Understanding Electricity: Step One to reThinking Solar Energy (Part 1)
Daniel J. Stouffer
May 19, 2008
The intent of this article is to help you to understand enough about electricity so that you can understand the technology used in solar photovoltaic (PV) systems. You most likely will review a lot of information and learn many new solar energy terms when you begin the process of purchasing or renting a home solar power system.
When you start researching residential solar energy systems, or even taking a close look at your electric bill, you hear a lot about kilowatts and kilowatt hours. You may have used these terms mistakenly as the same thing in the past. They are pretty close in meaning. Both terms are just a measure of relative electricity sizes.
However, they are very different measurements, as you will learn through the electricity definitions included here. In order to understand what they mean, you also need to understand a few basic concepts about electricity.
When talking about electricity, you will be using terms like power and energy. The average person often uses these terms interchangeably in daily speech along with current, potential, charge, electrons, and even photons. You might have learned about all of these electricity terms way back in high school. In use as part of your daily life, you may have confused their meaning.
Common Residential Electricity Terms
Here are the most important electricity concepts you need to know when you begin the process of purchasing or renting a solar energy system for your home. It may be surprising to you that the actual meaning of a few of these is not quite what you expected.
Power: The rate at which work is performed or energy is provided. Power is the amount of energy required or expended for a given unit of time. It is measured in watts (W).
Energy: The actual work done by solar panels installed on your home. In other words, energy is power supplied over a period of time. It is typically measured in joules or watt hours (Wh).
Potential: The capacity of an electric field to do work (i.e. to provide energy). This is similar to the height of water behind a dam. It has capacity to do work. The higher the water, the more potential energy that is available. Potential is measured in volts (V).
Current: A movement or flow of electrically charged particles. This is not unlike the speed of water flow in a river. It is measured in amperes (I or in common terms amps).
Resistance: The property of a material, object, or circuit to resist the flow of electricity. Materials that allow electricity to flow easily (with low resistance) are called conductors while materials that resist the flow of electricity are called insulators. Resistance is measured in ohms (R).
Charge: A property of some subatomic particles, i.e. the charge on an electron (subatomic particle is negative). Charge determines how subatomic particles interact. Electrically charged matter is influenced by and produces electromagnetic fields. Charges are either negative or positive and have measurable strength.
Field: An effect produced by an electric charge that exerts a force on charged objects in its vicinity.
Electron: A negatively charged subatomic particle. The current is caused by the movement of electrons from different energy levels within its atomic structure.
Photon: An elementary particle that is the carrier of electromagnetic radiation of all wavelengths. The photon is different from many other elementary particles, such as the electron, because it has no mass. That means that it travels at the speed of light across the vacuum of space. Trillions and trillions of photons are blasted out from the sun every second.
Upgrading Your Home to Solar Power
To understand solar electric systems and how they work, you first need to understand the basic principles of electricity. This means learning the language used to explain these principles. In our next article which is a ongoing series related to renewable energy, we will dive into understanding the language of residential solar electric systems.
Becoming comfortable with the electricity jargon and technical terms is an important step when considering purchasing or renting a solar energy system for your home. You should feel comfortable talking with solar industry experts about your home solar options. In future articles, we will dig deeper into the details and emerging options for home solar power systems.
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