In this section we are going to break down what “power” is and how it works. We are not talking about “political power” or “power of attorney”. No, we are talking about electrical power.
What is electricity?
Let’s start at WHAT electricity is. Electricity is a form of energy. To get a little more scientific it is the flow of electrons or energy from one thing to another. You see this flow of electrons happen every day; when you turn the lights on (if the electricity is working) there is power flowing from your local power plant to your light bulb and when you plug anything into the wall outlet it is receiving power from an exchange of electrons or energy.
AC/DC not just a great band!
Electricity gets even more interesting from here. There are two different “types” of electricity: Alternating Current (AC) and Direct Current (DC). They mean exactly what they sound like. DC is a direct flow of power in one direction while AC is power that changes or alternates direction.
A few facts about DC power:
- Most vehicles use DC power….to run the lights, the radio and even to start
- It is the only “type” of power that can be stored in something like a battery.
A few facts about AC power:
- Most “Wall Plugs” are AC power systems. That kind of power comes from a power plant.
The most common power plants are Hydro (water), Coal, or Nuclear.
- AC power is much better at traveling over long distances.
Watts going on?
It’s time to get down to the nitty-gritty; Watts, Volts and Amps. You really don’t need to be worried, let’s take it one step at a time.
Electricity consists of the flow of electrons through a conductor such as an electric wire. You can’t see electrons but a helpful analogy is to think of electricity as the flow of water through a pipe. We measure the rate of flow of electricity as an electric current (notice the water analogy again if we think of a river current). Electric current is measured in Amperes, shortened to Amps or simply the letter A. A current of 2 Amps can be written as 2A. The bigger the current the more electricity is flowing.
So what makes the current flow in the first place? A device such as a battery provides a potential difference in an electric circuit. If we go back to our water analogy, the battery is like a water pump that propels water through a pipe. It creates pressure in the pipe causing the water to flow. So how do we measure this pressure? We call electrical pressure Voltage and measure it in Volts, shortened to V. A voltage of 3 volts can be written as 3V. The bigger the voltage the higher the pressure and the more current flows. But in order for the current to flow, the electrical conductor or wire must loop back to the battery. If we break the circuit, with a switch for example, then no current flows.
So how do Current and Voltage relate to one another? Well, the bigger the current the brighter the light and similarly the bigger the voltage the brighter the light. Both the voltage and the current in the bulb determine how much energy is released in a certain time. The Watt is a measure of power or how much energy is released per second. It can be shortened to W. One Watt can be written 1W. We can calculate the power released in a bulb by multiplying the voltage in Volts across the bulb by the current in Amps flowing through the bulb (W = V x A). For example a current of 2 Amps flowing through a bulb with 12 Volts across it generates 24 watts of power. In the UK, domestic power is supplied at 240 Volts. A 100 Watt bulb will therefore draw a current of 100/240 Amps (about 0.4A). This means a 1A fuse can be safely added to the mains plug of a desk lamp with a 100W bulb because 1A is much greater than 0.4A. In the USA, the domestic supply is typically 110V, safer than the UK, and this means a 100W bulb draws a current of 100/110 Amps (about 0.9A).
What is solar?
Solar power is energy that is collected from the sun. The amount of sunlight that reaches the earth is enough energy to power the needs of the entire world more than 8500 times over. How does it work? Solar power cells consist of two layers of treated silicon. The bottom layer is positively charged and the top layer is negatively charged. When the sun hits the panel electrons move and create electricity. What does solar efficiency mean? Manufacturers test their solar panels and cells in perfect conditions (74 degree, 1 MPH wind), which is never what actually happens in reality. However, with the correct orientation to the sun and good sunlight, you can expect on average around 60% of the rated wattage that the panel advertised.
What are the different types of solar and why do we use mono-crystalline?