As the price of power from the electricity grid keeps rising more and more people are becoming interested in off grid solar power as a viable option to eliminate quarterly power bills. Off grid solar power systems are a lot more involved than grid connect solar power systems as an off grid solar power system has to produce enough solar power to cover both the day time power consumption and the night time power consumption of the property, and obviously at night time the sun isn’t shining so any power to be used during the hours of darkness has to be stored for use at night. Gold Coast Solar Power Solutions are fully accredited for the design, supply and install of off grid solar power systems, why not contact us today to see how we can help you go off grid!
The picture above shows a large off grid stand alone solar power system installed on the island state of Tokelau by PowerSmart Solar of New Zealand.
Sizing an off grid solar power system
The size of an off grid solar power system in all its components is critical to providing a reliable source of power for years to come. Unlike grid connect solar power systems off grid systems do not have street power as a backup – if power is required and the system is not sized correctly the life of the expensive battery bank can be shortened dramatically due to overly deep discharging or it may require a backup generator to run for a good deal of the time – things which a well designed off grid solar power system will avoid.
To size an off grid solar power system correctly the following need to be taken into account:
- Available solar resource: Is their enough unshaded area for solar panels to provide the required amount of power?
- How much power is required? It is imperative that this is calculated correctly and to calculate correctly detailed information about each appliance and it’s daily usage is required. Without this information it is impossible to correctly size the components of an off grid solar power system! A chart to document this information is available here: Power Consumption Assessment Form (Excel Spreadsheet)
Important efficiency tips that will save you money with off grid solar power systems
Heating: Using electricity to heat is extremely inefficient use of power whereas gas is very efficient for heating.
For hot plates, ovens, even kettles we highly recommend using gas over electric appliances. For space heating
DO NOT use electric heaters! Insulate the building well and if you must use heating use gas. For water heating use solar hot water systems or gas.
Cooling: Air conditioners use a lot of electricity. If possible do not use these but rather use ceiling fans, insulate
the building well and try to employ cross ventilation, making use of natural convection and breezes. If you feel you must have air conditioning then keep it to small inverter split systems.
Summer Power Consumption
Over the summer months cooling appliances are usually used. Make sure these are accounted for when determining the appliance loads and power consumption of your property over the summer months.
Winter Power Consumption
Over the winter months the nights are longer so lights tend to be on for more hours and heating appliances
may be required. Make sure these are accounted for when determining the appliance loads and power consumption of your property over the winter months.
Days of autonomy: It’s highly likely that you solar panels will not provide sufficient power to charge your battery bank on heavily overcast days. Days of autonomy is the number of days that you intend to be able to have power available from batteries before having to resort to a generator if the solar panels are not providing enough charge during periods of bad weather. 2 to 4 days is quite normal however the price rises dramatically with each additional day of autonomy, so keep that in mind! If you have a generator and the batteries are running down you can always top up the the batteries with this, or if you see the weather forecast is supposed to be bad for the next week or so cut down your power consumption to extend the autonomous period you have to work with.