Ultimately, you will be calculating how many kilowatt hours of power you will need and find the correct system size to power your house.
Make your house solar ready. What is solar ready? Start with getting a solar geyser, gas hob and led lights, this will greatly reduce your consumption.
| Grid-Tied System (No Battery Back-Up)
Grid-tied systems are so named because they function alongside a working grid supply, and do not normally have any backup storage (battery) capacity.
Your grid tied inverter will utilise the power that you produce from your PV panels first, and top up with the grid, or feed power back into the grid during periods of low demand - if this is allowed in your area.
Generally the most cost-effective systems and easiest installation.
Inverters use your own power first before pulling power from the grid.
If feed-in is allowed in your area, excess power created can be fed back to the grid.
Critically, grid tied systems shut off when the grid itself is down. This means you can't use your PV power during power outages - this is due to local and international safety requirements.
No battery backup means there is no protection from power outages built into this system, although grid tied systems can be installed together with backup battery systems to run critical appliances during power cuts.
| Off-Grid System with Battery Storage
Off-grid systems are designed to be stand-alone systems that operate without any grid connection. The PV panels need to be sized to generate the full power requirement of the site, and recharge the batteries at the same time, and a large battery bank is needed to store power for periods when solar power is not available.
Generally the most expensive configuration due to the high number of batteries needed to store the entire home's power requirements for a few
days of backup.
May still result in blackouts when batteries are over-used or solar conditions are poor.
Off-grid systems often have a backup power source like a generator.
| What does Kilowatt (kW) hours mean?
Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent energy per unit time. For example, when a light bulb with a power rating of 100W is turned on for one hour, the energy used is 100.
1000 watts (W) = 1kilowatt (kW)
The ‘kilowatt hour’ (kWh) is a unit of energy equivalent to one kilowatt (1 kW) of power expended for one hour of time. The kilowatt-hour is not a standard unit in any formal system, but it is commonly used in electrical applications. So for example, if your geyser is 2000 watts, that means it is a 2kW geyser, and consumes 2kW of energy per hour it is running. The kilowatt hour is one unit of electricity that you get billed for.
| Grid-Tied/Hybrid System with Battery Storage
These are highly intelligent PV systems that offer the best of power worlds. Tied to the grid during normal operations, using solar power to charge batteries and allowing feed-in back to the grid (if allowed in your area), these systems can convert to stand-alone systems when the grid goes down, inverting power from the solar panels and batteries to provide for the home's needs.
Benefit from grid-tie when required.
Provides grid independence in the event of a grid power outage, pushing solar and battery power to the home.
Achieve high utilization of PV produced power compared to off-grid solutions.
More complex design and installation process.
| What does it mean to be Solar ready?
In order to be ready to install a PV system, it is important that you reduce your energy consumption by as much as possible, targeting the biggest “energy consumers” in your home first. The more you can reduce your kW usage, the less you will spend on a PV system:
Water Heating: By installing a solar geyser, you can reduce your bill greatly. This should be your starting point.
Heating and Cooling: Ensure good insulation & change to gas.
Appliances: Make sure you use the ‘eco’ cycle, and install energy efficient appliances.
Lighting: Swap to LED’s, not only do they last longer, but you’ll only use a fraction of the electricity.