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
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.