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Off Grid/Grid Down Power Systems: Part I

By: Tom Chatham

Whether you are thinking about moving off the grid or are concerned about a grid down scenario, the need for power production equipment can lead you in many directions depending on what you need. Many of the modern day conveniences we take for granted can be eliminated without causing serious deprivation but some things are beneficial to your standard of living. The need for refrigeration, water pumping and lighting are among those things that make life much easier if they can be done at the flick of a switch. While even these things can be performed with non-electric means with the proper planning, they free up time and energy for other things.

When planning for off grid/grid down operations you need to consider what your absolute needs are. While you may need power under both of these situations, the systems will have some subtle differences. The major difference will be the duration of grid down time. A short duration will require much less energy production capability in the form of liquid fuel storage.

For a short duration power failure you may only need alternative power for a few days. This will require less fuel reserves and less equipment overall. While a plan to deal with a long term power situation will work for short term situations the opposite is not true. A more robust and self sustaining system is needed for long term use. There are certain components you need to consider when building an energy system.

Energy source
Power production equipment
Energy storage
Power conditioning/conversion devices
Power usage devices

In a short term power situation you may opt to rely on a generator as many do. The generator will need a fuel supply that you must have on hand. The loss of power will prevent the purchase of fuel locally so this must be taken into account when this type of plan is devised. With a generator there are five negative aspects that must be taken into account. The generator must be used in a well ventilated place which opens up the possibility of it being stolen. A generator is noisy which will advertise the fact to your neighbors that you have resources they may not. A generator needs a constant supply of fuel that must be stored on site and last throughout the situation. A generator will only provide power while it is running. A generator has many electrical components that can fail at any time and prevent power production such as the coil, spark plug or control panel.

For a temporary power disruption these things might not present a problem but under prolonged disruptions, it could cause serious friction within your neighborhood unless you live in a remote location. The longer your neighbors have to live without power the more they may come to resent you for being prepared. It is for these reasons that alternate methods may serve you better.

With an engine of some sort to produce electrical power you will need a fuel source which could become a weak link in your plan over time. Unless you have the ability to produce the fuel you need, you may want to develop other options for prolonged use. The use of solar and wind present viable options for long term use while eliminating the need to store a fuel source. These systems can be the foundation of a multi platform production capability. The use of a power driven generator can provide good backup capability for this type of system, reducing the fuel needs of this type of device.

With a power generator there are six viable options for fuel. You can use gasoline, diesel, propane, natural gas, alcohol or wood gas. The use of natural gas and alcohol fuels are options but are not as readily available in many locations. Gasoline and diesel will require a large tank and the addition of fuel stabilizer for long term storage. Propane will store indefinitely but will also require a large supply on site. Wood gas can be used and the wood fuel produced from locally available sources. For long term viability, wood gas or alcohol would be the best options for local fuel production. Bio diesel produced from soybeans is also an option for self sufficiency. Information on alcohol and bio diesel production can be found in Brown’s alcohol motor fuel cookbook.

With a solar or wind system you eliminate many of the negative features of a power generator. These systems are quiet, non polluting, require no stored fuel supply and have minimal parts that can fail making them very durable. These devices charge a battery bank that can supply power even when the devices are not producing any power providing the ability of uninterrupted power for limited uses. With a battery pack you also need a power inverter to convert the 12v DC power into 120v AC power that household appliances can use.

One way to get around the expense of a power generator is to build your own. If you are using a battery pack for energy storage it may be more efficient to use a homemade generator to charge it. By combining a 3 hp motor with a car alternator, you can produce 12v power and charge your batteries. Depending on how much power you require you may be able to run your motor just 2 or 3 hours a day and have uninterrupted power around the clock. This could make the necessity of storing fuel much easier.

Where you might need 5 to 8 gallons of fuel a day for a typical generator, a homemade unit charging a battery pack may only consume ½ gallon a day. A typical alternator produces around 1,000 watts of power so producing and storing 2 or 3 KWH of power in a few hours is possible. A large deep cycle battery can hold about 1 KWH of power. A typical refrigerator/freezer or small deep freezer will use about 1.1 to 1.3 KWH of power a day so an hour and a half of run time can power your freezer for 24 hrs. The advantages of this type of system quickly become apparent. Even if you only have the homemade generator, inverter and several batteries, you could have continuous power for almost 2 weeks on the fuel needed by a conventional generator in one day.


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