Emergency powe part 1: portable generators

After Hurricane Irene, I figure I should touch on the topic of emergency power, the different modes that are available, and safety for not only you and your family, but also the devices you plan to operate. The most common source of backup power is generators. A generator converts mechanical motion into electricity. The mechanical motion is typically provided by a gas engine, but some engines also run on propane, and there are even some diesel models available.

I will start with a look at portable “contractor’s” generators, since that is the most common type of generator that most people use when the power goes out. They are available from most hardware stores, and typically sell for around 10 cents a watt. While these generators are simple, and inexpensive, and will get you by in a pinch, they are not the best way to get electricity when the power goes out.

Most of these generators are powered by what is basically a gasoline lawnmower engine, and this is where the problem lies with them. While these engines are plenty durable for the task, their speed regulation is not very precise. Most of these engines use a lever that is placed in the path of the air that cools the engine to regulate their speed. While this method works good for keeping a steady pace while cutting the grass in the yard, electricity generation requires much more precise speed control. These engines are also notorious for not running at the proper speed if they are not well maintained, which can happen if a generator has been sitting in storage for years, and then started up after a storm.

There are two measurements of electricity that are good to keep in mind when talking about generators. These are voltage, and frequency. Voltage is the pressure of the electricity, sort of like how hard the water comes out a faucet. To much voltage, and appliances run too fast, light bulbs can overheat, etc. Too little voltage is bad too, especially for appliances and electronics. Also there is frequency. Electricity at your wall socket is not a steady stream. It actually pulses back and forth sixty times a second. These pulses keep appliance motors running at the proper speed, and is also allows the voltage to be stepped up and down properly in electronic devices, like a laptop computer’s power adapter. The wrong frequency can result in the wrong speed, and the wrong voltages produced in power supplies.

Let’s look at a scenario at why speed control is so important in a generator. You have your flat-panel television, and your refrigerator plugged into your generator during the storm. Your refrigerator gets cooled down, and shuts off, a few seconds later, you hear your generator rev up, and your TV burns out! Well, what happened? When the refrigerator cut off, the load was suddenly lifted off the generator, and its engine sped up, producing much more voltage and a much higher frequency than it was supposed to. Because the speed regulator in the generator is slow and inaccurate, the TV was fed the wrong voltage and frequency, and you are now left with an expensive repair bill!

I have heard people say, if it costs more than the generator, don’t plug it into it, but even then, I think the best advice here is not to plug any type of electronics into a contractor’s grade generator. These generators are only designed to operate power tools and floodlights at construction zones! If your generator is not running PERFECT, do not plug anything into it! If you hear it speeding up and slowing down, or if it’s sputtering and stalling, it’s not ready to be used. Also, if you know your generator is running close to empty on fuel, disconnect it before it runs out of gas. When the generator runs out of fuel, it sputters and will not be running at the correct speed before it completely quits, and this can quickly damage your appliances.

Another big factor to think about when working with a portable generator is gasoline. Frequently, after widespread power failures, the gas stations are out of power too, so you need to keep gasoline on hand to power the generator…This causes a dilemma, because gasoline goes bad when it sits for a long time, and old, bad gasoline is responsible for lots of poor starting and bad running generators, so you need a plan to rotate your stock of gasoline so it doesn’t go stale. Many people have also started fires when attempting to refuel hot generators after they have just shut down, so take into consideration how you will safely refuel your generator in the middle of a dark night when it quits.  One last thing to consider when it comes to gasoline, and that is the engines in portable generators are not very efficient, and use a considerable amount of power for the amount of electricity they produce.  In Richmond, the electricty price is about $8.5 cents a kilowatt.  A typical portable generator makes the same amount of power for around $.50 to $.75 a kilowatt.  Do you really need to spend $50 in fuel to save $30 for food?

Now, let’s look at the safety factor with connecting a contractor’s generator. The biggest danger is how the generator is connected to your appliances. The most common method, which probably the safest, but the most inconvenient, is to run extension cords to the appliances you wish to power. The biggest safety factor here is tripping over the cords. You also do not want to run too small of an extension cord on a high-draw appliance, because it could overheat the extension cord and start a fire.

One of the most dangerous things to do is create a male to male cord and plug it into an outlet to back-feed power into the house. This method exposes electrified metal terminals. Some people make generator cords to go in their breaker panels. Again, if not done correctly, can expose live power on the ends of the cord. The best method of connecting a portable generator to a house’s power grid is to use a transfer switch. This will only allow either the generator, or the grid power to be selected at a time. If you absolutely must back-feed power from your generator back into the house, you MUST turn off the main breaker before attempting. If grid power is restored, your generator will literally explode when power is fed back through it. Also, power from your generator can energize the power lines and endanger the workers making repairs in your neighborhood.

Next I will discuss the alternatives to portable generators when it comes to emergency power, like whole-house generators, and even batteries and solar power.  I will also discuss what to power, and how to power your appliances for the best efficiency

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