Calculating your energy budget.

The first thing that happens with alternative energy is you go on an energy diet regulated by a strict budget. Right now your home is wired into a power grid capable of sending you incredibly large amounts of amps and volts as electricity, drawing from a pool of electricity that covers the entire continent of North America. This allows you to do lots of watts, which is work, such as have the lights, two televisions, the toaster, blender, dishwasher, electric toothbrush, hair dryer and air conditioner all working at the same time, making profits for the electrical utility companies.

To use energy so profligately and generate the power on site would require a very large capital expenditure, and in the context of expected Y2K disruptions, a fuel stockpile larger than most people will be able to competently deal with. A generator can use a gallon of gasoline an hour. If the generator is used only six hours a day for 30 days, you would need to stockpile 180 gallons of gasoline! Storing that much fuel may itself be a greater danger or hazard than lack of power.

Successful operation of an alternative power systems requires downsizing your power requirements and keeping to a strict energy budget, something that most of us have little experience with.

1. Decide what is essential in the particular circumstances of your family. Generally, the hierarchy of electrical needs will be something like this:

(1) heating (furnace fan, thermostats),

(2) necessary medical equipment

(3) lighting

(4) cleaning/clothes washing

(5) morale (radio, TV, stereo, computer)

(6) food processing

(7) refrigerator/freezer

Note that air conditioning, heating from electric space heaters and cooking are not on this list. These use so much electrical power that it is hardly practical to attempt them with an alternative, non-grid electrical system. The one possible exception may be a small microwave oven.

You must make your own decisions about how you rank these activities. If you have alternate heating such as a wood stove, and a member of your family requires the assistance of a medical device, that might be first on the list. If you have a propane refrigerator, or it is very cold outside so you can use a cold box to preserve your freezer or refrigerator food, cleaning and clothes washing may move up the list. If the disruption is prolonged, cleaning/clothes washing and morale might move up the list.

2. Determine how much power is required necessary for each electrical application you decide is necessary. This means accounting for everything that uses electricity everywhere in your house. Some sample continuous watt usage figures are:

Television 350W

Light bulb 100W

Small radio 50W

Furnace fan 600W

Vacuum 600W

Refrigerator/freezer 800W

Deep freeze 500W

12V DC battery charger 120W

Hot plate or electric stove 1500W (per burner)

You must not only determine the continuous use watts required (the amount required for the normal operation of the appliance), you must also determine the "surge power requirement".

Many electrical devices require more power to start than they do for continuous operation. For "resistive" loads (like light bulbs), there is no extra power required for starting. But for motors and other "inductive" loads, such as your refrigerator or freezer compressor, submersible pumps or a furnace fan, the start-up load requirement may be two to three times the continuous power use requirements.

An 800 watt compressor motor may need 2000 watts at initial start-up. When these start-up hungry inductive loads are deprived of their needs at start-up, they can stall and burn up. It seems odd that something could burn up because it did not get enough electricity but that is exactly what happens. Check the manufacturer's ratings for any motors you will use with your system, to ensure that your generator capacity is sufficient. Allow extra for any inductive start-up loads. Motors are found in your furnace fan, your refrigerator and freezer, your power tools.

3. Decide how many of these will be (or must be) working at any one time and develop an energy budget. This figure tells you what your maximum ability to deliver power must be for your system to successfully operate. You are developing a trade-off here between your essential needs and your financial ability to invest in the capital equipment required (generator, batteries, etc.)

Determine the total continuous load, and the total start-up surge load. Plan for the highest combined total possible to determine your potential power needs. If you plan to have four devices working at the same time, there is a potential for them to start up at the same time, so size accordingly.

Suppose you have 3 electrical lights @ 100 watts each, plus one TV at 200 watts and then the refrigerator kicks in with its cooling cycles.

3 (100 watt) lights + 1 (200 watt) television + 1 (800 watt) refrigerator = 1300 watts continuous. If you have 120 volts, this would require 10.8 amps.

With this example, unless you had over 2000 watts available, you could stall the refrigerator on start-up if it has more than a 200% power need at start-up. Add several high demand start-up loads to the equation and you can begin to see the problem with figuring energy needs. Purely resistive loads like incandescent light bulbs are no problem. They pull the same load at start as when running and are not damaged by reduced voltage, just the opposite of our inductive load motor type loads.

You can also see how much a single item like an energy-hungry refrigerator can add to your minimum power requirements.

We aren't generally used to dealing with energy budgets, we are much more familiar with financial budgets. Some of our financial skills can be transferred to this new situation. While it would be nice to buy a new car with cash, travel to Europe for an extended vacation, have an expensive Christmas, buy a new house and open a new business, all in the same fiscal year, it isn't a practical possibility for most of us. We only have so much money in the bank and so much income coming in.

If our money is unlimited, we can spend freely; if our money is restricted, we must be frugal. Practice keeping to this budget in advance of any emergency use of your alternative power system. If your freezer and refrigerator together require more than your generator can safely produce, you may have to alternate power between the two appliances on a time-share basis. Putting a freezer or refrigerator outside or in the garage can also require less total energy requirements as the units will cycle less often in the colder ambient temperatures. Just be careful they do not get too cold and freeze up. Ideally, such an alternative location for refrigerators and freezers would be cold places that never get as low as freezing like possibly a garage or detached workshop or shed.

4. You will get more done if you downsize your electrical requirements, so invest in appliances and lighting that are thrifty in their power consumption while still giving quality service.

A 22 watt compact flourescent light can deliver the same amount of light as a 100 watt lightbulb, and fit into the same lamp socket. They cost more than incandescent lights, but they literally last for years and the energy savings over their life cycles are substantial, 78 watts for every hour of use, a kilowatt every 12 hours. Install them right now and you can begin saving money immediately. Would you willingly pay $100 for a $22 pair of shoes? Would that make financial sense?

High efficiency refrigerators and freezers are also available, and can make economic sense even though the initial investment is greater than a conventional refrigerator. Even conventional refrigerators and freezers are more efficient that many sold in the past. Compare the electrical efficiency rating, or EER, on the tag of new appliances to determine their efficiency as compared to their price. If you are in an area where utility power is fairly expensive, these newer higher efficiency appliances may make a better investment for you now, even without having to go on generator power to appreciate their better efficiency value.

Even if you use existing light fixtures and appliances, their power needs can be reduced. Using conventional light bulbs, just going to a lower wattage bulb will allow the light fixture to still be functional but with a lower power usage. It is amazing how little light is necessary if we allow our eyes to adapt. Your refrigerator can be more efficient if you only open it when absolutely necessary. If the refrigerator was put in the garage like we mentioned above, it will help warm the garage as well as keep power consumption to a minimum for the refrigerator. Unheated garage temperatures are a cross between house temperatures and outside temperatures. A garage will help cool the refrigerator in Winter as well as keep it from getting too cold and freezing everything inside as might happen if the refrigerator was placed on an outside deck or porch. In most homes, having the refrigerator in the garage is only a few feet difference for the cook to walk from the kitchen but a lot of energy consumption difference for the appliance..

5. After you develop your power budget, add 20% for various losses, inefficiencies and contingencies. You may also need to increase that budget if you plan on using an inverter to change DC power into AC power. (See the next section, Power Part 3: Invertors.)

  1. Decide how you will provide the necessary power when, where, and for however long it is necessary, and in what form you will provide the power for that particular application. All appliances do not have to run off the same system. E.g., you could use DC lights powered by a battery, but run the freezer directly from a generator and use an inverter with battery bank whenever the freezer needs to be cooled.