Living "Off Grid" – Part 1

Living "off grid" means you are not connected to a utility company power line, the electrical grid. You must produce your own electrical power to meet your needs. This can be a challenging and rewarding experience!

The average cost of extending power lines is approximately $80,000 per mile. Check with the nearest utility to determine what your costs might be. Generally speaking, if you are more than 1/4 mile from the utility line, you can install a renewable energy (RE) system to produce your power at less cost than extending the power line.

While you won’t have electric bills with an RE system, there are periodic maintenance costs and costs for alternative fuels such as propane.

Conservation:

First, invest in conservation measures to reduce the amount of energy you need. See our Conservation Checklist and implement it’s suggestions aggressively. Reducing your energy needs can greatly reduce the cost of any RE system you install.

Space heating and cooling:

Space heating and cooling account for approximately 50% of annual energy use. Reduce your energy needs for heating and cooling by using passive solar design principles. Passive solar design can reduce heating and cooling needs by up to 90%.

Further reduce energy needs by "super-insulating" – doubling the insulation levels recommended by building codes. Earth berming, building into a south facing hillside or berming earth up on the north, west, and east sides of structures, further reduces heating and cooling energy needs. We can provide plans review or refer you to certified building designers experienced in passive solar design.

Back up space heating should be accomplished with either wood or propane. It is impractical to heat with an electric furnace, or heat pump, powered by an RE system. They require too much electricity. Back up cooling, if required, should be done with an evaporative cooler (swamp cooler) with an electric

fan motor. An air conditioner is too large an electrical load to power with an RE system.

Water heating:

Water heating is the next greatest energy need, approximately 20% of annual energy use. In an off grid home this is usually provided by an on-demand propane water heater, or propane hot water tank. If you are planning to use an on-demand propane water heater, insure it is a model designed to work with solar preheated water. Many on-demand systems will not work correctly with preheated water.

A solar hot water heater can provide the majority of your hot water and significantly reduce propane costs for water heating. For off grid homes, we recommend a closed loop solar hot water collector which circulates a glycol solution (freeze protected) using a separate small solar panel powered circulating pump. The glycol solution is pumped through a heat exchanger attached to a standard hot water tank.

This system does not require any power from the household RE system. Solar heating provides most of the hot water, backed up by an on-demand propane water heater or propane hot water tank.

Water pumping:

For an off grid home, pumping water from a well and powering a pressure tank are the next greatest energy loads. Standard well pumps are usually 240 volt AC. Before allowing your well driller to install a standard pump, consider if a DC powered or 120 volt AC pump will do. Inform the well driller that the pump will have to be run with a small generator. This will help him select a pump that will work well with your RE system.

Most RE systems produce DC power, which must be "inverted" to AC power. This conversion results in a 5% to 10% energy loss. A DC powered pump avoids this loss. Most RE systems produce 120 volt AC power and must use a 120/240 transformer or second inverter to power a 240 volt AC well pump. This transformer consumes a small amount of power, but can be switched off when not in use.

A second inverter can be costly. Many water pumps require a very large "surge" of power to start. This can be difficult or impossible to do with some RE systems. Ask your well driller for a pump that has a low starting surge, such as a Grundfos SQ pump.

The ideal situation is to have a DC powered pump that pumps water to a storage tank, which then feeds water to the home by gravity, avoiding the need for an electrically powered pressure tank. Every foot of fall from the tank provides .433 psi of water pressure, so the storage tank should be 50 feet or more above the home to provide reasonable water pressure.