Here's a question for you.  How many people does it take to turn on a light bulb?  The answer seems simple, just walk into a dark room, flip a switch and, instantly, you can see, right?

Well, the truth is once you go behind the light switch there are a lot of other people involved in generating and distributing the electricity required to light up this bulb.

Hi I'm Lee Patrick Sullivan, and this Energy 101 video takes a look at the electricity system behind the light switch and explains what it really takes to turn on a light bulb.  In order to understand energy, we need to start at the source, literally.

Mother Nature provides the natural resources we use to generate power.  From natural gas to coal, ocean tides, to mountain winds, the energy we need to create electricity must first be mined, harnessed or collected from the earth.  Some of these resources are finite, including fossil fuels like coal and oil, but others are unlimited, like solar and wind power.

But a lump of coal or a strong breeze alone won't create the power that turns on your light.  For every energy source, a chemical or mechanical process is required to convert into usable electricity.

Every day researchers work to find innovative ways to use our limited resources, process raw materials, harness renewables more efficiently, and develop new energy sources.

Today the majority of America's power comes from thermal power plants.  Fuels like coal, natural gas, biomass and uranium are used to heat water until it produces steam which powers a turbine and generates electricity.

The high temperature and pressured steam turns propeller-like blades around a rotor inside the turbine.  This turning rotor connects to a main shaft which spins magnets within a coil of wire.  This mechanical motion induces an electric current on the wire, which is the source of the electricity generated by the turbine inside the generator.

Steam-powered turbines are a popular method of producing electricity because the water can be heated by a variety of fuels, and that same water can also be recycled once it cools down.

Transporting electricity from the power plant to your home is an entirely different process.  Current technology cannot cost effectively store large amounts of electricity; so significant challenges exist when it comes to transferring power across long distances.

Just enough electricity has to be generated to meet demand at all times and be transmitted through power lines to reach your light switch.  Too much or too little power can strain the transmission system and cause a blackout. That's why a complex mix of infrastructure and coordinated management is needed to transmit electricity from power generators to consumers. Enter the electricity grid.

The North American electricity grid is actually made of four major grid systems: the western grid, the eastern grid, the Texas grid and a grid covering the Canadian province of Quebec.  These independent regional networks of power plants and transmission lines in several smaller regional networks carry electricity at high voltage within their area to local utilities.

But there are limited links between the four grids - which means, for example, the electricity generated from a wind turbine in West Texas cannot reach an apartment building in New York City.

For electricity to move through one of these regional power grids, its voltage must first be increased by a device called a transformer. Then the electricity can travel long distances across high voltage transmission lines.

These high voltage lines are generally strung between giant metal towers.  They stretch for miles from power plants to local substations in each neighborhood.  You've probably seen substations along the side of the road and wonder what they do.

Their job is stepping down electric voltages from levels as high as 765,000 volts to a lower voltage close to the 110 volts you use in your home. That's why the electricity from the power line on your street also passes through a transformer which steps down the voltage once more typically from 13,000 or 4,000 volts before it travels along another line into your house.

From there, the electricity enters your breaker box, and then it's distributed to light sockets and outlets.  All you have to do is flip a switch.

So as you can see, from the raw materials to the power lines on your street, there are a lot more people involved than you might think in turning on your light bulb.

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