Stand-alone renewable energy systems often referred to as “off-grid” systems, provide electrical power to homes, businesses, and remote equipment independent of the utility electrical grid. Modern stand-alone equipment and improvements in system design have produced off-grid electrical systems that are reliable, quiet, cost-effective, and environmentally friendly.
Off-grid living is as much a mindset as it is a technological achievement. Efficient use and conservation of energy will directly impact the size, and therefore the cost, of the system. Many people associate off-grid living with hardship and doing without, but nothing could be further from the truth. Today’s low energy appliances, energy-efficient lighting systems, and highly efficient heating systems can be combined to offer a standard of living that rivals any grid-connected lifestyle.
People choose to live off-grid for many reasons, including the desire to live in remote areas, reducing their cost of living, and lowering their environmental impact. Whatever your reasons are for getting off the grid, it is important that you discuss your project with a renewable energy professional right from the beginning.
The type and availability of a renewable energy source should be your primary consideration in your decision to live off-grid. Photovoltaic (PV) solar systems are the primary energy source for most stand-alone energy systems, but for those with an adequate wind or water resource, wind turbines or micro-hydro turbines can be an effective alternative. It is also common to combine two or more complementary energy sources into a hybrid energy system. Seasonal brooks and wind are often at their peak during the winter months when available solar energy is lowest.
At the heart of any stand-alone energy system is a battery bank. The size of the battery bank is wholly dependent upon the electrical demands placed on the system and the nature of the renewable energy source available for battery charging. Batteries are generally sized to provide two to three days of reserve energy for periods of low renewable energy, such as cloudy days for a PV system.
All stand-alone energy systems will require a means of charging the batteries, usually a solar PV array, wind turbine, micro-hydro turbine, or a combination of these technologies. A back-up gasoline, diesel, or propane generator will also be required to provide battery charging during those times when the renewable energy resource is not fully meeting usage demands. In addition to batteries and a charging source, you will need a means of controlling the charging process, inverters to convert the direct current (DC) into the alternating current (AC) required by most household appliances and Mxtures, disconnect switches, overcurrent protection, and AC and DC load centers where most of the wiring connections will be made.
Frequently asked questions about stand alone electrical systems:
- How long do the batteries last?
- How many batteries will I need?
- Are the batteries dangerous?
- If the local power grid eventually reaches my location, will I be able to connect to the grid should I decide to choose that option?
- How should I expect my lifestyle to change if I choose to live off-grid?