The nearest grid power to the house is over 6 miles away and it would cost $60,000 to run a line! Not that it makes a difference as we want to be self sufficient for power.

So the diagram to the right shows the components we will be using for power. Of course in sunny Arizona photovoltaic cells will be the primary power source, but for those stormy days when sunlight is low a wind turbine will provide a secondary source. As with all systems there is a back-up in the form of a propane generator. Propane being preferred as it is less polluting than diesel or petroleum.

All power sources connect to a regulator that charges the battery bank and if needed will automatically turn on the generator.  The regulator also has a built in inverter that converts the DC current of the batteries to AC for use in the house.

The challenge in designing the system is having good estimates on how much power we will need, and how much generating capacity will be needed to meet that need. The battery pack must be sufficient to power the house through periods when generation is low. The temptation is to over design the system, but the costs can climb rapidly.  Some of the new regulators come with communication ports that allow a computer to track the performance of the system.  So with this facility we intend to design the system closer to the estimated requirements and accept that the generator may be used more frequently in the earlier days. Analysis of the performance data will then allow us to add additional PV modules to match our loads more accurately.