Watt’s Up?

Good question – pun or not. There are a lot of terms floating around that can confuse and/or mislead. Energy terms in particular - so we thought this would be a good time to conduct a little lexicography.

Everyone who gets an electric bill (yes, there are some who don’t) knows the term Kilowatt-hours. Those are the units measured on the electric meter at the point of service – home or apartment.

OK, now a kilowatt-hour is a kilowatt of power used for one hour.

And a kilowatt is one thousand watts.

A watt is work done when one ampere of electricity flows through a circuit with a potential difference of one volt. One amp times one volt equals one watt!

If you take 100 watt bulb and leave it on for an hour you have used 100 watt-hours. And since a kilowatt is a thousand watts 100 watts is 0.1 kilowatts.

And so your bulb has used 0.1 kilowatt-hours.

Now when we’re talking about BIG blocks of power, like not thousands but millions of watts we have larger units:

Megawatt (MW) is one million watts. Or a thousand kilowatts
Gigawatt (GW) is one billion watts
Terawatt (TW) is one trillion watts
Petawatt (PW) is one quadrillion watts

These can be pretty big numbers and for a little perspective the average power used by humans in a lifetime is 15 TW. (15,000,000,000,000). Imagine the usage of an entire country for a year. Thank goodness for the shortcut-acronyms.

And there are units for fractions of watts such as Nanowatt, Microwatt and Milliwatt.
If you’re interested in these ”you could look ‘em up.”

So as we proceed in our process of finding out where we are and the truth about where we can and ought to be going we have at least a handle on some of the units of energy measurement that will have more and more meaning as we go along.