What is an Off Grid System?
Off grid systems are installations that are not tied to outside electrical lines. They operate independantly from
the grid and thus must store power on-site in large battery banks. These systems contain three main
components, a power collection device, power conditioner/inverter/control module and battery bank.
The power collection devices capture energy from the sun, wind or flowing water.
The conditioner/inverter/control module are the brains of the system. They regulate the flow of power
between the collection devices, battery bank and house.
The battery bank acts as a buffer, storing power while you collect more than you use, and releasing power to
the house when you call for more than you collect.
Since these systems must generate all the power available to the user, the selection of appliances, lighting
and the other loads is extremely important. Careful selection of appliances and lighting will help to ensure the
most bang for your buck in any off grid installation.
Which Off Grid System is right for me?
Selecting the right off grid system involves careful understanding of three things, your power load, your usage
and your site. Together these factors will determine what system is right for you so it is important to
understand what each one is and how it is determined.
Your Power Load.
Your power load is the total power usage of your location on an average day as measured in Kilowatt hours
and it is the primary factor in determining the size of your system. The size of your power load will determine
which power conditioner and control centre needed for your installation.
If your location is already existing and is on the grid then this information can be gleaned from your power bill,
otherwise you need to add up the power usage of all the electrical devices you use in your home. To do this
you simply take the power rating of a device and multiply it by the amount of time you would use that device in
an average day. Take the time to list out all of your electric loads, being careful not to miss any or
underestimate your usage of each device. Proper load sizing is crucial to ensure that your system works
properly.
Your Usage Pattern.
Usage is extremely important when considering an off grid installation as it is usage that helps to determine
the mix between collector and storage capacity. Usage is defined as how often your location is occupied. Full
time, part time or seasonal part time are the typical usage categories but things like week long vacations
spent at a cottage must also be taken into consideration when determining a location's usage.
Full time use locations need to have more collection capacity than their average daily use to ensure that
when power is being generated it can recharge the batteries that have been drained down during high use or
low production days.
Part time use locations like cottages can generally get away with a smaller collector capacity than an full time
use location with the same power load. This is because there are regular, extended periods of little or no
power usage when the system can recharge.
Seasonal part time locations are those that are used sporadically and are rarely used for extended periods.
These locations can generally get away with much smaller collector and storage capacities for a given power
load since they have very long periods in which to recharge and do not require many days of backup.
Usage is not necessarily a clear issue as many locations don't reliably fall into one category. Carefully
consider things like extended vacations, possibility of retirement living and other such issues when
determining your usage.
Site.
The last thing to consider in any off grid installation is the physical site itself. Some locations are particularly
sunny, some are very windy. The combination of particular factors on your site will help to determine what
system is right for you.
Modern photovoltaic cells can produce power even in dim or diffuse light, however, a southern exposure that
receives unobstructed sunlight are the recommended site characteristics.
Residential sized wind turbines generally require an annual average wind speed of over 10mph and must be
mounted at least thirty feet higher than the highest object within 500 feet. With our wide range of tower
options this is almost always feasible, however, some locations preclude the mounting of a wind turbine even
if the site meets the minimum wind speed requirements.
Off-Grid: