OZ Farm has always been “off-the-grid,” that is, independent of PG&E's power lines. Historically, most lighting was propane or kerosene fueled; power for water pumping on the property was provided by gasoline-powered pumps and generators, though there was a time when wind-driven pumps provided some of the water distribution. We finally got fed up with running a generator for hours each day—they're noisy, polluting and expensive. But the cost of bringing in electricity one half mile from Mountain View Road into our operation was large enough to warrant close scrutiny of “alternative energy” sources.
After a lot of head scratching as well as good expert advice—provided most notably by Bob Gold, Jim Blomquist, Sonny Mason and Rob Harlan—we installed a combined solar-wind system in the fall of year 2000 and completely redesigned OZ Farm's water system. The power and water systems are intimately related because most of the power is used to pump water for our agricultural and retreat operations.
The end result is an integrated system with 8 kilowatts of power (6.5 kW of solar panels and a 1.5 kW Bergey wind generator) providing water to all our buildings and cabins and to all the agricultural beds and the orchard. We added new slow-start Grundfos water pumps to two interconnected wells and 21,600 gallons of new water storage capacity, bringing our total storage capacity to 43,600 gallons. The potable water system is isolated into a separate tank and pipes so it can be easily filtered or treated if necessary. Fortunately, we are blessed with pure and good tasting water.
The solar-wind power system charges a common bank of batteries in the Battery Shed and then runs through two Trace inverters to provide power at 110 volts to the Community House and farm buildings as well as the Manager's Cabin. The Domes and Newbird Cabin also run solar power through inverters. The remaining cabins are equipped with solar panels, which provide 12-volt direct current lighting to those cabins, primarily for reading lights.
Even with this new system, we still have to use a back up gas generator a few hours each month. (It's easy to tell when a retreat group has stayed up late because the batteries are lower than usual the next morning!) But we are refining the system as we gain more off-the-grid experience: this summer we will be adding a 7-meter section to the wind generator tower to make it more efficient.
So that's how it all works.
Please turn off the lights when you leave!