Day-to-day, barely a minute passes that is not touched by electricity. Do you check your phone first thing in the morning? Do you spend your day working on a computer? Do you cook your dinner in the oven at night? Electricity is omnipresent. In one form or another, it makes daily life as we know it possible. I, for one, would not have a job without it! But what is it? Where does it come from? How did it get its start? We’ll give you a bit of history, and then explain how electricity makes it’s way from a power plant to your toaster.
Electricity has a long and fascinating history. The ancient Egyptians, Greeks, Romans, and Arabs all knew that there was something special about the electric fish they encountered in their rivers. These ancient cultures also discovered what you and I learned in the first grade: static electricity! They discovered that an amber rod (like a balloon) could be rubbed with fur (or your hair) to attract other light objects. Fast forward to the 1600s when an English scientist named William Gilbert conducted some of the first controlled electrical experiments and discovered that the lodestone effect (a lodestone is a naturally magnetized mineral) was different from static electricity. He coined the word electricus (“from amber”) from the Greek word elektron (“amber”).1 Subsequent research into electricity would be conducted by a murderers’ row of the greatest minds in science including Benjamin Franklin (kites!), Alessandro Volta (Volt; unit of voltage), André-Marie Ampère (Ampere; unit of current), Michael Faraday (Farad; unit of capacitance), Georg Ohm (Ohm; unit of resistance), Edison, Kelvin, Tesla, Westinghouse, and Einstein!
Now that we’ve covered 4000 years of history, let’s talk some basics. [Warning: the following explanation is going to be a gross oversimplification and is not intended to be scientifically rigorous.] Electricity, at its simplest, is electrons moving through a conductor. A conductor can be many things, such as metal or your tongue when you test a 9 volt battery. A voltage “pushes” the electrons through the conductor to create an electric current.2 3 A commonly used analogy that is a bit easier to visualize is a system of water pipes. In this analogy, the water pressure is the voltage, the flowing water is the current, and the pipe is the conductor. The diameter of the pipe is comparable to what is known as resistance (how difficult it is to push the water through the pipe).
In order to generate the voltage and current, we need a generator. At this point, it is worth remembering that electricity is just a form of energy. If you remember your high school physics class, you might recall that the First Law of Thermodynamics states that energy can neither be created nor destroyed. It can only change forms. That is in essence what a generator does. It takes the chemical (primary) energy stored in coal, natural gas or uranium and turns it into electrical (secondary) energy. A generator does this by releasing the chemical energy (burning or nuclear fission) and using that energy to heat water and create steam. The steam in turn spins a turbine which generates electricity.4
After the electricity is generated, it needs to be delivered to the end user. This is a multi-stage process. The first step is to transform the newly generated electricity to a very high voltage using a transformer. Typical transmission voltages can be as high as 765,000 volts. This very high voltage allows the electricity to be transmitted long distances and minimizes power losses. It is interesting to note that the reason the electricity can be transformed to such high voltages is because it is AC (alternating current – like your home outlet) as opposed to DC (direct current – like a battery).5 The high voltage electricity then travels over transmission lines to an area distribution substation where the electricity is transformed down to around 14,000 volts. At this point the electricity is transmitted over the poles running down your street. Before it gets to you, the electricity is stepped down one more time on the pole outside of your home. The large “can” on the top of the telephone pole on your street is actually another transformer. It steps down the voltage to 240/120 volts, which is what you use to power your toaster and cook your Pop-Tarts!
It’s curious that as dependent on electricity as we are, it is so easy to take it for granted. Wasting a little bit of energy here and there doesn’t seem like much but it can add up, especially when you multiply it by millions of households over many years. The most important factor in making a change is having the necessary information. At Sense, we hope to help you better understand the way you use electricity by giving you the information you need to make intelligent decisions. I hope that we have shed some light on the slightly mysterious-but-essential force of nature that is electricity. As always, happy sensing!
1. Baigrie, Brian (2006), Electricity and Magnetism: A Historical Perspective, Greenwood Press, pp. 7–8, ISBN 0-313-33358-0
2. Fun Fact: Electrons actually move in the opposite direction of the flowing current due to an unfortunate naming convention. See http://xkcd.com/567/
3. Remember kids, it’s not the voltage that kills you, it’s the current. https://www.physics.ohio-state.edu/~p616/safety/fatal_current.html
4. It never ceases to amaze me that a generator is just a motor in reverse. Whereas a motor takes electricity and turns it into a spinning force, a generator takes a spinning force and turns it into electricity! http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/motorac.html
5. In the late 1800’s there was a battle between Thomas Edison and Nikola Tesla/George Westinghouse to determine whether AC or DC should be the standard. http://energy.gov/articles/war-currents-ac-vs-dc-power