Let me save you $50,000 or so and share what I learned in grad school. I came away with a diploma and exactly four worthwhile things.
Power is the ability to influence things. Often times the word "power" is used in a bad sense. Generally, if you talk bad about a politician exercising power you are just being truthful. However, you can use power for your own good. In fact, if you are not exercising your power you will pay the price.
If you can influence who gets what shift, then you have used power. Or who stays late Friday afternoon. Or who is team captain. More to the point for working people is getting your great ideas accepted and integrated into your work so things go better. That's power.
If you are the boss, or the one who can punish, or the one with the money, you have those forms of power. However, the rest of us have access to two other forms of power. The first is called "referent"; really, who you are. Do you have such a positive reputation at work that people will do what you ask just because it's you? This is an aspect of power strongly in line with informal leadership. You can build your ability to get things done by leading people to where they want to go. It makes them happy, it makes you happy, and life is good.
The other sort of power non-managers have is "knowledge" power. That is, you know stuff other people do not. This is a tricky power though, as any IT person will tell you. In the IT world it is common to know a heck of a lot more about computers than anyone else in the company. However, no one really cares any more. Geeks lost their power when they thought knowledge was all they needed. IT people have so isolated themselves from the business of the company that they are viewed as a cost center and not really part of the business team. Manpower levels and budgets are showing the problem with that image.
While it is cool to know stuff other people do not, remember to not make that your only source of power. Figure out people and how to support them being successful in a way that lets you be successful too. If you are a geek, learn how to use all those CPU cycles to make things easier for Sales and Marketing.
What sources of power do you have, and how are you using them?