Independence from the power company is an attractive concept.
Sometimes it is an anti-bureaucratic response because folks see the power company taking hard-earned money month after month. Others perceive power as expensive and believe going off the grid will mean economic savings. Sometimes folks are simply tired of blackouts and want power security, especially if they live in rural areas.
The alternative to grid-connected power is off-grid power, which means just that: you are off the grid, on your own. In effect, you own the electrical utility and are responsible for it. That means you are responsible for the capital cost of that off-grid system, for the full maintenance of it and significantly, that you must live within the system’s capacity.
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On the other hand, off-grid power also means your power will still operate when the grid-tied neigh-bours’ houses go dark.
We use power for a lot of purposes, including lighting, appliances and tools. We use power to heat livestock waterers, operate engines and cook meals. We are also largely unaware of how much power we actually use.
As an example, most of our equipment use is measured in watts, but our consumption is measured in kilowatt-hours (kWhr). A 100 watt light bulb running for 10 hours uses 1,000 watts, or one kWhr. A 1,000 watt heater operating for one hour also uses one kWhr.
Average household use, when electricity is not used for space heating or heating water, is 25 to 30 kWhr per day.
Let’s look at a fictional residential power system in the southern Prairies in the wintertime.
We’ll assume average daily residential power consumption is 25 kWhr per day and sunshine is 2.5 average hours per winter day. Other power uses, such as a farm or shop, would have higher power consumption.
Collecting 25 kWhr in 2.5 hours means you would have to collect 10 kW per hour. It also means your system would have to face the southern winter sun squarely and have a capacity of at least 10 kW.
This power would be stored in batteries so it could be withdrawn at night or when it is cloudy or the sun is not shining.
Such a solar powered system would occupy 645 sq. feet and require a battery bank for three days reserve capacity of 6,250 amp-hours. This is about the size of 60 car batteries. At an approximate installed cost of $6.50 to$7.50 per watt, a 10 kW off-grid system would cost $65,000to $75,000.
Winter makes things worse. As the days grow shorter, the solar resource’s value decreases while electrical consumption increases because of greater demand for lighting and heating. So in reality, daily winter power consumption would be higher than the average 25 kWhr in our example.
As well, dust on the solar panels, inefficiencies of inverters and energy transfer in and out of batteries can result in at least 20 percent losses in production.
Getting out from under the grid comes with an increased cost. So how does anyone ever go off-grid? A number of things come into play:
- The property in question does not have grid power. It might easily cost $20,000 to $30,000 to have it installed and you still have a monthly power bill. That outlay could go a long way toward paying for an off-grid system.
- Electrical consumption must be reduced by transferring major heating loads to other sources of energy. Electrical clothes dryers and water heaters can be replaced by gas-powered units. Hot water heating can also be done with solar thermal systems or be fired by gas or wood. Your building’s energy efficiency, passive solar collection and natural indoor lighting become much more important when trying to get off the grid.
- Appliance purchases are given careful consideration because of their need and power consumption. Lower power consumption is worth extra money when you are paying for power generation systems.
- A major part of off-grid power generation is lifestyle modification. You can no longer casually leave on lights or equipment when not in use. When using electrical appliances you must consider your reserve capacity. You must pay attention to standby power used by electrical chargers and electronic devices that are sucking on your system. Off-grid power is like a paycheck: it is finite.
- Off-grid power users become more conscious of natural weather cycles. Sunny days are the time to do high power consumption activities such washing clothes, vacuuming or using power tools. .
- An off-grid system requires ongoing maintenance and investment. Batteries require monitoring, periodic special charging and eventual replacement. Solar panels are remarkably reliable and long-lasting and often have a 20 to 25 year guarantee. Electrical components, such as wind turbines, have a much shorter lifespan. But with the off-grid system you are the master of your own electrical destiny.
An off-grid renewable energy system can be a practical alternative to grid power if you are looking at property some distance from the power grid. If you are on the grid and thinking your power bill is expensive, consider renewable energy alternatives and realize that the bill is perhaps not quite so unreasonable.
