You Can’t Push Power

Here’s some basic circuit theory for you today.

You can’t push current nor can you push power down a wire.

But wait! My generator produces 1000W, that’s power, right? Not necessarily. Your generator produces a voltage across a pair of wires, that’s all. If you have nothing hooked up to those wires, you get no power sent anywhere. There’s nothing to use it, so it isn’t produced. Your generator doesn’t produce extra power only to have it disappear; physics says it can’t work that way. Once you hook some kind of load (a resistor, say – a light bulb, refrigerator, stove, etc.) across those wires, now current can flow and power can be delivered to that load. But only the amount of power will be produced that will satisfy that load, and no more. Ohm’s Law has something to say about that: Voltage = Current times Resistance, or Power = Voltage times Current. Your generator will produce a certain voltage, no more no less. So the lower the resistance you put across the output wires of the generator, the more current will be flowing in the circuit. The amount of current depends on the size of the load. And because of that, the amount of power (generated and delivered) depends on the size of the load.

What about my solar array or my wind turbine?

If you have it hooked up to the utility, all of your neighbors (and you) have things plugged in. Those are loads, and something has to supply them. As it turns out, you share the supply of those loads with the utility, up to the maximum capability of your solar/wind system. As long as you’re hooked up to the utility, unless you’re a mega-producer of electricity you will be delivering as much power to those loads as you can produce because those loads will demand everything you can supply.

Makes sense? I hope so, because i’ll refer to this again when we discuss Net Metering in a later posting.

 

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