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Living “off-grid” refers to living in a self-sustaining manner without reliance on one or more utilities. Some consider disconnecting from the electrical utility to be off-grid, while others take a more intense view and consider a truly off-grid application to be one that is disconnected from all public services (electricity, city sewer, water, waste disposal and even mail). For purposes of E3A, off-grid is concerned only with disconnecting from the electrical utility.
There are many reasons why people do not connect to the utility grid. For agricultural producers, off-grid applications are common for remote stock water facilities that are distanced from available electrical supply. Homeowners may also opt to be off-grid because the distance (and cost) of running electrical service to the home is prohibitive. Some homeowners pursue being off-grid out of concern for the environment and a desire to reduce dependence on fossil fuel-based sources of energy. Others like the idea of being more self-sufficient and being rid of monthly utility bills. No matter your motivation for considering off-grid living, there are a few facts about being off-grid that may help to determine whether it is right for you.
Design of an off-grid system can be complicated. In addition to considering one or more sources of electrical generation, you must also consider the use (load), storage, voltage, and quality of the electricity. In off-grid agricultural applications (such as stock water facilities) these considerations are not overly complicated. However, in a home, there are many system design considerations, including determining how to heat your living space and water. There are qualified off-grid system designers who can assist you in these decisions, but at present, finding a qualified designer may pose a major challenge. If you intend to design your own off-grid system, consider attending classes, such as those offered by Solar Energy International, to learn more about appropriate system design.
Space heating can be provided by propane, but can also be accomplished through building design and using solar thermal technologies. A building can generate natural heat and cooling using passive solar design principles. In passive solar design, the building has a northwest axis. In the northern hemisphere, the sun’s lower-angled, direct winter rays enter the south-facing wall’s windows. Thermal mass materials (typically masonry flooring) absorb the energy and radiate it back into the space as heat. Roof overhangs and awnings block the sun’s higher-angled, direct summer rays keeping the building cooler. Passive solar design buildings have high levels of insulation to help retain the conditioned air. This strategy is called “passive” solar because these design elements entail no moving parts. Passive solar buildings can include “active” elements such as fans for air distribution and heat recovery ventilators, etc. For existing buildings, solar air collectors can be used to generate heated air. They can be retrofitted into a wall or roof. They use the sun’s energy to heat individual rooms and supplement existing HVAC systems, or to pre-heat ventilation air (transpired solar collectors).
Off-grid-buildings can use propane or solar thermal technology to heat water. For more information on solar hot water systems, refer to the E3A Solar Hot Water folder. Be aware, however, that solar hot water systems typically used in colder climates do require electricity for controls and to pump liquids through the collectors.
Off-grid applications can utilize many modern conveniences, but still require at least one source of power. While petroleum-fueled generators can be used, it is more typical (and usually more cost effective) for off-grid applications to use renewable energy technologies. Solar and wind applications are commonly found in off-grid applications.
Safe utilization of the electrical current generated in an offgrid application requires additional equipment to condition and transmit the electricity. This additional equipment can account for up to half of your total system cost (U.S. DOE, 2011). The amount of equipment and expense will vary according to your system design, but typical components of an off-grid system (especially in a home) include:
Inverters range in cost based on the quality of the power you intend to use, as well as the features that you include in your power-conditioning package. The conditioning equipment you require is dependent on many factors and needs to match the voltage, phase, frequency and sine wave profiles of your generation
source. A qualified off-grid system designer can help you to determine your needs.
A key benefit of being off-grid for many consumers is getting rid of utility bills. However, as you consider living off-grid, do not forget that you may have up-front costs associated with installing your system. Upfront costs of off-grid systems tend to be higher than grid-connected renewable energy systems, especially as the additional system components add to the expense. You should also remember that you will have annual operation and maintenance expenses associated with your system. As part of your research process when considering living off-grid, be sure you consider how you will finance your system and what terms are available to you. Also, talk to your home mortgage lender. Some conventional lenders either do not offer loans or require additional appraisal requirements for off-grid homes.
Back-up Generation and Hybrid Systems
In order to maintain a certain level of battery charge and ensure constant availability of electricity, you will need a back-up generation source and/or a hybrid system. Hybrid systems utilize more than one renewable energy system (usually wind and solar) to provide more consistent electrical generation. As an example of how this pairing of systems works, when it is cloudy and stormy and the solar system output is less, the wind is likely to be blowing. While hybrid systems can provide more consistent power, off-grid homeowners often have back-up generators in place as well. Generators are used to recharge batteries and supply electricity to the home if the renewable energy systems are not operational, or if load demands draw the batteries down to the point where additional generation is needed to recover a level of charge.
All off-grid systems need to consider conservation and storage of electricity. Unless you invest in a system that can accommodate every convenience, living off-grid magnifies those considerations. Here are a couple of examples:
Off-grid living is possible, but requires an increased awareness of energy consumption. System design is especially important. Do-it-yourselfers may welcome the challenge of researching and undergoing training to design an optimized system, but be aware that these are complex systems (if you intend to have modern conveniences) and selecting a qualified system designer may be your best option.
U.S. DOE. (2011, February 9). United States Department of Energy EERE. Retrieved August 3, 2011, from Energy Savers: Batteries for Stand-Alone Systems: http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=10630
U.S. DOE. (2011, February 9). United States Department of Energy EERE. Retrieved August 4, 2011, from Energy Savers: Charge Controllers for Stand-Alone Systems: http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=10640
U.S. DOE. (2011, February 9). United States Department of Energy EERE. Retrieved August 4, 2011, from Energy Savers: Power Conditioning Equipment for Stand-Alone Systems: http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=10650
U.S. DOE. (2011, February 9). United States Department of Energy EERE. Retrieved August 4, 2011, from Energy Savers: Saftey Equipment for Stand-Alone Systems: http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=10660
U.S. DOE. (2011, February 9). US Department of Energy EERE. Retrieved August 3, 2011, from Energy Savers: Equipment Required for Stand Alone Systems: http://www.energysavers.gov/your_home/electricity/index.cfm/mytopic=10620