Solar panels, not be confused with solar hot water panels use silicon crystalline cells to convert sunlight to DC electricity. High quality panels are becoming more reliable and efficient with up to 22% conversion efficiency now achieveable and lasting over 25 years with little degradation. Considering the energy source is free and limitless and solar panels require minimal maintenance this is an incredible technology.
Solar panels (or photovoltaic panels) generate power as direct current (DC) power but most home appliances use the alternating current (AC) power which is supplied from the electricity grid.
The solar inverter converts the DC power to AC power which can then be used in your home or in some situations feed-directly into the grid. Because the solar irradiation or sun intensity varies throughout the day (as the sun rises and falls or clouds move around) the solar inverter must constantly track and adjust the amount of solar energy generated. To help solar inverters use special power point tracking electronics to ensure up to 99% of the solar DC power is converted to AC power. Most of the larger inverters have multiple trackers to monitor different sets or strings of solar panels which may be on different parts of a building roof. Most solar inverters now also have wifi connections and smart phone apps so you can monitor the energy generation in real time.
In more technical terms a solar inverter converts the variable direct current (DC) output of a photovoltaic (PV) solar panel into an alternating current (240V AC) that can be used by your household appliances or fed into the electrical grid.
Off-grid and solar hybrid systems
Off-grid or stand-alone power systems use a combination of solar and battery storage to create an independent power system for homes, farms or businesses. These systems are now very advanced and can incorporate multiple inverters to create AC coupled systems which in effect work as a micro-grid. Together with remote monitoring and back-up generators (for continuous bad weather) these systems can provide very reliable secure power supply for almost any situation.
Hybrid systems work in much the same way as an off-grid system but can also interact with the electricity grid to optimise energy use depending on the time of day or how much energy is being consumed. Most hybrid systems can also work in off-grid mode during a black-out to provide seemless back power. These systems are much more economical than off-grid systems as they only require a small battery system with enough capacity to cover the peak evening energy use, unlike an off-grid battery system which should be sized to last 3 or more days and can easily cost over $15k for an average home.
Commercial Solar installations often do not require a battery system as the energy consumption coincides well with the day light hours, however in some circumstances a solar hybrid system can be very effective at reducing electricity consumption and associated energy costs.