Term coined by
Solar Electric Specialties in
Willits, Ca to describe a
stand alone power system consisting of
solar photoelectric panels, a
battery bank, a motor
generator, an
inverter and the
control systems required to tie the system together. A system can be scaled to provide
electricity for as simple as a week-end
cabin to any size house. A most basic set up would be a single solar panel, a
12 volt deep cycle battery, a 500 watt inverter and a small gas generator. This type of set could be had for about $800. A system that could power any tract house would require multiple solar panels, a larger battery bank using 6 volt batteries, a diesel generator and a larger inverter.
The most difficult home power load to supply with an alternative system is the refrigerator, it requires a constant source of power at relatively high amperage. Low voltage (12 volt) solid state coolers are now available, but a
propane powered refrigerator is the best alternative, although they are very expensive. Inverters can be wired to be remotely turned on as can motor generators which can be wired with sensors to start when battery bank voltage drops.
Lighting is easily accomplished with either 12 volt
incandescent or
flourescent bulbs, and because of their low amperage requirements 12 volt lighting can be wired using the same types of wire and components as normal household wiring. Intermittent heavy loads such as the washing machine or power tools are easily handled by the generator on a demand basis.
If a person were to buy a $10,000 power system, it could provide electricity for 20 years of normal household use. The panels will last 25 years, the solid state inverters provide clean enough waveforms to run computers. The component that has the shortest life span is the battery bank. The best bet would be a set of
electric forklift batteries which come in 2 volt cells. Also telephone companies use banks of 2 volt cells to provide their back up power and sometimes these can be obtained.
Real Goods in
Hopland, CA has a large complex in Northern California demonstrating the various alternative power options, they have been a major player in the promotion of solar,
wind and small scale
hydro power for many years.