To start off, let’s get something straight. Power and energy are not the same thing. I am asked all the time, “How much solar power does my home need to eliminate my electric bill?” The right answer is usually how much energy the home needs.
Power is a rate of consumption. Energy is a quantity of consumption. Power over time equals energy!
Pull out your electric bill. you will not find how many kilowatts your home consumed last month. Kilowatts is a measure of power – how much electricity you are using at any given time. What you will find is Kilowatt-hours, abbreviated kWh or KWH, which is a measure (unit) of energy. You are billed on how much energy you consume each month, not on how much power you use. (Caveat: some businesses are billed on a combination of peak power usage and energy consumed).
In other words, I need to know how much power you use over time to tell you how much solar electricity will do the trick. That’s pretty easy, because it’s right there on your electric bill!
The way I explain this to kids (adults, cover you ears) is that power is like the size of the river, but energy is how much water is flowing down the river. A huge lazy river, and a small raging river might be putting the same amount of water into the Gulf of Mexico.
What uses more energy – a hairdryer running for one minute or a 60 watt light bulb running for 20 minutes? Stay tuned – the answer is coming in a later post.