commonly used in America), the following equation shows the method of conversion from Celsius to Fahrenheit.

F = 32 + 1.8 times ° C