Science In Real Life

Like most things in life, Science in Real Life can benefit from the addition of MORE POWER ARH ARH ARH.

… Anyway. This is the first of a three-parter addressing the sources and mechanisms by which we generate power, in the form of electricity, for use in powering the institutions and appliances of modern society. Part the first will focus on what I’m referring to as conventional power sources – those that rely on burning a fuel source to run a steam turbine to run a generator. First, a note about definitions. Power, in the English language, is a rather nebulous term, referring as it does to abstract entities in the political and athletic fields as well as the physical. In physics, power means the rate of energy transfer over time. Nothing more, nothing less.

From here on out we will follow a time honored tradition in physics: working backwards. We begin, therefore, in a small house on a nondescript street such as might be found almost anywhere save the truly impoverished countries of the world. A lamp flickers on, then holds steady, piercing the darkness. Electrons run through the cramped filament with all the determination and speed of a british comedian running sequential marathons. They do this because they are pushed forward by the electrons in the house’s wiring, which are in turn pushed by current flow in the neighborhood grid, going back to the local transformer, to the regional grid, in a giant game of Elbow Room going all the way back to the power plant.

Sliding into the power plant through the cables like a fancy Hollywood special effect, we pass through layers of insulation and conference rooms to find, at last, the architect of this affair, the assembly of apparatus known as the generator. You may think that at this point we must differentiate between the various and sundry fuels available to us, but I am going to back up one step further, and here is where the crux of the complicated physics happens. It is known as electromagnetic induction, and it operates equally well regardless of the initial energy source.

Some of you may remember from the Electromagnetism two-parter that electricity and magnetism are two sides of the same coin, and a very valuable coin it is at that. Thanks to a British gent named Mike Faraday (one of a handful of physicists who has his name attached to more things than does Newton), it was discovered that relative motion of a magnet and an electrical conductor (such as a coil of wire) will create an electric current. So we set up a ring of magnets and a wire coil on a shaft so that the coil can rotate inside the ring. (You might find this animation helpful for visualization purposes).

Now all we need is something to spin our shaft (pipe down, peanut gallery). Here is where all the different fuels become options – what to use? We could latch up some horses, or harness some failing CEOs and tell them there’s a government bailout in the corner, but perhaps steam is a more reliable method. Most of the power generated today comes from burning some substance to heat water into steam, then directing the steam into a turbine. The force of the steam on the turbine blades then rotates the shaft. It’s just like a windmill, except we generate the wind in the form of very very hot gaseous water.

Historically and currently, the following substances have been used in this capacity: wood, coal, petroleum, and methane, just to name a few. When someone refers to “fossil fuels” they don’t mean your grandmother’s oatmeal – it is because the latter three formed over hundreds of millions of years from ancient and decomposing lifeforms that somehow even today have enough energy to produce light and sound all over the world. In that sense they are not dissimilar from the Rolling Stones.

Unlike the Rolling Stones, however, the fossil fuels will eventually dry up and run out. In addition, the process of burning them is generating more carbon dioxide than the planet is accustomed to handling. Since Captain Planet has, for some unfathomable reason, not yet appeared to deal with the problem, we are forced to develop alternative methods for generating power. By no coincidence whatsoever, almost all of the most promising sources of energy are either directly or indirectly powered by the sun. And so it is that next time, part II will focus on solar power and its myriad uses. The exception is nuclear power, which is being such a diva about this that it gets its own essay, also known as part III. Full power ahead!